Malcolm P. North

My current research is focused on the effects of disturbance on the structure, composition and function of Sierra Nevada mixed-conifer ecosystems. Mixed-conifer and ponderosa pines forests have been seriously impacted by a century of fire suppression and selective logging. In many areas this has reduced the number of large, old trees and increase stem densities, particularly of shade-tolerant species such as white fir and incense cedar. Fire and in some cases thinning, will be needed to restore historic forest conditions, however, the effect of these two restoration methods on ecosystem structure and function has not been systematically compared. Disturbance alters a forest's scaffold initiating changes in vegetation pattern, composition, microclimate and edaphic conditions. These in turn affect fundamental ecosystem processes (respiration, decomposition, nutrient cycling), trophic structure (invertebrate and fungal based food chains) and wildlife habitat. While many of these processes are difficult to measure, they are often strongly linked to forest structure and composition. Establishing the linkage between ecosystem function and stand structure can provide forest managers with a surrogate measure of the impacts of their activities on ecosystem health.

My research has focused on the influence of forest structure, pattern and composition on ecosystem function and wildlife habitat. I've worked on identifying the particular structural features associated with spotted owl foraging and nesting, and the abundance of truffles, the main food source for the owl's prey, in these stands. With this interest I've worked on methods for describing and quantifying forest canopy structure, and how this structure varies in forest stands at different successional stages.

In the future, I plan to explore carbon stocks and how carbon emissions may be reduced as the global climate changes.