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Scientia Silvae Sinicae ›› 2019, Vol. 55 ›› Issue (9): 103-110.doi: 10.11707/j.1001-7488.20190911

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Reconstruction Dynamic Models of Height to Crown Base of Larch(Larix olgensis)Plantation Applying Knot Analysis Technique

Chen Dongsheng1, Li Fengri2, Sun Xiaomei1, Zhang Shougong1   

  1. 1. Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration Research Institute of Forestry, CAF Beijing 100091;
    2. School of Forestry, Northeast Forestry University Harbin 150040
  • Received:2017-07-28 Revised:2018-05-19 Published:2019-10-28

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Abstract: [Objective] The dynamic model of height to crown base was built to show crown recession in larch plantation by knot analysis technique, and to evaluate the influence of individual tree and stand variables on crown recession.[Method] Based on falling 40 sample trees in 8 plots of larch plantation in 2007, the dynamic data of height to crown base were obtained by applying knot analysis technique. The traditional linear model, Richard and Logistic non-linear model were used to construct the dynamic model of height to crown base.[Result] Linear model, Richard and Logistic nonlinear model could well fit the dynamic change process of height to crown base, model parameters were statistically significant (P<0.01). One of the highest fitting precision was based on Richard equation model, but the model had heteroscedasticity, by adding the weight to eliminate heteroscedasticity, eventually model R2 was 0.904, Bias and RSME were 0.002 and 1.251 respectively. The model form is HCB=(3.146+0.036CCF+0.225Bas+0.788HT-0.481CL)(1-e-0.086 t)4.278.[Conclusion] Dynamic process of height to crown base was consistent with the stand growth rule which it was accordance with the "S" type growth curve. It can be explained through crown competition factor (CCF), stand basal area (Bas), tree height (HT) and crown length (CL). The height to crown base increased with the increase of HT, CCF and Bas, accelerating larch crown recession. From 10 years to 41 years, crown length of larch plantation fell from 75% to 36% in biggest CCF(187.33), however, fell from 75% to 40% in smallest CCF(105.82). We also found that a mean annual increment of height to crown was 0.66 m in larch plantation. The dynamic process of height to crown base of larch plantation was well simulated by model, crown recession could be explained by tree, stand variables. Consequently, knot analysis technology was considered as an effective method to acquire a long-term dynamic data of crown.

Key words: larch plantation, height to crown base, crown recession, linear and nonlinear model, knot analysis technique

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