Increase structural complexity through retention of biological legacies in living and dead wood

Late-successional and old-growth forests store more carbon compared to young or secondary forests, such that stand age is often a reliable predictor of carbon stocks for a given forest type. Older forests typically have greater structural complexity, including higher density of carbon stocks in both live and dead trees. Particularly in temperate deciduous forests, moderate severity disturbance in late-successional and old-growth forests transfers carbon from live to dead pools that increases carbon storage. The greater structural complexity that results from this moderate severity disturbance increases resource-use efficiency and resource availability to maintain greater levels of carbon sequestration rates than previously thought. Silvicultural practices that increase structural complexity through maintaining older or larger-diameter legacy trees and greater amounts of dead wood including snags, down logs, and coarse woody debris may increase carbon storage. Coarse woody debris may contribute to enhanced soil carbon stocks and nutrient pools, directly contributing to carbon storage in mineral soils as well as influencing forest carbon sequestration into the future. Downed logs and coarse woody debris can serve as nurse logs or provide microclimates important for seed germination or seedling establishment, which may play an important role for a species’ persistence or colonization of new habitat as environmental conditions change.

Climate change is projected to increase the potential for severe disturbance events that reduce forest ecosystems carbon stocks, while additionally affecting the growth and regeneration of extant species. Many forest management decisions aim to limit the negative impacts of disturbances while enhancing the growth of residual trees and the regeneration of desired species that represent the current and future capacity of the ecosystem to sequester carbon. Often these management actions aim to enhance existing forest conditions, such as species composition and stand structural diversity that are key to the desired services provided by the forest. Slight adjustments in forest conditions can improve the retention of carbon within various forest carbon pools or enhance the rate of recovery following a disturbance event without dramatically altering the character of forest ecosystems.