With the changing climate introducing greater variability and weather extremes to our seasons, it is perhaps to be expected that the insect and disease pests that we deal with have also been impacted, and are expected to be further impacted moving forward. Insects and disease pathogens are poikilothermic (e.g., “cold-blooded” ectotherms that rely on their environment for heat), and so their development and activity are greatly impacted by ambient temperature. As conditions warm, so too can their rates of feeding or infection, and maturation and reproduction.

Critical growing degree day (GDD) thresholds are frequently being reached earlier than in years past. Although there are upper limits at which higher maximum temperatures stop increasing plant and pest growth, the greater portion of the increase in average temperatures that we’ve seen in Maine is from higher minimum temperatures, both within individual days and across seasons. This can mean greater lengths of time above GDD thresholds associated with pest activity, and/or shorter or less regular instances of low temperature thresholds like frosts and hard freezes. The combination of greater accumulations of heat, and longer periods of time without low temperatures (which may have arrested growth or other behavior in prior years), have resulted in “new” pest species being found in Maine, as well as new behaviors of “old” pest species that were already familiar to Maine growers.

Climate Impacts on Arrival and Behavior of Pest Species

When a “new to Maine” species shows up, climate change is often mentioned, if not completely blamed. However, the arrival of a new species can also simply be an introduction of an organism that did not occur here previously and may not be met with natural enemies that otherwise limit its population and impact in its biome of origin. 

Two examples of relatively new pests to Maine that we cannot blame climate change for are the leek moth and the swede midge. Both of these species were novel introductions to North America in relatively recent history, and while they were new to Maine in the past decade, they entered the Northeast United States from Canada and have actually been working their way south into the country. 

An example of a species showing up in Maine that I feel we can essentially blame climate change for entirely is Stemphylium gray leaf spot of tomatoes. Gray leaf spot is not at all a “new” disease of tomatoes for the Southern and Mid-Atlantic states that provide the hot and humid conditions in which it thrives. However, it has gradually been increasing its range northward and creating new problems for Maine growers that, like me, had never previously had reason to know of its existence.

Even if many “new” pests to Maine are simply the result of introductions — and not the sole result of climate change — the continued spread and impact of introduced species are expected to be very much influenced by climate change moving forward. For example, the forest pest hemlock wooly adelgid was introduced into the United States about 100 years ago, but it is still spreading relatively slowly in Maine, as particularly cold winter temperatures can cause high levels of winter mortality. This natural check to the spread of hemlock wooly adelgid is expected to diminish moving forward, depending upon the rate at which Maine’s winter minimum temperatures continue to inch higher. 

Other relatively recently introduced species of concern for growers — which may be kept partially at bay by Maine’s current climatic conditions — include the spotted lanternfly and the brown marmorated stink bug (Fig. 1). Both of these species have entered southern New England and have been found in Maine, but, as of now, neither have established a solid enough foothold to cause the level of damage that they may in the future. In contrast, the cabbage white, also known as the imported cabbageworm, familiar to generations of Maine growers since its arrival about 150 years ago, is expected to find Maine’s future climatic conditions to be less hospitable.

For growers and non-growers alike, concerns regarding tick populations and potential consequences for the spread of tick-borne diseases seem near universal. Lone-star ticks, native to states much further south, could easily become commonplace in much of Maine according to some climate modeling (see Fig. 2)

The future spread of species described above are only some of the “known unknowns,” as we cannot say for sure what their eventual distribution will be. I can’t begin to imagine what surprise “unknown unknowns” await our discovery (similar to how gray leaf spot surprised us in the past few years). Regardless, we will still need to deal with more species that are new to Maine, or new to more areas within Maine, than previously. The specific difference between climate-driven spread and simple introduction of new species will not be as important as understanding the biology and impact of each species individually, monitoring their spread, and implementing management strategies as appropriate.

New Behaviors of Old Species

Some pest species that we already know well are expected to shift their behaviors in response to the changing climate, and may have begun to shift already. The example I share most often is the fact that squash vine borers used to only produce one generation of adult moths per growing season but are increasingly emerging in two waves. The second wave is suspected to be a second generation that can take advantage of longer warmer summers, and not simply a difference in how long sub-populations take to pupate. The potential for multiple generations of insect pests that previously had more predictable ebbs and flows may result in the need for more continuous monitoring and management. This may allow pest populations to grow to exponentially higher levels in their final generation of the season than they would have previously — potentially resulting in higher overwintering populations as well.

In addition to temperature impacts, the increasingly prolonged stretches of either wet or dry weather also have an impact on the pests we deal with — though likely in a season-by-season manner instead of a more continuous change as with increasing temperatures. Dry years tend to favor pests like thrips and two-spotted spider mites, while wet years tend to favor moisture-loving slugs and snails, and diseases that can best infect and spread with prolonged periods of leaf wetness, like early and late blights of tomato, or Phytophthora capsici, which has a lifecycle stage that can actually swim through standing water in a field. Some familiar diseases do not need liquid water and can spread rapidly in our increasingly warm humid growing seasons, such as powdery mildews and downy mildews.

The Trade-Off of Controlled Environments

Because many of the most common damaging crop diseases require prolonged leaf wetness to successfully infect, the trend for more controlled-environment growing spaces (i.e., greenhouses and high/medium/low tunnel spaces) has largely removed their impact for many growers. Unfortunately, the honeymoon period of tomatoes with practically no foliar disease issues has ended for many growers, as increasingly humid conditions are making management of diseases that do not require liquid moisture — such as botrytis, leaf mold, and gray leaf spot — much more difficult by limiting the ability to draw in outside air that is actually drier than the air already around the plants when venting protected growing spaces.

Additionally, the protection that controlled environments provide from the coldest winter temperatures, combined with the trend towards higher minimum winter temperatures, can allow these spaces to act as a “green bridge” between growing seasons for some pests that would have otherwise not persisted in a Maine winter, or at least taken much longer to build up to a damaging population in the following year. Examples that I have seen on Maine farms include cabbage aphids overwintering on high tunnel kale and infesting the next spring’s brassica crops, and onion downy mildew jumping from overwintered onions to the much larger main-season onion planting.

Climate Impacts on and Interactions with Organic Pest Management Strategies

Our traditional organic pest management approaches prioritize prevention: selecting disease-resistant varieties; ensuring good air circulation; optimizing soil health to support robust plant defenses; and practicing careful crop rotation and sanitation. This foundation will continue to be important for future efforts — perhaps even more so. New climatic conditions are likely to provide new challenges for management with pesticide products when foundational cultural approaches are insufficient and, surprisingly, new possible opportunities for biological controls.

Issues and Opportunities for Sprayed Materials

Prolonged wet and humid conditions may increase pathogen growth and reproduction rates, increasing the frequency at which preventative fungicides need to be applied. Additionally, greater rainfall intensity may wash away applied materials, requiring reapplications, or other shifts in strategy: commercial growers may need to utilize “sticker” spray adjuvants more frequently, and any grower may want to consider applying protective fungicide as soon after heavy rainfall events as possible, instead of rushing to apply it before a rain event. In addition to escaping the need to reapply the material after it gets washed away, this strategy will hopefully still protect plant surfaces before the wet conditions spur the release of new spores from pathogens already present, and before any spores that arrived with the rain have had time to germinate and infect plant tissue — acting during that limited window of time is critical, however!

Although I may be grasping for good news, a possible upside to increasing precipitation and humidity is the potential for greater success rates of some biological control species and biopesticide products. Entomopathogenic nematodes and entomopathogenic fungi, like Beauveria bassiana, both tend to be more successfully deployed, and survive longer, in conditions with more water and higher humidity.

This article was originally published in the fall 2025 issue of The Maine Organic Farmer & Gardener.

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It perhaps goes without saying that one of the most frustrating aspects of gardening impacts from the changing climate is our lack of control in the face of such large forces and systems at work. We must reckon with our usual preparations for previously normal seasonal changes and weather events no longer being adequate. Yet, in many ways the gardening-specific climate challenges are the same as any other for growing — only more so. You need your plants and soil to get enough water, but not too much water. Frost-sensitive crops shouldn’t go out before the last frost of the spring, and you need to at least harvest the bulk of them before the first frost of the autumn.

Adaptation vs. Mitigation

When talking about climate change, it’s helpful to make sure we’re using words in the same manner. Climate adaptation involves adjusting to observed or expected climate effects, i.e., adapting to life in a changing climate. The goal is to reduce our vulnerability. These adaptations also include making the most of any potential beneficial opportunities associated with climate change (for example, longer growing seasons or increased yields in some regions). Adaptation practices might include adding irrigation and/or improving drainage. Climate mitigation involves reducing the flow of heat-trapping greenhouse gases into the atmosphere, either by reducing sources of these gases, or enhancing the “sinks” that accumulate and store these gases (such as the oceans, forests, and soil), i.e., reducing the scale at which human activities are rapidly changing the climate. Electrifying equipment and reducing erosion are both examples of mitigation practices. Reducing single-use plastics (plastic mulch film, drip tape irrigation, etc.) is an example of a climate mitigation practice that would potentially be counter to climate adaptation, as these plastics can make soil moisture management easier to control but release fossil fuel-derived carbon in their manufacture and later disposal and decomposition. Planting more long-lived species (trees, shrubs, etc.), building soil health, and increasing soil organic matter content are all examples of practices that can serve as both adaptation to and mitigation of climate change.

Soil Health: Your Climate Adaptation Foundation

Extremes of precipitation (too much or too little) are probably the most impactful aspects of climate change on gardening. While commercial growers may have protected growing spaces like high tunnels or greenhouses, the average gardener has fewer options to shelter their growing from extreme climate events. This makes usual approaches to organic disease management (e.g., selection of disease-resistant varieties, cultural practices to promote rapid drying, and sometimes fungicides as a last resort) even more important in wet years. Hopefully, you are already exercising these first two approaches! Outside of protected growing spaces, such as greenhouses and high tunnels, most of what is in your control comes back to the soil. Without structures keeping rain off of plants and, importantly, the soil, it is important to be prepared to handle conditions of both too little and too much water. Optimizing your soil’s health will help in both situations.

A soil’s health is often defined as its capacity to support crop growth — in terms of tilth, nutrient-holding capacity, water infiltration, storage and drainage, and the success and diversity of beneficial soil life. Much of that is already determined by your soil’s texture (the proportion of different particle sizes: clay, silt, and sand), and most of us can’t reasonably change our soil texture — but we can sometimes improve our soil’s structure. Healthy, well-aggregated soils (Fig. 1) with an ideal crumblike structure interact with water in ways that maximize their plant growth potential, relative to similar soils with poor health and structure.

Principles for improving soil health over time include reducing disturbance (reducing tillage when possible), maximizing soil cover (with cover crops and/or organic mulches), maximizing presence of living roots (using cover crops, double cropping, intercropping), and maximizing biodiversity (with crop rotations, by feeding soil life different forms of organic inputs, and minimizing pesticide use).

Thinking Through Not Enough Water

Water is the vehicle for all nutrient flow into your plants. It is also needed for evaporative cooling of leaves (important for photosynthetic efficiency) and is the source of hydrogen for photosynthesis (Fig. 2). By the time a plant has begun wilting, its capacity to photosynthesize and grow has already been reduced.

Insufficient rain is often preferable to too much rain. Home gardeners typically have an advantage over commercial farmers, as they can more easily irrigate their entire growing area. However, a healthy well-aggregated soil with higher organic matter content requires irrigation less frequently because it has a much greater rate of infiltration to capture water falling on it that might otherwise runoff. It also has a greater water-holding capacity — both in the diversity of pore sizes created by soil aggregates and in the greater amount of organic matter they contain. Organic mulching materials can reduce soil temperature and evaporation rate, as well as contribute to organic matter in the soil, feeding soil microbes as it is broken down over time.

Too Much Water

A well-structured healthy soil has a greater water infiltration capacity, allowing it to absorb much more water, more quickly. While that helps to make the best use of limited rainfalls, as described above, it also helps to reduce soil erosion from heavy rain events (Fig. 3). That same effect can also improve vertical water drainage into lower soil layers, or to foster horizontal drainage into pathways between raised garden beds, which can serve as temporary drainage ditches. Minimizing the topsoil’s saturation time is particularly important, as the negative consequences of saturated soil conditions are likely to be the most hindersome climate impact we encounter.

Soil is ideally spongelike, with about half of its volume consisting of pore spaces (voids between soil particles and aggregates). As soil pores fill with water, air is forced out, creating anaerobic soil conditions. Very prolonged anaerobic conditions will impair root functioning at best and at worst kill plant roots. Starting in as little as 15 minutes of anaerobic conditions, some soil microbes begin to utilize nitrate, in lieu of oxygen, to continue their metabolic processes. This converts the nitrate to a gaseous form that is easily lost to the atmosphere. The immediate consequence of this is to reduce the amount of readily plant-available forms of nitrogen in your soil, but some of these gaseous forms are also highly potent greenhouse gases, making efforts to improve soil drainage a climate mitigation practice as well as an adaptation practice.

Even without denitrification conditions, large amounts of water moving through soils will take nutrients with it as it leaches into lower soil layers. Particularly susceptible nutrients include nitrate (due to its negative electrostatic charge) and boron (due to the lack of electrostatic charge). This makes organic matter an important reservoir of nutrients to once again be released into the soil water as organic matter is broken down and cycled by soil life.

A Note About Improving Soil Health as Mitigation Strategy and Its Limitations

Sequestering carbon as soil organic matter is a very appealing method to draw down atmospheric carbon dioxide levels. Improving soil and reducing climate risks at the same time is a win-win situation, however, there are unfortunately a lot of devils hiding in the details that I encourage you keep in mind as you consider this approach’s climate mitigation potential.

While every avenue to sequester atmospheric carbon needs to at least be investigated and hopefully pursued, I get very nervous when I encounter proclamations that certain agricultural practices can “solve” or “fix” the climate crisis. Most concerning to me is a risk for complacency regarding additional climate actions that we as a society urgently need to take to give us our best shot at minimizing climate impacts, i.e., ending the burning of fossil fuels as fast as possible.

Every soil type (specific texture and mineralogy) is typically considered to have a “carbon saturation limit” in whatever context it exists in. That context includes influences from climate (annual temperature and rainfall amounts being large factors), plant species composition and presence over time, and levels of disturbance (i.e., tillage intensity). We can change some of these factors, but only to an extent. Eventually, even in the most optimal conditions to build up more soil organic matter, we will encounter a “declining return on investment.” In a soil that is below carbon saturation, new inputs of organic matter, whether they’re being added from elsewhere, like manure or compost, or produced in place, like biomass and root exudates from cover crops, can build up the soil’s carbon content in the “mineral associated organic matter” pool, while also contributing to a more actively cycled “particulate organic matter” pool. Eventually, the amount of mineral surfaces available for organic matter to become associated with become saturated, and further carbon inputs can mostly only build up as particulate organic matter. Higher levels of particulate organic matter are great for soil health and crop production — microbes cycle this organic matter more readily, helping plants grow well but also making this pool of carbon less stable over the long term.

In thinking through soil carbon in the state of Maine, we need to first define our starting point. Many folks, intentionally or not, begin with the contemporary and look forward. While that is important for thinking about ways to draw down atmospheric carbon, I would argue that we should at least look backwards to the 17th century to establish our baseline. Though Indigenous peoples’ land management practices varied across the continent, the most drastic changes to soil carbon in what is now Maine, occurred with the influx of European settlers and the large-scale land clearing that happened since then. The majority of carbon released from the soils of Maine at that time — and since then — is still in our atmosphere. Even if we can figure out how to sequester as much carbon in Maine soil as existed pre-colonization (and more to account for the soil which has been made more or less permanently unavailable for this approach by being buried under pavement, buildings, etc.), we are still paying down the carbon debt of the “original climate sin” of large-scale land use change. Only after repaying that carbon debt can further increases in soil carbon begin to pay down the further debt of carbon released from the burning of fossil fuels. Additionally, that newly sequestered carbon needs to be carefully managed in a way that ensures it will not be re-released for a very long time, as any terrestrial carbon is at much greater risk of being remobilized into the atmosphere than the deep subterranean sequestration that keeps untapped fossil fuel carbon out of the atmosphere.

I do not intend to be discouraging here. We can sequester carbon into soil and timber products, and already have, particularly with the reforestation that has occurred in the past 100 years. Every kilogram of CO₂ that is sequestered from the atmosphere today is one less to worry about tomorrow, if well managed. I just don’t want us to be lulled into complacency that carbon credits (whether in an official accounting scheme or not) will allow us to carry forward towards carbon neutrality without being paired with a much more important, concerted effort to reduce the extraction and burning of fossil fuels as rapidly as we can.

This article was originally published in the summer 2025 issue of The Maine Organic Farmer & Gardener and is part of a series on climate change and gardening, and follows a prior article describing observed and expected climate impacts affecting gardens in Maine.

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Climate impacts are already impacting your garden — whether that’s temperature fluctuations, or periods of drought, or severe or prolonged precipitation. Here I will discuss what impacts have already been observed, and what to expect moving forward. Though I have an interest in matters of weather and climate, I am neither a meteorologist nor a climatologist and can only share my understanding of the most critical components as I understand them — surely, I’ll have left something out! Weather and climate impacts interact with each other, further complicating things. While much of my understanding has been informed by the work of Maine’s state climatologist, Sean Birkel, any errors are more than likely to be my own.

Increased Temperatures

Having grown up calling climate change “global warming,” it feels almost silly to state that one of the most obvious climate impacts that we’re experiencing is increasing temperature. The Northeast’s average annual temperature has increased 3 degrees Fahrenheit since 1895. The simplicity of that statement belies the greater intricacies involved within it. We notice the increased temperature in terms of more warmer-than-normal and fewer cooler-than-normal days in a given year.  There are also more daily high temperature records getting set than records for low temperature. However, focusing on this alone overlooks a few important things.

Firstly, maximum daily temperature records are just looking at the top end of the temperature range for any given day. The overnight low temperatures have actually been increasing more than daytime high temperatures. This is associated with increasing humidity — warmer air holds more moisture than colder air, and humid conditions lead to less heat loss overnight than dry conditions.

Secondly, growing degree days should be considered. A growing degree day is a measure of accumulated heat that is well correlated with growth and development of crops and/or pests. Relatively small increases in minimum, maximum, or average daily temperature may not amount to a lot in terms of individual degrees measured at a given moment, but when we consider growing degree day units, we see that relatively small increases in daily temperature minimums and maximums can quickly add up to much higher levels of accumulated heat, allowing for faster growth and development of both crops and pests. There are several different ways to calculate growing degree days, tailoring the calculation to the crop or pest of interest, but the overall idea is that each day’s heat accumulation can be measured as the difference between that day’s average temperature and a minimum development threshold temperature relevant to the species of interest. For example, apple tree flower bud development occurs at temperatures above 43 Fahrenheit. For calculations, 43 F therefore becomes the base temperature. You’ll also need the average temperature, which can be determined by adding the high and low temperatures for the day, and then dividing that value by two.  Every degree above the base temperature (i.e., 43 F) on a given day is added to the growing degree days that we use to predict flower bud emergence. With only slightly warmer weather in the late winter and early spring, flower buds may accumulate enough heat to break dormancy and expand, or even fully bloom, earlier in the season. (Unfortunately, these same increased temperatures don’t come with any guarantees that we won’t still receive frosts and killing freezes in the spring, potentially causing major losses to more precociously blooming apple varieties).

Thirdly, while there are warmer temperatures in all seasons throughout the year, the biggest changes are happening at times when we’re not typically thinking of high temperatures — the fall and winter. Though the productive growing season appears to be extending both earlier and later, the most noticeable impact has been milder autumn conditions. Many growers are harvesting far later into the year than previously, and many are pushing their garlic planting date later and later into the year to avoid premature sprouting before the onset of winter conditions. I planted my own garlic in mid-November of 2024; previously, I would have aimed for mid to late October. These warmer late-season conditions have many growers re-working their typical late-season planting dates as well as reconsidering expectations for what can be grown when. However, warmer temperatures are only a piece of the equation for plant growth. Even in warmer autumn conditions, plant growth will eventually be limited, or entirely inhibited, by the shorter daylength of late autumn. At this point in the season, a plant may only be able to produce, via photosynthesis, a similar amount of sugars as it is using to maintain itself without any significant growth.

With these three considerations in mind, in the next 30 years the growing season across Maine’s coastal climate division may become more like that of present-day Connecticut, according to climate model projections of the high-emissions warming scenario (RCP 8.5).

Stagnant Weather Patterns and Weather Extremes

Rising temperatures also drive changes in weather patterns, leading to more extremes. Higher temperatures, especially in the oceans, increase water evaporation — intensifying hydrologic cycles and leading to changes in atmospheric circulation. This can lead to us getting stuck in a weather “holding pattern,” as we saw in some of our recent growing seasons that provided either too much or too little rain for too long. It has also increased the likelihood of heavy precipitation.

While prolonged dry or wet conditions in the main growing season are probably the most noticeable impacts to growers, the shift from one temperature extreme to the other, which is at times very rapid, can be among the most damaging. “Whipsaw” conditions in the winter or autumn seasons, where extended mild or warm periods swing to very cold temperatures, can cause winter injury to perennial plants that have not achieved sufficient dormancy. The same pattern in the late winter can cause a “false spring” — encouraging perennial plants to break dormancy, at which point their buds may be vulnerable to frost and freeze damage, as we saw in many Maine locations in May of 2023.

With increased global water cycling occurring due to higher temperatures, the Northeast region now receives, on average, about 6 inches more precipitation throughout the year compared to records beginning 1895. Although we still get some abnormally dry years, and have certainly seen some prolonged dry spells with little rain — particularly in the later portions of the growing season — average total annual precipitation is expected to increase an additional 5-14% by the year 2100. Unfortunately, the increase in total precipitation has not been in our ideal scenario of regular gentle rains spaced evenly throughout the year. Instead, the greatest increases in precipitation are happening in the summer months, with heavy rain events — where more than 2 inches of rain fall at a time — becoming increasingly common.

We are already experiencing the growing realities of our changing climate, with more noticeable extremes in temperature, dry spells, and severe or prolonged precipitation. Though we are expected to see more of these, growers of all scales have begun adapting — whether intentionally or not! While the challenges are significant, so too are the opportunities to innovate and grow in harmony with our evolving environment. By staying informed and proactive, we can ensure that our growing practices are resilient and productive.

This article originally appeared in the spring 2025 issue of  The Maine Organic Farmer & Gardener.

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Organic farming is grounded in the principle and reality of a vibrant living earth, supporting healthy plant-animal-human communities. This linkage has been encapsulated in the contemporary and somewhat abstract term “ecosystem services,” essentially referring to the benefits humans obtain from natural systems, as formulated in the early work of Paul Ehrlich and Gretchen Daily at Stanford University.

Organic practices, conceptualized and evolved over the last century, seamlessly align as key elements to enhance contemporary interpretation of ecosystem services.

In a nutshell, organic management, which nurtures ecosystem services, involves both avoidance practices (steering clear of ecologically harmful inorganic nutrients and pesticides) and embracing practices like composting, crop rotation, cover cropping and companion bee-friendly planting. In contrast, in conventional farming yield-centric practices dominate and many of these ecosystem services are deemed irrelevant.

The price consumers pay for organic products reflects this extra effort to enhance ecosystem services. Consumers who acquire these products at the asked-for price in the free marketplace show their recognition and confidence in these practices.

In conventional farming, practices detrimental to ecosystem services are often disregarded (or considered nonexistent), leading to apparent lower food costs. However, these passed-along offsets do possess real value. In a stunning assessment in 2023, the International Monetary Fund (IMF) defined all forms of ignored offsets as environmental subsidies. Like IMF, which reports on worldwide fossil fuel economies, I believe the costs apportioned, in this case to conventional farming, have also been incorrectly calculated. This is underscored by data from geochemist William Schlesinger who showed that the carbon dioxide (CO2) released in production and distribution of chemical nitrogen fertilizer effectively negates any carbon value from crop yields enhanced by the fertilizer. In this case, the CO2 offset in manufacturing nitrogen has not been correctly calculated into its cost and therefore the fertilizer is subsidized to the detriment of farming.

This narrative begins with the response of a particular emerging sector in society to the global threat to ecosystem services. This response involves the initiation of reward programs for carbon sequestration, with a significant focus on farming. After the introduction of the “4 per mille” concept of carbon sequestration in the 2015 Paris Climate Accord, carbon trading markets gained momentum. The idea behind the initiative is a calculation showing that an annual increase of 0.4% in carbon across the world’s arable soils would theoretically offset all global net CO2 emissions.

Through the mechanism of proposed voluntary carbon markets (a recent Environmental Defense Fund report lists 12 voluntary protocols), a broker arranges a payment to a grower for an increment of increased soil carbon, the monies for which to be paid presumably by an industry that is damaging ecosystem services. The broker takes a variable and sometimes large cut of the fees.

But, as I have already mentioned, organic farming, as presented herein, already includes the costs of ecosystem services in its products. Worldwide these products are sold with slight to large premiums because the price to a willing consumer reflects the real cost of the positive environmental-social offsets arranged and fostered by the grower.

At the farm level it is more difficult and therefore more costly to manage soil for enhanced biological activity that could result, for example, in improved earthworm counts, a major ecosystem service. The famous early study by the German Ministry of Agriculture in 1977 found that organic-biodynamic farms had 400% more earthworm counts (among other attributes) when closely compared to conventionally managed farms of similar size and soil type. At that time, the concept of the value for an ecosystem service — i.e., the worms — was not remotely comprehended. Recently, a study in Ireland calculated the positive offset value of just soil organisms and earthworms (maintaining fertility and nutrient cycling) at 1 billion euros per year.

It is essential for all product valuations to be transparently recognized in a real buyer-seller interaction. Therefore, the introduction of a second market, where growers sell a comparable concept of the product to “wrongdoers” (i.e., the carbon emission industry purchasing carbon credits), is inherently flawed.

A significant issue arises as this emerging carbon market disrupts and alters the trust dynamic between growers and consumers. It achieves this by establishing a reward system that favors a third party, namely climate brokers and their clients, that is not involved during the actual provision of the service. An additional and very significant flaw is the questionable ethics: the trade represents a double payment to the grower. Are growers comfortable in explaining this? If the broker were not there to collect, would the transaction ever have happened in a real local market? We are asked to imagine our position selling a soil-grown product in a real marketplace, and then ask for an additional payment for a fractional component of our ecosystem services that went into producing it.

Ethical issues are quickly catching up with new carbon markets. Questionable tactics came to light as Greenpeace’s journal Unearthed documented, in May 2022, a surge in brokerage companies offering low farmgate value for carbon and then selling for high, “all done sitting on a computer making connections … while the farmers were out there working … to keep it alive.” More recently, in January 2023, The Guardian, a British daily newspaper, dropped a bombshell in reporting that more than 90% of carbon sequestration credits sold by Verra, a major certifier of carbon credits, did not represent actual validated carbon reductions (Bloomberg News presented a similar analysis). In this still unfolding scandal, The New Yorker’s Heidi Blake described the path to multiple failures in how carbon sequestration projects launched by South Pole, the world’s largest carbon-offsetting firm, and verified by Verra, were unscrupulously developed, and improperly validated, with evidence of shoddy work overlooked or suppressed — all this resulting in millions of credits sold for carbon reductions that weren’t real. Verra is a familiar name in New England, encouraging growers to plant crops, such as hemp, for brokering carbon credits. A significant number of these vast credit schemes, involving hundreds of millions of dollars annually, are directly implicated in the so-called “carbon neutral” labels advertised for vehicles, airline flights, and products from chocolate to clothing.

One way to achieve the goal of correcting this misuse would be for organic growers, buyers and sellers to collectively consider the inclusion of the authentic carbon value in farm products for the benefit of consumers. This concept could be realized in the form of a label reading something like “Carbon Included” — indicating that the buyer has directly contributed to this, as opposed to a broker’s clients in New York or Zurich.

Obviously, in attempting to build this new perception, opposition may arise from existing carbon marketers and the consulting scientists working with them. I have heard arguments that this critique will depress carbon innovations, turning away sellers — the farmers — who are essentially being offered free money. In fact, organic growers are simply fighting to keep the value of their own efforts and products within their own space. They may need to be prepared to enhance their own tools and methods for substantiation to accurately indicate viable soil carbon levels. They should beware of detractors who may say, borrowing on the recent Irish study, that organic growers are now selling “earthworm credits.”

For nearly a century, organic farmers have consistently invested additional efforts in enhancing soil health, minimizing chemical impacts and revitalizing ecosystem services. It is essential not to isolate and commodify organic farming soil carbon in a piecemeal, reductionist approach. The late Vermont-based organic grower Jack Lazur addressed the potential inequity of emerging carbon markets at a meeting sponsored by Tufts in 2019. He pointed out that during the past 50 years he invested to increase his soil organic matter and therefore is not likely to benefit from the cash offered for new carbon increments. Lazur is correct since carbon is validated from baseline and that in soil it reaches a natural plateau — under organic management it won’t just keep increasing. In this sense, it seems ironic that conventional growers who chose not to pursue climate-enhancing technologies originally may benefit disproportionately. This conclusion is supported by a 2022 IFOAM Organics Europe position paper on carbon farming: “First movers, such as organic farmers, who are already contributing to higher carbon stocks, should not be penalized, as carbon farming schemes are likely to reward ‘additional’ efforts.”

For those interested, the IFOAM paper is a worthwhile read, contending that a market approach to carbon is just the wrong way to do this. The idea that the price of a carbon credit should decide whether a grower chooses to increase soil carbon is viewed as most unfortunate. Or that this price is not being determined by the real cost of sequestration, such as by real farmer efforts, but arbitrarily, from buyers who may be large companies with favorable market advantages. It was just after the IFOAM report came out that we learned how this has played out with carbon operators in America and Europe.

An authentic transaction concerning soil carbon and its value should take place in close proximity to the farmgate, and consumers can expect favorable results. Organic farming is already well-positioned to rightfully claim its credit.                                                          

Will Brinton is a soil and plant scientist, founder and emeritus CEO of Woods End Soil Laboratories, and an expert advisor on the Demeter USA Soil Monitoring Protocol Committee. Woods End Lab is a 2023 recipient of a U.S. Department of Agriculture (USDA) grant called IDEA, which is intended to instruct growers on robust soil carbon assessment procedures, in which he will be an instructor. MOFGA is listed as an education and outreach sponsor in addition to Stone House Farms and Stone Barns (New York) and the Somali Bantu Community Association (Maine). References for this article are available by contacting the author at will.brinton@gmail.com.

This article was originally published in the spring 2024 issue of The Maine Organic Farmer & Gardener.

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This spring, the United Nation’s body for assessing science related to climate change, the Intergovernmental Panel on Climate Change (IPCC), issued its sixth assessment report (AR6) on climate change since the group’s establishment in 1988. The report was announced to the world with a press release declaring: “Urgent climate action can secure a liveable future for all.”

The Earth’s temperature has already risen nearly 1.1 degrees Celsius (2 degrees Fahrenheit) since 1880, when global temperature observations were first recorded.

The 2015 Paris Agreement defines a global warming of 2 degrees Celsius as the upper limit for life as we know it, with 1.5 degrees as a target that could help minimize the worst effects of climate change around the globe. The IPCC’s 2023 report, which was approved during a week-long session in Interlaken, Switzerland, in March, says that hitting 1.5 degrees Celsius is now inevitable. To curb the Earth’s rising temperature to 1.5 degrees, the report’s authors say that emissions will need to be cut nearly in half by 2030.

Just days after the report’s release on March 20, 2023, with the clock set at less than a decade and ticking, I spoke with Sean Birkel, Maine state climatologist and research assistant professor with a joint appointment to the Climate Change Institute and Cooperative Extension at the University of Maine. As a federally recognized state climatologist, Birkel provides climate services, including collecting, disseminating and interpreting climate data to help inform decision making and planning. Birkel’s research background is in climate variability and modeling. In particular, he studies climate variability over a range of time scales, including paleo climate and modern climate, and evaluates climate projections for the future. This work includes writing computer code to process and visualize climate and weather datasets (check out his website, climatereanalyzer.org, developed with support from the Climate Change Institute). Birkel is also developing the Maine Climate Office, and works with colleagues at Cooperative Extension to provide climate and weather data to farmers.

This interview was edited for clarity, and some responses were submitted via email.

As Maine’s State Climatologist, you collect, disseminate, and interpret climate data to help inform decision-making and planning. What kind of data are you collecting and how?

Sean Birkel: I work primarily with existing datasets and models that are publically available from NOAA (National Oceanic and Atmospheric Administration) and the National Weather Service. These include surface weather observations, a type of recent historical climate data product called reanalysis, and also climate models that project future conditions. I use these datasets to better understand climate patterns, trends and impacts, and then contribute findings to reports such as the Maine’s Climate Future series, and, as a member of the Maine Climate Council’s Scientific and Technical Subcommittee, I contributed to the 2020 report “Scientific Assessment of Climate Change and Its Effects in Maine.” In my extension role I also provide weather forecast and seasonal climate outlook information to growers by contributing to newsletters and fielding individual data requests. I also disseminate climate and weather data and visualizations through climatereanalyzer.org and the Maine Climate Office website.

Although I do not currently maintain weather stations, I am interested in historical climatology and recording anecdotal information, which can be very important to have alongside data observations from weather stations. For example, what were conditions like 30 or 40 or 70 years ago? What do people remember? And, in particular, what information at the local scale might not be captured in station data? There are written records and photographs of Penobscot Bay when it froze during five or six really cold winters in the early 1900s. There’s also still some living memory related to that: people whose grandparents said that, when they were children, they could walk across to Vinyl Haven from the mainland. And in the book “History of Castine, Penobscot, and Brooksville, Maine” published in 1875, there is explicit mention of the bay having frozen from Castine to Camden in the winter 1780-81 (during the American Revolution) so as to permit travel over the ice. This document also notes the bay froze three consectutive times in the early 1800s, starting with the winter of 1815-16 — this happens to follow the 1815 eruption of Mt. Tambora in Indonesia, which is now well known to have cooled climate worldwide and caused the 1816 “Year Without a Summer” in New England that devastated crops!

In relation to agriculture, I’m very interested in collecting observations from people describing the changes that they’ve seen — especially over the past 20 or 30 years — and how these changes have been impacting their operations on the farm. We can certainly analyze weather station data and in a quantitative way say how the climate has been changing, but to hear what that means on the ground, from the people who are working every day in the field about how they see their own livelihoods being impacted, that’s information I’m very interested in.

We’ll get to some ag-specific questions shortly, but first I wanted to talk about your climate modeling work. You’ve been working on the Climate Reanalyzer since 2012, and I’m wondering how visualizing data over the course of the last decade has helped you gain insight about Maine’s climate.

Birkel: My purpose in developing the Climate Reanalyzer website has been to bring together a variety of publicly available climate datasets. Different types of observations can be ingested into a framework called “reanalysis,” where a weather model then calculates heat and moisture flow to estimate the state of the atmosphere at any given moment in time at the surface and through the vertical column. State-of-the-art reanalysis products begin with the era of continous satellite monitoring (generally beginning in 1979) and can also extend to when weather ballon observations became widespread in the late 1940s. “Reanalyzer” is in the name of the website because it was started initially accessing reanalysis.

To give you an example of how data visualization can provide insights … A former Ph.D. student of mine examined summer precipitation in Maine and the Northeast, and published results indicating that our region tends to see more rainfall when high pressure blocking (picture a loop in the jetstream that persists for days) develops over Greenland. This was a prominent large-scale teleconnection in summer from about 2004-2015 when Maine saw a historically wet decade. This particular project started after using Climate Reanalyzer to make a mean sea level pressure map for the decade in question, and the spatially coherent pattern over Greenland seeded the idea.

Could variability produce another wet decade? Or will short-term drought become more common here in summer as the climate warms? These are the types of questions that can be investigated with reanalysis and climate models to help provide guidance for the future.

From warmer, shorter winters to hotter, longer summers, can you provide a synopsis of changes to Maine’s climate based on climate modeling you’ve conducted?

Birkel: Maine’s climate is warmer and wetter than it was a century ago. Since 1895, Maine’s climate has warmed about 3 degrees Fahrenheit. Also, during that time, Maine’s total annual precipitation has increased by about 6 inches.

We’ve seen, especially the last 20 years, a change in overall precipitation towards a tendency for heavy, or extreme, precipitation events that can deliver a lot of rainfall in a short period. This is one of the challenges that growers are dealing with: how to manage heavy rainfall that can damage crops, produce runoff. The warming worldwide is associated with the warming ocean, which enhances evaporation over the ocean and entrains more moisture in the atmosphere, which in turn provides the moisture for these extreme rainfall events. We’ve also observed a tendency towards what are called atmospheric blocking patterns in which a particular weather pattern might persist in what becomes either a cold wave or heat wave.

What other climate and weather impacts are affecting farmers in Maine?

Birkel: Another impact is the longer growing season, which on the one hand can be beneficial, but can also be a challenge because it’s coming with additional heat that may be more or less beneficial to certain crops. This is in conjunction with short-term drought that can be very detrimental, as we’ve seen in recent years, perhaps most notably in 2020. It’s managing these extremes that are happening more frequently, both in terms of precipitation delivery and this tendency towards short-term drought that’s emerged in the last several years.

Even though the growing season is lengthening, variability in the weather can still produce late-season frost in the spring or early-season frost in the fall. There’s an interesting potential to have a growing season with significantly more accumulation of growing degree days than 30 years ago, yet still end early because of an event-driven killing frost.

Then there’s the much milder winters that we’re seeing overall and an earlier onset of mud season — we saw an extreme of the latter this past winter — and mid-winter thaws that disrupt dormancy for plants and insects. In the spring, warm temperatures and an early snow melt can lead to soil dryness and reduced stream flows heading into the growing season. The detrimental hydrological effects of early snowmelt could be offest if in a given spring above-normal rainfall developed. However, with warmer temperatures and a shorter snow season there is increased potential for dryness.

Circling back to what you mentioned earlier about an interest in anecdotal evidence in relation to the data that you’re analyzing, I’m wondering if there are any anecdotes that have stuck with you or influenced your work?

Birkel: In 2009, it was a very wet summer, and I understand that some growers reported fields going fallow because there was too much rain. As I mentioned earlier, the wettest decade on record in Maine was from 2004 to 2015, which followed the early 2000s drought. The Maine Drought Task Force had last activated in 2002 and then not called at all until drought conditions developed in the summer of 2016. I have heard people relaying their experiences of not having water concerns for 10 years. People who started farming in the mid-2000s generally didn’t have to worry about irrigation.

I was one of those people. I believed rain comes from the sky; you don’t need to water.

Birkel: Then 2016 hit! That year was a very interesting year for a number of reasons. There was a mega El Nino (warming of the equatorial Pacific Ocean surface waters in association with changes in weather patterns worldwide). There are only two others of similar magnitude on record, 1982-83 and 1997-98, and then of course this one in 2015-16. If we look at the summer atmospheric pressure field on average over the Arctic since 2016, the pressure has been relatively low in comparison to the decade or so before. And our part of the world got drier — this ties in with the summer precipitation study that I mentioned. The coincidence between the 2015-16 El Nino and changes in the Arctic and here in Maine suggests there could be a teleconnection. The El Nino could have been a trigger, but more research is needed to say for certain. I have to wonder if these last few years of dryness is a part of variability, and maybe we’ll see a return to several wet years. We don’t know. I haven’t yet done a thorough analysis, but there could be a decadal type variability involved.

Speaking of El Nino … The Gulf of Maine is warming faster than 99% of the world’s oceans. Can you speak to water acting as a heat sink and potentially hiding some effects of climate change, and how this phenomenon may or may not interact with La Nina (when the water is cooler than normal) and El Nino (when the water is warmer than normal)?

Birkel: First, yes, the Gulf of Maine has warmed significantly, and there have been several marine heat waves since about 2010. The warm-water season has lengthened by three or four weeks since the 1980s — all of which has had a huge impact on the marine ecosystem and fisheries. The surface waters of the North Atlantic as a whole have been tracking at record temperature in recent years based on NOAA datasets going back to the mid-1800s.

The warm North Atlantic also has a significant impact on our climate. Many people have noticed that recent summers, especially in August into September, have felt more humid than they used to. I grew up in Bangor, and I’ve certainly noticed that. The data show most of the relative lengthening of the warm season has occurred in late summer into early fall.

In terms of the oceans as a heat sink, they are storing the majority of the excess heat accumulation resulting from greenhouse gas emissions. For the past three years there has been a rare “triple dip” La Nina where cool waters from depth have been brought to the surface and in effect moderated global temperatures. However, La Nina conditions have ended, ENSO (the El Nino Southern Oscillation) is in neutral state heading toward El Nino, and the mean global ocean surface temperature has reached record levels — warmer now than during the 2015-16 El Nino. It’s been quite shocking to see the values go “off the chart” this April!

On the opposite end of the temperature spectrum, Mainers witnessed a spike of deep cold this past winter due to a polar vortex disruption that drove frigid air from the Arctic southward. Is global warming causing these types of disruptions to the polar vortex? Can we expect to see more instances of plummeting cold in the future?

Birkel: Yes, that intense cold wave in early February followed a sudden stratospheric warming, which led to the breakup of the polar vortex. These phenomena were first observed many decades ago, and we don’t know for certain yet to what extent climate change will impact the frequency and severity. However, we are seeing more extremes in general, and there is research that suggests blocking patterns (waves in the jet stream that persist for days) from which both cold and heat waves develop could become more common. Other recent examples of these extremes are the March 2012 heat wave that brought temperatures into the low 80s (March 21-22) in parts of southern and central Maine, and the monthlong cold of February 2015. February 2015 was the coldest in Maine since 1934, and it developed from an unusually persistent ridge-trough wave pattern over North America where record high temperatures were seen across much of the west, while intense cold was funnelling down from the Arctic over the east. The warming in the Pacific led into what became the 2015-16 mega El Nino — yet another example of an extreme!

How will the stratosphere dynamics change in the future? Does a warming world mean more stratospheric disruptions that can produce these intense cold waves in the middle altitudes? It’s possible, but we don’t know for certain yet.

Does your work forecast what impacts to agriculture we might expect to see in the future? You gave an overview of what’s happening now but I’m wondering, will it be more of the same or what other impacts might we see?

Birkel: When we look into the future, when we look at the results from climate models and what they project for Maine through this century to 2100, Maine could see a warming of anywhere from 2 to 10 degrees Fahrenheit. That large range of uncertainty is due primarily to the range of possible greenhouse gas emission trajectories worldwide. With these possible temperature increases we could see anywhere from a two-week to four-week increase in the length of the growing season. Likewise, there would be a comparable reduction in the length of the winter snow season.

Maine’s climate is projected to get wetter on the order of 10 to 20% more annual rainfall in a given year by the end of the century. How the seasonal distribution of precipitation changes is uncertain: some seasons could see either increases or declines; and there is still the potential for decadal variability. As highlighted in the Maine Climate Council’s scientific assessment report, we cannot say for certain whether or not drought will become more or less prevalent, but there is a tendency towards more extremes. We should be prepared for the possible outcome of more frequent short-term impactful droughts, such as what we have seen in in recent years. However, with an overall wetter climate there could still be years in which the additional rainfall offsets the increased drying effect of warmer temperatures, via increased evaporation and evapotranspiration.

The IPCC recently released its sixth assessment report (AR6), which states that global warming is on track to reach 1.5 degrees Celsius above pre-industrial levels — regardless of how much greenhouse gas emissions rise or fall over the course of the next decade. What does this mean for Maine and for the local food system?

Birkel: 1.5 degrees Celsius is a lot — but this is in reference to an 1850-1900 baseline. The AR6 report indicates an expected increase of 0.4 Celsius (or about 0.7 Fahrenheit) over the next 20 years. Here in Maine, this is comparable to the mean annual warming that has occurred over the past 20 years. The implication is a continuation of climate trends we have observed recently. Perhaps most significant would be the addition of several days to the growing season (and more overall heat accumulation), and likewise further diminishment of winter. On average, later frosts in the fall, more frequent thaws in winter, earlier onset of spring, and higher temperatures in summer will lend to increased evaporation and drier soils if the weather in a given season produces precipitation deficits.

It’ll be interesting to see, because there’s still variability within the system and some regions might be more impacted during that time than others because of the variability associated with Enso, El Nino Southern Oscillation, which operates over a three-to-five-year time scale. The focus of the additional warming might be on one region over another and so it wouldn’t be just a linear increase in Maine, but those numbers don’t bode well. We should plan for a warmer climate and expect that impacts we’ve seen will be exacerbated.

The authors of AR6 also state that to keep the Earth’s temperature from rising beyond 1.5 degrees — and to maintain a “liveable future” — that immediate action is needed. Climate change, for many, is an incomprehensibly large problem — and it is causing climate anxiety that might lead to inaction. You’re deeply immersed in climate change. How do you find hope in your work?

Birkel: I think that we’re in a good place here in Maine because, although we face significant challenges and Maine’s climate will be much different 30 and 50 years from now, the region is not facing unmanageable heat and catastrophic drought. Instead, we are facing warmer temperatures, a longer growing season, and more precipitation overall. For agriculture I think there are both potential benefits and caveats. The challenge is how to adapt to these changes and manage some of the extremes that can develop, such as the possibility of more common occurrences of seasonal drought and periods of heavy rainfall that produce runoff and flooding. Coastal communities will have to implement adaptation measures as sea level rise produces more erosion and flooding that affects both ecosystems and civil infrastructure. Warming in the Gulf of Maine and how it impacts the marine ecosystem and fisheries in the coming decades is a major concern. But Maine is taking aggressive action on climate change now in preparation for the future. And that gives me hope.

This article was published in the summer 2023 issue of The Maine Organic Farmer & Gardener, MOFGA’s quarterly publication.

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In the past several years, farmers in Maine have struggled to cope with drought, severe precipitation events, excessive wind, temperature extremes and hail storms. Across the world, farmers are on the frontlines of volatile weather caused by climate change. From vegetable and small fruit producers to dairy farmers and forest managers, climate change threatens seasonal crop loss, financial risk and worse.

A new one-year pilot program, which is wrapping up in January 2022, seeks to empower vegetable farmers and small fruit producers in the Northeast, and the agricultural service providers that work with them, to lead the way in identifying creative, field-based solutions to become more resilient in the face of climate unpredictability.

The Climate Adaptation Fellowship, coordinated through the University of Maine, in partnership with Rutgers and the USDA Northeast Climate Hub, and funded by the Northeast Sustainable Agriculture Research and Education program (NE-SARE), integrates climate science and land-based knowledge through a peer-to-peer learning model in which approximately 20 pairs of farmers and agricultural service providers collaborated on envisioning and enacting climate adaptation practices in real time on real farms.

Rachel Schattman, the program’s coordinator and an assistant professor of sustainable agriculture at the University of Maine, has worked as both a commercial farmer and an agricultural service provider and sees synergistic and practical reasons for partnering the two. “Climate change is a time-sensitive issue. We really don’t have time to mess around,” says Schattman.

“Farmers have this deep, endemic knowledge of their land and what it is like to be a grower.” She adds that they are also intimate with the constraints of agriculture. “Running a farm is a very complicated endeavor and nobody knows it better than they do.”

Agricultural service providers, which Schattman defines as anyone who provides direct assistance to growers, whether it’s through Cooperative Extension, a federal or state agency, a conservation district or a private entity, bring other things to the table, including specific training and dedicated time to devote to investigating and answering questions in different ways.

Both groups, says Schattman, are eager to address climate change on the ground. They’re “ready to get down into the weeds about what it means on the farm to adapt — what the capacity is to use farm-scale production to contribute to mitigation.”

The fellowship allows them to do just that. With collaborators spread across nine northeastern states — with Maine being the most widely represented — the program began with climate-specific workshops on principles of energy efficiency, carbon sequestration, water usage and soil health.

From there, each pair conducted a climate risk assessment of the grower’s farm, including gauging risks particular to their operation and location, and what they could do to minimize these threats. While producers were not required to change anything on their farm as part of the program, many opted to do so.

Among other things, the producers expressed worry about inconsistent precipitation and extreme temperatures. “There was a lot of concern about heat … the number of really, really hot days in the summer and having that be bad for both the plants and … the workers,” says Schattman. A fellowship project in Connecticut trialed possible ways to lower the temperature of pumpkin flowers, as pollen viability declines in relation to temperature, to lessen crop loss resulting from heat waves.

There was also concern around dealing with drought, in terms of soil management to retain moisture during critical periods and water management to ensure irrigation was feasible when it was needed most — without investing a lot of money into deeper or additional wells or pumping systems to draw off surface water. Soil moisture was a focus for multiple pairs within the pilot’s cohort.

A flower farmer and service provider in Massachusetts assessed soil moisture loss in walkways treated with various mulches in relation to water availability in the production area of calendula. Another project in Maine, detailed below, compared moisture readings between sweet corn grown with treatments of straw mulch, interseeded cover crops and bare ground cultivation.

Most striking of all, says Schattman, was that many participants felt that climate mitigation was important for the long term. “A lot of folks took a really big picture view and expressed a lot of concern about the well-being of future generations and our ability to produce food into the future, and not wanting to be part of a system that made things worse.”

Monitoring Soil Moisture: A Case Study in Corn

At Morrison Center’s Opportunity Farm in New Gloucester, Maine, farm and greenhouse manager Ben Crockett and Jason Lilley of the University of Maine Cooperative Extension assessed available soil moisture in sweet corn plantings throughout the 2021 growing season to inform irrigation practices of long-term vegetable crops already in rotation on the farm. Crockett and Lilley applied three treatments — straw mulch, an interseeded cover crop and open cultivation — to four varieties of bicolor synergistic sweet corn from Johnny’s Selected Seeds (Allure, Montauk, Sweetness and Temptress) that met the needs of Crockett’s existing crop plan.

The subject plots were planted in a hilltop field with Paxton fine sandy loam soil, good drainage and exposure to prevailing wind conditions. The ground was tarped for four weeks before eight 100-foot beds (4 feet apart on center) were formed with a borrowed tractor. Crockett seeded each bed with two rows of corn, with 16 to 18 inches between rows, and two beds were planted of each variety. Each treatment (straw, interseeded cover crop and bare ground) spanned one-third of each bed (33 feet); the lay-out was such that both sides of each bed were bordered by the same treatment (i.e., 2 feet of straw mulch, cover crop or clean cultivated area).

A single line of Netafim drip tape with 12-inch emitter spacing was set up within the beds, passing through all three treatments. Irrigation was applied evenly to each treatment.

At crop emergence, Crockett spread square bales of straw by hand at an approximate depth of 2 to 3 inches over and between the beds for sufficient ground coverage. For the cover crop treatment, a mix of crimson clover and annual ryegrass was broadcast by hand, at a seeding rate of 30 pounds per acre, in the between-row zone when the corn reached “V5” crop growth. (That is when the growing point of the corn plant is above the soil line and the fifth leaf “collar” — where the leaf sheath and leaf blade join — is visible). The remainder of the subject plots were left as bare soil, which Crockett cultivated every 10 days or so using a combination of hand tools — namely a stirrup hoe and wire hoe — to keep weed pressure down without disturbing the drip irrigation set-up.

They monitored soil moisture across the varieties and treatments throughout the season using 12 moisture sensors set at a depth of 12 inches, where the corn plant’s roots are. To better understand soil moisture changes throughout the soil profile, they also set four probes at a depth of 4 inches in one variety. The sensor placement followed randomized replicated design protocols to mitigate the impact of natural variance (i.e., greater exposure to westerly wind) across the test plots. The Irrometer Watermark soil sensors (roughly $40 each) connected to a single digital reader (about $250).

They hoped to use the quantifiable moisture data collected over the season to reduce irrigation overall while also fine-tuning the watering strategy to avoid irrigation at times it would not benefit the crop (i.e., when it was too early or when the irrigation would exceed water needs). Data collected by Schattman informed the project design — it showed that when farmers rely on a moisture field test or an irrigation schedule, they tend to overwater or underwater.

Observational data regarding corn maturation windows, harvest yields, the appearance of corn stalks and size of ears across the treatment were also collected. Additionally, Lilley was interested in assessing interplanting cover crops with a long-season crop that would remain in the ground into September. Late-season crops like sweet corn reduce the window of opportunity for farmers to plant a cover crop post-harvest — meaning these fields are often left bare and exposed over the winter months. Among other benefits, successfully interseeding and establishing living cover crops early could protect the soil from run-off and sequester carbon.

Q&A with Climate Adaptation Fellows

Q: Why did you choose to study soil moisture for your Climate Adaptation Fellowship?

Ben Crockett: There are multiple practices and strategies that were identified at the beginning of the CAF project for Opportunity Farm that would improve our adaptability to climate change, but in the end the focus on soil moisture was easy to implement and monitor over the period of the CAF program. The sandy loam soils and hilltop placement of the farm create frequent droughty conditions. 

Jason Lilley: Ben and I did a deep dive into the various climate concerns on the farm. We discussed perennial plantings as windbreaks due to the farms’ hillside location, methods for increasing organic matter due to the sandy loam soils, and reduced tillage approaches to minimize soil erosion. Ultimately we identified soil moisture management as a primary problem due to the windy location and drought-prone soil type. 

Q: Was there a measurable difference in soil moisture across the three treatments in your study? How did having real-time, site-specific moisture data influence your irrigation practices in the corn plantings this season?

Ben: On average, moisture levels were highest under the straw mulch. Moisture levels also had much less variability under mulch. Depending on the crop this may be desirable, but during wet periods moisture could be held in excess. Open cultivated/bare plots needed the most additional irrigation and had the widest swing between dry and wet soils. The intercropping seemed to be a good “happy medium,” shading the ground and reducing moisture loss at the surface, and absorbing extra moisture for their own growth, balancing between heavy rains and dry/hot stretches. The timing of intercrop seeding and species mix would most likely have varying effects.

Jason: It was very interesting to see the differences between our perceived estimates of soil moisture need, and actual need based on the soil moisture needs. The probes were set at 12 inches, which is where the majority of the crop roots are. The moisture levels at that depth proved to be very different from what we were experiencing at the soil surface. As a result, Ben decided to cut back on irrigation duration. 

Ben: Plus, it helped me reduce irrigation in other crops as I got a “feel” for how quickly or slowly soil moisture was changing.

Q: Ben,is there any observational data that you would like to share?

Ben: Somewhat related to treatments, our lowest yields for plots were in the straw-mulched sections. There could be multiple reasons for this, but one obvious reason is high vole pressure, and the stands of corn in straw mulch sections getting eaten and mowed down by voles during early growth. Probably would have worked better if mulch was applied later during the growth period, like when we applied interseeding treatments (around V5 growth stage). Beyond that, the greatest difference was probably on maturation of corn, with interseeded treatment areas being a little slower and longer than the open cultivated control areas. My guess is that moisture stress response in the corn encouraged earlier ripening and maturation in open cultivated areas.

Q: Jason, past research points to benefits of intercropping cover crops to achieve multiple benefits, including soil stability and resilience during periods of heavy rainfall. What did you observe with the interplanting of clover, rye and sweet corn this season?

Jason: The site at Opportunity Farm was one of four interseeding trials that we ran this season. Three of those plots were in sweet corn, and one in fall brassicas. The sweet corn plots were all seeded at last cultivation. I was pleasantly surprised by the big reduction in weed growth and density in the interseeded plots compared to the bare soil plots. At one farm we experienced rill erosion down each of the bare soil rows from heavy September rains. The neighboring interseeded rows were fully protected. We did observe that the crimson clover really outcompeted the annual ryegrass, so there is still more research to be done on species selection, seeding-mix ratios, as well as timing and placement of the seed. In these trials, we waited until the V5 stage in the corn, or 30 days after transplanting brassicas, to avoid water and nutrient competition, and creating habitat for rodents. 

Q: Ben, how will you apply your findings at Morrison Center in the future? What farm planning decisions can you make based on what you learned?

Ben: In the sweet corn (and most likely my other crops) I was overwatering and running irrigation longer than necessary. The farm’s water resources are old and reliability is waning, so using them efficiently and when most needed is a priority for a successful growing season. Exploring soil treatments’ effects on soil moisture has also encouraged me to update our SOPs for core 2021 crops; for example, I’m planning to interseed all of our sweet corn, and use a straw mulch in our cucurbits where crop moisture needs to be stable during fruit development. Both of these would be combined with 2 to 3 early season cultivations to reduce weeds and allow soil to warm up in the spring.

Q: Do you plan to apply any of these treatments to corn grown at Opportunity Farm next season? If so, which one(s) and why?

Crockett: As mentioned above, I definitely want to do some sort of interseeding in the sweet corn next year. This may grow into using similar methods on the farm with other late-season crops like fall squash or peppers. I think more importantly, and necessary to understand the effects of any treatment, is to do at least some soil moisture monitoring every year. Without data to back up theories, you can spend time and money on solutions that don’t really work for your farm. I’m planning to incorporate soil moisture readings into our day-to-day operations, just like we would measure and record rainfall or daily temperatures. Only thing I would change from this year is figuring out how to automate soil moisture recordkeeping, reducing labor time for data collection, and increase quality and frequency of data.

Q: Jason, what teachable takeaways are there for other farms in Maine? As an agricultural service provider, how does this impact your work in supporting farmers?

Jason: I was pumped to hear that Ben found the soil moisture data useful and really leaned into relying on that data to inform his decisions. Sometimes when us ag service providers identify tools and resources we think will be helpful for growers there can be logistical hurdles to feasibility and adoption on farms. The fact that Ben is planning to continue using this practice and saw benefits from their use is encouraging and I definitely plan to lean on him as a spokesman! 

I was also encouraged about the interseeding results. I plan to continue doing research in this area, but feel comfortable encouraging and working with farms to implement this practice within the parameters of past identified hurdles. Seeing how well it worked to spread the seed immediately prior to last cultivation to get the seed into the soil was great data to have. That incorporates the past research data with the logistical and labor constraints of this practice being adopted on more working farms. 

The Climate Adaptation Fellowship was made possible by SARE (subaward number ENE20-164-3426) and a final report will be available to the public.

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The weather instability that farmers are dealing with today is truly “unprecedented,” according to Laura Lengnick, a soil scientist and the founder of Cultivating Resilience, LLC, in Asheville, North Carolina. Farmers have always had to assess weather-associated risks, but not like this. “Never before in the history – the 10,000 year history of agriculture – have farmers ever had to manage the kind of variability that farmers today are faced with,” she said during her keynote address at MOFGA’s 2020 Farmer to Farmer Conference.

When Lengnick first started working in climate change adaptation in agriculture about 12 years ago, she was struck by the lack of research being conducted in the U.S. that asked farmers what kinds of weather changes they were seeing and how they were adapting to those changes.

This led Lengnick to conduct her own “climate listening project,” in which she asked farmers to share their stories. The project aimed at giving farmers a voice and grew into a book titled “Resilient Agriculture: Cultivating Food Systems for a Changing Climate” (previously reviewed in the spring 2016 issue of The MOF&G, a second edition is forthcoming from New Society Publishers in July 2021).

“So for more than a decade, farmers and ranchers all over the U.S. are saying that weather is changing,” said Lengnick. Common changes being reported by farmers include: too much or not enough water, variable temperatures and rainfall, warmer winters and nights in some parts of the country, more frequent and intense heat waves, and new pest and disease pressures. “Sometimes these are just higher [population numbers] or longer seasons of traditional pests, but there are also new pests and diseases moving into different areas,” said Lengnick.

These changes are happening at different rates in different regions so farmers across the U.S. are not being universally burdened. In addition to location, the type of agriculture can impact how the changes are felt – with certain conditions being harder to mitigate for vegetable growers than livestock producers and vice versa.

Maine’s 2020 growing season was particularly challenging, due to a wet spring followed by a severe drought. Lengnick gathered clips from local media whose headlines announced “an unprecedented number of wildfires” as well as “historic drought” in some regions in Maine. One headline succinctly summarized what farmers everywhere are experiencing: “when it comes to weather, abnormal is the new normal.” Another way that Lengnick has heard farmers say it, “It is becoming predictably unpredictable.”

The fourth and most recent National Climate Assessment, released in 2018, published high-level findings from scientists regarding climate change and agriculture. Among them, it was noted that agriculture is going to experience reduced productivity and quality of crops and that soil and water resources will become progressively degraded “primarily because of the increased intensity and frequency of heavy rain events … punctuated by longer dry periods and droughts,” said Lengnick.

This translates to increased competition for declining water resources – this is true in for the Eastern U.S. as well as the West, where water has already been managed for 200 years, she continued.  Competition for resources – including land and nutrients in addition to water – will strain relationships between farmers and communities.

It’s going to get more difficult and more expensive to grow food, Lengnick cautioned. “Some farmers around some parts of the country have already experienced what it’s like when a city says, ‘No, we’re going to use that water. We’re shutting it off to farmers,’” said Lengnick.

“But the light in this story is that it turns out that agriculture and agricultural landscapes have kind of a super power,” said Lengnick. “Depending on how they’re managed and depending on the relationships that farmers and other growers make with the communities that they’re serving, agriculture can actually be part of the solution to climate change.”

How to Adapt to Unprecedented Conditions

While co-writing a USDA report, “Climate Change and Agriculture in the United States: Effects and Adaptation,” released in February 2013, Lengnick first discovered resilience science. It’s the perfect body of knowledge, in Lengnick’s opinion, to apply to climate change; it can also be used as a framework to adapting to any disturbance or shock, such as farming during the COVID-19 pandemic.

Resilience science is a 50-year-old system science that is rooted in ecology. “It doesn’t assume stability, and so it gives us language and tools to … manage and shape change,” said Lengnick.

Resilient systems have three complimentary capacities: “response capacity,” “recovery capacity” and “transformation capacity.”

Many people think about resilience as recovery capacity or the ability to bounce back. “But it’s actually the other two capacities that I think are much more useful as we think about how we’re managing change in the food system,” said Lengnick.

Response capacity refers to the ability to design or manage a system so that when there is a disturbance, there is little or no damage. If farms and food systems are designed to navigate change effectively, there is no need to recover. Recovery capacity means that a system design can rebound swiftly and at a low cost. Transformation capacity is the ability of a system to recognize when it’s time to change in order to improve upon the response and recovery capacities.

The Three Rules of Resilience

According to scientific analysis, resilient systems of any kind – whether families, farms or food systems – tend to follow three important rules. “The first is that the systems are made up of diverse relationships of mutual benefit,” said Lengnick.

Within a farm system, the relationships include every aspect of the farm, i.e., between humans and plants and between plants and soil, as well as relationships formed with the community in which the farmer resides. Lengnick noted that organic farmers, with their emphasis on healthy soil as the foundation of any farm system, have a lot to offer the rest of agriculture.

The second rule is that resilient systems tend to have regional self-reliance, meaning community resource systems in a region are designed and managed to produce all of the critical resources necessary to sustain the region’s well-being. There is very little importing of critical resources like water, energy, nutrients and food as well as human resources including ingenuity, innovation, human capacity and management. It also means that these resources are not being exported to a large degree. While Lengnick thinks that organic farming has to lot to offer others in terms of adopting this second rule, she also expressed that there is room for improvement.

Lastly, resilient systems accumulate community-based wealth, which is a lot more than financial wealth. Resilient systems cultivate all the kinds of wealth that sustain community well-being including natural, human and social resources, along with locally adapted physical and technological resources.

The three complimentary capacities of resilience – response, recovery and transformation – are cultivated when these three rules are followed at different scales within the region, from individuals, to families, to businesses and community organizations, to regional governance.  

Resilience Thinking

Designing and managing resilient systems requires a shift in the basic assumptions of modern industrialism. Lengnick says that we can no longer assume optimum conditions in a farm or food system and must instead shift to a framework which embraces variability. “Remember, we have left a time in our 10,000-year-old history as a species in which we were living in a climate stability,” said Lengnick.

We also need to move from industrial design and management principles to ecological design. Likewise, a hyper-focus on efficiency should be shed and robustness prioritized. “The window of vitality” refers to “a sweet spot between not enough diversity and too much diversity,” said Lengnick. Modern, highly efficient systems do not have adequate diversity to sustain themselves through disturbances. Though too much diversity doesn’t bode well either.

Lengnick cited research developing around community supported agriculture (CSA) systems and the optimum level of diversity. “It turns out that CSAs that have sustained themselves over time, tend to reduce the number, the diversity, of species being grown on any particular farm to around … roughly 15 to 20 from maybe starting out with 40 or 50,” said Lengnick.

Resilience thinking emphasizes tailoring expert knowledge and scientific thinking based on place-based knowledge. Along with moving from imported to regional resources, resilience thinking also requires a shift from extractive to regenerative economies.

Resilience on the Farm

Lengnick sees many parallels between resilience thinking and sustainable agriculture systems, known for incorporating ecological principles, place-based knowledge, regional resources and regenerative economies. With her climate listening project, Lengnick sought out organic and sustainable farmers and ranchers across the country and asked them what weather changes they were seeing, how they were adapting, and if they were managing for resilience.

From conversations with 27 farmers, Lengnick identified several key resilience practices that “showed up no matter where the farmer or rancher was located, and no matter what they were producing.” She said, “I don’t think any of these will be particularly surprising to a group of organic farmers, but hopefully it will be encouraging.”

The key resilience practices are as follows: soil health; planned biodiversity; diverse, high-value markets; improved water management; physical protection; and recovery reserves. 

Managing soil health as a resilience practice buffers the extremes of temperature and precipitation that are becoming more frequent and intense. “These farmers and ranchers viewed this buffering ability of soil health, the ability to absorb heavy rainfall and then to store it for plants to use during dry periods in drought, as particularly important to managing the changing weather patterns,” said Lengnick.

Lengnick also found that farmers were utilizing diversity as a tactic both on the farm – assessing where and how to place different species – and in their marketing strategies.

Due to more variable water conditions, farmers spoke of increased need for irrigation during more frequent dry periods and drought as well as using physical structures such as hoop houses and plastic mulch to protect soils and crops from heavy precipitation.

Planning for recovery included having reserves ­– from financial capital to livestock feed – while also increasing land and water resources. “That was because they were seeing more frequent and intense disruptions to their farms that were requiring some kind of repair from a damage being done by weather,” said Lengnick.

The Future of Food

There are many different solutions being presented for farming and eating in a changing climate: from local agriculture to lab-grown meat. Lengnick said that resilience thinking can help determine which solutions can work for individuals and communities. She suggests interrogating any potential solution using the three rules of resilience: Does this solution cultivate diverse networks of mutually beneficial relationships? Does it cultivate regional self-reliance? Does it accumulate a diverse wealth portfolio for communities?

Lengnick cited several real-world examples of resilience thinking being used to re-imagine food systems. A sustainable development concept known as the “city region” offers a model of resilience thinking in regional planning. City regions strive to promote mutual, beneficial relationships between urban and rural areas. Essentially, rural areas provide urban areas with myriad benefits, including food, clean water and air, and open space for recreation. “The idea of the city region is that we begin to change the nature of the relationship between urban and rural areas to allow resources to flow back into rural areas, rather than just having urban areas extract the value out of them,” said Lengnick.

The New England Food Vision used the city region model to assess how realistic it would be for New England to feed itself. Another interesting example comes from Houston, Texas, with the Water as a Crop project. Houston’s municipal water and electrical suppliers, along with city breweries, paid ranchers in the surrounding watershed to implement conservation practices to increase water quality and quantity in the region.

Harnessing Hope

To stay positive while studying climate change, Lengnick has taken a “deep dive into hope.” And it turns out that psychologists have done so as well, delineating at least seven different kinds of hope in the process. Lengnick finds “grounded hope” to be the most relevant in talking about agriculture and food systems. “It’s the kind of hope that is generated by working towards a desired future in community,” said Lengnick. “Psychologists tell us that grounded hope creates a sense of agency.”

To practice grounded hope in the pursuit of a resilient future, Lengnick suggests applying resilience thinking to every phase of your life, from family to farming to community involvement. Everyone can practice grounded hope by supporting regional, diversified agriculture systems – though it’s going to “take more than just buying local food to slow and reverse climate change,” said Lengnick.

“We need to be looking every way we can in our lives to promote action on climate change: in all the different places that we stand in, all the different ways that we’re leaders. We need to act to stop climate change now,” said Lengnick.

During her career as a soil scientist, researcher, policymaker, educator, author and farmer, Laura Lengnick has worked to apply sustainability values to agricultural and food systems. As the founder and principal of Cultivating Resilience, LLC, in Asheville, North Carolina, she works with organizations, including small-scale organic farms, to integrate resilience thinking into their operations. Lengnick’s keynote address at MOFGA’s Farmer to Farmer Conference was broadcast on Common Ground Radio on WERU FM Community Radio on November 12, 2020, and is archived at weru.org.

The post Climate Change, Resilience and the Future of Food appeared first on Maine Organic Farmers and Gardeners.

I have the good fortune to be the owner of a 25 acre woodland in Southern Maine. Abandoned as a pasture in the late 1930’s, it is now a flourishing and well stocked forest of the oak-pine variety. In 2016 I conducted a timber inventory and found that carbon stored in live trees was approximately 44 tonnes per acre or 162 MTCO2e. The average or common practice for my area is 76 MTCO2e.

Improved forest management is increasingly thought of as an important climate solution. Currently in Maine the forest in total is sequestering approximately 12 million MTCO2 or close to 75 percent of Maine’s total annual CO2 emissions.

What follows is a discussion of best management practices(“BMPs”) for maximizing carbon sequestration, with specific reference to my woodland.

Based on studies by the University of Maine¹, it seems reasonably safe to conclude that the let-it-grow or proforestration approach achieves the best result in Southern Maine. The adjacent graph highlights the results of a careful study of the Penobscot Experimental Forest near Bangor, ME over a 60 year period of forest management. As can be seen, the reference or proforestration approach sequestered close to 40% more carbon than the selection or shelterwood methods and close to 70% more than clear-cut. The lion’s share of the difference is in the resulting overstory – defined as above and below ground portions of live trees and shrubs. While some of the carbon removed in harvests was stored in long lived wood products such as boards, this storage was a small fraction of the carbon released to the atmosphere as a result of harvest removals.

The authors are careful to point out the limitations of this study. The treatment sample sizes are small and the forest type is specific to the Acadian Forest, a transitional zone between the eastern North American broadleaf and boreal forests. Further it does not address the problem of leakage, whereby the carbon withheld from the wood products market by the proforestration approach would be made up by stepped up production on other woodlands. For this reason, forest carbon projects factor in a buffer for leakage, often in the range of 20%. Even with a buffer of this magnitude, the proforestration approach would still maximize carbon sequestration in comparison to other approaches.

However, like many landowners, I have a joint goal of maximizing carbon sequestration in tandem with modest, periodic harvests for wood products and firewood for home use. In this situation what might be best management practices?

As a first step, let us consider the growth and yield profile of an oak-pine forest in the Northeast.²

The culmination of mean annual increment is where a given forest is adding volume and thus carbon at its maximum annual rate. It is the intersection between the mean annual increment (MAI) and the periodic annual increment (PAI). In this data series the period is a decade. For an oak-pine forest like mine, the culmination point is 38 years.

In other words, to maximize carbon sequestration per year a mixed-age forest should be relatively young with a carbon stocking in the range of 30 tonnes per acre. As the average age/stocking grows , the annual rate slows down but is still sequestering carbon at the PAI rate of 0.23 tonnes per year at an average age of 125. As mentioned, the carbon stocking level of my woodland is 44 tonnes per acre so is a bit past its prime at an implied average of around 65 years.

This conclusion was confirmed in an e-mail exchange with Anthony D’Amato³, Professor at the Rubinstein School of Environment and Natural Resources University of Vermont. He wrote “if you were only focused on maximizing sequestration, you would manage for that age range.”

As a second step, let us further consider my parallel goal of periodic harvests of wood products. While wood volume and stored carbon increase in tandem, the value of a harvest is also a function of the board feet of saw logs that can be realized.

For an estimate of the growth and yield of saw logs, I entered the 2016 inventory data into the Forest Vegetation Simulator tool maintained and available from the U.S. Forest Service. As shown in the graph below the culmination MAI for saw logs is around 105 years – almost 70 years older than for carbon.

From a dollar and cents point of view, this extra saw log growth is very material. In 2016 my saw log inventory had an estimated value of about $3,100 per acre. Per the FVS results, letting it grow the extra 40 years to the culmination MAI and assuming the same wood prices would more than double the value per acre to around $6,500 per acre.

Like most woodlands, the economic value resides in the saw logs – in my case around 85% and predominantly white pine and red oak.

Thus, the goal of maximizing carbon sequestration Is in conflict with the goal of maximizing the value of wood products. They are not mutually exclusive however. As my woodland matures towards the culmination MAI for saw logs, it is still sequestering carbon albeit at a slower rate than a younger woodland. My management plan is therefore to target the 100 average age range with a goal of steadily improving the timber quality over the years.

Also from a carbon sequestration perspective, the higher the yield in saw logs from a given harvest the higher the amount of carbon stored in long-lived wood products such as boards, building materials and the like.

Turning now to silviculture, what observations can be made about BMPs to maximize carbon sequestration.

As mentioned and shown in more detail in this table from the Puhlick article, the preponderance of the carbon is sequestered in the overstory. Further, as between the reference/proforestration and the active management treatments, the difference in total ecosystem carbon is almost entirely explained by differences in the overstory.

Committed as I have been to low impact forestry, I find this a somewhat surprising result. For my own work, I use a chainsaw and a skidding winch on a small rubber-tired tractor. I am careful not to disturb the soil or the litter on the forest floor. I leave the slash in brush piles as I go. These are common sense approaches and surely make a difference at the margin, but the big driver in carbon appears to be the growth in the overstory. The above study indicates that most of the harvesting was done with chain saws and rubber tired skidders with some horse logging; these are relatively low impact systems compared to the whole tree systems in use presently. Further study would seem to be needed to control for differences between low and high impact forestry.

Lastly, what should be the role of thinning cuts as a companion to removals for high value saw logs? Certainly, thinning is shown to improve overstory growth and enhance the quality of the remaining stand. Such thinning however produces very little revenue for the land owner and sequesters carbon not at all in the case of biomass and only for a short period in the case of pulpwood. In my woodland, I thin for quality by girdling the tree. Standing dead trees retain carbon until they fall and also provide ecosystem services. Once on the ground, the retained carbon is released over time but with a half-life of up to 70 years.⁴

In summary, proforestration would appear the best approach to maximizing carbon sequestration in Southern Maine. For landowners like myself who seek to maximize carbon sequestration in tandem with harvesting high quality timber, the following BMPs might be indicated:

1 Puhlick, J et al 2016 Long-term influence of alterative forest management treatments on total ecosystem and wood product carbon storage. NRC Research Press

2 Smith, J et al (2005) Methods for Calculating Forest Ecosystem and Harvested Carbon with Standard Estimates for Forest Types of the United States USDA

3 D’Amato, A and Catanzaro, P (2019) Forest Carbon Amherst MA: University of Massachusetts

4 Achterman,G et al (2006) Forests, Carbon and Climate Change Portland OR: Oregon Forest Resources Institute

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Connect with MOFGA’s Low Impact Forestry Project to learn about carbon sequestration in our woodlands. English photo

By Mitch Lansky and Peter Hagerty

Years ago the Low Impact Forestry (LIF) Project surveyed MOFGA members who owned forestland. We asked for feedback from landowners, whether they owned 1 acre or 500. The survey was not scientific, but it did reveal that the acreage of those members’ forests greatly exceeded the acreage of their fields or gardens.

Today, 20 years later, carbon emissions are clearly destabilizing global climate, and these problems will become more severe if annual emissions to the atmosphere are not reduced dramatically. While the main strategy for reducing carbon emissions is to use less fossil fuel,  cost-effective opportunities also exist to increase carbon capture and storage through changes in management of Maine’s forest land.

Northern New England is one of the most densely forested regions in the United States. Even modest gains from increasing wood volumes in the forest could significantly impact capturing and storing carbon – carbon that would otherwise enter the atmosphere.

MOFGA members can increase carbon sequestration by preventing deforestation; reserving more acres of unmanaged forest that are in, or have the potential to transition to, higher-volume stands; and changing forest practices to increase the amount of carbon stored in managed stands over time.

The LIF Project has been meeting with members of the New England forestry community over the past year in hopes of revising the present LIF curriculum to include the latest procedures that would increase carbon sequestration. We know that the climate issues we face are global and that forestry alone cannot solve the problem of climate change; but we want to explore what we can do locally, and forestry is one place where we can make a difference.

These opportunities should be welcomed by owners of both large woodlands and small “family forests.” We have the power to help increase the amount of carbon captured and stored across our forested landscapes in trees, living and dead, and in the soil that holds the trees.

The LIF Project would like to invite you to a conference this summer (date TBA) where these and other  issues would be addressed in the spirit of what is best for our forest environment and the role the forest plays in fighting climate change. Please contact us for more information: Mitch Lansky, lanskymitch@gmail.com; Peter Hagerty, peter@peacefleece.com.

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While the southern range of bumble bees is moving north, the northern range seems to be stationary. English photo

By Sue Smith-Heavenrich

As the planet warms, many animals – and even plant populations – are migrating to cooler areas.  Some expand their ranges northward; others move upslope, to higher elevations. But not bumble bees.

A team of  Canadian, U.K. and U.S. scientists discovered this when they assembled a database of approximately 423,000 georeferenced observations for 67 bumble bee species from Europe and North America. They divided the records into different periods – 1975 to 1986, 1987 to 1998 and 1999 to 2010 – and compared them to a baseline period from 1901 to 1974. For each kind of bumble bee, they mapped its northern and southern range limits, its “thermal range” (the warmest and coolest temperatures it occupied) and the mean elevation of the population.

Agricultural researchers have already documented northward range expansion for butterflies and for mountain pine beetles and other pests, so the bumble bee scientists expected to see something similar. Instead they found that while the southern limits of the bumble bee territories retreated – 300 km (186.4 mi) – the northern edge did not change. This held for bumble bees in both the U.K. and North America. The scientists also discovered the bees had moved to higher elevations – 300 meters (984 feet) up mountain slopes.

The researchers built statistical models to test whether the range shifts might be due to land use (agriculture or urban development) and pesticide exposure (in particular, neonicotinoids). Those models indicated that a warming climate is responsible for squeezing the bees between a rock and a hot place.

A recent study at North Carolina State University reinforces those findings. There, researchers tested the heat tolerance of 15 species of native bees in the lab. To mimic climate change they observed bee populations in urban “heat islands” – areas where the abundance of cement and steel and the lack of greenery contributed to higher temperatures than the surrounding environments. Over two years the team followed bee populations at 18 locations in Wake County. When they compared bee populations in warmer areas to those at cooler sites, they found that bees with low heat tolerance in the lab, including bumble bees and sweat bees, tended to be less abundant in heat islands.

Why aren’t the bees expanding their range to the north? The difference in daylight or perhaps in food resources could be responsible, as could the small size of bumble bee colonies, usually 50 to 100 individuals, and their slow growth. Jeremy T. Kerr, biology professor at the University of Ottawa, observed that the buff-tailed bumble bee (Bombus terrestris) is an exception: It has expanded its range north and is, he says in Science, the “dandelion of the bumble bee world.”

Saving Maine’s Natives

Maine has 17 native bumble bee species, but according to Frank Drummond, two of those, the rusty patched bumble bee (B. affinis) and yellow-banded bumble bee (B. terricola), are almost extinct in southern Maine and are rare in the northern part of the state. Drummond would know: He’s a biology professor at the University of Maine and has been studying insects, particularly Maine’s native bees, for many years.

In 1989, when Drummond started collecting bees, the rusty patched bumble bee made up 20 percent of the state’s bumble bee population. By 1990 it was hard to find, and in December 2016 it was listed as an endangered species.

Even the common eastern bumble bee (B. impatiens) is getting hard to find and now makes up only 20 percent of the total bee population Drummond sees. Bumble bees are important to Maine farmers because they’re active at cooler temperatures, even on cloudy and foggy days. Honeybees are less active under those conditions. Bumble bees also pollinate plants using a rapid vibration called “buzz pollination,” which is more efficient than honeybees’ method, and they visit more flowers than honeybees over the same period of time.

Without bumble bees, many of Maine’s crops would have lower yields, so Drummond collaborated with colleagues to produce pamphlets and fact sheets encouraging gardeners and homeowners to plant native species that provide pollen for native bees.

Be a Bumble Bee Hero

The good news is that people can help native bumble bees. The first step is to reduce our carbon footprint. Beyond that are specific actions to help save our native bumble bees.

Learn about bumble bees. Protecting them starts with knowing as much as you can about their ecology, why they’re important, and ongoing conservation efforts. Then share what you learn. A lot of people are afraid bees (and other insects), so tell your family and friends how important bumble bees are. Encourage them to watch bumble bees and even take photos.

Create habitat! Become a steward of bumble bee habitat in your backyard, school, community parks and rooftop gardens. Converting lawns to native plants would create millions of acres of bumble bee habitat. Some states encourage solar farms to grow pollinator plants between rows of solar panels.

Feed the bees. Bumble bees and other native bees need pollen and nectar all summer, so when  planning gardens or planting trees, make sure to plant some that bloom early as well as some that bloom into fall. Choose native plants when possible. Early bloomers include maples, apples, cherries, plums, willows, violets, crocuses, raspberries, black berries and dandelions. For midseason flowering, plant roses, rhododendrons, milkweed, purple coneflower, oregano, mint, marigold (single-flowered), borage, sunflowers, clover and field thistles. Late season flowers include asters, phlox, coneflowers, goldenrod and cosmos.

Find out more about pollinator plants suitable for Maine and the Northeast at the Xerces Society (xerces.org/pollinators-northeast-region/), the Wild Seed Project (wildseedproject.net/) and NRCS (https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_010204.pdf).

Support local and organic agriculture. Agricultural areas provide both food and danger to native bees. Vegetable and fruit plants provide pollen-filled blossoms, but pesticides harm bumble bee colonies. Encourage local farmers to reduce or eliminate spraying.

Help scientists determine where bumble bees are abundant and where their populations are declining. Become a citizen scientist and collect data in your area by joining a project such as one of those below.

• Bee Hunt – Collect data by photographing bees at study sites and other activities. (discoverlife.org/bee/)
• Great Sunflower Project – Count the number and types of pollinators visiting plants (especially sunflowers) in yards, gardens, schools and parks (greatsunflower.org/).
• Bumble Bee Watch – Upload photos of bumble bees to a virtual bumble bee collection. Photos also help researchers determine the status and conservation needs of bumble bees and locate rare or endangered populations of bumble bees. (bumblebeewatch.org/)
• Maine Bumble Bee Atlas – Trained citizen scientists help document the diversity, distribution and abundance of bumble bees in Maine. (mainebumblebeeatlas.umf.maine.edu/)

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Carpenter Bee or Bumble Bee?

Bumble bees look like furry flying teddy bears. Another large black-and-yellow bee looks a lot like a bumble bee: carpenter bees. Both are hairy, large and relatively slow-flying. But look closer. A carpenter bee’s abdomen is bare and shiny black. Bumble bees have hairy abdomens, with some yellow or orange markings. Also, carpenter bees tunnel into wood to nest, while bumble bees nest in the ground.

Need help identifying bumble bees? The Xerces Society provides a downloadable field guide to eastern bumble bees (xerces.org/bumble-bee-identification/) as does the USDA Forest Service (www.fs.fed.us/wildflowers/pollinators/documents/BumbleBeeGuideEast2011.pdf), and the Maine Bumble Bee Atlas project lists bumblebees found in Maine, with links to photos. (mainebumblebeeatlas.umf.maine.edu/me-bumble-bees/maine-species-list/)

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Crops Pollinated by Bumble Bees

Apples
Apricots
Blueberries
Cranberries
Cucumbers
Currants
Eggplant
Melons
Peaches
Pears
Peppers
Scarlet runner beans
Squash
Sunflowers
Tomatoes
Watermelons

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