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Scientia Silvae Sinicae ›› 2022, Vol. 58 ›› Issue (8): 53-62.doi: 10.11707/j.1001-7488.20220806

• Research papers • Previous Articles     Next Articles

Altitudinal Differences in Intraspecific and Interspecific Competition Index of Natural Forests of Quercus aquifolioides in Southeast Tibet

Huifang Yao1,2,3,Jie Lu1,2,3,*,Jiaqin Zeng4,Daqing Luo1,2,3,Xinsheng Zhang1,2,3,Chao Wang1,2,3,Deshui Yu1,2,3   

  1. 1. Institute of Tibet Plateau Ecology, Tibet Agricultural & Animal Husbandry University Nyingchi 860000
    2. Tibet Key Laboratory of Forest Ecology in Plateau Area, Ministry of Education Nyingchi 860000
    3. Linzhi National Forest Ecosystem Observation & Research Station of Tibet Nyingchi 860000
    4. College of Resources and Environment, Tibet Agricultural & Animal Husbandry University Nyingchi 860000
  • Received:2021-04-06 Online:2022-08-25 Published:2022-12-19
  • Contact: Jie Lu

Abstract:

Objective: Through quantitative analysis of Interspecific and inter-specific competition index of natural forest of Quercus aquifolioides at different altitudes in southeast Tibet, the influence of altitude on forest competition index was revealed, which provides a theoretical basis for the management and protection of Q. aquifolioides natural forest. Method: Four sample plots were set up in the Q. aquifolioides natural forest according to the altitudinal gradients in Lulang Town, Bayi District, Nyingchi City, Tibet, with dark brown mountain soil and mixed coniferous and broadleaved forest. Competitive and target trees sample plots were investigated. Hegyi single tree competition model was used to study the interspecific and inter-specific competition in the Q. aquifolioides natural forests at different altitudes; a total of five models, including the power function, logarithmic, exponential, polynomial and Logistic model were used to fit the regression relationship between DBH of target trees of Q. aquifolioides and their competition index, and the optimal function was selected. Result: 1) The competition index of Q. aquifolioides natural forest at different altitudes was different. The Interspecific competition index of 3 740 m (plot a), 3 640 m (plot b), 3 540 m (plot c)and 3 440 m (plot d) accounted for 17.11 %, 22.26 %, 30.79 %, and 70.13 % of the total competition index, respectively, indicating that plot a, b, and c were dominated by inter-specific competition, and plot d was dominated by intra-specific competition. 2) Among the associated tree species of Q. aquifolioides, the competitiveness of Abies georgei var. smithii was the strongest, followed by Betula platyphylla, and the weakest was B. utilis. 3) In all plots, the competition index of Q. aquifolioides decreased with the increase of DBH, showing a significant negative correlation. In plot a, the optimal model of the relationship between DBH and competition index of the competitive tree is the power function model, the optimal models of plot b and c are the cubic polynomial model, and the optimal model of plot d is the exponential function. Conclusion: Q. aquifolioides natural forest in southeastern Tibet is dominated by intraspecific competition at an altitude of 3 440 m, and interspecific competition at an altitude of 3 540-3 740 m. The competition index of Q. aquifolioides decreased with the increase of DBH, and tended to be stable when DBH reached 25 cm. The fitted model can be used to effectively predict the competition index of Q. aquifolioides forest.

Key words: Quercus aquifolioides, intraspecific competition, interspecific competition, competition index, southeast Tibet

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