Research on forest structure and relations between tree species of Castanopsis phuthoensis in forest rehabilitation in Cau Hai, Phu Tho

Abstract

Castanopsis phuthoensis Luong is an endemic tree species of Phu Tho
province, only distributed narrowly in forest rehabilitation in two
communes belonging to Doan Hung district. As it is difficult to find the
seedling in the nature, research on forest structure and relations between
tree species is very necessary to define method of conservation for this
species. The species is dominant tree species in the forest rehabilitation
with both IV% indexes and percent of each species for number of trees
above 5% in nature regeneration forest and enrichmnet forest by
additionally planting in holes in the forest, particularly nearly 10% in
nature regeneration forest with high and medium density, and reaching
14.5% in enrichmnet forest by additionally planting in the holes, density
of this species is very low, only from 3.1 to 11.1 trees per hectare.
Diameter distributions of the species of number of trees is characterized
by curve style with a peak in 20cm or 24cm diameter classes. Its height
distributions are also curve style with a top in 18m or 20m heigh classes.
This peaks are higher than diamter and heigh average of the rehabilitation
forest. Both the diameter and heigh distributions are not suitable to Meyer,
Weibull and Interrupted distribution. This species occurs itself and 31
other tree species, clearly grows in population, and often appears six other
native tree species, including Ormosia balansae, Erythrophloeum fordii,
Castanopsis cerebrina, Quercus platycalyx, Gironniera subaequalis and
Garcinia oblongifolia.
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