Simulated increases in fire activity reinforce shrub conversion in a southwestern US forest

By: , and 



Fire exclusion in historically frequent-fire forests of the southwestern United States has altered forest structure and increased the probability of high-severity fire. Warmer and drier conditions, coupled with dispersal distance limitations, are impeding tree seedling establishment and survival following high-severity fire. High-severity patches are commonly dominated by non-forest vegetation, a state that can be reinforced by subsequent fire events. We sought to determine the influence of fire probability on post-fire vegetation development in a severely burned landscape in New Mexico, USA. We used LANDIS-II to simulate three fire probability scenarios—historical fire probability, contemporary fire probability, and the mean of the two—with contemporary climate. As fire probability increased, the mean size of the largest fires and the mean landscape fire severity increased. These changes in fire characteristics resulted in decreased total aboveground biomass and photosynthetic capacity on the landscape after 50 years. Additionally, the distribution of individual species biomass shifted, with early successional species, especially those that resprout after fire, increasing as a fraction of total biomass with increasing fire occurrence. Counter to empirical data, our simulations did not show a conifer establishment limitation, suggesting a source of uncertainty that will need to be addressed to improve projections of forest dynamics under future climate. Even without limited conifer regeneration, continued increases in fire frequency are likely to favor resprouting species and result in a loss of forest biomass and ecosystem productivity in this southwestern forest landscape.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Simulated increases in fire activity reinforce shrub conversion in a southwestern US forest
Series title Ecosystems
DOI 10.1007/s10021-020-00498-4
Volume 23
Year Published 2020
Language English
Publisher Springer
Contributing office(s) Fort Collins Science Center
Description 12 p.
First page 1702
Last page 1713
Country United States
State New Mexico
Google Analytic Metrics Metrics page
Additional publication details