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多年来,围场山区油松植苗造林,多采用两年生苗木,因此油松育苗要在苗圃培育两年,第三年春天起苗栽植。围场气侯寒冷,生长期短(平均120天),年降雨量平均500mm左右,而且多集中在夏天,因此,给油松育苗造成二次突长,苗木多头,木质化不好,严重地影响苗木质量,影响造林成活率。据几个国营林场调查,每年因多头、木质化不好而造成油松废苗率达15—20％,秋天雨水多的年份,废苗率高达30％以上。
Over the years, the yard paddy pine plantation, the use of two-year-old seedlings, so Pinus tabulaeformis nursery nursery to cultivate two years, the third year of spring seedlings planted. The climate of the paddock is cold and the growth period is short (an average of 120 days). The average annual rainfall is about 500 mm, and most of the rainfall is concentrated in the summer. Therefore, the secondary growth of the seedlings of P. tabulaeformis seedlings, the long seedlings and poor lignification are seriously affected Seedling quality, affecting afforestation survival rate. According to several state-owned forest farms survey, each year due to long, poor lignification caused by waste oil seedling rate of 15-20%, autumn rainy years, waste seedlings rate as high as 30%.