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本文是杨树引种试验研究结果的一部分,就目前在试验林中生长较好的尤金杨等八种杨树与对照种欧美杨的苗期和造林后的生长量进行了初步的分析研究。试验是在陕西省武功县境内的二道原西北农学院原教学试验林场进行的。在1963年苗期予备试验的基础上,于1964—1965年进行了苗期比较试验,研究了一、二年生苗木的生长量,田间试验设计采用多次重复法;并于1964年栽植了试验林,进行造林比较试验,从1973年起,结合试验林的间伐,用树干解析的方法,研究了林木的生长量。试验结果分别用数理统计的 t 测验、方差分析和多重比较进行了差异显著性的测定。试验结果初步表明:1.目前生长最快的为尤金杨,与对照种欧美杨及其它七种杨树比较,均为差异极显著。解析木中最大的1株,12年生高24.8米,胸径34.0厘米,树干带皮材积0.89879立方米。10年生材积的总生长量平均比对照种提高137％,比陕西省目前推广的生长较快的15号杨提高52％。目前,尤金杨的材积连年生长量仍大于平均生长量,正处于旺盛生长时期。撒尔红杨、箭河小杨和15号杨为生长快的杨树,与对照种相比较均为差异显著。莱比锡杨、德国158号杨、健杨和合作杨与对照种生长相近,差异不显著。2.苗期生长量的大小与林木生长量的大小之间并不完全一致,有的树种苗期生长快,而林木生长亦较快,如15号杨;有的树种苗期生长慢,而林木生长却很快,如尤金杨。因此,仅仅根据苗期生长量的大小决定引进树种的推广与否是不完全适宜。3.苗期生长量的大小因树种和苗令而异。有的树种一、二年生苗生长均快,如15号杨;有的树种一、二年生苗生长均慢,如尤金杨;有的树种一年生苗生长快,而二年生苗生长则变慢,如合作杨。因此,苗期比较试验的年限不应少于两年。4.有些树种苗期生长虽慢,而生长率却高,以至造林后其材积生长速度较快,如尤金杨。因此,在苗期比较试验中,对于那些生长缓慢而生长率却高的树种,不宜过早淘汰。
This paper is part of the introduction of poplar pilot study results, the current good growth in the experimental forest of Euonymusia popularis and other species of poplar and seedling growth and afforestation after a preliminary analysis. The experiment was conducted in the original teaching and experimental forest farm of Erdao Yuan Northwest Agricultural College in Wugong County, Shaanxi Province. Based on the preliminary experiment of seedling in 1963, the comparative experiment of seedling stage was conducted from 1964 to 1965, the growth of one-year and two-year seedlings was studied, and the repeated design of field experiment was adopted. In 1964, the experiment was planted Forest, the comparison test of afforestation, since 1973, combined with the thinning of the pilot plantation, tree trunk analysis method to study the growth of trees. The test results were statistically significant t test, analysis of variance and multiple comparison were significant differences in the determination. The results show that: 1. At present, the fastest growing Eugene Young, compared with the control species of poplar and seven other poplar, were significantly different. Analysis of the largest one in wood, 12-year-old height of 24.8 meters, 34.0 cm in diameter, tree trunks of 0.89879 cubic meters. The total biomass of 10-year-old biomass increased by 137% on average compared with the control, which was 52% higher than that of the 15-year-old popularized in Shaanxi Province. At present, the volume of Eugene Yang annual growth rate is still greater than the average growth rate, is in strong growth period. Sally poplar, arrowhead river and poplar 15 for the fast growing poplar, compared with the control species are significant differences. Leipzig Young, Germany 158 Yang, Jian Yang and cooperation Yang and the growth of similar species, the difference was not significant. 2. The amount of seedling growth and the size of the amount of forest growth is not exactly the same, some tree growth fast, and forest growth is also faster, such as 15 Yang; some tree growth slow , But the growth of trees is fast, such as Eugene Yang. Therefore, only according to the size of the seedling growth decided to promote the introduction of tree species or not is not entirely appropriate. 3. The amount of seedling growth due to species and seedlings vary. Some tree species grow rapidly in one or two years, such as the 15th poplar; some trees grow slowly in one or two years, such as Eugene Young; some trees grow fast one year and two years grow slower, such as cooperation Young. Therefore, the seedling period of comparative test should not be less than two years. 4. Although some tree seedling growth is slow, but the growth rate is high, even after afforestation of its volume growth faster, such as Eugene Yang. Therefore, in the comparative experiment of seedling stage, it is not suitable to prematurely remove those species that grow slowly but grow at a high rate.