Bark beetles and wildfire: influence of overlapping disturbances on wood and light in a sub-boreal headwater system

Forest disturbances provide an important link between terrestrial and freshwater ecosystems. In this study I ask 1) how the recruitment of wood to streams varies depending on whether trees were dead or alive prior to a wildfire; and 2) what is the quantitative contribution of fallen wood spanning small streams to stream light. I found that wood recruitment is affected by overlapping, short-interval disturbances of insect outbreak followed by wildfire since being killed prior to fire makes a tree twice as likely to topple immediately post-fire. Additionally, the toppled wood lying above-stream provided a detectable buffer to incoming light in a post-fire landscape. The effects of disturbance history on stream communities and microclimate via wood warrants further study to improve our understanding of how landscape scale terrestrial processes are drivers of localized and watershed-scale changes to aquatic primary productivity and thermal variability.