Relationships of Chamaecyparis formosensis crown shape and parameters with thinning intensity and age


  • Tian-Ming Yen Department of Forestry, National Chung-Hsing University; Address: No. 250, Kuo Kuang Road, South District, Taichung, 40227, Taiwan



thinning effect, thinning trial, crown form parameter, crown profile equation


Taiwan red cypress (Chamaecyparis formosensis Matsum) is an indigenousand important cypress conifer with a broad area of natural forests and plantations in Taiwan. Because of the high economic value and multiple uses of the species, numerous researchers have studied its growth and yield within plantation forests. However, few studies have examined how the crown characteristics of the tree respond to different thinning regimes, particularly in the long run. The crown is a dominant outline of aboveground component of a tree that can sensitively reflect competitions from trees located nearby. This study evaluated the crown form of Taiwan red cypress at three different growth stages with different thinning intensities over 20 years. The study began in 1982, when the three plantations examined were aged 7, 15, and 21 years, and when thinning treatments began. In 2002, crown form parameters (CFPs) and crown profile equations (CPEs) were used to analyze the thinning effects at the tree level. Two-way analysis of variance (ANOVA) revealed that age class influenced most CFPs and that thinning treatments influenced all CFPs, indicating that both factors could simultaneously affect the CFPs. Moreover, the CPEs fit the observed data well for all age classes, demonstrating that the equation had a high capacity for predicting crown form. The CPEs were used to determine the mean crown shape profile for each thinning treatment and age class. According to the mean crown profile predicted by CPEs, we found that crown length and width increased with thinning intensity for all aged trees, especially after a heavy thinning treatment.


Baldwin Jr V. C., Peterson K., Clark, III A., Ferguson, R. B. Strub, M. R., Bower, D. R., 2000. The effects of spacing and thinning on stand and tree characteristics of 38-year-old Loblolly Pine. ForestEcology and Management 137: 91–102. DOI: 10.1016/S0378-1127(99)00340-0 BaldwinJr. V. C., Peterson K. D., 1997. Predicting the crown shape of loblolly pine tree. Canadian Journal of ForestResearch 27: 102–107. DOI: 10.1139/x96-100 Brix H., 1981. Effects of thinning and nitrogen fertilization on branch and foliage production. Canadian Journal of ForestResearch 11: 502–511. DOI: 10.1139/x81-069 Cai S., Kang X., Zhang L., 2013. Allometric models for aboveground biomass of ten tree species in northeastChina. Annals ofForestResearch 56(1): 105–122. Chen Y. T., Yen T. M., Li C. L., 2010. Crown characteristics and crown shape of Japanese cedar (Cryptomerica japonica D. Don) in an even-aged stand. Quarterly Journal of Chinese Forestry 43:213–221. (in Chinese with English abstract). Filipiak M., 2005. Changes of Abies alba crown state and stand quality class in theSudetyMountains. Dendrobiology 54: 11–17. Ginn S. E., Seiler J. R., Cazell B. H., Kreh, R. E., 1991. Physiological and growth responses of eight-year-old loblolly pine stands to thinning.ForestScience 37: 1030–1040. Hashimoto R., 1991. Canopy development in young sugi (Cryptomeria japonica) stands in relation to changes with age in crown morphology and structure. Tree Physiology 8: 129–143. DOI: 10.1093/treephys/8.2.129 Hwang K. K., 1977. Studies on the growth of planted forest of red cypress. Quarterly Journal of Chinese Forestry 10: 95–109. (in Chinese with English abstract). Kramer P. J. Kozlowski T. T., 1979. Physiology of Wood Plants.MiGraw Hill,New York. Lee J. S. 1985., Studies on the thinning ofTaiwanred cypress plantation. Technical bulletin of department of forestry, National Chung-Hsing university. (in Chinese with English abstract). Lee J. S., Yen T. M., 2000. Evaluation of forest potential productivity of Chamaecyparis formosensis plantations- a study on site index curve. Quarterly Journal ofForestResearch 22: 51–60. (in Chinese with English abstract). Li L. E., Yen, T. M. 2010. Thinning effects on stand and tree levels ofTaiwanred cypress (Chamaecyparis formosensis Matsum.) 4 years after years after thinned. Quarterly Journal of Chinese Forestry 43: 249–260. (in Chinese with English abstract). Liu Y. C., Lu F. Y., Ou C. H., 1988. Trees ofTaiwan. Monographic publication No.7 College of Agriculture,NationalChung-shingUniversity.Taichung,Taiwan. pp. 76–80. (in Chinese). Mäkinen H., Isomäki A., 2004. Thinning intensity and long-term changes in increment and stem form of Norway spruce trees. ForestEcology and Management 201: 295–309. DOI: 10.1016/j.foreco.2004.07.017 Pinkard E. A. Neilsen W. A., 2003. Crown and stand characteristics of Eucalyptus nitens in response to initial spacing: implications for thinning. ForestEcology and Management 172: 215-227. DOI: 10.1016/S0378-1127(01)00803-9 Ruark G. A., Martin G. L., Bockheim J. G., 1987. Comparison of constant and variable allometric ratios for estimating Populus tremuloides biomass.ForestScience 33: 294–300. Simard S. W., Blenner-Hassett,T., Cameron I. R., 2004. Pre-commercial thinning effects on growth, yield and mortality in even-aged paper birch stands in British Columbia. ForestEcology and Management 190: 163–178. DOI: 10.1016/j.foreco.2003.09.010 Taiwan Central Weather Bureau, 2014 TaiwanForestry Bureau, 1995. TheThirdNational ForestResources and Land Use inTaiwan.TaiwanForestBureau. pp. 1–258. (in Chinese with English summary). Wang J., Fan J., Fan X., Zhang C., Wu L., Gadow K. v., 2013. Crown and root biomass equations for the small trees of Pinus koraiensis under canopy Dendrobiology 70: 13–25. Weiskittel, A.R., D. A. Maguire, and R.A. Monserud. 2007. Response of branch growth and mortality to silvicultural treatments in coastal Douglas-fir plantations: Implications for predicting tree growth. ForestEcology and Management 251: 182–194. DOI: 10.1016/ j.foreco.2007.06.007 Yen T. M. 1999. Comparisons of direct and in direct estimation methods for stand structure of Chamaecyparis formosensis plantations. Quarterly Journal of Chinese Forestry 32: 347–356. (in Chinese with English abstract). Yen T. M., 2002. Stand density management of Chamaecyparis formosensis plantations. Quarterly Journal of Chinese Forestry 35: 55-67. (in Chinese with English abstract). Yen T. M., Ai L. M., Li C. L., Lee J. S., Huang K. L., 2009. Aboveground carbon contents and storage of three major Taiwanese conifer species.TaiwanJournal ofForestScience 24: 91–102. Yen, T. M., 2015. Comparing aboveground structure and aboveground carbon storage of an age series of moso bamboo forests subjected to different management strategies. Journal of ForestResearch 20:1–8. DOI: 10.1007/s10310-014-0455-0 Yen, T. M., Lee, J. S., Li, C. L., Chen Y. T., 2013. Aboveground biomass and vertical distribution of crown for Taiwanred cypress 20 years after thinning. Dendrobiology 70: 109–116. DOI: 10.12657/denbio.070.012 Yen, T. M., Liu, C. C., Chang, W. J. 2006. Crown characteristics of China-fir (Cunninghamia lanceolata) in low stand density. Quarterly Journal of Chinese Forestry 39: 303–314. (in Chinese with English abstract). Yen, T. M., Wang, C. T. 2013. Assessing carbon storage and carbon sequestration for natural forests, man-made forests, and bamboo forests in Taiwan. International Journal of Sustainable Development & World Ecology 20(5): 455–460. DOI: 10.1080/13504509. 2013.811445 Yu S., Chambers J. L., Tang Z., Barnett J. P., 2003. Crown characteristics of juvenile loblolly pine 6 years after application of thinning and fertilization. ForestEcology and Management 180: 345–352. DOI: 10.1016/S0378-1127(02)00582-0






Research article