In view of evident changes in the reaction of European beech (Fagus sylvaticaL.) to environmental changes, five plots with young trees of the same age were established and studied on natural beech sites. Beech trees were equally distributed along the light gradient and were divided according to light conditions. The parameter used for evaluation of light conditions was the indirect site factor (ISF) obtained by the WinScanopy analysis. Three groups of canopy – light conditions were defined: stand conditions (ISF25). In all categories light saturation curves and curves describing dependence between intercellular CO2concentration in leaves and assimilation rate (A-Ci) were measured under the same fixed parameters (temperature, flow and CO2concentration, humidity, and light intensity) with Li-6400, to compare responses between different light categories and different plots within comparable light conditions.
Differences between canopy, edge and open area responses were confirmed with high significance on all plots as well as between studied forest complexes. On plots from Kočevje region, young beech indicated more shade tolerance, the response to increased light intensity and different CO2concentration was greater than the response of young beech on Pohorje plots within the same light intensities. Responses of trees on plots in managed and virgin forest were also different: young beech response in virgin forest plot was more shade-tolerant, compared to response of young beech from plots in managed forest.Glede uočenih promjena u reakciji bukve (Fagus sylvaticaL.) u odnosu na ekološke promjene, odabrano je pet ploha mlade bukve jednake starosti na prirodnim staništima, koje su bile jednakomjerno raspoređene na svjetlosnom gradijentu od zastora odrasle sastojine, šumskog ruba do svjetlosnih uvjeta na otvorenome. Kriterij za grupiranje bio je neizravni stanišni čimbenik (ISF), dobiven analizom hemisfernih snimaka pomoću sustava Win-Scanopy: zastor krošanja (ISF25), koji su bili jednaki na svim plohama. Za izmjere fotosintetskog kapaciteta, krivulje svjetlosnog zasićenja (0, 50, 250, 600 i 1200 µmol/m2s) i A-Ci krivulje (0, 100, 400, 700 i 1000 µmol CO2/l) dobivene su pomoću Li-Cor LI-6400 u kontroliranom okruženju (temperatura, protok i koncentracija CO2, zračna vlaga). Analize sadržaja dušika u lišću napravljene su Leco CNS-2000 analizatorom.
Potvrđene su signifikantne razlike u reakciji mladih bukava između odabranih kategorija, kao i između različitih šumskih kompleksa. Mlade bukve na plohama iz Kočevskog pokazale su veću toleranciju na sjenu, a odziv na porast koncentracije CO2je pri istim intenzitetima osvijetljenosti bio veći nego kod mladih bukava iz Pohorskog kompleksa. Odziv mladih bukava bio je signifikant no različit između prašume (Rajhenav) i gospodarske šume unutar istog šumskog kompleksa: odziv u prašumi pokazuje veću toleranciju na sjenu
