Patterns of pine regeneration following a large, severe wildfire in the mountains of southern California

Abstract

We examined establishment patterns of pines following a large, severe wildfire in the Peninsular Ranges of southern California, USA. The October 2003 Cedar Fire caused 98% pine mortality. In this study, we asked (i) where did seedlings establish and survive in formerly forested areas of the Cuyamaca Mountains 5 years following the high severity fire and (ii) what factors were associated with the spatial pattern of seedling establishment? Factors analyzed were pre-fire vegetation type, fire severity, post-fire vegetation characteristics, topography (slope, aspect, and elevation), and mapped soil type. We used a unique belt-transect survey method following the existing trail network that resulted in a representative sample of post-fire environments. Almost 1300 100 m × 20 m quadrats were searched in 2008–2009, one third of which supported juvenile pines. Regeneration primarily consisted of Coulter pine ( Pinus coulteri D. Don), a weakly serotinous pine that was establishing at densities of 5–2320/ha on half of the quadrats where it had occurred pre-fire. Pinus coulteri regenerated in areas burned at high severity where pre-fire pine cover was high and its abundance was positively associated with higher elevation and cover of bare soil. In contrast, minimal regeneration of nonserotinous pines occurred patchily in areas that were not severely burned.