Abstract:

In order to provide more timber for pulp-making, 14 fast growing poplar varieties were widely cultivated in Shandong Province and were studied with respects to their volume growth, fiber shape, chemical composition and economic indices and systemic techniques. The results showed that: (1) The average fiber length and fiber content of 14 poplar varieties in 6-year-old stand is 0.863～1.051mm and 51.37%～58.17% respectively. All the varieties conformed to the pulp-making standard. Taking both the growth and fiber characteristics into consideration, poplar varieties of Populus×euramericana‘Zhong Lin 46', P. × eur. ‘Zhong Lin 23', P. deltoides cv.`LUX' and P. × eur. ‘Zhong Lin 28' were the best choice to afforest the pulp-making stands and. P. × eur. ‘San Martino', P. × eur. ‘Zhong Lin 14', P. × eur. ‘Zhong Lin 45', P. × eur. ‘Luisa Avanzo' and P. × eur. ‘Cima' were also suitable for it. (2)The technical maturity of stands for pulp-making was basically 6～8 years old with the optimal age of 8 years. In order to get high yield and obtain the optimal fiber that were suitable for pulp-making, the optimal stand density is 840～1 665 tree·hm^-2. With the intensive cultived techniques, the optimal rotation age for poplar stands with the density of 1 665, 1 110 and 840 tree·hm^-2 were 6, 6～7 and 7～8 years respectively. (3) Intercropping, fertilization and tending etc. were necessary for high wood yield and high level benefit. Adoption of comprehensive measures and pulp-oriented cultivated techniques could short the oriented age and result in high yield. The annual volume growth of poplar varieties could be as high as 27～31.5、m3·hm^-2. The net benefit, CBR, investment effect coefficient, IRR, NPV and PVI were 3 687.0 yuan·hm^-2, 0.22, 25.5%, 9 472.5 yuan·hm^-2 and 1.80 respectively, which showed a positive investment.

Key words: Poplar, Pulp wood, Oriented cultivation, Economic effect