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This paper systematically studied nine cultivars in the production of poplar clones growth pattern of Yang Shufeng the production forest cultivars density of 4 × 6m, conventional cultivation measures under reasonable, mature, mature technology, economically mature research to explore rotations. Studies have shown that the poplar clones tree height, diameter at breast height, tree volume growth and age showed significant slow - fast - slow growth pattern. Logistic Equation 9 Aigeiros clones were 11-year-old forest tree height, diameter and volume growth law to fit the results show that the fitting results are obvious: the use of the logistic equation, correlation coefficients are 0.90. Clones and growth process is divided into early growth, fast-growing and late growth stage 4 period, the amount of growth in the three periods showed significant slow - fast - slow \The clones into the speed of the fast-growing period, the tree height growth than DBH growth of the early to enter the fast-growing volume growth of the latest to enter the fast-growing. Clones tree height increment and The DBH increment to reach the fast-growing inflection point time less in 2 years; volume inflection point late in the first 5 to 6 years. Clones as soon as possible growing period into the slow growth period of the first diameter at breast height, tree height, followed by the latest volume. The results showed that, 11 years old 9 black Yang sent poplar clonal system is still in the stage of growth strong, it's wood product growth of the amount of the increase in nearly a straight line, wood product average annual growth also did not reach the maximum, not yet intersect with the annual increment, did not reach the number of mature. Growth curve simulations show that the common poplar planting density 4m x 6m conditions, the number of mature age between 13 to 19a at a time when the growth of the fast-growing period, should be delayed harvesting. Such as short rotation cultivation, can increase the density per unit area in order to improve volume growth. L324 is the only one tested nine clones reached a mature system of the harvesting period, the number of mature age around 10.5a; the 9 Aigeiros poplar clones process mature age between 12 to 14a; The average annual net discounted value determined poplar optimal rotations, 9 Aigeiros the poplar clones cultivate large-diameter timber rotations economic maturity age 10 ~~ 21a between. Mature technology, the key consideration economic maturity, an appropriate balance between the number of mature, and ultimately determine the 9 Aigeiros asexual Department L35, T26, T22, L323, I-102, I-802, L324, T66, I-107, Holland 1 No. reasonable rotations were: 17a, 16a, 14a, 19a, 15.5a, 13a, 14a, 15a, 18a, is much larger than usually think of 7 to 8a. The growth characteristics of the various growth stages of trees to explore the law of forest growth and the determination of the sound rotation, laid a theoretical foundation for the poplar short rotation intensive culture of Yang Shufeng production and cultivation, improve land the productivity of the reference.
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