古尔班通古特沙漠人工梭梭林群落生态特征研究

为探究古尔班通古特沙漠南缘莫索湾地区33年来人工梭梭林群落(依靠天然降水)的生态特征,本文对两种造林技术(积雪-客沙造林和秋灌造林)人工梭梭林地梭梭的长势、草本植物、土壤水分进行了调查和监测。结果表明:(1)积雪-客沙造林和秋灌造林梭梭至今生长良好,目前植株高度和冠幅均大于2 m和2 m~2,当年新生枝条长度均大于20 cm;初始造林梭梭存活率较高,分别为40%和63%;经过自然更新,现有密度均有所提高,人工林形成异龄复层混交林,林下生长有不同优势种的草本植物;土壤含水量均2.00%,能够满足梭梭生长。(2)由于两种造林技术的土地处理方式和初期水分供给量不同,导致两种林地梭梭生长、林下草本植物盖度和多样性以及天然更新梭梭植株数量均有很大差异,整体秋灌造林地的状况优于积雪-客沙造林地。(3)两种造林技术对于当地生态条件均有很好的适应性,虽然积雪-客沙造林密度相对较低,但优于自然植被状况,且造林成本低;秋灌造林密度较大,天然更新植株数量较多,但造林成本高,后期生长较缓慢,需要采取一定的人工措施调整密度。综上可知,积雪-客沙造林和秋灌造林梭梭目前生长均较稳定,后者对该区生态条件适应性更强。

Ecological characteristics of cultivated Haloxylon ammodendron communities in Gurbantunggut Desert

The ecological characteristics of Haloxylon ammodendron communities cultivated under rainfed conditions for 33 years in Mosuowan of Southern Gurbantunggut Desert were analyzed under two afforestation techniques-snow-sand dressing afforestation and autumn-irrigated afforestation. The growth potential, understory vegetation and soil water content were monitored and recorded. Results showed that:1) H. ammodendron had strong growth with an average plant height and canopy spread under both cultivation techniques exceeding 2 m and 2 m², respectively. The average length of new branches was more than 20 cm, with a survival rate of afforestation of 40% under snow-sand dressing and 63% under autumn irrigation. The den-sity was enhanced and uneven-aged mixed forest was formed due to natural regeneration. There were different kinds of dominant species herbs in the forest. The average soil water content under the two forest treatments both exceeded 2.00%, which was enough to support H. ammodendron growth. 2) There were obvious differences between the two forests cultivation techniques in terms of vegetation cover and species diversity and natural regeneration of H. ammodendron due to the differences in the treatments, site conditions and initial water supply. 3) The two communities were highly adaptable to the local ecological conditions. Compared with autumn irrigated afforestation, the density, vegetation cover and number of natural regeneration were lower in snow-sand dressing afforestation. The cost also was lower, but grew slowly under autumn irrigated afforestation after irrigated was stopped. There was the need for effective artificial measures to reduce the density of H. ammodendron. In conclusion, H. ammodendron growth under snow-sand dressing and autumn irrigated afforestation was both stable with the latter well-adapted to the local ecological conditions.