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| Comparative study of coppice and seeding forest of Robinia pseudoacacia L. |
| Key Laboratory of Silviculture of Shandong Province, Agro-Ecoenvironmental Laboratory of Shandong Agricultural University, 271018, Tai'an, Shandong,China |
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Abstract Robinia pseudoacacia L. is an important timber and non-commerical species. The representative plantations of initiation and sprouting second generation were selected in Mountain Yi(E 118°36’,N 36°10’) and Mountain Tai (E 117°19, N 36°17’) of Shandong Province. To solve the problems of sprouting regeneration embarrassment, plantation structure characteristics, plant growth process and trunk form were investigated and analyzed. Results showed that: 1) Trunk height before 22 years, trunk total volume growth and the average volume growth before 17 years, and volume growth in successive years before 14 years of sprouting second generation plantation were higher than that of initiation generation, but afterwards, all indexes are lower than initiation generation. 2) Trunks of the initiation generation plantation of R. pseudoacacia L. were straight, while most of the sprouting trunks were crooked. 3) The index of the trunk bending could be used to describe the truck bending degree.According to this index, five levels, i. e. , straight truck, mainly straight truck, slightly bending truck,medium bending truck, and seriously bending truck were divided. We found that in R. pseudoacacia L.plantation medium bending and seriously bending truck trees accounted for 34.8 percent, the straight truck tree was few which only accounted for 0.86 percent, the mainly straight truck trees accounted for 33.8 percent. Based on the study of growth retardation, bad trunk form and non-timber problems with regard to the R. pseudoacacia L. sprowting regeneration plantation, we suggested that sprouting regeneration was a very important problem which required much more attentions and researches.
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Received: 28 June 2012
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