Thin the Trees to Save the Trees

Climate change is intensifying threats to forests across the Northeast, including the Adirondacks, where milder winters help invasive insects and plants spread. The region’s history adds to its vulnerability: after extensive logging in the 1800s, many forests regenerated at roughly the same time, leaving dense stands of similar-aged trees. Pests such as hemlock woolly adelgid, emerald ash borer, and beech leaf nematode, along with drought, excess rain, deer browsing, and invasive plants, are putting trees under stress and preventing native seedlings from taking hold. Public-land managers face limits on cutting trees, while private forest owners can try more active approaches.

At Pack Demonstration Forest, researchers are testing whether carefully planned thinning can make forests more diverse and resilient. They compare different ways of removing trees around hemlocks, aiming to improve light and air circulation without encouraging other species to replace hemlock. Harvested wood may also provide landowners with income. Other strategies include monitoring invasives through community reports, using biological controls, and identifying surviving trees that may carry resistance to pests. Since many invaders cannot be eradicated, experts argue that management must prioritize which species and places to protect, while accepting that forests will change. Even widespread tree deaths may create openings for new growth, and restoration may eventually require reconsidering whether some non-native species can serve a role in severely degraded areas.