Short Communication. Recruitment and early growth of Pinus pinaster seedlings over five years after a wildfire in NW Spain

L Calvo,E Luis-Calabuig,L Valbuena,O Torres

doi:10.5424/fs/2013223-04623

Abstract

Aim of study: The main aim of this study was to analyse the post-fire recruitment and growth of Pinus pinaster seedlings during the first five years after wildfire and also to analyse the effects of climatic conditions on the survival of P. pinaster seedlingsArea of study: The study area was located in a P. pinaster stand in León province (NW Spain) burned in 1998.Material and Methods: Three sites in the burned area were selected. In each site three permanent transects of 20m x 1m were placed. In each transect, twenty 1m2 sampling units were marked and the number and height of each pine seedlings was recorded at 7, 8, 9, 10, 11, 12 months and 2, 3, 4 and 5 years after the wildfire. The soil of study area is Cambisol.Mean results: Mean Pinus regeneration densities varied between 33.2 seedlings/m2 after 7 months and 6 seedlings/m2 five years after wildfire. In this P. pinaster stand, maximum mortality appeared during the summer months in the first year of regeneration. There was a significant increase in seedling height associated with a decrease in density.Research highlights: The post-fire recruitment is considered enough to ensure good natural Pinus pinaster forest regeneration. In the short term post-fire management strategy in this type of forest could be the remaining branches with cones of burned trees that allow the dissemination of the seeds during the first few years after fire and ensure natural regeneration.Keywords: Fire effects; natural regeneration; León province (NW Spain); seedlings density; growth and survival.

Highlights

The population of Pinus pinaster Ait. in the Sierra de Teleno (NW Spain) is characterised by high frequency lightning fires (>1 fire 100 km–2 year–1) (Gil et al, 1991, Tapias et al, 2004)
The study area is located in a P. pinaster stand in the Sierra del Teleno, León province (NW Spain), at an elevation of 1,100 m
The density of seedlings is higher than those reported by other authors (Gallegos et al, 2003) in studies carried out in a P. pinaster forest in the south of Spain

Summary

Introduction

The population of Pinus pinaster Ait. in the Sierra de Teleno (NW Spain) is characterised by high frequency lightning fires (>1 fire 100 km–2 year–1) (Gil et al, 1991, Tapias et al, 2004). Since P. pinaster is a seeder species and has fixed serotinity in this population (Tapias et al, 2004), its regeneration relies on the recruitment of a post-fire cohort of seedlings. It produces an abundant yearly seed crop, part of which is held in serotinous cones, constituting a cumulative canopy seed bank, as occurs in other types of Mediterranean pine species (de las Heras et al, 2002). Post-fire seed germination takes place almost exclusively during the first postfire stages, as in the case of P. halepensis (Arianoutsou and Ne’eman, 2000). Seedling mortality has been reported in the first post-fire year (Thanos et al, 1996) or at some locations during the second year (Ne’eman, 1997)

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