Forest disturbance interactions and successional pathways in the Southern Rocky Mountains

Forest Ecology and Management
By: , and 

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Abstract

The pine forests in the southern portion of the Rocky Mountains are a heterogeneous mosaic of disturbance and recovery. The most extensive and intensive stress and mortality are received from human activity, fire, and mountain pine beetles (MPB;Dendroctonus ponderosae). Understanding disturbance interactions and disturbance-succession pathways are crucial for adapting management strategies to mitigate their impacts and anticipate future ecosystem change. Driven by this goal, we assessed the forest disturbance and recovery history in the Southern Rocky Mountains Ecoregion using a 13-year time series of Landsat image stacks. An automated classification workflow that integrates temporal segmentation techniques and a random forest classifier was used to examine disturbance patterns. To enhance efficiency in selecting representative samples at the ecoregion scale, a new sampling strategy that takes advantage of the scene-overlap among adjacent Landsat images was designed. The segment-based assessment revealed that the overall accuracy for all 14 scenes varied from 73.6% to 92.5%, with a mean of 83.1%. A design-based inference indicated the average producer’s and user’s accuracies for MPB mortality were 85.4% and 82.5% respectively. We found that burn severity was largely unrelated to the severity of pre-fire beetle outbreaks in this region, where the severity of post-fire beetle outbreaks generally decreased in relation to burn severity. Approximately half the clear-cut and burned areas were in various stages of recovery, but the regeneration rate was much slower for MPB-disturbed sites. Pre-fire beetle outbreaks and subsequent fire produced positive compound effects on seedling reestablishment in this ecoregion. Taken together, these results emphasize that although multiple disturbances do play a role in the resilience mechanism of the serotinous lodgepole pine, the overall recovery could be slow due to the vast area of beetle mortality.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Forest disturbance interactions and successional pathways in the Southern Rocky Mountains
Series title Forest Ecology and Management
DOI 10.1016/j.foreco.2016.05.010
Issue 375
Year Published 2016
Language English
Publisher Elsevier Science Pub. Co.
Contributing office(s) Geosciences and Environmental Change Science Center
Description 11 p.
First page 35
Last page 45
Country United States
State Colorado, New Mexico, Wyoming
Other Geospatial Rocky Mountains
Online Only (Y/N) N
Additional Online Files (Y/N) N