Surface wildfire in conifer broad-leaved forests of the Hyrcanian region of Iran: short-term effect on regeneration and damage to trees

Abstract

Wildfires in recent years have resulted in degradation and damage to the Hyrcanian forest ecosystems in Northern Iran. This study was carried out to investigate fire damage to trees and changes in regeneration in early-season growth after wildfires in the Golestan Province. For this purpose, a random sampling plan was used, with 60 circular plots (each plot is 1000 m2) for each stand and 240 circular (25 m2) plots for regeneration within the burned and unburned areas, respectively. In each plot, habitat factors were recorded, including crown canopy percentage, forest stratum, herb-layer cover percentage, species, diameter at breast height, tree and regeneration quality, and quantity of seedlings and saplings. Our results showed that bark is an important factor for fire resistance in Hyrcanian forests. The Persian ironwood and European yew has the highest and lowest fire resistance; as broad leave species are more resistant than needle leaf species. Density of regeneration in unburned area was higher than burned area, and statistical analysis showed significant differences for all species between two areas. Fire effects on sapling were different among species which indicates sapling has different resistance to fire. Forest floor fuel, season, stand composition and microclimate have more effects on fire severity while environmental factors, regeneration and management practices shaping future composition stands.