色季拉山急尖长苞冷杉天然更新影响因素

Natural regeneration factors of Abies georgei var. smithii on Sejila Mountain

为了弥补高原高山森林天然更新研究的不足,促进急尖长苞冷杉Abies georgei var. smithii种群更新和恢复,通过野外样方调查,分析了海拔与坡向、种子质量、林隙等对急尖长苞冷杉种子特性和幼苗数量的影响,进而分析了林分郁闭度、种子带翅长度、种子质量、苔藓厚度、凋落物厚度与幼苗数量的相关性等。结果表明:由于海拔与坡向的不同,急尖长苞冷杉种子带翅长度、种子去翅长度、种子宽度、种子厚度均存在差异性,尤其是阴坡与阳坡种子带翅长度均表现为显著差异;阴坡种子千粒重分布范围为3.32~12.86 g,阳坡为3.72~14.68 g,阳坡种子质量要优于阴坡;在海拔3 800与3 900 m处千粒重表现为显著差异,阴坡与阳坡亦然。在阴坡与阳坡,种子带翅长度、种子去翅长度、种子宽度、种子厚度、种子千粒重随着海拔的升高均呈先升高后下降的趋势,幼苗数量亦然。林隙研究结果为天然更新幼苗数量林隙>林缘>林下。林分郁闭度、种子带翅长度、种子质量、凋落物厚度均呈显著正相关,苔藓厚度呈极显著正相关,说明这些因素可能有利于急尖长苞冷杉天然更新,其中苔藓厚度是影响其天然更新最重要的因子。

This study lays the foundation for improving the natural regeneration effect of Abies georgei var.smithii.Using standard field observations,the main influencing factors on natural regeneration of Abies georgei var.smithii including elevation,slope,seed weight,and forest gaps,were analyzed.A correlation analysis of seedling numbers versus canopy density,length of seeds with wings,seed weight,thickness of the moss layer,and thickness of litter was conducted.Results showed that because of differences in elevation and slope,the length of seeds with wings,length of seeds without wings,width of seeds,and thickness of seeds were different,especially length of seeds with wings in shady and sunny conditions.In shade,the 1000-grain weight was from 3.32 to 12.86 g;whereas,in sunshine,the 1000-grain weight was from 3.72 to 14.68 g.Seed quality in sunshine was better than the shade.The 1000-grain weights in the shade and sunshine at 3 800 and 3 900 m were very different.In the shade and sunshine as altitude increased,the length of seeds with wings,length of seeds without wings,width of seeds,thickness of seeds,and 1000-grain weight all increased at first and then decreased;the number of seedlings was about same.The gap study showed gap>forest edge>forest.Canopy density(r=0.773),length of seeds with wings(r=0.860),seed weight(r=0.643),and thickness of litter(r=0.833)showed a significant positive correlation;thickness of moss layer(r=0.919)showed a highly significant positive correlation.Thus,these factors could be beneficial to natural regeneration of Abies georgei var.smithii in plateau mountain forests,and this study has important practical implications for promoting regeneration and recovery with thickness of the moss layer being the most important factor.[Ch,2 fig.6 tab.24 ref.]