Why Old-Growth?

– maps by William B. Greeley, US Forest Service

~page under construction~ last updated 5/20/17


“Creating the structure and composition found in old-growth forests helps us ‘keep every cog and wheel’ and undoubtedly conserves crucial habitats for insects, fungi, and other organisms yet to be documented. Therefore, restoring these once common habitats is of central importance to conserving the full suite of our region’s native plants and animals.”

D’Amato, Anthony and Paul Catanzaro. “Restoring Old-Growth Characteristics.” University of Massachusetts–Amherst, UMASS Extension (2007)


“Wildlife and thick, old growth forests go together…A forest with beetle-killed trees is a healthy forest because dead trees are an important component of naturally healthy forests. The beetles provide food for woodpeckers. Woodpeckers then drill holes in trees for their nesting cavities which are then used by many other birds that can’t drill out their own nesting holes. When the dead trees fall, they provide cover and habitat for snowshoe hares and squirrels, which in turn are eaten by pine marten, fisher, lynx, goshawks and great gray owls. The downed trees also provide important cover for elk, lynx, and grizzly bears. All these species depend on mature and old growth forests with plenty of dead trees to provide them habitat.”

Johnson, Dr. Sara Jane. Quote from “Conservation Groups Challenge Timber sale in the Swan Valley to protect big game and fisher habitat.” Alliance for the Wild Rockies (2016)


“Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can adthe same amount of carbon to the forest within a year as is containein an entire mid-sized tree.”


Stephenson, N.L.et.al. “Rate of tree carbon accumulation increases continuously with tree size.” Nature (2014)
“For example, in our western USA old-growth forest plots, trees >100 cm in diameter comprised 6% of trees, yet contributed 33% of the annual forest mass growth.”
Stephenson, N.L.et.al. “Rate of tree carbon accumulation increases continuously with tree size.” Nature (2014)


“In their study, Stephenson and his colleagues analysed reams of data on 673,046 trees from 403 species in monitored forest plots, in both tropical and temperate areas around the world. They found that the largest trees gained the most mass each year in 97% of the species, capitalizing on their additional leaves and adding ever more girth high in the sky.”


“Our results demonstrate that old-growth forests can continue to accumulate carbon, contrary to the long-standing view that they are carbon neutral. Over 30 per cent of the global forest area is unmanaged primary forest, and this area contains the remaining old-growth forests…Old-growth forests accumulate carbon for centuries and contain large quantities of it. We expect, however, that much of this carbon, even soil carbon, will move back to the atmosphere if these forests are disturbed.”

Luyssaert, Sebastiaan et al. “Old-growth forests as global carbon sinks.” Nature (2008)

Soil in old-growth forests can accumulate 
atmospheric carbon at a very high rate.

Guoyi Zhou, et al., “Old Growth Forests Can Accumulate Carbon in Soils,” Science 314 (Dec. 1, 2006): 1417.




“…nor would planting avail much towards getting back anything like the noble primeval forests. During a man’s life only saplings can be grown, in the place of the old trees—tens of centuries old—that have been destroyed. It took more than three thousand years to make some of the trees in these Western woods,—trees that are still standing in perfect strength and beauty, waving and singing in the mighty forests of the Sierra.”

Muir, John. “The American Forests.” The Atlantic (1897)


“Each town should have a park, or rather a primitive forest of five hundred or a thousand acres, where a stick should never be cut for fuel, a common possession forever, for instruction and recreation…Let us keep the New World new, preserve all the advantages of living in the country.”

Thoreau, Henry David. Written October 15, 1859, in his Journal, vol. XII, p. 387