Forests play a significant role in reducing greenhouse gas emissions and in mitigating the rate and impacts of climate change. Forests remove carbon from the atmosphere and store that carbon as above-ground and below-ground organic matter (living and dead).
Some of the many ecological functions performed by forests include:
- regulating water cycles (purifying water and preventing flooding)
- regulating climate extremes
- maintaining biodiversity
Old-growth forests often have a complex structure of multiple layers and age classes of trees, as well as canopy gaps that create a varied ecosystem. This old-growth ecosystem supports diverse flora and fauna, from mosses and liverworts to large mammals and some species at risk. Old-growth forests provide habitat for many birds, mammals and amphibians.
Some species are dependent on old-growth forests for survival. Marbled murrelet birds, for example, nest exclusively in old-growth trees. Northern goshawks depend on old growth for nesting and forage habitat. Species such as the fisher, marten, and pileated woodpecker, rely on large, coarse, woody debris and snags in various states of decay for foraging, nesting, denning and shelter. Both the quantity and distribution of suitable decaying woody material influence species’ presence and abundance. Woodland and mountain caribou rely on old-growth forests for forage and winter shelter.