民勤绿洲人工治沙林自然更新能力调查研究

民勤绿洲治沙造林以梭梭、柠条、沙拐枣为主要树种,经多年定点观测研究,结果表明:梭梭、柠条、沙拐枣在民勤地区均能实现一定量的自然更新,更新量与当年降水量及降水的理想分布呈正相关;梭梭更新一般发生在春季,但春夏无有效降水的情况下,秋季也有少量更新,而柠条、沙拐枣的更新以秋季为主,翌年春季也有更新;3树种自然更新对林木盖度增加几无影响,6年间梭梭、柠条、沙拐枣每hm2株数分别增加了16.7%、8.0%、37.2%;3树种自然更新有明显的地域差异性;个例调查,沙拐枣良好更新具有普遍性,柠条次之,而梭梭只能为个例;更新能力沙拐枣柠条梭梭。

Investigation on Natural Regeneration Ability of Plantation for Wind Protection and Sand Fixation in Minqin Oasis

Haloxylon ammodendron,Caragana korshinskii and Calligonum mongolicum were main tree species for control land and reforestation in Minqin oasis,based on the fixed observation and study were conducted for many years,the results indicated：Haloxylon ammodendron,Caragana korshinskii and Calligonum mongolicum all had natural regeneration in Minqin oasis,there was a positive correlation between amount of regeneration and precipitation amount of precipitation ideal distribution of precipitation,regeneration of Haloxylon ammodendron generally occurred in Spring,however,if there wasn＇t in spring and summer,small amout of regeneration occurred in autumn,regeneration of Caragana korshinskii and Calligonum mongolicum were main in autumn,also in spring of the next year,three kinds of natural regeneration had little effect on the increase of forest coverage,tree number of Haloxylon ammodendron,Caragana korshinskii and Calligonum mongolicum increased 16.7%,8.0%,37.2% per hm2 respectively for six years,three kinds of natural regeneration had apparent regional difference,case study showed that Calligonum mongolicum was fine and its regeneration was common,Caragana korshinskii was second,Haloxylon ammodendron in one region had very good natural regeneration and it was a case,regeneration ability of three species was ranked as follows：Calligonum mongolicumCaragana korshinskiiHaloxylon ammodendron.