林窗对格氏栲天然林更新层物种竞争的影响

采用Hegyi单木竞争指数模型探讨林窗和林下格氏栲(Castanopsis kawakamii)幼苗幼树种内和种间竞争强度,分析林窗对格氏栲天然林更新层物种竞争的影响。结果表明:随着对象木高度的增加,林窗和林下格氏栲幼苗幼树的种内竞争强度逐渐减少。林窗种间竞争强度的顺序为:梨茶(Camellia octopetala)>褐毛石楠(Photinia hirsuta)>黄润楠(Machilus grijsii)>桂北木姜子(Litsea subcoriacea)>毛鳞省藤(Calamus thysanolepis)>酸味子(Antidesma japonicum)>少叶黄杞(Engelhardtia fenzelii)>矩圆叶鼠刺(Itea chinensis)>小叶赤楠(Syzygium grijsii)>山黄皮(Clausena dentata)>光叶山矾(Syplocos lancifolia)>沿海紫金牛(Ardisia punctata)>丝栗栲(Castanopsis fargesii)>狗骨柴(Diplospora dubia)>木荷(Schima superba)>赤楠(Syzygium buxifolium)>杜茎山(Maesa japonica)。林下种间竞争强度的顺序为:桂北木姜子>梨茶>黄润楠>木荷>毛冬青(Ilex pubescens)>狗骨柴>毛鳞省藤>香港新木姜子(Neolitsea cambodiana)>酸味子>沿海紫金牛>山黄皮>光叶山矾>赤楠>小叶赤楠>尖叶水丝梨(Distyliopsis dunnii)>杜茎山>丝栗栲。格氏栲幼苗幼树的竞争主要来自种间竞争,种内竞争对格氏栲影响不大,林窗格氏栲幼苗幼树的种内竞争强度和种间总体竞争强度大于林下。通过筛选林窗和林下格氏栲对象木树高与竞争强度的竞争模型,发现对象木树高与竞争指数之间存在负相关,预测结果表明,在林窗格氏栲幼苗生长初期应加强对其保护,林下格氏栲幼苗高度达到100～150 cm后适当采取创造林窗环境以实现其快速生长,从而有效促进林窗和林下格氏栲种群的保护与更新。

The Influence of Forest Gap on Species Competition of Castanopsis kawakamii Natural Forest Updated Layer

The intraspecific and interspecific competitions intensity of C.kawakamii seedlings and samplings in forest gaps and understory were quantitatively analyzed by using Hegyi’s competition index model respectively and analyzed the effect of forest gaps on the species competition of C.kawakamii natural forest updated layer.The results showed that the intraspecific competition intensity in C.kawakamii seedlings decreased gradually with the increasing of height class in different habitats.The order of the interspecific competition intensity in forest gap was: C.octopetala>P.hirsuta>M.grijsii>L.subcoriacea> C.thysanolepis>A.japonicum>E.fenzelii>I.chinensis>S.grijsii>C.dentata>S.lancifolia>A.punctata>C.fargesii>D.dubia>S.superba>S.buxifolium>C.kawakamii>S.glabra>M.japonica.The order of the interspecific competition intensity in forest understory was: L.subcoriacea>C.octopetala>M.grijsii>S.superba>I.pubescens>D.dubia>C.thysanolepis>N.cambodiana>A.japonicum>A.punctata>C.dentata>S.lancifolia>S.buxifolium>S.grijsii>C.kawakamii>D.dunnii>M.japonica>C.fargesii.The competition of C.kawakamii seedlings and samplings was mainly from interspecific competition while intraspecific competition had little effect on it.Intraspecific competition and overall interspecific competition in forest gaps were higher than those of forest understory.The best models of trees’ height of C.kawakamii and competition intensity were selected and the relationship between them presented a negative correlation.According to the prediction results,it should strengthen the protection of C.kawakamii seedlings in the early stage of forest gaps and the gap environment should be created to accelerate the growth of C.kawakamii seedlings and samplings after the height up to 100~150 cm in forest understory which could effectively improve the conservation and regeneration of C.kawakamii population in forest gaps and understory.