Geographical Distribution And Bio-ecological Characteristics Of Michelia Balansae

Michelia balansae is an indigenous species of Viet Nam with high economic value.It distributed in the north and the north-central provinces such as Ha Giang,Tuyen Quang,Yen Bai,Nghe An,Ninh Binh,etc.Michelia balansae is always the object was illegal exploitation in natural forest.In Red Book of Vietnam,it classified as Vulnerable.This study selected the stands where Michelia balansae distributed concentration in four sites of Cuc Phuong National Park,Vietnam(zone 1,zone 2,zone 3,zone 4),setting five plots in each zone,a total of 20 plots were established to study systematically investigate about the characteristics of Michelia balansae communities,including the characteristics of individual(height,diameter,crown),the regeneration status of seedlings and saplings,the distribution of plant communities,the characteristics of geographic,topographical,climatic and soil where Michelia balansae distributed.Analysis of ecological factors affected Michelia balansae distribution density.At the same time,analysis of the structure of the stands and the regeneration characteristics of Michelia balansae so that the basis for proposing the conservation solutions this species in Cuc Phuong.1.The characteristics of Michelia balansae distribution and ecological factors affecting its distribution density:in zone 1,2,3,and 4 of Cuc Phuong National Park in Vietnam,Michelia balansae are focus distributed in the evergreen broad-leaved forest,with an altitude of 90-400m,and the slope 5-25~o,red-yellow and black-gray Ferralsols,thin soil horizon 30-60 cm p H 5.7-7.2.It preferred porous soil,moist,rich humus,the content of phosphorus and potassium are average or higher(humus content≥4%,nitrogen content≥0.1%,phosphorus content≥0.1%,and potassium content≥1%).Through the correlation analysis of eight ecological factors affecting the distribution,the distribution density of Michelia balansae is influenced mainly by the crown cover,and Michelia balansae don’t distribute in the stands with crown cover is less than 0.3.The distribution density of this species is highest in the stands with the crown cover of 0.6-0.8.2.The structure of the stand:in the stands,the number of trees concentrates mainly in the diameter class of 10-30 cm and the height class of 10-15 m.The structure of forest stratum is divided into five layers:emergent layer,canopy layer,understory layer,shrub layer,and herb layer.Michelia balansae was in canopy layer,understory layer,and shrub layer,so that in the natural forest Michelia balansae is the medium-sized tree,a shade-tolerant species,and easy to encounter it at the canopy layer.Michelia balansae stands have the diversity about the composition of species(13-17 species).Dominant species are light-loving species as Castanopsis indica,Terminalia myriocarpa,Amoora gigantean,Saraca dives,Litsea baviensis,etc.Dominant species are shade-tolerant as Ficus callosa,Machilus platycarpa,Sterculia tonkinensis,Vitex quinata,Streblus macrophyllus,etc.3.Ecological relationship of Michelia balansae with other species in the stand:Michelia balansae belongs to the group of dominant species in the stand.Important value index(IVI)of Michelia balansae ranged from 4.0%-9.6%in the species composition.The relationship of Michelia balansae is random with Gironniera subaequalis,Ormosia pinnata,Triadica cochinchinensis,Pometia pinnata;it has a support relationship with Terminalia myriocarpa,Aglaia spectabilis,and has a competitive relationship with Castanopsis indica,Saraca dives.4.Regenerative characteristics of the stand and Michelia balansae:in four stands investigated(zone 1,zone 2,zone 3,zone 4),the number of seedlings was abundant with the density was from 14,000 to 18,167 trees/ha.The number of seedlings in the stands is large;most of them have a height of less than 20 cm.The number of seedlings is more than the number of coppices.Distribution pattern of seedling on the ground is a clumped distribution type.The number of Michelia balansae seedlings is numerous in the crown cover of 0.6-0.8.5.Michelia balansae conservation should prioritize in-situ conservation,nature regeneration promotion,seedling thinning and reinforcement planting at suitable locations.Need to relieve the thickness of the litter layer so that seedling can develop more favorably.Tends Michelia balansae at the nursery that should shading 60-80%for seedling.Planting a mixed forest between Michelia balansae with other tree species that should select species such as Gironniera subaequalis,Ormosia pinnata,Triadica cochinchinensis,Terminalia myriocarpa,Aglaia spectabilis,Pometia pinnata;and limit choice or remove species Castanopsis indica,Saraca dives.