What is a healthy forest?

This is a difficult question to answer because it depends upon the values that you place upon the forest. In order to simplify our assessment of forest health, the National Forest Health Monitoring Program developed the following measures to describe the health of the forest:

• Ecosystem Sustainability: is the ability to maintain the desired condition.
• Productivity: Physical output per unit of time for commodity and non-commodity products. Board feet of timber, wildlife demographics or the ability of a stand to sequester carbon are all examples of productivity.
• Biodiversity: Species richness and species abundance. Habitat suitability index would fall into this category.
• Aesthetics: Big trees and hardwoods are valuable. People like to look at big trees while saplings are often viewed negatively by the public. This certainly confounds this measure.
• Extent of Ecosystems: How many acres of condition X do we have?, how much do we need?

How Healthy are Michigan's Forests?  Forest stressors such as drought, storms, late spring frosts, diseases and insects coupled with the age of various forest types have played a significant role in shaping Michigan's forests. Some forest types show significant signs of decline while others appear healthy and productive. Northern pin oak in the Northern Lower Peninsula is in a state of decline and has been since the early 1990's. Oaks growing on better sites are for the most part healthy and vigorous. A white birch decline detected earlier this decade is showing significant signs of recovery in standing trees, especially on richer less disturbed sites. However, birch continues to be a very difficult species to regenerate. On the other hand, northern hardwood, a type dominated by sugar maple continues to grow healthy and contributes significantly to Michigan's overall forest health. Generally, our forests are quite healthy and productive!  Local problem areas do occur in types that are beyond pathological rotation age. This is especially true in "even aged" stands. Foresters are now attempting to mitigate age class distributions to reduce risk. Forest stressors add to declines sometimes exacerbating an already difficult situation to manage.