北京延庆平原区主要造林树种生态需水估算

Ecological Water Requirement Estimation of Typical Plantation Tree Species in Beijing Yanqing

生态需水估算是造林地水资源优化配置和维持生态环境安全的重要研究内容之一。本文以北京延庆蔡家河流域平原造林地为研究对象,基于遥感和GIS技术,利用Pleiades高分卫星数据,解译典型造林树种并统计面积,并结合Penman公式计算了研究区典型造林树种最小生态需水量。研究结果表明,刺槐、杨树和油松最小生态需水量分别是150.38mm、179.00mm和116.97mm,适宜生态需水量分别为364.13mm、432.58mm和282.74mm。平原造林地生态需水量在8月份达到峰值。适宜生态需水条件下,典型造林树种刺槐、杨树和油松的实际需水量分别约为830.22m^3、4 983.67m^3和1 278.12m^3。2014年为枯水年,生长期降雨量为331.10mm,而有效降雨量仅为265.34mm,在这种情况下,均不能满足刺槐、油松和杨树的正常生理作用所需要的生态需水量,刺槐、杨树和油松生态亏缺水量分别为90.59mm、138.04mm和8.20mm。

The estimation of ecological water requirement is one of the important research contents in optimizing the allocation of water resources and maintaining the safety of the ecological environment. The plantation in Caijiahe Basin Plain of Beijing Yanqing County was studied based on remote sensing and GIS support. With Pleiades satellite data,the plantation area and number of typical afforestation tree species were interpreted,and the minimum requirement of ecological water needed for typical afforestation tree species in study area was estimated by Penman formula.It was found that: the minimum ecological water requirements for Robinia pseudoacacia,Populus canadensis and Pinus tabulaeformis were 150. 38 mm,179. 00 mm,and 116. 97 mm,respectively,and the appropriate water requirements for the three were 364. 13 mm,432. 58 mm,and 282. 74 mm,respectively. The ecological water requirement in the studied plain area comes up to its peak in August. With appropriate water supply,the actual requirements for the three typical afforestation tree species mentioned were 830. 22 m^3,4 983. 67 m^3,and 1 278. 12 m^3,respectively. In 2014 the dry year,the rainfall of growth period was 331. 10 mm,while the effective rainfall was only 265. 34 mm,in this case,the ecological water could not meet the need for normal physiological function of the three tree species,with the ecological water shortage up to 90. 59 mm,138. 04 mm,and 8. 20 mm,respectively.