Mixed forests are more productive, contribute to climate resiliency

Forest Canopy – photo: Don Fisher

Today, 63% of New York’s land area is covered with 19.0 million acres of forest land. About 14.0 million acres, or 74% of New York’s forest land, are owned by a diverse group of nearly 700,000 private landowners. These private forest lands provide many public benefits including clean air and water, forest products, wildlife habitat, jobs, scenic beauty, and outdoor recreation opportunities. Protecting and sustainably managing New York’s private forest land is essential in order to maintain these public benefits.

A recent meta-analysis of 126 case studies established at 60 sites spread across five continents and published in The Royal Society Biology Letters, concluded that the productivity of mixed-species forests was 15% greater than the average of their component monocultures, and not statistically lower than the productivity of the best component monoculture. Productivity gains in mixed-species stands were not affected by tree age or stand species composition but significantly increased with local precipitation.

“We know of the many advantages of mixed forests,” states Professor Hans Pretzsch, co-author of the study and author of a recently released, internationally acclaimed book on the ecology and management of mixed-species stands. “Mixed-species forests are ecologically more valuable as versatile habitats. They mitigate climate change, as they mean a higher carbon sink.”

Trees in mixed-species forests are often better supplied with light, water, and soil nutrients via their complementary crown and root systems. “This makes mixed stands more resilient during dry years. In addition, they are more stable against pests and visually more appealing,” adds Prof. Pretzsch.

The results of this study should guide better use of tree species combinations in managed forests and suggest that increased drought severity under climate change might reduce the atmospheric carbon sequestration capacity of natural forests.

Private Forestry

If you are looking to protect and improve your woodland, the NYS DEC Forest Stewardship Program can help you. DEC service foresters can help by providing you no cost one-on-one technical assistance that includes creating a stewardship plan tailored to your goals and objectives for your woodland. Regardless of your goals a professional forester can help you meet your objectives for the production of timber products, improving wildlife habitat, or planting trees on your woodland.

But keep in mind the benefits of a mixed-species approach.