Trees with a large diameter comprise only a minority of stems yet account for a majority of above-ground carbon storage. These are the findings of a recent study examining Pacific Northwest forests.
A recent study in the Pacific Northwest region of the US has shown that although large-diameter trees (≥ 21 inches) only comprised 3% of total stems, they accounted for 42% of the total aboveground carbon storage, announced a statement.
The researchers highlight the importance of protecting large trees and strengthening existing forest management policies so that large trees can continue to sequester carbon and provide valuable ecosystem services as a cost-effective natural climate solution in worldwide forest ecosystems.
In the Pacific Northwest region, a 21-inch diameter rule was enacted in 1994 to slow the loss of large, older trees in national forests. However, proposed amendments to this limit would potentially allow widespread harvesting of large trees up to 30 inches (76.2 cm) in diameter with major implications for carbon dynamics and forest ecology.
Dr David Mildrexler, who led the study, highlights: “Large trees represent a small proportion of trees in the forest, but they play an exceptionally important role in the entire forest community – the many unique functions they provide would take hundreds of years to replace.”
The study also revealed that trees >30 inches in diameter only constituted 0.6% of the total stems, but these giants accounted for over 16% of the total aboveground carbon across the forests examined. Once trees reached a large size, each additional increment in diameter resulted in a significant addition to the tree’s total carbon stores.
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