 |
Impact of Wind and Salvage-Logging on Ecosystem Dynamics in a Subalpine Forest |
||
|
Evidence that salvage-logging after wind disturbance delays ecosystem recovery As the earth system incurs greater and more frequent disturbances, understanding the mechanisms that enable an ecosystem to regenerate following disturbance is critical to sustaining ecosystem function. This study examines the response of a subalpine forest ecosystem to both a natural and anthropogenic disturbances. The study site is a subalpine forest that sustained a catastrophic blowdown in 1997; portions of the blowndown forest were salvage-logged in 1999. Results from this four-year study indicate that salvage-logging significantly reduced the winddisturbed ecosystem's ability to regenerate into subalpine forest. Soil erosion was significant following salvage-logging activities, but not following the 1997 windstorm. Consequently soils in salvage- logged areas contain less organic and inorganic nitrogen than unlogged blowdown areas. Logging removed large volumes of readily decomposable leaf material, which increased nitrogen cycling rates in blowdown areas relative to control areas of intact forest. Plant-available nitrogen was also significantly elevated in blowdown areas relative to intact forest areas. Salvagelogging also altered the soil microclimate by removing downed wood which provides shade to re-growing vegetation. Summertime soil temperatures in salvage-logged areas routinely reached 30 C and were on average 10 C higher than in unlogged areas. Consequently, vegetation diversity and cover were reduced in salvage-logged areas, and greatest in unlogged blowdown areas. Similarly, tree seedling density is significantly reduced in salvage-logged areas relative to blowdown areas due to the mechanical destruction of seedlings during the logging process. The results of this study highlight the importance of organic matter in maintaining biotic control over ecosystem recovery of nutrient cycling in a wind-disturbed forest. Furthermore, this study shows that subalpine forests are relatively resilient to wind disturbance. Finally, salvagelogging appears to have the unintended consequence of delaying ecosystem recovery of this wind-disturbed forest by removing tree seedlings and soil organic matter, and by altering microclimate conditions. Media reports of this research were published in Discover Magazine, the Arizona Daily Sun, Rapid City Journal, the Colorado Daily, the Environmental News Network, and several other media outlets. |
CIRES Research Theme Project Personnel Funding Source(s) Publications Rumbaitis-del Rio, C.M. and Wessman, C.A.. Biogeochemical consequences of catastrophic wind disturbance and salvage logging in a subalpine forest ecosystem. To be submitted to Ecological Applications. |
|
216 UCB