Atmospheric deposition in mature fir (Abies nordmannianna (steven) spach subsp. equi-trojani (Asch.& Sint. Ex boiss.) Code & Cullen ) stands in Aladağ- Bolu

Sampling areas for throughfall, stemflow and bulk deposition were established in 4 different elevation steps in Aladag forests of Bolu province. The samplings was conducted between June 2013 and November 2014. The laboratory analyzes of the weekly samples were carried out on monthly laboratory samples prepared by pooling method. Bulk, throughfall and stemflow precipitation concentrations obtained were evaluated. In all elevation, approximately 70% of the precipitation falling to the open area falled in to the ground in the base of the stand through the gaps of the crown and less than 1% flowed through the stemflow. So, approximately 1/3 of the incoming precipitation is kept by the crown. During the sampling period, the highest precipitation average was realized as 366 mm in open area and 197 mm under the canopy of the stand area at an altitude of 1600 meters, in June. The lowest precipitation average was determined as 11 mm in open area and 6,7 mm under forest. The pH average values were determined as 6,8 ± 0,5 in open field and 6,4 ± 0,4 under forest. The most prominent among the analyzed anions and cations are sulfate, nitrate, potassium and calcium The highest average values of sulfate, nitrate, potassium and calcium occurred in September and under forest precipitation. These values are 17,5 ± 6,1 mg l-1, 7,3 ± 6,7 mg l-1, 13, 7 ± 11 mg l-1 and 6,9 ± 4,5 mg l-1, respectively.