Why go "beyond old growth"?
Human values, such as aesthetic and spiritual qualities, drive many public debates about old growth—ecology and biodiversity are secondary for many people. Although social values and issues lie at the heart of many old-growth controversies, ecological perspectives are needed if new policies are to lead to successful management.
Even if consensus is never reached on a broad ecological definition of old growth, managers need specific working definitions to conserve biodiversity effectively. Old-growth forests share many attributes, but they also differ in many ways. Efforts to conserve biodiversity must be sensitive to these differences and must consider forests of all developmental stages, not just the oldest ones. Forest policies and management practices may need to be as diverse as the forests they address. Unless some younger forests become older forests, one day in the future there will be no “old growth.”
This publication is the product of an effort to synthesize some overarching commonalities and significant differences in the findings of five NCSSF-sponsored workshops. Its purpose isn’t to debate definitions of old growth, but to go beyond them. This is why the Commission has chosen to use the neutral term “older forests” wherever possible instead of old-growth forests, ancient forests, virgin forests, or any of a myriad of other widely used terms. “Older forests” acknowledges that many of today’s forests on land that was cleared or logged over the past couple of centuries have key ecological characteristics that traditionally have defined old-growth forests. With effective management, these forests can acquire the values that make what we know as old growth such a precious resource.
For example, it is not widely appreciated that even commercially managed timberland in northern New England still has a biologically significant component of older forest—stands in which there is a cohort (a group of trees in the same age class) 100 to 200+ years old. Such older stands have been virtually “invisible” as either a conservation problem or a conservation opportunity for several reasons.
First, ecologists and the environmental community have tended to focus on conserving “true” old growth, of which there is very little. Most remaining old growth has already been protected. But forests develop along a continuum via complex pathways. Old-growth characteristics don’t develop instantaneously at some magical age; they accrue over time (Fig. 1). Thus even stands with a history of timber harvesting can have old-growth characteristics. Effective conservation of forest biodiversity requires us to see the forest as plants and animals experience it, not as black or white (e.g., pristine old-growth vs. everything else). Many older-forest species don’t understand the word “pristine” and occur in stands with old-growth characteristics. Forests in this stage and species that use them often slip through the coarse filter of conservation.
Second, because we haven’t adequately appreciated the ecological significance of forests with harvest histories, we haven’t built an understanding of biodiversity in older forests that are not accepted as “true” old growth. We are relatively uninformed about what species might be lost if this age class disappears from the landscape. However, scientists are beginning to realize that the abundance of older forest in managed landscapes will likely make or break the conservation of biodiversity in forest-dominated regions.
The ultimate goal of this effort is to provide useful information that will contribute to policies and practices that keep older forests a biologically functional part of our nation’s forestlands
This is a chapter from Beyond Old Growth (report).
Previous: Chapter 1: What is old growth? | Table of Contents | Next: Chapter 3: Why are older forests important?