The effect of fire intensity on the understorey species composition of two Pinus canariensis reforested stands in Tenerife (Canary Islands)

Abstract

Wildfire in the Pinus canariensis forest of Tenerife is of ecological significance, but has been little studied. Fire is considered an ecological catastrophe that should be prevented in Tenerife. The present study was designed to report the effects of fire intensity on understorey species composition as a means to evaluate this premise. Due to the effect of the site in the species composition, we suggest the use of multivariate analysis of the species composition under the effect of fire. These methods allow us to eliminate the sources of variability related with the site and to evaluate the fire intensity effect per se on species composition. P. canariensis were planted in the sites during the 1940s and 1950s for reforestation purposes, but no other management activities have been carried out in the last 30 years. The pine forest is a fire-prone ecosystem within which species have a high ability to regenerate after fire. Although the rate of fire has on the whole increased in recent years, the affected area is on an average much lower. Knowing this, our results suggest that a regular occurrence of fire as an internal process of the ecosystem, will favour and accelerate the change of the pine stands to more natural forests, as is the aim of the reforestation.