Equivalent clear cut area thresholds in extensively disturbed forests Andres Varhola (MSc started January 2008) The massive attacks that the mountain pine beetle (MPB) (Dendroctonus ponderosae) is causing to lodgepole pine (Pinus contorta) forests in British Columbia have generated ecological debate. Because of the known link between forest and hydrology, the latter has become a major concern in regards to this vast disturbance. In the absence of forests or when extensive disruption of their canopies such as the ones caused by MPB occur, transpiration and interception take place differently compared to other land-uses or healthy stands. Due to the nature of MPB attacks (gradual loss of needles during several years), changes in the tree canopies are responsible for the potential effects on snow interception and melting, raising important resource management questions. The problem arises because such an impact with unprecedented magnitude lacks the information necessary to get valid answers, either due to lack of models and/or the need of extensive information about forest attributes. The purpose of this research is to address the issues of a widespread insect disturbance as MPB, its effects on forest structure and consequently on snow hydrology, the lack of models to understand the impacts plus the availability of a remote sensing approach, to produce a new suite of methods to link these aspects and provide proper analysis tools. The methodology consists in describing disturbed forest structure attributes with detail in a 200 km transect between Quesnel and Vanderhoof —both using remotely sensed (LiDAR) and ground based inputs— and correlating the key variables with real snow accumulation and melting rates.               The innovative tools for this research correspond to LiDAR technology (laser scanning that can derive forest structure metrics) which can be combined with aerial photography to elaborate 3-D illustrations of the forests (picture in the left), and prototype sensors that continuously measure snow depth, air temperature and humidity (picture in the right).

Landscape pattern analysis of mountain pine beetle infestation using a multi-date image time series Steve Gillanders (MSc started May 2007) The current epidemic of mountain pine beetle (Dendroctonus ponderosae Hopkins) in British Columbia presents a considerable challenge to forest resource managers. As a result of anthropogenic and climatic influences on the lodgepole pine ecosystem, mountain pine beetle populations in the central interior of British Columbia have reached epidemic proportions leading to tree mortality at a regional scale.  While several management options exist to minimize the impacts of mountain pine beetle, knowledge of the spatial and temporal patterns of infestation at the landscape level has the potential to contribute to the effectiveness of these techniques and lead to new management options. Furthermore, this information is critical to predict the effects of landscape changes on both biodiversity and ecosystem functioning and services. Mountain pine beetle-induced tree mortality and operational logging (including related salvage and mitigation activities) lead to habitat fragmentation at both a landscape and local scale. This has important ecological implications related to habitat abundance, biodiversity, and the influence that changes in spatial pattern have on a variety of ecological processes. Using a time-series of nine Landsat images spanning a period of 15 years positioned in the central interior of British Columbia, landscape pattern indices will be used to identify and measure changes in the degree of landscape fragmentation and connectivity associated with both beetle infestation and logging. The information gained from these analyses will provide the means to characterize forest conditions prior, during, and subsequent to mountain pine beetle infestation and will contribute to a better understanding of mountain pine beetle outbreaks, forest stand mortality, and landscape disturbance and recovery.