Planting spacing affects canopy structure,biomass production and stem roundness in poplar plantations |
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Authors: | Tet Nay Tun Jiao Guo Ye Tian |
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Institution: | 1. College of Forestry, Nanjing Forestry University, Nanjing, People’s Republic of China;2. Department of Forestry, Yezin University of Forestry, Nay Pyi Taw, Myanmar;3. Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, People’s Republic of China |
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Abstract: | To improve the productivity and wood quality of poplar plantations, effects of four planting spacing on canopy characteristics, biomass production and stem roundness in poplar plantations were evaluated over 8 years. Planting spacing influenced canopy characteristics of the plantations, and further affected the understory vegetation and plantation productivity. Understory vegetation biomass and Shannon-Wiener index were negatively correlated with leaf area index, but both diversity indexes and aboveground biomass of understory vegetation were higher in stands with a wider spacing. Tree diameter growth increased with increasing planting spacing, while the increment in plantations of square configurations (5?×?5 m and 6?×?6 m) was higher than those with rectangular configurations (3?×?8 m, 4.5?×?8 m). The highest poplar biomass production was achieved in the plantation with 5?×?5 m spacing at age 8. Moreover, poplar trees showed a tendency with better stem roundness in a square configuration. The results suggest that planting spacing not only affect canopy characteristics, understory vegetation and tree growth but also wood quality, and square configurations (5?×?5 m and 6?×?6 m) could be a better option for poplar plywood timber production at similar sites. |
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Keywords: | Poplar clone planting density leaf area index tree growth stem roundness understory vegetation biomass Shannon-Wiener index |
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