Alteration of light intensity in different natural and artificial forest types of Hyrcanian region
2011
Sagheb-Talebi, Khosro
Considering the importance of light as one of the important ecological factors in silviculture and forest ecology, this paper aims to present some information about light regime in different forest stands. For this purpose, sample plots were laid out in different natural forest types including Ironwood (Parrotia persica)-Hornbeam (Carpinus betulus), Chestnut leaved Oak (Quercus castaneifolia)-Hornbeam, pure and mixed Beech (Fagus orientalis), Hornbeam-Beech and mixed broadleaves stands as well as in some man made pure stands including chestnut leaved oak, Maple (Acer velutinum), Alder (Alnus subcordata) and Cypress (Cupressus sempervirens). Quantitative characteristics of trees were assessed and one hemispherical photo was taken with fisheye camera within the plots. The photos were analyzed with GLA. Results showed that the canopy openness varied from 9.6% to 29.4% in the natural stands and from 0.9% to 17.2% in the plantations. Relative light intensity varied between 11.8% (pure beech) and 35.9% (hornbeam-beech) in the natural stands and between 1.4% (pure cypress) and 25.1% (pure alder) in the plantations. The minimum Leaf Area Index (LAI=1.4) was computed in the hornbeam-beech stand, whereas the maximum (LAI=5.8) was found in the pure cypress plantation. A various range of sun flecks was observed within the studied stands from 20 sun flecks with 200 minutes of direct sun light in the ironwood-hornbeam stand up to 2100 sun flecks with receiving of 2 minutes direct sunlight per day in the pure alder plantation. The maximum received energy in the studied stand of the Caspian forests was 43 MJm-2 in June.
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