Promote structural diversity: Diversify tree age classes

Promote diverse tree age classes

Climate change is predicted to increase the frequency and intensity of storm events. Pests are also predicted to increase. These disturbances often have a disproportionate impact on certain ages of trees. For example, a wind storm is likely to do more damage to an old, large tree than a sapling. Certain pests may prefer young trees. Diversify the tree ages in order to increase resiliency. If one of these disturbances impacts your woods, there will likely be trees of different ages there to take its place.

To diversify tree ages, create gaps in the canopy to let sunlight reach the forest floor. The canopy gap size will depend on which species you are trying to regenerate. For example, sun-loving early successional species will need large gaps (>1/2 acre), while shade-tolerant late successional species, such as maples and balsam fir, need only the gap created by felling a single mature canopy tree. Diversifying tree ages will also provide a diversity of habitat conditions; some wildlife species prefer young, seedling forest while others prefer mature forest with many canopy layers and many prefer a little of both. In addition, promoting forests with diverse age classes may increase the forest’s ability to store carbon by increasing the area occupied by trees (i.e., packing younger smaller trees underneath larger, older trees). Carbon storage refers to the amount of carbon contained in tree biomass in a forest. In fact, about 50% of a tree’s mass is carbon. Recruiting new age classes relies upon successful tree regeneration, which can be challenging on sites with high levels of deer pressure or invasive plants. Refer to the resources below on strategies for increasing tree regeneration.