Understanding long-term post-fire regeneration of a fire-resistant pine species

The long-term effect of forest fires in the regeneration of Pinus canariensis was studied. Forest fires had little long-term effects on seed production, seedling germination and seedling mortality. The characteristics of different forest stands across the island had influence in some of the regeneration parameters studied. Despite the importance of forest regeneration dynamics after wildfires, little is known about its long-term evolution after a fire. We tested the effect of fire on the long-term regeneration dynamics of P. canariensis. In a forest fire chronosequence of five fire ages (time elapsed since the last fire) plus an unburned stand, we monitored seed production, seedling germination and mortality during 2 years. We detected significant differences among forest stands in seed production, seedling density and mortality but not in germination and turnover. These differences were unrelated to fire age. Seed production was conditioned by the number of large adults and elevation, germination by diameter at breast height (DBH) and soil nitrogen content and mortality by DBH. We detected no long-term effect of fire on the regeneration of P. canariensis in natural pine forest; however, during the first years after fire, modification of nitrogen availability in soil can reduce germination. Stand conditions in natural pine forests appear to mainly control regeneration dynamics. The regeneration strategies and fire-resistance traits of this species have ensured its persistence in the long term.