Impact of light and position in gap on quantitative and qualitative characteristics of oak (Quercus castaneifolia C.A.M) seedlings in Loveh, Gorgan.

Chestnut leaved oak (Quercus castaneifolia C.A.M) is one of the most commercial tree species in the Hyrcanian forests of Iran and Caucasus. Having a good knowledge of tree species habitat is essential for silvicultural intervention and treatments of different forest stands. Light has been accepted as one the important ecological factors which can be altered within silvicultural intervention that could affect the tree and wood quality. This paper aimed to study the impact of light on oak seedlings within different gap sizes and position within the gap. For this purpose, 10 gaps were selected in the Loveh oak stands, near Gorgan in eastern Hyrcanian region. Nine microplots, each 4 m2, were laid out from the gap center to the gap edge and under the mariginal tree in four directions. Hemispherical photos were taken over each microplot and the data were analysed with GLA. Quantitative (collar diameter, height, shoot length and crown width) and qualitative (mode of branching, stem form, crown shape, vitality and health) characteristics of seedligs were measured or assassed and were then analysed by SPSS and EXCEL softwares. Results showed that mean realtive light intensity varied between 9.1% under the mariginal trees and 31.7% in the gap center. The maximum of mean annual height increment of seedlings (8.7±1.2 cm) was measured in the medium gap size (200 to 500 m2). The prportion of oak seedlings at the medium gap sizes was higher than in small (< 200 m2) and large (>500 m2) gaps. The average relative light intensity at the medium gap size was computed about 20.1±7.1 %. Resultes indicate that despite categorizing chestnut leaved oak as a light demanding tree, it's seedlings need shadow in the early stages. Therefore medium gap size could be introduced to achieve better quantitative and qualitative results.