东灵山地区辽东栎幼苗的建立和空间分布

 研究树木实生苗的建立对森林生态系统的保育和恢复具有重要意义，在北京东灵山地区调查了辽东栎(Quercus liaotungensis)实生和萌生幼苗在几种典型的植被类型中的空间分布以及辽东栎一年生实生幼苗在1个林窗梯度上的建立。选择几种典型的植被类型，研究辽东栎实生幼苗和萌生幼苗在森林中的空间分布。结果显示，在不同植被类型中辽东栎实生和萌生幼苗的密度存在空间差异，实生苗密度随幼苗年龄增大逐渐降低，种群的更新主要依靠萌生苗完成。在1个落叶阔叶林中选择1个林窗，在不同梯度(即林窗中间、林窗和树冠连接处，以及树冠下)上，播种辽东栎坚果，第二年秋季调查实生幼苗的2个生长指标和出苗率。结果显示，林窗对一年生实生幼苗的生长高度有影响。幼苗高度在林窗中比在树冠下大；林窗对辽东栎幼苗最长叶片长度和幼苗的出苗率没有影响。说明辽东栎实生幼苗的良好生长需要阳光比较充足的生境条件。本项研究结果建议，对辽东栎种群的更新，应该适当择伐一些较大个体，使森林形成一些林窗或林中空地，以利于辽东栎实生幼苗的建立，这样才能使辽东栎种群通过实生苗进行更好的自然更新。

ESTABLISHMENT AND SPATIAL DISTRIBUTION OF QUERCUS LIAOTUNGENSIS KOIDZ. SEEDLINGS IN DONGLING MOUNTAIN

As sexual reproduction plays an important role in maintaining genetic diversity of plant population, investigation of seedling establishment is critical for effective forest ecosystem conservation. Therefore, the seedling establishment and spatial distribution of seedlings and sprouts of Quercus liaotungensis Koidz. in different vegetation types, in Dongling Mountain, northern China were investigated. The vegetation types studied are including Pinus tabulaeformis forest, broad-leaved forest, Betula platyphylla forest, shrubland, Betula dahurica forest and Larix principis-rupprechtii forest. The spatial distribution and density of seedlings and sprouts varied between vegetation types. Even in the same vegetation type, the density appeared to vary for seedlings and sprouts. Seedling density decreased with seedling age. Growth characteristics measured in 3 grades of micrositegap, under canopy and at the interaction sites between canopy and gap in a broad-leaved forest, suggest that the height of seedlings in gaps is greater than that under canopy, whereas the length of the longest leaf was not different among 3 grades of gap, nor did the percent of germinated seedlings. These results suggest that seedlings prefer sun microsites over shade ones for growth, and that the formation of gaps in the forest is beneficial for natural regeneration of oak population.