The increasing number of fires, fire size, and decreasing fire recurrence intervals are major environmental factors in Mediterranean-type ecosystems, and are known to affect Aleppo pine (Pinus halepensis) forests. The fact that in the Mediterranean basin most fires are man-made increases the danger of fires recurring at short intervals. P. halepensis is a lowland Mediterranean species with a disjunct east-Mediterranean population in Israel and Jordan, with the Mount Carmel population as one of the few native pine forests in Israel.Here we assess the effect of recurrent fires on the regeneration and spatial distribution of P. halepensis, as reflected by the number of trees at 18 sites, according to the number of previous fires and the time elapsed since the last fire. At each site, 100×1m-2 squares were randomly placed to record numbers of trees. Results indicate that in most cases the number of pines per unit area is inversely proportional to the number of fires. For example, tree density in sites that were last burnt during the spring of 2005, varied between 1.2treesm-2 (single-fire), and 0.25 and 0.39treesm-2 in two- and three-fire sites, respectively, while in the unburnt control sites pine density was 0.46treesm-2. The effect of recurrent fires, however, was particularly evident when the time interval between two successive fires was shorter than 20years - the time needed for P. halepensis trees to mature and produce an adequate canopy seed bank. Apparently, not only the number of fires, but also the fire season has a major effect on regeneration dynamics. Although frequent recurrent fires reduce the number of pines at the site, their total elimination from any site never occurred, demonstrating the resilience of this species and its accommodation to short-interval recurrent fires. These results are crucial for establishing post-fire management programmes in fire-prone Mediterranean ecosystems.
Bibliographical noteFunding Information:
This research was supported by a grant from the Israeli Nature Reserves Authority and the National Parks Protection Authority (NPA), and by a grant from the Mount Carmel Research Center. We would like to thank Amit Kliner, Lior Negreen, and Tal Porat for their help in the field work, and Natan Elbaz, Eyal Cohen, and Naftali Gedalyahu of the Israel Nature and Parks Authority-Carmel Park for their assistance in the field work. The Jewish National Fund provided aerial photographs and other valuable data. Dr. Yuval Sapir and Prof. Ido Izhaki provided major help in the statistical analyses. We thank Noga Yoselevich for the cartography and graphic editing of the paper.
- Mediterranean ecosystems
- Mount Carmel
- Pinus halepensis
- Recurrent forest fires
ASJC Scopus subject areas
- Nature and Landscape Conservation
- Management, Monitoring, Policy and Law