广东南澳岛不同森林群落的林窗环境对 3种移植树苗生长的影响

THE INFLUENCES OF GAPS IN DIFFERENT FOREST COMMUNITIES ON THE GROWTH OF SEEDLINGS OF THREE TRANSPLANTED TREE SPECIES IN NAN'AO ISLAND, GUANGDONG

先锋种和非先锋种可能对林窗产生不同的反应。在广东南澳岛 4个不同的森林群落样地里移植了大叶相思 (AcaciaauriculaeformisA .Cunn .)、尾叶桉 (EucalyptusurophyllaS .T .Blake)和荷木 (SchimasuperbaGardn .etChamp) 3种树苗 ,其中大叶相思和尾叶桉是先锋种 ,而荷木是非先锋种 ,测定了林窗和非林窗生境中的透光率和幼苗生长高度。结果表明 ,林窗的透光率大于非林窗的 ;各群落的透光率有季节性的变化 ,变化幅度各不同。 3种幼苗在林窗内比非林窗的乔木层下生长快 ;大叶相思和尾叶桉幼苗在林窗内的高度增长量大于非林窗下的 ,而且这种差异显著 ,对荷木来说 ,这种差异仍有 ,但不如前两者那么显著。大叶相思和尾叶桉幼苗在林窗内比荷木幼苗生长快 ,这证实了先锋种和非先锋种对林窗的反应不同。

Tree seedlings of pioneer species and non-pioneers may respond differently to canopy gaps. We used a field experiment to test this in four forest communities in Nan'ao Island, Guangdong, China. We measured the ratio of light penetration (RLP) in gaps and in adjacent non-gap sites. We also measured seedling growth of three tree species transplanted into these gaps and non-gap sites. These species included two pioneer species, which were Acacia auriculaeformis A. Cunn. and Eucalyptus urophylla S. T. Blake, one non-pioneer species, which was Schima superba Gardn. et Champ . The RLP were much higher in gaps and have changed with season. The changes were different among communities. The seedlings of the three species grew faster in gaps than that in non-gap sites. The height growth of seedlings of the two pioneer species (A. auriculaeformis, E. urophylla) differed significantly between gaps and non-gap sites. The difference, which was not as significant as for the two pioneer species, still occurred for the non-pioneer species (S. superba). Seedlings of the two pioneer species grew faster in gaps than that of the non-pioneer. This showed that pioneer species and non-pioneers responded differently to canopy gaps.