Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

New Biomass Estimates for Chaparral-Dominated Southern California Landscapes

Version 1 : Received: 17 March 2021 / Approved: 18 March 2021 / Online: 18 March 2021 (10:15:42 CET)

How to cite: Schrader-Patton, C.; Underwood, E.C. New Biomass Estimates for Chaparral-Dominated Southern California Landscapes. Preprints 2021, 2021030467 (doi: 10.20944/preprints202103.0467.v1). Schrader-Patton, C.; Underwood, E.C. New Biomass Estimates for Chaparral-Dominated Southern California Landscapes. Preprints 2021, 2021030467 (doi: 10.20944/preprints202103.0467.v1).

Abstract

Chaparral shrublands are the dominant wildland vegetation type in southern California and the most extensive ecosystem in the state. Disturbance by wildfire and climate change have created a dynamic landscape in which biomass mapping is key in tracking the ability of chaparral shrub-lands to sequester carbon. Despite this importance, most national and regional scale estimates do not account for shrubland biomass. Employing plot data from several sources, we built a random forest model to predict above ground live biomass in southern California using remote sensing data (Landsat NDVI) and a suite of geophysical variables. By substituting the NDVI and precipi-tation predictors for any given year we were able to apply the model to each year from 2000-2019. Using a total of 980 field plots, our model had a k-fold cross validation R2 of 0.51 and a RMSE of 3.9. Validation by vegetation type ranged from R2 = 0.17 (RMSE=9.7) for Sierran mixed conifer to R2 = 0.91 (RMSE = 2.3) for sagebrush. Our estimates showed an improvement in accuracy over a two other biomass estimates that included shrublands, with an R2 = 0.82 (RMSE = 4.7) compared to R2 = 0.068 (RMSE = 6.7) for a global biomass estimate and R2 = 0.29 (RMSE = 5.9) for a regional biomass estimate. Given the importance of accurate biomass estimates for resource managers we calculated the mean year 2010 shrubland biomass for the four national forests which ranged from 3.5 kg/m2 (Los Padres) to 2.3 kg/m2 (Angeles and Cleveland). Finally, we compared our estimates to field-measured biomass from the literature summarized by shrubland vegetation type and age class. Our model provides a transparent and repeatable method to generate biomass measure-ments in any year, thereby providing data to track biomass recovery after management actions or disturbances such as fire.

Subject Areas

Biomass; Carbon sequestration; Chaparral; NDVI; Fire frequency; Mediterranean-Type Climate Regions; National Forests

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 0
Metrics 0


×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.
We use cookies on our website to ensure you get the best experience.
Read more about our cookies here.