Studying on the natural regeneration ability on the land after of shifting cultivation in Cau river watershed, Bac Kan province
2014
Nguyen Thi Thu Hoan; Le Sy Trung; Le Sy Hong
In order to study on the natural regeneration ability on the land after of shilling cultivation in Cau river watershed,. Bac Kan province, this study was done two years from 2011 to 2013 and conducted in 36 plots at two districts named Cho Moi, Cho Don. This study was carried out in the forest type of IA, IB and lC. This is corresponding time after of shifting cultivation 1-3 years, 4-6 years and 7-9 years. The collected results showed that: Number of tree species regeneration dependent recovery time, after 1-3 years of fallow grass was dominate, the next 3 years regeneration density increased from 169 trees per ha to 355- 525 trees per ha after 12 years. Recovery is long time, regenerating tree species composition is diversity, index H 'regeneration varied from 1.6 in recovery time less than 3 years to 3.82 in recovery time is 9-12 year. Regenerating tree density also increases proportionally with time, the average density of tree regeneration from 133 to 3160 trees per ha according to the different recovery time. Average height of tree regeneration prospects are rising average of 0.26 meter per year. Number of shrub and vegetation changes early years fallow, the first time the total number of species shrub and vegetation are 16 species and then increased 4 species in 2013. Much of the increase Cop 2 to Cop 3, in the period recover 4-12 years, shrub and vegetation slowly increase due to the increased density of tree regeneration.
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