The effect of disturbance on biophysical processes and carbon cycling is not well-understood for the boreal forest. Fire, insects, and now logging clearly affect the biophysical and ecophysiological dynamics of vast areas in the boreal region. Large-scale logging, in particular, is a newcomer to the boreal region, and can be expected to increase in impact in the next century, in response to human demand for forest products.

Because of the long time frames involved, it is difficult to assess the full importance of the successional processes that are set in motion by these disturbances. In this study, a chronosequence field study, data synthesis, and ecosystem modeling approaches are combined to examine the effects of logging on Canadian boreal forests during succession. A chronosequence of environmentally similar jack pine (Pinus banksiana Lamb.) stands logged at four different times in the past century and a mature unlogged stand established by wildfire over 70 years ago will be studied to determine the carbon budgets and net ecosystem exchange (NEE) of the stands. This empirical data will be used to test a conceptual model, stated in the form of hypotheses, for the development of NEE and its components during post-logging succession in a jack pine stand. A synthesis of results for similar studies which looked at carbon cycling following logging in other boreal forest communities will be compiled, allowing the conceptual model to be extended to other types of logged stands.

Aspatially explicit data set of land cover change for Canadian boreal forests affected by logging since the early 1900s will be produced using a combination of remote sensing, ground-based data, and historical harvest records. Next, a process-based terrestrial ecosystem model, IBIS (Integrated Biosphere Simulator), will be evaluated for the jack pine chronosequence and other sites in various stages of succession in the Canadian boreal region. The measurement-derived calculations for major components of the carbon budget (net primary productivity, soil surface CO2 flux, heterotrophic respiration, and NEE) will be compared to analogous model-derived estimates. Once IBIS has been tested for the jack pine age sequence and other boreal forest sites, it will be used to derive past carbon budgets for all areas of the Canadian boreal forest affected by logging since the early 1900s, using the data set produced earlier. During the final stages of this study, I will extend the analysis to explore the potential effects of multiple logging scenarios on future carbon budgets, including effects of global climate change scenarios.