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白榆是我县主要速生用材树种。据82年林业区划调查,栽植总数达226万株,占林木总数的39.78％,蓄积量50793m~3,占总蓄积量的30.62％。但由于过去造林用种良莠不齐,使白榆速生特性不能得以充分发挥。据统计,我县尚存劣种白榆196万株,每年少产木材7350m~3,折款147万元。因此,白榆遗传改良、更新换代已成为当务之急。自1974年开始,我们着手对白榆进行选择优树、采种育苗、无性繁殖、造林试验、示范推广等一系列工作。到目前为止,全县已推广8052、8045、8033、8024、8015、8019等优良无性系计115万株,营造丰产林1000余
Ulmus is my county’s main fast-growing timber species. According to the 82-year forestry zoning survey, the total number of planting was 2.26 million, accounting for 39.78% of the total number of trees, with a stock volume of 50793m ~ 3, accounting for 30.62% of the total stock volume. However, due to the past good and bad variety of afforestation, so that elm fast-growing features can not be fully demonstrated. According to statistics, there are 1.96 million inferior elm species remaining in our county, 7350m ~ 3 less timber per year and 1.47 million yuan in discount. Therefore, genetic improvement, replacement of elm has become a top priority. Since 1974, we have started to carry out a series of work on the selection of elm tree, seed breeding, asexual reproduction, afforestation experiment, demonstration and popularization. So far, the county has promoted 1.15 million clones of excellent clones such as 8052, 8045, 8033, 8024, 8015 and 8019,