Undergraduate Honors Theses

Thesis Defended

Spring 2013

Document Type

Thesis

Department

Ecology and Evolutionary Biology

First Advisor

Dr. Carol Wessman

Abstract

Compound disturbances occur when multiple disturbances happen in rapid succession, and may result in changes to ecosystem recovery processes. Activities performed by management agencies ,such as salvage-logging, following severe disturbances may act as a compound disturbance by altering the ecosystem’s recovery mechanisms. The site of the present study, located in Routt National Forest, Colorado, sustained a catastrophic blowdown event that impacted over 10,000 ha in 1997 and was partially salvage - logged between 1998 and 2001. The present study evaluates the interacting effects of these two disturbance events on soil characteristics, seedling regeneration, growth and density, and any changes to community composition. These measurements were recorded within ten heavily wind-damaged Picea-Abies stands, ten salvage - logged blowdown stands, and ten intact control stands. While soil characteristic results suggest a long-term significant difference between treatments, trends initially observed post disturbance generally diminished over time. Similarly, regeneration characteristics were significantly different between treatments but less significant so than for the short-term effects. This apparent differential recovery suggests that salvage-logging following severe blowdown results in reduced regeneration and in lasting alterations of soil properties. The present findings thus suggest that salvage-logging does act as a compound disturbance. With climate change, more frequent and severe disturbances may occur, and it is thus necessary for management agencies to quantitatively evaluate the potential compounding effects of their decisions.

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