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白桦属高大乔木,喜光耐严寒,是北方高寒地区主要次生林树种。北部山区海拔1600米以上的低山常与云杉,落叶松、山杨等组成混交林,在海拔1600米以下高山常以纯林形式生长,30年生树高达12米胸径16cm。近年来随着防风固沙和三北防护林体系建设等林业生态工程的实施,白桦已被广泛列为山区造林和城镇绿化的优势树种。1 种子的采集和处理1.1 采种,每年九月份,果穗由绿变黄时进行采集,采后果穗放在露天水泥地上晒5-7天,用磙子压或用棍棒打,将种子和苞片分开,因为苞片比种子重,风选可以将种子和苞片分开,种子的纯度不低于60%,
Betula platyphylla is a tall tree, hi light resistance to cold, is the main alpine region in the northern secondary forest tree species. In the northern mountains, the low mountains above 1600 meters above sea level often consist of mixed forests of spruce, larch and aspen, often growing in pure forests at an altitude of 1,600 meters above sea level. The 30-year-old tree has a diameter of 16 cm at a height of 12 meters. In recent years, with the implementation of forestry ecological projects such as windbreak and sand fixation and the construction of the Three North Shelterbelt system, Betula platyphylla has been widely classified as the dominant tree species for afforestation and urban afforestation in mountainous areas. 1 seed collection and processing 1.1 Seeds, September each year, the ear is collected from the green to yellow, post-harvest spike on the open air ground 5-7 days, with razor pressure or sticks, the seeds and bracts Separated, because bracts are heavier than seeds, the winnowing can separate seeds and bracts, the purity of the seeds is not less than 60%