What is Old Growth? The term “old growth” came from foresters in the early days of logging. In the 1970s research ecologists began using the term to describe forests at least 150 years old that developed a complex structure characterized by large, live and dead trees; distinctive habitats; and a diverse group of plants, fungi, and animals.
Old growth forests are those where the overstorey is in the late mature to over mature (senescent or partly dying) growth stage with the presence of relatively large old trees, many containing hollows and often with the presence of dieback or dead branches in the crown. Structural old-growth criteria are based on data relating to age distributions, size distributions and spatial patterns of both live and dead trees, and they are basically formulated to identify stands with gap phase dynamics (Wells et al. 1998).
The following three criteria for age structure proposed by Mosseler in 2003 summarized the most important aspects:
*Uneven, multi-modal or inverse J-shaped age structure;
*Mean age of dominant species approaches half the maximum longevity for the respective species; and
*Some old trees are close to their maximum longevity
Environmental groups use the term “old growth” to describe forests with large, old trees and no clearly visible human influences. Many forest scientists do not see the absence of human activity as a necessary criterion for old-growth, but there is no consensus on this in the scientific community.
Old growth forests are recognised as having very high aesthetic, cultural and nature conservation values. Their protection and management is extremely important in maintaining biodiversity.
Virgin forest
