Assessment of the possibility of growth and protection of species parashorea (Parashorea chinensis) in area watershed protection da river

Abstract

Da river watershed is a important protection areas in the northern mountainous region of our country. Surrounding area Hoa Binh hydropower reservoir mostly forest and forest land with high slopes, have more forest cover but low quality protection, mostly poor secondary forest, with tree species have low protection value. The results of the paper refers to the adaptability and protection of species Parashorea (Parashorea chinensis) in the Da river watershed. The study results showed that , after 10 years of planting trees for only average Dbh from 7.7 to 12.0 cm, growth from 0.96 to 1.03 cm/year; The average tree height from 11.3 to 12.0m , growth from 0.59 to 0.65 m/year; The average canopy diameter reached 4.5 to 5.4m , growth from 0.29 to 0.38 m/year). Rate of good quality plants reached 86.6%, averaging 10% and 3,33% bad tree. Forest land under the impact of Parashorea specie, relatively sour, the humus content medium, Nts fairly. K dt, Pdt content in very poverty. The falling amount each year in obtained was 6.0 tones/ha (1.5 times compared to the control). The Parashorea model brings environmental efficiency, manifested in the ability to limit erosion and runoff, nutrient restriction lost under the surface flow. The amount of erosion
was 2. 11 tonnes/ha/year (reached 60,5% DC), the amount of runoff is 154.500m3/ha/year (reached 61 .85% DC). Nutrients are lost annually in low and much lower than the controls (N lost 4.64 kg/ha/year by 20.7% compared to controls; P lost 6.18 kg/ha/year in 19.1% compared with the control. The amout of K lost 5.72 kg/ha/year by 28.0% compared to controls.