Into the Woods: What makes a forest healthy?
Landowners always ask me: “is my forest healthy?” While this seems like it should warrant a simple “yes” or “no” answer, the question almost always makes me pause, my eyes glazing over. Like many parts of our world, the deeper we dig into forests the less clear things become, and judging if a forest is “healthy” or not is profoundly complex.
One of the many things that foresters are is scientists. As part of a scientific approach to management we want to use objective, measurable means to help us understand forests and how to take care of them. In school, one of the ways I was taught to define forest health was through the metrics of Acceptable Growing Stock (AGS) and Unacceptable Growing Stock (UGS). In forestry, an AGS tree is generally defined as one that may someday yield a sawlog (a higher-quality log that is sawn into boards) and has no obvious health issues that will kill it in the short-term. Conversely, a UGS tree is one which doesn’t meet those standards. By comparing the relative abundance of AGS trees to UGS trees, we can form an idea of how healthy the forest is.