بررسي كيفيت اسيديته نزولات جوي جنگل تحقيقاتي واز (چمستان نور)

Monitoring the acidity of precipitation in Vaz Research Forest.

Investigation on precipitation quality from lowland to up land areas of Vaz Research Forest in Caspian Sea region (1000, 1600 and 2200 meters altitude) was carried out in the period 1999 to 2003. There were varied amount of rainfall from 900 mm in low lands area, to 600 mm for 1000 and 1600 meters elevations and 300 mm in 2200 meters elevation. Acidity (pH) of precipitation was in the ranged neutral and alkaline criteria, and average PH for precipitation with respect to any elevation were higher 7 in PH value. Amount of pH increased accordingly for 300, 1000, 1600 and 2200 meters elevations respectively. Measurements of pH in snow and rain samples of Vaz Research Forest showed that average pH in March and April snow samples is 0.5 unit (in pH value) were higher than in winter snow samples. Seasonal sampling of precipitation regard to pH showed that, there was significant difference between cold and warm seasons in level of 0.01 confidence. Amounts of SO4 -- were 21, 45, 28, 2.5 kg/ha.yr and concern to Cl- were 1080, 620, 784, 337 kg/ha.yr regard to 300, 1000, 1600 and 2200 meters elevation respectively.