Changes in fire intensity have carry-over effects on plant responses after the next fire in southern California chaparral

Journal of Vegetation Science
By: , and 

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Abstract

Question

Do variations in fire intensity within a stand determine changes in fire intensity and plant demographics in a subsequent fire?

Location

San Diego (CA, USA); chaparral dominated by Adenostoma fasciculatum (resprouter) and Ceanothus greggii (seeder).

Methods

In 2003, a wildfire burned a young (16-yr-old) stand containing a set of experimental plots burned in 1987 with various levels of fire intensity. In 2004, all the 1987 plots were sampled for Adenostoma survival and the recruitment of both species. Similar measures were carried out in the adjacent old (75-yr) stand. Fire intensity in 2003 was estimated by a surrogate fire severity measure [minimum diameter of burned branches (branch diameter)].

Results

In the young stand, branch diameter in 2003 was similar to the control plots in 1987, but lower than in the old stand. Fire intensity in 1987 did not significantly affect branch diameter in 2003. Survival of Adenostoma in the young stand was very low, much lower than after the 1987 burn and that in the old stand. Fire intensity in 1987 did not affect Adenostoma survival. Recruitment in Adenostoma increased, and in Ceanothus decreased, with increased fire intensity in 1987.

Conclusions

We demonstrate that there is a carry-over effect of fire intensity across a whole fire cycle on plant recruitment of the two dominant species. The 2003 fire partially reversed the relative effects on recruitment caused by elevated fire intensity in 1987. Arguably, this effect was driven by the contrasted relationships of the two species to fire intensity. Adenostoma survival in the young stand was much lower in 2003 than in 1987, despite similar branch diameter, and was also lower than in the old stand, despite higher branch diameter in this case. The causes of such mortality are unknown.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Changes in fire intensity have carry-over effects on plant responses after the next fire in southern California chaparral
Series title Journal of Vegetation Science
DOI 10.1111/j.1654-1103.2012.01466.x
Volume 24
Issue 2
Year Published 2013
Language English
Publisher International Association for Vegetation Science
Publisher location Uppsala, Sweden
Contributing office(s) Western Ecological Research Center
Description 10 p.
First page 395
Last page 404
Country United States
State California