Title
Analysis of Vegetation Regrowth: One Year After the Camp Fire
Author

Nate Cox
American River College, Geography 350: Data Acquisition in GIS; Fall 2019
Abstract

I used image classification on a study area surrounding Paradise, CA, before and after the Camp Fire. I was able to determine what vegetation was lost, and what has grown back after one year.
Introduction

2018 saw the deadliest and most destructive wildfire in California history, consuming approximately 240 sq. miles, 18,000 structures, and 84 lives within a 17 day period. I wanted to see how Paradise, and surrounding areas affected by the fire, were healing one year later.

Camp_Fire_Pic


Background

Results highlight significant decreases in tree regeneration in the 21st century. Annual moisture deficits were significantly greater from 2000 to 2015 as compared to 1985–1999, suggesting increasingly unfavourable post-fire growing conditions, corresponding to significantly lower seedling densities and increased regeneration failure. Dry forests that already occur at the edge of their climatic tolerance are most prone to conversion to non-forests after wildfires. Major climate-induced reduction in forest density and extent has important consequences for a myriad of ecosystem services now and in the future. (Ecology Letters, 2017)
Methods

To begin this analysis I first downloaded LANDSAT 8 images, that covered the study area, from the USGS EarthExplorer website. The images I selected were taken on 10-07-2018(one month pre-fire) and 10-26-2019(eleven months post fire). After putting the images into an ArcGIS Pro project the next step was to run an object-based image classification. I created four categories to classify the pixels; forest, shrub, barren, and water. Once the image classification was complete I ran the Zonal Histogram tool which produced the exact count of pixels within each category. With this exact count I was able to compare the percentage of landover type, and discover how things had changed.

10-07-18 LANDSAT 8

10_07_18_Pic


10-26-19 LANDSAT 8

10_26_19_Pic


Results
I observed the following changes; Barren land increased by 5% from 20% to 25%, Shrub type landcover increased by 12% from 18% to 30%, forest landcover decresed by 17% from 56% to 39%, and hydrologic landcover remained the same at 6%.

10-07-2018 Cell Count Forest Shrub Barren Water
1,124,802 369,635 396,874 116,204

10-26-2019 Cell Count Forest Shrub Barren Water
774,947 605,157 502,021 125,390


Figures and Maps
10_07_18_Chart


10_26_19_Chart


10-07-18 classified


10_07_18_Classified


10-26-19 classified


10_26_19_Classified


Analysis
Initially I had the idea of running this analysis on images taken every two months. Which would have produced a more accurate regrowth timeline. Unfortunatley due to snow cover this was not possible. However the results are still accurate.
Conclusions
These results are indicative of typical regrowth patterns following large fires. A total recovery would consist of the same mix of grasses, trees, and shrubs. Typically grasses and short shrubs are the first to grow, followed by small trees. Total recovery may take decades. But the landcover that grows back is dependent on the region’s climate conditions. Drought resistant shrubs may replace trees that require more water. With the current changing climate, it is hard to predict if a total recovery is even possible.
References
USGS Earth Explorer

Camille S. Stevens-Rumann, Kerry B. Kemp, Philip E. Higuera, Brian J. Harvey, Monica T. Rother, Daniel C. Donato, Penelope Morgan and Thomas T. Veblen. (2017), Evidence for declining forest resilience to wildfires under climate change, Ecology Letters.

Appendices
Material may be included in various appendix sections at the student’s option.