Importance of scale and process in forest disturbance legacies

Abstract

Ecological memory is the information and material legacies—the adaptations, individuals, and materials that persist after disturbance—that guide ecosystem response to disturbances. Resilience is directly related to ecological memory, and because resilience is desired in forest management, it is important to consider how ecological memory works. We propose that six spatial scales are needed to characterize ecological memory and its interactions with disturbance. These scales are: micro, tree, neighborhood, stand, meso and landscape. The nested hierarchy of microsites-tree-stand-landscape is well known, with widespread recognition of the need for diverse microsites, tree species and ages, and stand ages to create a managed landscape that harbors biodiversity. However, roles of the neighborhood and meso scales have been considered less often and have not been well integrated into overall legacy theory and its application to forest management. Here we show the key role of processes at these scales and their interactions with disturbance to maintain ecological memory, using cold-temperate and boreal forests from Minnesota, USA as a case study.