8.01.01 - Old growth forests and forest reserves
Old-growth forests are a stage of forest development that is characterized by large/old trees and structural complexity including live and dead trees, and vertical and horizontal heterogeneity. Globally, the extent and diversity of these forests have been greatly reduced by human activities and in many regions well-developed old-growth forests exist only as small fragments or are completely absent.
The structural diversity of old growth forests often supports distinctive biodiversity in the form of animals, plants, and fungi. In addition, the long-period of forest development without stand replacement disturbance allows many poor-dispersing species to accumulate. Old-growth forests can provide other distinctive ecosystem services as well, including high levels of carbon sequestration, clean water, and non-timber forest products.
Maintaining and restoring old-growth forests can increase the ecosystem services. In many cases old-growth forests are best maintained by through reserves that limit or exclude human activities. For some landscape and forest types it may be necessary to actively manage to restore or maintain old growth conditions. This is especially the case for fire-prone old growth forest types that depend on particular regimes of frequency and intensity of fire. In situations where old growth has been replaced by even-age young plantations, variable density thinning in plantations may be needed to restore old-growth structures and developmental pathways. In situations where intensive land management has change species composition and structure it may be necessary to plant desired species and control unwanted vegetation.
Our aim is to understand the ecology of old-growth forests, their role in biodiversity conservation, the impacts of forest harvesting and silvicultural practices, and methods for the maintenance, management, and restoration of old-growth forests.
The state of knowledge about old growth varies widely among forested regions. In some areas such as the Pacific Northwest of the USA, we know relatively more about old-growth forest ecology and conservation. Other regions where scientific knowledge about old growth is relatively high include, Australia, Canada, Scandinavia, North Eastern United States and some areas of eastern Europe. Knowledge of old growth is relatively weak in regions where logging and landuse activity have eliminated it. New areas of research include effects of climate change on old forests and trees, restoring old growth in areas where it has been lost, and incorporating old-growth structures and functions in forests managed for multiple values.