Abstract:
The ability of vegetation to recover from a fire event occurs at different rates depending
on environmental conditions and land management techniques. Immediately following a
fire, short-term vegetation monitoring helps land managers plan for and apply appropriate
land treatments. Long-term post-fire vegetation assessments are less common, but are
also needed to understand the impact of management techniques on vegetation recovery
over time. A challenge to long-term monitoring is that traditional field assessments can
be resource intensive. The purpose of this study is to examine the ability of remote
sensing based vegetation indices to capture annual and long-term vegetation recovery for
three fire sites in the Winnemucca District of Nevada. The study uses Landsat Thematic
Mapper imagery from 1985-2005 to calculate the Normalized Difference Vegetation
Index (NDVI) and a version of the Modified Soil Adjusted Vegetation Index (MSAVI2)
for the three fire sites. The results of this study suggest that annual differences in vegetation indices provide an indication of changing vegetation response, but on their
own are insufficient to categorize whether this signifies a change in phenology or
vegetation type. The study concludes seasonal intra-annual analysis is necessary as a first
step to identifying the different stages of plant phenology before comparison of
vegetation change can occur across years. The long-term trend analysis used in this study
identified areas experiencing a long-term pattern of change after fourteen years, but not
after twenty. Further studies would be required to confirm whether a long-term trend
corresponds to a change in vegetation type.
