| Rattan are the category of climbing plants which widely distribute in the tropical and subtropical forest with higher economic value,the native species in China mainly exist in small region of Hainan,Yunnan,Guangxi provinces.Plantations in area still less,and corresponding cultivation techniques are quite deficient,thus some measures need to be urgently enhanced.Base on it,rattan in natural forest of Ganzhalin,Hainan Island had been targeted in this research,by analyzing the correlation between growth,distribution characteristics of rattan and site factors,the distributing and growing traits of natural rattan stand and the mainly factors were explained in this paper,revealing the mainly restrict and promoting factors to rattan species,and proposing some cultural operations to rattan resources for highly efficient cultivation of rattan.The main results are presented in the paper as follows:(1)Good regeneration across rattan in the region,however,distributing frequency and diversity varies in different species.6 species of Calamus faberii(Cf),C.rhabdocladus(Cr),Daemonorops jenkinsian(Dj),C.tetradactylus(Ct),Plectocomia microstachys(Pm),C.simplicifolius(Cs)belong to 3 genus were discovered in plots,the frequentness of those were 0.95,0.93,0.82,0.67,0.55,0.13.Cf and Cr belonged to widespread,by contrast,Pm and Cs had narrow distribution.4?5 seedlings species were found coordinately in 44.44%and 33.33%plots,the distribution divided with growing,single species existed in specific site at the climbing period.Rattan distribution was mainly affected by physical and chemical properties of soil and microtopography,the sites with Total K(TK),minimum water-holding capacity(IWC)and hydrolysable nitrogen(HN)were greater than 42 g·kg-1,140 g·kg-1 and 80 mg·kg-1 respectively or with the rock coverage greater than 40%and 10?20° slope degree had the most richness of species.(2)Different density features were revealed among different species in growing stages.The order was Cr>Cf>Dj>Ct>Pm>Cs.On the whole,seedling stage had the greatest density,clump stage took second place and climbing stage took the last one.There is some discrepancy among survival strategy of rattan,the survival curves of Cf,Ct and Dj were Deevey-? type,Cr tended to Deevey-II type.A survival phenomenon with high breeding and low survival was presented among the species.The density was mainly affected by landform,soil factors and vegetation,whereas there was difference of environmental factors affecting to rattan species.Total P(TP),available P(AP)and organic matter(OM)of soil played a decisive role to seedling density of Ct,the site at straight slope where the TP>0.120 g·kg-1,AP>3.00 mg·kg-1 and OM>30 g·kg-1 had the maximum density of Ct seedling,Ct at tiller stage was mainly affected by total K(TK),Canopy height(CH),slope degree(GRD)and slope position(SLP),the site at lower slope with the TK<60 g·kg-1,CH<13m,and GRD<10° had the maximum density.TN and litter height(LH)negatively impacted seedling density of Ct,the site with TN<0.6g·kg-1,LH<4.0cm more benefit its regeneration;However,GRD and TK negatively affected the density of Ct at tillering stage.The tiller density of Cs was significantly affected by unit weight(VW),the site that VW<1.55 Mg·m-3 more favorable to its breeding.Meanwhile,the seedling of Cr was mainly affected by CH,and density was largest when CH>13 m.The key factor to Dj seedlings was GRD,and density was largest GRD at 20?30° The tiller bundle density of Dj were quite larger at site of CH<13 m.(3)Growing traits in base diameter,height in species and the mainly affecting factors were different.The base diameters of seedling and clump of Ct were 0.4 cm,0.88 cm,and Cs were 0.61 cm and 1.91 cm,the seedling diameters of Cf,Cr and Dj were about 0.4 cm,clump's diameters were 156?1.68,and a large difference of height in different stage among species,the H/D ratio increased rapidly with growing,resource allocation placed extra emphasis on the growing of height.Affecting factors to rattan species between base diameter and height growth were different.The impact of Ct seedling height growth were mainly from total venting quality(TVQ),AP,pH and LH,the seedlings at the site of TVQ with 20-30%,AP<1.0 mg·kg-1,pH<5,LH<4 cm had the greatest height,the clump height was largest at the region of TSP<35%,SD<0.8.The height of seedling increased with the increase of non-capillary porosity,when the non-capillary porosity>18%,Cf seedlings height was mainly affected by non-capillary porosity(NCP),but rock bareness and stand density(SD)were mainly affected height growth at clump stage.Cs's height at clump stage was mainly effected by drainage ability(DRA),especially at the region of DRA<8 mm.Cr seedlings were mainly effected by TK,meanwhile,CH mainly effected height of clumps.Both of Dj base diameters at seedling and clump were mainly effected by CH and SD,and the trait at CH<13m,SD<7000 plant hm-2 had greatest value.(4)Suggestion on cultural operations of rattan resource.? Rich resources of rattan were found at Ganzhalin region of Hainan Island,where could be the cultivation base of rattan resource.Among the 6 native species of 3 genera in the test site,Cf and Cr had well-adjusted abilities to environment,and could be the priority species of cultivation.? Artificial promotion to natural regeneration is the one of key way to rattan cultivation in Ganzhalin region,according to relieve limiting factors and improve promoters could promote rattan breeding and growing.? On account of difference among species traits and affecting factors,"matching rattan species with choosing site location" or "matching rattan species with change site condition" are the key methods to regeration and growth.Pointedly regulate the main factors to relevant species of rattan could promote its growth.For example,cleaning litter,loosening soil may promote reproductive and growth of Cf seedling,thinning forest may accelerate the growth of clump plants of Cf;loosening soil may accelerate Cr tillering,increasing K fertilizer is conducive to growing of Cr stem.? Survival strategy of rattan is high breeding withstand low survival,big young plant is proposed when afforestation,which could enhance survival rate. |
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