意大利楊樹繁殖培育

匈牙利的林業(yè)專家研究出一種用集裝箱密集繁殖白楊樹的方法，良種白楊樹可以用無性繁殖的方法培育根系。放入集裝箱的壓條周圍堆上泥炭和珠光石，集裝箱周圍開一些孔，從孔里可以看見壓條。這種集裝箱苗圃具有與溫室一樣的條件，營養(yǎng)期結(jié)束后，從箱里取出壓條。采用這種方法一根壓條能長100～150條樹根，而傳統(tǒng)方法只能長10～15條樹根。

Based on the results of more than ten year's scientific research and practice, some key techniques for cultivating poplar veneer glued wood were summarized systematically. The results were as follows: (1)Selecting appropriate poplar clones for various cultivation zones according to their growth rate and wood quality. (2)Choosing good sites being suitable for poplar clone growing (at least SI≥18?m). (3)Adopting reasonable planting density which can produce more timbers to meet the need of plywood(the tree spacing should be more than 5?m×5?m). (4)Using correct planting methods for different soil conditions, however, large seedling with 2 year old root and 1 year old stem (seedling height>4?m)were advocated. (5)Taking effective measures to tend the stand, the most effective measure was interplanting with crops. (6)Pruning was neccessary to produce non node timber, but pruning method, pruning intensity and pruning season should be controlled properly. If the 6 measures mentioned above were carried out, the poplar forests with a high yield and high quality could be ensured. In order to provied some theoretical basis for cultivating poplar veneer glued wood, 4 optimum cultivation patterns were also established using the method of two dimensions system.