A Maine grower wrote: "Another topic I would like us to think about is orchards carbon footprint. I think I heard a while back that orchards were pretty much carbon neutral, which is a good selling point for us! Maybe there is someone who could speak on that topic. "
1. If you know of someone (including yourself) who might be available to speak on this topic, even briefly via Zoom, please let me know. 2. I referred the query to two folks with expertise in soil carbon and they both agreed to this: "I suspect your trees offer nominal C sequestration, and it would depend on the accounting rules will matter for the fruit harvested and branches pruned. I suspect the soils don't change a lot from year to year for old orchards, but are increasing if it was a cultivated field that was converted to an orchard, and decreasing if it was cleared of forest and turned into an orchard. " 3. A 2010 article by Alan Lakso https://nyshs.org/wp-content/uploads/2016/10/estimating-the-environmental-footprint-of-new-york-apple-orchards.pdf found that: "The cooling effects of orchards were estimated to be: Trees – 3.5-4 billion BTU’s per acre per season (equivalent to about 85-90 air conditioners of 10,000 BTU capacity running 24/7 for 6 months). Whole Orchard including cover crops – 5-5.5 billion BTU’s/ acre (equivalent to 120-125 air conditioners of 10,000 BTU capacity running 24/7 for 6 months). These are substantial cooling effects per acre." "The crop sequesters carbon but only for a short time until the fruit is eaten. We can estimate how much carbon is sequestered in the structure of trees but all too often trees are burned when they are grubbed, thus releasing all the sequestered carbon." "A major limitation is understanding the fate of carbon that goes to and through roots. A key in this aspect is to improve soil organic matter (OM). However, soil OM values tend to level out at higher percentages. In arid climates where they have done clean cultivation, their soils are often low in OM and they can sequester C via increased OM additions. In general, in NY we have quite high soil organic matter, so our potential to sequester more is somewhat limited (we have already been doing a good job for decades!)." "Overall, with our modern orchards that produce good yields on dwarf trees on heavier soils with generally high organic matter we probably have limited opportunity to sequester much more carbon that we do now, " "Apple orchards in NY have several positive environmental impacts. An acre of orchard each season fixes about 20 tons of CO2 from the air, releases 15 tons of oxygen, and provides over 5 billion BTU’s of cooling power. Carbon is sequestered by trees, though estimates are hard to make at this time due to lack of key knowledge." -- Glen Koehler University of Maine Cooperative Extension Pest Management Unit Voice: Office 207-581-3882, Cell 207-485-0918 17 Godfrey Drive, Orono, ME 04473 UMaine Apple IPM https://extension.umaine.edu/ipm/programs/apple/ Every individual has a skill, a voice, a career to wield as a tool to address climate change. Ultimately, climate action is not powered by the Paris agreement – it’s powered by people. ...We each have a part to play in limiting the devastation of the climate crisis. -- Dr. Victoria Herrmann. Arctic Institute University of Maine Cooperative Extension supports UMaine's land and sea grant public education role through community-driven, research-based programs in every Maine county. UMaine Extension helps sustain and grow the food-based economy as the only entity in our state that touches every aspect of the Maine Food System: policy, research, production, processing, commerce, nutrition, food security, safety and 4H youth education.
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