The impact of intraspecific competition on tree growth in planted Korean pine forest
Keywords:Pinus koraiensis, competition index, individual tree growth.
The aim of this study was to explore the correlation of competition indices (CIs) on individual tree growth for Korean pine (Pinus koraiensis) plantation using partial correlation analysis and generalized linear models. The data were collected from 15 permanent plots in Mengjiagang forestry farm, Northeast China. The results showed that the distance dependent CIs have a higher predictive capacity for individual growth of pine trees. The control index of competitive trees number (CI1) combined with the selection fixed competitor trees (M2) was found to be the most well correlated competition measure with five - years diameter increment. Thus, the competition index (CI1- M2) was recommended for developing individual tree growth models. The subject tree diameter at breast height, crown width, height to crown base, tree volume and basal area all showed a significantly linear correlation with tree competition intensity (P < 0,05). Diameter at breast height, crown width, tree volume and basal area all decreased with increasing competition intensity, whereas the height to crown base increased. There was no significant relationship between competition intensity and tree height (P > 0,05). The optimal model of predicting individual growth with logarithm of diameter at breast height and CIs as the independent variables due to the best fitting performance. This results also showed considerable improvement in predicting individual tree periodic growth when including competition indices that the mean absolute error is reduced in the range of 22−25%.
Bella I. E., 1971. A new competition model for individual trees. Forest Science, 17(17): 364–372.
Coomes D. A., Allen R. B., 2007. Effects of size competition and altitude on tree growth. Journal of Ecology, 95 (5): 1084−1097.
Corona P, Ferrara A., 1989. Individual competition indices for conifer plantations. Agriculture, Ecosystems & Environment, 27 (1-4): 429–443.
Daniels R. F., Burkhart H. E., Clason T. R., 1986. A comparison of competition measures for predicting growth of loblolly pine trees. Canadian Journal of Forest Research, 16(6): 1230−1237.
Dong L. H., Li F. R., Gu W. W., 2013. Effects of tree competition on biomass and biomass models of Pinus koraiensis plantation. Journal of Beijing Forestry University, 35(6): 15−22 [in Chinese].
Edgaras L, Andrius K, Heinz R., 2014. The impact of Competition for growing space on diameter, basal area and height growth in pine trees. Baltic forestry, 20(2): 301−313.
Freckleton R P, Watkinson A R., 1999. The mis-measurement of plant competition. Function Ecology, 13(2): 285−287.
Huang X. F., Kang X. G., Sun L., 2011. Establishment of Individual Basal Area Growth Model of Korean Pine. Journal of Northwest Forestry University, 26(3): 143−146 [in Chinese].
Ledermann T., 2010. Evaluating the performance of semi distance independent competition indices in predicting the basal area growth of individual trees. Canadian Journal of Forest Research, 40(4): 796‒805.
Lorimer C. G.,1983. Tests of age-independent competition indices for individual trees in natural hardwood stands. Forest Ecology and Management, 6(4): 343−360.
Nguyen, T. T., Tai, D. T., Zhang, P., Razaq, M., & Shen, H. L., 2019. Effect of thinning intensity on tree growth and temporal variation of seed and cone production in a Pinus koraiensis plantation. Journal of Forestry Research, 30(3): 835−845.
Nishimura N., Hara T., Miura M., 2002. Tree competition andspecies coexistence in a warm-temperate old growth evergreen broad-leaved forest in Japan. Plant Ecology, 164(2): 235−248.
Peet R. K., Christense N. L., 1987. Competitionand tree death. Bioscience, 37(8): 586−595.
Perot T, Goreaud F., Ginisty C., 2010. A model bridging distance-dependent and distance-independent tree models to simulate the growth of mixed forests. Annals of Forest Science, 67 (5): 501−511.
Shainsky L., Radosevich S., 1992. Mechanisms of competition between Douglas-fir andred alder seedlings. Ecology, 73(1): 30−45.
Shao G. F., 1985. Study on individual tree growth model for Korean pine plantations. Journal of Northeast Forestry University, 13(3): 38−46 [in Chinese].
Schroder J., 2004. Modeling of growth and competition in pine/beech forest conversion stands in Northwest Saxony. Germany: Dresden University of Technology.
Zhang Q., Hong W., Wu C., 2005. Studies on intraspecific and interspecific competition in natural communities of Tsuga longibracteata. Guangxi Botany, 25(1): 14−17 [in Chinese].
Zhang C., Huang R. L, Li J., 2006. Quantitative relationships of intra-and interspecific competition in Cryptocarya concinna. Chinese Journal of Applied Ecology, 17(1): 22−26 [in Chinese].
Tilman D, 1982. Resource competition and community structure. Princeton, NJ: Princeton Univ, 296 pp.
Yu H., Yang X. H., Ci L. J., 2009. Competition intensity of Mongolian pine forests in Hulun Buir sand region of Inter Mongolia, China. Chinese Journal of Applied Ecology, 20(2): 250−255 [in Chinese].
Zi L. B., Mai M. T., Yang H., 2012. A review on competition indices of individual trees. Journal of Northwest Forestry University, 27(6): 152−158 [in Chinese].