ABSTRACT
Light requirements and spatial distribution of major forest tree species in Turkey hasn’t been analyzed yet. Continuous surface solar radiation data, especially at mountainous-forested areas, are needed to put forward this relationship between forest tree species and solar radiation. To achieve this, GIS-based modeling of solar radiation is one of the methods used in rangelands to estimate continuous surface solar radiation. Therefore, mean monthly and annual total global solar radiation maps of whole Turkey were computed spatially using GRASS GIS software “r.sun” model under clear-sky (cloudless) conditions. 147498 pure forest stand point-based data were used in the study for calculating mean global solar radiation values of all the major forest tree species of Turkey. Beech had the lowest annual mean total global solar radiation value of 1654.87 kWh m-2, whereas juniper had the highest value of 1928.89 kWh m-2. The rank order of tree species according to the mean monthly and annual total global solar radiation values, using a confidence level of p < 0.05, was as follows: Beech < Spruce < Fir species < Oak species < Scotch pine < Red pine < Cedar < Juniper.The monthly and annual solar radiation values of sites and light requirements of forest trees ranked similarly.
ABSTRACT
Soil degradation is perceived as a major threat in the Mediterranean region due to land use pattern and projected climate change. As the high altitudinal mountainous lands are sensitive lands, the land use patterns at Alaçam mountains were investigated in this study. The assessment of land use distribution is arranged with the altitude, exposure, slope and bedrock parameters. The spatial database of project was created using GRASS GIS open source software (GRASS Development Team, 2008). The scanned land use and main rock map of the project area rectified, digitized, and attributes of land use and bedrocks were entered into the database tables. Also raster SRTM3 data were imported into these databases for making physiographical factor (elevation, slope, aspect) maps. Our findings illustrated that the whole area of Alaçam mountains is 282 480 ha where most of the area of the mass is located between 700-1300 m asl with 200 585 ha corresponding to 71% of the whole area. We detected two kinds of mis-land use; (1) agricultural activities applied at the slopes above 17% (representing 35 220 ha) and agricultural activities applied on metamorphic rocks (representing 872 ha). Total misuse of lands reached 36 092 ha comprised 12.77% of the whole area.