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黑山县为解决造林树种单一问题,经过考察,于1978年从河南省新乡地区孟县引进白榆(钻天榆)。1983年大量栽植,到1986年底白榆造林面积39013亩,大多数为农田防护林和护路林,少量是白榆与杨树混交林,栽植的白榆纯林很少,表现不好。据调查,四间房乡安家河村社员房西栽植的白榆,8年生树高13m,胸径19.9 cm,单株材积
In order to solve the single problem of afforestation tree species in Heishan County, after the investigation, in 1978, Baishu (Dried Sky Ulmus) was introduced from Meng County, Xinxiang, Henan Province. In 1983 a large number of planting, by the end of 1986 alburnina afforestation area 39013 mus, most of the farmland shelterbelts and road protection forest, a small amount of white elm and poplar mixed forest, planted with pure white elm very few, poor performance. According to the survey, the four rooms of the village home Anjihecun west planted elm, 8-year-old tree height 13m, diameter 19.9 cm, single plant volume