论文部分内容阅读
来自亚拉巴马州不同苗圃和不同种源的火炬松实生苗,其苗高与“优劣”造林地的成活率和高生长量有关。三年的成活率低于75％,总高生长量低于75毫米划为劣造林地。劣造林地与优造林地比,苗高与成活率呈负相关,回归斜率高出4倍。在劣造林地,原苗高与二年的高生长量也呈负相关,二年后,矮苗与高苗的总苗高达到相同。结果,二个生长季后,劣造林地的原载植苗高对总苗高没有什么影响。因此,当成活率低于75％时,栽植苗高超过20厘米没有高生长优势。在优造林地,苗高20—34厘米问题不大。在美国南部成活率低的造林地用矮苗造林,预计可以大大提高火炬松实生苗的成活率。
Seedlings of Pinus taeda from different nurseries and different provenances in Alabama are related to the survival rate and high growth of “good and bad” sites. Three-year survival rate of less than 75%, total height growth of less than 75 mm planted as bad forest land. The ratio of bad forest land to superior forest land was negatively correlated with the survival rate and the regression slope was 4 times higher. In inferior forests, the original seedling height was also negatively correlated with the two-year high growth. After two years, the total seedling height of the low-seedling and high-seedlings reached the same level. As a result, the original plantation height of spoilage forests had no effect on the overall plant height after the two growing seasons. Therefore, when the survival rate is less than 75%, planting height more than 20 cm does not have high growth advantage. In the excellent woodland, the height of 20-34 cm is not a big problem. Afforestation with seedlings in lowland afforested areas in the southern United States is expected to greatly enhance the survival rate of Pinus taeda seedlings.