作者用1975～1981年六年时间,先后对北京、河北、山东、山西、辽宁五省市28个县39个公社61个大队、2个省属果树试验场、2个林场和1个园艺场,进行了枣疯病生态条件的调查。调查范围从北纬35～41度,东经111～121度,海拔50～2500米的地 The author used sixteen years from 1975 to 1981, and successively studied 61 battalions of 39 communes in 28 counties of Beijing, Hebei, Shandong, Shanxi and Liaoning provinces, two provincial fruit tree test sites, two forest farms and one horticultural field , Conducted a survey of jujube ecotone ecological conditions. The survey ranged from 35 to 41 degrees north latitude, 111 to 121 degrees east longitude and 50 to 2,500 meters above sea level