engleski

Microclimate in uneven-aged forest ecosystems in Gorski kotar Croatia with different vitality of silver fir (Abies alba Mill.) trees

Microclimate of forest ecosystems depends on macroclimate, forest stand structure, tree species, crown defoliation, as well as relief characteristics. Tree dieback and consequent salvage cut of such trees changes the morphology of forest stand, canopy structure and stand structure of uneven-aged forests. Salvage cutting is a frequent operation to remedy the dieback of silver fir trees (Abies alba Mill.). The paper shows results of microclimate research in the area of Gorski Kotar (mountainous Croatia), in three vital silver fir forest stands and in the three forest stands of diminished vitality. Forest stand vitality was determined on a basis of average crown defoliation of the silver fir trees and frequency of salvage cutting. For vital forest stands, average crown defoliation it was < 60 % and in cutting cycles there were one regular cut. For stands with diminished vitality, average crown defoliation was > 60 % and there were three salvage cuts in cutting cycles. Air temperature, relative air humidity, precipitation, solar radiation, relative light intensity, wind speed, potential evapotranspiration, as well as air temperatures and soil volumetric water content in beech-fir forest ecosystem were compared and analyzed. As a result of significant crown defoliation and tree dieback of silver fir in the research area, salvage cuts were frequent. The consequence is interrupted and incomplete canopy in stands of diminished vitality. In such stands there has been a change in forest microclimate. In stands of diminished vitality was found higher percentage of light, higher air temperature, solar radiation, relative light intensity, wind speed and potential evapotranspiration in comparison to vital stands of silver fir. Average air humidity and soil volumetric water content were lower in diminished forest stands in comparison to vital stands. Differences between microclimatic elements were significant (p<0.05), except for wind speed. Knowing how ecological factors effect and how members of ecosystems react to those factors is crucial in order to support natural functioning of forest ecosystem under human management.

silver fir, tree and stand vitality, microclimate

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