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我区从1974年开始,引种了美国优良速生树种——湿地松、火炬松。至1981年全区已发展达六万六千余亩。在重点发展县布设33个样方进行了全面的调查。综合分析如下: 一、国外松原产地与本区发展县的生态条件相近。1674年至今所营造的幼林生长看,表现良好。如1982年5月在资中县国营林场调查300亩湿地松,100亩火炬松。8年生的幼林。结果湿地松八年生平均胸径11.28厘米,最大胸径21.05厘米,树高7.06米,年平均径生长1.41厘米,年平均树高生长0.88米。火炬松八年生平均胸径生长10.21厘米,树高7.36米,年平均径生长1.28厘米。前三年火炬松亩平均蓄积0.56立方米,后五年平均增加蓄积湿地松0.6961立方米,火炬松0.5496立方米。两者比较径生长,湿地松大于火炬松。高生长则是火炬松优于湿地松。
My district since 1974, the introduction of the United States excellent fast-growing tree species - pine, loblolly pine. By 1981, the whole region has grown to more than 66,000 mu. A total of 33 sample plots were laid in key development counties for a comprehensive survey. Comprehensive analysis is as follows: First, the origin of Songwon County and the development of the county’s ecological conditions are similar. The growth of young forests from 1674 to the present has been good. As of May 1982 in Zizhong County State Forest Farm investigation 300 acres of Pinus elliottii, 100 acres of loblolly pine. 8 year old young forest. Results The average annual DBH of the eight-year-old Pinus elliottii was 11.28 cm, the maximum DBH was 21.05 cm, the height of the tree was 7.06 m, the average annual diameter was 1.41 cm, and the annual mean tree height was 0.88 m. The average annual diameter of loblolly pine eight years growth 10.21 cm, height 7.36 meters, the average annual diameter of 1.28 cm. In the first three years, the acreage of acreage increased by 0.56 m3 on average, and after that, the average increase of accumulated pine was 0.6961 m3 and 0.5496 m3 of loblolly pine. The diameter of the growth of both, pine is greater than loblolly pine. High growth is better than Pinus taeda.