Forest Ecology

Maintaining productivity, biodiversity, and wildlife habitat.

  • H.J. Andrews LTER landscape of different aged stands.
  • Douglas-fir forest ecosystem.
  • Carbon storage in coarse woody debris in Pacific Northwest forest ecosystems.
Research

As a graduate student in the Powell Lab I developed model systems of nitrogen cycling in forest ecosystems. My modeling research emphasized the role of local, meter-scale variation in ecosystem properties on the evolution of model results. I demonstrated that, although modeling the spatial variation that was observed in Douglas-fir forests affected the detailed pattern of modeled nitrogen distribution, stand-scale mean nitrogen pools remained constant whether model simulations included or excluded spatial heterogeneity. The application of my models to Douglas-fir forest management demonstrated that 80-year harvest rotations common on federal lands allowed modeled nitrogen pools to return to pre-perturbation steady state conditions, while 40-year harvest rotations common on private lands resulted in a chronic decline in forest productivity.

My modeling approach focused on simplified, dynamic models of nitrogen cycling between plant, microbe, and soil phases; model systems which are amenable to both analytic and simulation techniques. By studying simplified model systems, it is possible to attribute system behavior to a specific process or relationship. Ultimately, a thorough exploration of patterns that result from these tractable models can be used to link simplified model systems into a complex framework for application to environmental concerns.

In order to model spatial heterogeneity in biogeochemical properties, I documented natural heterogeneity of carbon and nitrogen in forest ecosystems of the HJ Andrews LTER in the western Cascades of Oregon. I collected and analyzed soil, litter, and plant samples from managed and old-growth Douglas-fir forests and applied this data as a template for imposing nutrient variation in my model systems.

I began my modeling work as an undergraduate in Ecology and Evolutionary Biology at Princeton University. I worked with Professor Stephen W. Pacala on SORTIE, a model of forest community dynamics. My research focused on modifying the growth module and on exploring potential climate change scenarios.

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