Soil Nutrient, Woody Understory and Shoot and Root Growth Responses of Pinus brutia Ten. Saplings to Fire

Nine years after a wildfire, above- and below-ground morphology of Pinus brutia Ten. saplings and the microsite factors prevailing in understorey (unburned area) and postfire conditions (burned area) of the Forest Park of Thessaloniki were studied. Major stand characteristics (density, tree canopy cover, tree height, crown height, and diameter) were measured in the unburned area. Light and soil conditions as well as plant cover of woody species were recorded in both areas (burned and unburned). A random sample of pine saplings, of uniform age, was taken from both burned and unburned areas, and their above-ground (height, diameter, number and total length of branches, needle biomass) and below-ground morphological characteristics (taproot length, total length of coarse and fine roots, and number of coarse roots) were measured. Data analysis showed that above- and below-ground morphology of pine saplings was adversely affected in saplings grown in understorey conditions, compared to those grown in postfire conditions. P. brutia is a shade-intolerant tree species and thus the light conditions seem to be the critical factor affecting the growth of pine saplings. Light is not a limiting factor in the burned area compared to the understorey, where density of the tree canopy limits available light.