Canopy mechanical abrasion between adjacent plants influences twig and leaf traits of Tsuga chinensis assemblage in the Mao’er Mountain

doi:10.17521/cjpe.2020.0319

Abstract

Abstract:

Aims Mechanical abrasion is an important ecological process in the adjacent plant canopy bordering area, which can significantly influence the physiological and morphological characteristics of branches and leaves. However, there is a lack of in-depth research on the characteristics and trade-off mechanisms of the mechanical abrasion on neighboring plant canopies in branches and leaves from the perspective of functional traits.

Methods This study focused on the Tsuga chinensis from the Mao’er Mountain in Guangxi, China. The leaf area, length, and width, as well as the leaf area of the dominant and inferior branches were compared between adjacent canopy layers in mechanical abrasion zones and nonmechanical abrasion zones. Differences in leaf thickness, specific leaf area, leaf dry matter content and leaf dry mass, terminal twig water content, and twig diameter were also analyzed. Moreover, variation and trade-off relationship between branch and leaf functional traits under the influence of mechanical abrasion were evaluated.

Important findings Mechanical abrasion significantly affected the leaf dry matter content, specific leaf area, and leaf dry mass of adjacent canopy leaves. Specifically, the leaf dry matter content of the dominant branches in the mechanical abrasion zone was significantly greater than that in the inferior branches and nonmechanical abrasion zone. Moreover, the specific leaf area of the dominant branches was significantly lower than that of the inferior branches and nonmechanical abrasion areas, whereas the leaf dry mass of the inferior branches was significantly lower than that of the dominant branches and nonmechanical abrasion area. Noteworthy, mechanical abrasion was found to differently influence the relationship between branches and leaves in terms of functional traits. Leaf area- leaf length showed a consistent positive relationship in the mechanical abrasion zone dominant branches, inferior branch, and the nonmechanical abrasion zone. Leaf area-leaf width, leaf area-leaf dry mass, leaf width-leaf thickness, leaf length-leaf width, and leaf thickness-terminal twig diameter were only significantly positively correlated within dominant branches in the mechanical abrasion zone. Leaf area-terminal twig diameter and terminal twig diameter-terminal twig water content were only significantly negatively correlated in the inferior branches. Moreover, leaf dry matter content-leaf thickness was only significantly positively correlated in the inferior branches. Other traits did not show a significant relationship in the dominant branch, inferior branch, and nonmechanical abrasion zone. These results indicate that canopy mechanical abrasion between forest plant neighbors can significantly change the trade-off relationship between branches and leaves regarding to functional traits.

Key words: neighbor canopy, competition, twig and leaf trade-off, mechanical abrasion, twig and leaf traits

TAN Yi-Bo, TIAN Hong-Deng, ZENG Chun-Yang, SHEN Hao, SHEN Wen-Hui, YE Jian-Ping, GAN Guo-Juan. Canopy mechanical abrasion between adjacent plants influences twig and leaf traits of Tsuga chinensis assemblage in the Mao’er Mountain[J]. Chin J Plant Ecol, 2021, 45(12): 1281-1291.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2020.0319

https://www.plant-ecology.com/EN/Y2021/V45/I12/1281

Figures/Tables 5

References 53

[1]	Asner GP, Knapp DE, Anderson CB, Martin RE, Vaughn N (2016). Large-scale climatic and geophysical controls on the leaf economics spectrum. Proceedings of the National Academy of Sciences of the United States of America, 113, E4043-E4051.
[2]	Brannon TML (2012). Examining Methodologies to Assess Abrasion in Tree Crowns. Master degree dissertation, University of Tennessee, Knoxville. 1-8.
[3]	Cao JY, Liu JF, Yuan Q, Xu DY, Fan HD, Chen HY, Tan B, Liu LB, Ye D, Ni J (2020). Traits of shrubs in forests and bushes reveal different life strategies. Chinese Journal of Plant Ecology, 44, 715-729. DOI URL
	[ 曹嘉瑜, 刘建峰, 袁泉, 徐德宇, 樊海东, 陈海燕, 谭斌, 刘立斌, 叶铎, 倪健 (2020). 森林与灌丛的灌木性状揭示不同的生活策略. 植物生态学报, 44, 715-729.]
[4]	Chen C, Zhang SJ, Li LD, Liu ZD, Chen JL, Gu X, Wang LF, Fang X (2019). Carbon, nitrogen and phosphorus stoichiometry in leaf, litter and soil at different vegetation restoration stages in the mid-subtropical region of China. Chinese Journal of Plant Ecology, 43, 658-671. DOI URL
	[ 陈婵, 张仕吉, 李雷达, 刘兆丹, 陈金磊, 辜翔, 王留芳, 方晰 (2019). 中亚热带植被恢复阶段植物叶片、凋落物、土壤碳氮磷化学计量特征. 植物生态学报, 43, 658-671.] DOI
[5]	Cleugh HA, Miller JM, Böhm M (1998). Direct mechanical effects of wind on crops. Agroforestry Systems, 41, 85-112. DOI URL
[6]	Coomes DA, Grubb PJ (2000). Impacts of root competition in forests and woodlands: a theoretical framework and review of experiments. Ecological Monographs, 70, 171-207. DOI URL
[7]	DeClerck FAJ, Barbour MG, Sawyer JO (2006). Species richness and stand stability in conifer forests of the Sierra Nevada. Ecology, 87, 2787-2799. PMID
[8]	Falster DS, Warton DI, Wright IJ (2006). User’s Guide to SMATR: Standardised Major Axis Tests & Routines Version 2.0. [2020-09-06]. http://www.bio.mq.edu.au/ecology/SMATR/.
[9]	Fish H, Lieffers VJ, Silns U, Hall RJ (2006). Crown shyness in lodgepole pine stands of varying stand height, density, and site index in the upper foothills of Alberta. Canadian Journal of Forest Research, 36, 2104-2111. DOI URL
[10]	Franklin KA, Whitelam GC (2005). Phytochromes and shade- avoidance responses in plants. Annals of Botany, 96, 169-175. PMID
[11]	Gao J, Wang JN, Xu B, Xie Y, He JD, Wu Y (2016). Plant leaf traits, height and biomass partitioning in typical ephemerals under different levels of snow cover thickness in an alpine meadow. Chinese Journal of Plant Ecology, 40, 775-787. DOI URL
	[ 高景, 王金牛, 徐波, 谢雨, 贺俊东, 吴彦 (2016). 不同雪被厚度下典型高山草地早春植物叶片性状、株高及生物量分配的研究. 植物生态学报, 40, 775-787.] DOI
[12]	Hajek P, Seidel D, Leuschner C (2015). Mechanical abrasion, and not competition for light, is the dominant canopy interaction in a temperate mixed forest. Forest Ecology and Management, 348, 108-116. DOI URL
[13]	Han L, Zhao CZ, Xu T, Feng W, Duan BB (2017). Relationships between leaf thickness and vein traits of Achnatherum splendens under different soil moisture conditions in a flood plain wetland, Heihe River, China. Chinese Journal of Plant Ecology, 41, 529-538. DOI URL
	[ 韩玲, 赵成章, 徐婷, 冯威, 段贝贝 (2017). 不同土壤水分条件下洪泛平原湿地芨芨草叶片厚度与叶脉性状的关系. 植物生态学报, 41, 529-538.] DOI
[14]	Han WX, Fang JY (2008). Review on the mechanism models of allometric scaling laws: 3/4 vs. 2/3 power. Journal of Plant Ecology (Chinese Version), 32, 951-960.
	[ 韩文轩, 方精云 (2008). 幂指数异速生长机制模型综述. 植物生态学报, 32, 951-960.] DOI
[15]	He D, Yan ER (2018). Size-dependent variations in individual traits and trait scaling relationships within a shade-tolerant evergreen tree species. American Journal of Botany, 105, 1165-1174. DOI URL
[16]	He YY, Guo SL, Wang Z (2019). Research progress of trade- off relationships of plant functional traits. Chinese Journal of Plant Ecology, 43, 1021-1035. DOI URL
	[ 何芸雨, 郭水良, 王喆 (2019). 植物功能性状权衡关系的研究进展. 植物生态学报, 43, 1021-1035.] DOI
[17]	Huang XG, Xie Q (2000). A preliminary study on the structure and dynamics of the Tsuga tchekiangensis population on Maoershan Mountain. Journal of Guangxi Normal University (Natural Science), 18, 86-90.
	[ 黄宪刚, 谢强 (2000). 猫儿山南方铁杉种群结构和动态的初步研究. 广西师范大学学报(自然科学版), 18, 86-90.]
[18]	Hultine KR, Marshall JD (2000). Altitude trends in conifer leaf morphology and stable carbon isotope composition. Oecologia, 123, 32-40. DOI PMID
[19]	Ishida A, Nakano T, Yazaki K, Matsuki S, Koike N, Lauenstein DL, Shimizu M, Yamashita N (2008). Coordination between leaf and stem traits related to leaf carbon gain and hydraulics across 32 drought-tolerant angiosperms. Oecologia, 156, 193-202. DOI URL
[20]	Lasky JR, Uriarte M, Boukili VK, Chazdon RL (2014). Trait-mediated assembly processes predict successional changes in community diversity of tropical forests. Proceedings of the National Academy of Sciences of the United States of America, 111, 5616-5621.
[21]	Li K, Xiang WH (2011). Comparison of specific leaf area, SPAD value and seed mass among subtropical tree species in hilly area of Central Hunan, China. Journal of Central South University of Forestry and Technology, 31, 213-218.
	[ 李凯, 项文化 (2011). 湘中丘陵区12个树种比叶面积、SPDA值和种子干质量的比较. 中南林业科技大学学报, 31, 213-218.]
[22]	Li L, Wei SG, Huang ZL, Cao HL, Mo DQ (2012). Regenerative condition and analysis of spatial distribution pattern of two relic plants in Mao’ershan Mountain, China. Chinese Journal of Plant Ecology, 36, 144-150. DOI URL
	[ 李林, 魏识广, 黄忠良, 曹洪麟, 莫德清 (2012). 猫儿山两种孑遗植物的更新状况和空间分布格局分析. 植物生态学报, 36, 144-150.] DOI
[23]	Li Q, Zhao CZ, Zhao LC, Wang JL, Zhang WT, Yao WX (2017). Empirical relationship between specific leaf area and thermal dissipation of Phragmites australis in salt marshes of Qinwangchuan. Chinese Journal of Plant Ecology, 41, 985-994. DOI URL
	[ 李群, 赵成章, 赵连春, 王建良, 张伟涛, 姚文秀 (2017). 秦王川盐沼湿地芦苇比叶面积与叶片热耗散的关联性分析. 植物生态学报, 41, 985-994.] DOI
[24]	Li XT (1990). Preliminary investigation on the ecological characteristics of Tsuga chinensis in Mao’er Mountain forest region. Guangxi Forest Science and Technology, 19(4), 22-23.
	[ 李晓铁 (1990). 猫儿山林区南方铁杉生态学特性初步调查研究. 广西林业科技, 19(4), 22-23.]
[25]	Li YH, Luo TX, Lu Q, Tian XY, Wu B, Yang HH (2005). Comparisons of leaf traits among 17 major plant species in Shazhuyu Sand Control Experimental Station of Qinghai Province. Acta Ecologica Sinica, 25, 994-999.
	[ 李永华, 罗天祥, 卢琦, 田晓娅, 吴波, 杨恒华 (2005). 青海省沙珠玉治沙站17种主要植物叶性因子的比较. 生态学报, 25, 994-999.]
[26]	Li YN, Yang DM, Sun SC, Gao XM (2008). Effects of twig size on biomass allocation within twigs and on lamina area supporting efficiency in Rhododendron: allometric scaling analyses. Journal of Plant Ecology (Chinese Version), 32, 1175-1183.
	[ 李亚男, 杨冬梅, 孙书存, 高贤明 (2008). 杜鹃花属植物小枝大小对小枝生物量分配及叶面积支持效率的影响: 异速生长分析. 植物生态学报, 32, 1175-1183.] DOI
[27]	Ma XY, Liu LL, Yin MQ, Song HJ, Zhu PC, Yu XN, Du N, Wang RQ, Guo WH (2021). Variation in plant functional traits of Phragmites australis based on field investigation and common garden experiment. Acta Ecologica Sinica, 41, 3755-3764.
	[ 马香艳, 刘乐乐, 尹美淇, 宋慧佳, 朱鹏程, 于晓娜, 杜宁, 王仁卿, 郭卫华 (2021). 基于野外调查和同质种植园实验的芦苇植物功能性状变异研究. 生态学报, 41, 3755-3764.]
[28]	Meng SX, Rudnicki M, Lieffers VJ, Reid DEB, Silins U (2006). Preventing crown collisions increases the crown cover and leaf area of maturing lodgepole pine. Journal of Ecology, 94, 681-686. DOI URL
[29]	Peng X, Yan WD, Wang GJ, Zhao MF (2018). Leaf morphological characteristics and leaf area estimation model for Cunninghamia lanceolata. Acta Ecologica Sinica, 38, 3569-3580.
	[ 彭曦, 闫文德, 王光军, 赵梅芳 (2018). 杉木叶形态特征与叶面积估算模型. 生态学报, 38, 3569-3580.]
[30]	Perez-Ramos IM, Urbieta IR, Zavala MA, Maranon T (2012). Ontogenetic conflicts and rank reversals in two Mediterranean oak species: implications for coexistence. Journal of Ecology, 100, 467-477. DOI URL
[31]	Pitman EJG (1939). A note on normal correlation. Biometrika, 31, 9-12. DOI URL
[32]	Putz FE, Parker GG, Archibald RM (1984). Mechanical abrasion and intercrown spacing. American Midland Naturalist, 112, 24-28. DOI URL
[33]	Qi HY, Jin ZN, Yang QP, Yuan RB, Qiu LH, Shi JM, Ouyang M (2014). Growing law and cause of poor regeneration of Tsuga chinensis var. tchekiangensis in Jiangxi Wuyishan National Nature Reserve. Acta Agriculturae Universitatis Jiangxiensis, 36, 137-143.
	[ 祁红艳, 金志农, 杨清培, 袁荣斌, 裘利洪, 施建敏, 欧阳明 (2014). 江西武夷山南方铁杉生长规律及更新困难的原因解释. 江西农业大学学报, 36, 137-143.]
[34]	Reich PB, Wright IJ, Cavender‐Bares J, Craine JM, Oleksyn J, Westoby M, Walters MB (2003). The evolution of plant functional variation: traits, spectra, and strategies. International Journal of Plant Sciences, 164, S3, S143-S164. DOI URL
[35]	Shi QR, Xu MS, Zhao YT, Zhou LL, Zhang QQ, Ma WJ, Zhao Q, Yan ER (2014). Testing of corner’s rules across woody plants in Tiantong region, Zhejiang Province: effects of micro-topography. Chinese Journal of Plant Ecology, 38, 665-674.
	[ 史青茹, 许洺山, 赵延涛, 周刘丽, 张晴晴, 马文济, 赵绮, 阎恩荣 (2014). 浙江天童木本植物Corner法则的检验: 微地形的影响. 植物生态学报, 38, 665-674.] DOI
[36]	Siefert A, Violle C, Chalmandrier L, Albert CH, Taudiere A, Fajardo A, Aarssen LW, Baraloto C, Carlucci MB, Cianciaruso MV, de L Dantas V, de Bello F, Duarte LDS, Fonseca CR, Freschet GT, et al. (2015). A global meta- analysis of the relative extent of intraspecific trait variation in plant communities. Ecology Letters, 18, 1406-1419. DOI PMID
[37]	Song LL, Fan JW, Wu SH, Zhong HP, Wang N (2012). Response characteristics of leaf traits of common species along an altitudinal gradient in Hongchiba grassland, Chongqing. Acta Ecologica Sinica, 32, 2759-2767. DOI URL
	[ 宋璐璐, 樊江文, 吴绍洪, 钟华平, 王宁 (2012). 红池坝草地常见物种叶片性状沿海拔梯度的响应特征. 生态学报, 32, 2759-2767.]
[38]	Su YJ, Hu TY, Wang YC, Li YM, Dai JY, Liu HY, Jin SC, Ma Q, Wu J, Liu LL, Fang JY, Guo QH (2020). Large-scale geographical variations and climatic controls on crown architecture traits. Journal of Geophysical Research: Biogeosciences, 125, e2019JG005306. DOI: 10.1029/2019JG005306. DOI
[39]	Tan YB, Shen WH, Tian HD, Fu Z, Ye JP, Zheng W, Huang SQ (2019). Tree architecture variation of plant communities along altitude and impact factors in Mao’er Mountain, Guangxi, China. Chinese Journal of Applied Ecology, 30, 2614-2620. DOI PMID
	[ 谭一波, 申文辉, 田红灯, 付孜, 叶建平, 郑威, 黄善琪 (2019). 猫儿山不同海拔植物群落树木构型差异及其影响因子. 应用生态学报, 30, 2614-2620.] PMID
[40]	Wang ZG, Wang CK (2019). Mechanisms of carbon source- sink limitations to tree growth. Chinese Journal of Plant Ecology, 43, 1036-1047. DOI URL
	[ 王兆国, 王传宽 (2019). 碳供给与碳利用对树木生长的限制机制. 植物生态学报, 43, 1036-1047.] DOI
[41]	Warton DI, Weber NC (2002). Common slope tests for bivariate errors-in-variables models. Biometrical Journal, 44, 161-174. DOI URL
[42]	Webb VA, Rudnicki M, Muppa SK (2013). Analysis of tree sway and crown collisions for managed Pinus resinosa in southern Maine. Forest Ecology and Management, 302, 193-199. DOI URL
[43]	Westoby M, Falster DS, Moles AT, Vesk PA, Wright IJ (2002). Plant ecological strategies: some leading dimensions of variation between species. Annual Review of Ecology and Systematics, 33, 125-159. DOI URL
[44]	Wilson PJ, Thompson K, Hodgson JG (1999). Specific leaf area and leaf dry matter content as alternative predictors of plant strategies. New Phytologist, 143, 155-162. DOI URL
[45]	Wright IJ, Reich PB, Westoby M (2001). Strategy shifts in leaf physiology, structure and nutrient content between species of high- and low-rainfall and high- and low-nutrient habitats. Functional Ecology, 15, 423-434. DOI URL
[46]	Wright IJ, Reich PB, Westoby M, Ackerly DD, Baruch Z, Bongers F, Cavender-Bares J, Chapin T, Cornelissen JHC, Diemer M, Flexas J, Garnier E, Groom PK, Gulias J, Hikosaka K, et al. (2004). The worldwide leaf economics spectrum. Nature, 428, 821-827. DOI URL
[47]	Xun YH, Di XY, Jin GZ (2020). Vertical variation and economic strategy of leaf trait of major tree species in a typical mixed broadleaved-Korean pine forest. Chinese Journal of Plant Ecology, 44, 730-741. DOI URL
	[ 荀彦涵, 邸雪颖, 金光泽 (2020). 典型阔叶红松林主要树种叶性状的垂直变异及经济策略. 植物生态学报, 44, 730-741.]
[48]	Yang KT, Chen GP, Li G, Yu XY, Zhang K, Tang D, Zhang WX, Guo YJ (2020). Trade-off among leaf traits of typical greening tree species in Lanzhou. Chinese Journal of Ecology, 39, 1518-1526.
	[ 杨克彤, 陈国鹏, 李广, 俞筱押, 张凯, 汤东, 张文祥, 郭英杰 (2020). 兰州市典型绿化树种叶性状间的权衡关系. 生态学杂志, 39, 1518-1526.]
[49]	Zhang RY, Li YP, Ni YL, Gui XJ, Lian JY, Ye WH (2019). Intraspecific variation of leaf functional traits along the vertical layer in a subtropical evergreen broad-leaved forest of Dinghushan. Biodiversity Science, 27, 1279-1290. DOI
	[ 张入匀, 李艳朋, 倪云龙, 桂旭君, 练琚愉, 叶万辉 (2019). 鼎湖山南亚热带常绿阔叶林叶功能性状沿群落垂直层次的种内变异. 生物多样性, 27, 1279-1290.] DOI
[50]	Zhang ZX, Liu P, Cai MZ, Kang HJ, Liao CC, Liu CS, Lou ZH (2008). Population quantitative characteristics and dynamics of rare and endangered Tsuga tchekiangensis in Jiulongshan Nature Reserve of China. Journal of Plant Ecology (Chinese Version), 32, 1146-1156.
	[ 张志祥, 刘鹏, 蔡妙珍, 康华靖, 廖承川, 刘春生, 楼中华 (2008). 九龙山珍稀濒危植物南方铁杉种群数量动态. 植物生态学报, 32, 1146-1156.] DOI
[51]	Zhao XF, Xu HL, Zhang P, Zhang QQ (2014). Influence of nutrient and water additions on functional traits of Salsola nitraria in desert grassland. Chinese Journal of Plant Ecology, 38, 134-146. DOI URL
	[ 赵新风, 徐海量, 张鹏, 张青青 (2014). 养分与水分添加对荒漠草地植物钠猪毛菜功能性状的影响. 植物生态学报, 38, 134-146.] DOI
[52]	Zhong YQ, Zhong QL, Li BY, Yu H, Xu CB, Cheng DL, Le XG, Zheng WT (2020). Effects of Phyllostachys edulis expansion on leaf structural traits of main tree species in subtropical evergreen broad-leaved forests. Acta Ecologica Sinica, 40, 5018-5028.
	[ 钟雅琪, 钟全林, 李宝银, 余华, 徐朝斌, 程栋梁, 乐新贵, 郑文婷 (2020). 毛竹扩张对亚热带常绿阔叶林主要树种叶结构型性状的影响. 生态学报, 40, 5018-5028.]
[53]	Zhu JD, Meng TT, Ni J, Su HX, Xie ZQ, Zhang SR, Zheng YR, Xiao CW (2011). Within-leaf allometric relationships of mature forests in different bioclimatic zones vary with plant functional types. Chinese Journal of Plant Ecology, 35, 687-698. DOI URL
	[ 祝介东, 孟婷婷, 倪健, 苏宏新, 谢宗强, 张守仁, 郑元润, 肖春旺 (2011). 不同气候带间成熟林植物叶性状间异速生长关系随功能型的变异. 植物生态学报, 35, 687-698.]

树号 Tree number	胸径 Diameter breast height (cm)	树高 Height (m)	枝下高 Height under branch (m)	冠幅 Crown width (m)		叶厚度 Leaf thickness (mm)	叶干物质含量 Leaf dry matter content (g·g^-1)	叶面积 Leaf area (cm²)	叶长 Leaf length (cm)	叶宽 Leaf width (cm)	比叶面积 Specific leaf area (cm²·g^-1)	末端枝含水率 Terminal twig water content (%)	末端枝直径 Terminal twig diameter (mm)	叶干质量 Leaf dry mass (g)
树号 Tree number	胸径 Diameter breast height (cm)	树高 Height (m)	枝下高 Height under branch (m)	南北冠幅 North-South crown width	东西冠幅 East-West crown width	叶厚度 Leaf thickness (mm)	叶干物质含量 Leaf dry matter content (g·g^-1)	叶面积 Leaf area (cm²)	叶长 Leaf length (cm)	叶宽 Leaf width (cm)	比叶面积 Specific leaf area (cm²·g^-1)	末端枝含水率 Terminal twig water content (%)	末端枝直径 Terminal twig diameter (mm)	叶干质量 Leaf dry mass (g)
1	27.60	13.50	8.70	5.00	5.20	0.40	0.51	0.29	1.32	0.23	70.89	71.66	3.30	4.16 × 10^-3
2	33.50	11.50	6.40	7.00	6.00	0.41	0.54	0.26	1.18	0.23	63.84	78.00	3.43	4.12 × 10^-3
3	35.70	12.60	7.80	5.60	4.00	0.42	0.53	0.26	1.24	0.22	69.60	64.83	3.95	3.96 × 10^-3
4	25.50	10.80	6.50	3.00	4.00	0.43	0.54	0.30	1.32	0.23	72.25	62.36	3.83	4.42 × 10^-3
5	55.90	12.00	7.10	8.60	8.00	0.43	0.55	0.25	1.16	0.23	67.76	67.25	4.06	3.84 × 10^-3
6	34.60	12.50	6.90	7.50	6.50	0.39	0.48	0.25	1.11	0.23	72.14	67.10	3.05	3.14 × 10^-3
7	27.80	12.20	7.20	6.40	5.50	0.43	0.57	0.25	1.12	0.22	59.41	66.67	3.50	4.10 × 10^-3
8	27.80	11.00	6.90	6.00	6.00	0.39	0.54	0.25	1.16	0.22	76.32	64.88	3.97	3.25 × 10^-3
9	23.70	10.00	6.40	3.00	5.00	0.40	0.52	0.22	1.09	0.22	71.15	67.06	3.78	2.94 × 10^-3
10	41.70	12.00	7.50	9.00	8.00	0.40	0.53	0.21	1.03	0.22	61.93	63.56	3.47	3.57 × 10^-3
11	25.30	11.00	6.80	5.60	5.00	0.39	0.56	0.24	1.12	0.22	67.77	66.41	3.20	3.81 × 10^-3
12	33.60	10.00	6.40	6.00	5.50	0.41	0.52	0.25	1.15	0.22	73.69	67.81	3.64	3.33 × 10^-3
13	44.00	11.00	6.50	7.50	6.00	0.37	0.52	0.24	1.15	0.22	72.23	76.74	3.06	3.29 × 10^-3
14	49.30	11.50	6.30	10.00	8.00	0.42	0.54	0.24	1.12	0.22	70.43	78.11	4.04	3.15 × 10^-3
15	35.50	12.50	7.40	7.60	6.50	0.37	0.51	0.22	1.13	0.23	73.36	67.44	3.60	3.16 × 10^-3
16	15.60	10.50	6.70	7.00	7.00	0.45	0.53	0.24	1.10	0.23	71.56	70.91	3.81	3.34 × 10^-3
$\bar{x}$± SE	33.57 ± 2.57	11.54 ± 0.25	6.97 ± 0.16	6.55 ± 0.48	6.01 ± 0.32	0.41 ± 0.001	0.53 ± 0.001	0.25 ± 0.001	1.15 ± 0.005	0.22 ± 0.000 3	69.65 ± 0.28	68.80 ± 0.31	3.61 ± 0.02	3.60 × 10^-3 ± 2.77 × 10^-5

树号 Tree number	胸径 Diameter breast height (cm)	树高 Height (m)	枝下高 Height under branch (m)	冠幅 Crown width (m)		叶厚度 Leaf thickness (mm)	叶干物质含量 Leaf dry matter content (g·g^-1)	叶面积 Leaf area (cm²)	叶长 Leaf length (cm)	叶宽 Leaf width (cm)	比叶面积 Specific leaf area (cm²·g^-1)	末端枝含水率 Terminal twig water content (%)	末端枝直径 Terminal twig diameter (mm)	叶干质量 Leaf dry mass (g)
树号 Tree number	胸径 Diameter breast height (cm)	树高 Height (m)	枝下高 Height under branch (m)	南北冠幅 North-South crown width	东西冠幅 East-West crown width	叶厚度 Leaf thickness (mm)	叶干物质含量 Leaf dry matter content (g·g^-1)	叶面积 Leaf area (cm²)	叶长 Leaf length (cm)	叶宽 Leaf width (cm)	比叶面积 Specific leaf area (cm²·g^-1)	末端枝含水率 Terminal twig water content (%)	末端枝直径 Terminal twig diameter (mm)	叶干质量 Leaf dry mass (g)
1	27.60	13.50	8.70	5.00	5.20	0.40	0.51	0.29	1.32	0.23	70.89	71.66	3.30	4.16 × 10^-3
2	33.50	11.50	6.40	7.00	6.00	0.41	0.54	0.26	1.18	0.23	63.84	78.00	3.43	4.12 × 10^-3
3	35.70	12.60	7.80	5.60	4.00	0.42	0.53	0.26	1.24	0.22	69.60	64.83	3.95	3.96 × 10^-3
4	25.50	10.80	6.50	3.00	4.00	0.43	0.54	0.30	1.32	0.23	72.25	62.36	3.83	4.42 × 10^-3
5	55.90	12.00	7.10	8.60	8.00	0.43	0.55	0.25	1.16	0.23	67.76	67.25	4.06	3.84 × 10^-3
6	34.60	12.50	6.90	7.50	6.50	0.39	0.48	0.25	1.11	0.23	72.14	67.10	3.05	3.14 × 10^-3
7	27.80	12.20	7.20	6.40	5.50	0.43	0.57	0.25	1.12	0.22	59.41	66.67	3.50	4.10 × 10^-3
8	27.80	11.00	6.90	6.00	6.00	0.39	0.54	0.25	1.16	0.22	76.32	64.88	3.97	3.25 × 10^-3
9	23.70	10.00	6.40	3.00	5.00	0.40	0.52	0.22	1.09	0.22	71.15	67.06	3.78	2.94 × 10^-3
10	41.70	12.00	7.50	9.00	8.00	0.40	0.53	0.21	1.03	0.22	61.93	63.56	3.47	3.57 × 10^-3
11	25.30	11.00	6.80	5.60	5.00	0.39	0.56	0.24	1.12	0.22	67.77	66.41	3.20	3.81 × 10^-3
12	33.60	10.00	6.40	6.00	5.50	0.41	0.52	0.25	1.15	0.22	73.69	67.81	3.64	3.33 × 10^-3
13	44.00	11.00	6.50	7.50	6.00	0.37	0.52	0.24	1.15	0.22	72.23	76.74	3.06	3.29 × 10^-3
14	49.30	11.50	6.30	10.00	8.00	0.42	0.54	0.24	1.12	0.22	70.43	78.11	4.04	3.15 × 10^-3
15	35.50	12.50	7.40	7.60	6.50	0.37	0.51	0.22	1.13	0.23	73.36	67.44	3.60	3.16 × 10^-3
16	15.60	10.50	6.70	7.00	7.00	0.45	0.53	0.24	1.10	0.23	71.56	70.91	3.81	3.34 × 10^-3
$\bar{x}$± SE	33.57 ± 2.57	11.54 ± 0.25	6.97 ± 0.16	6.55 ± 0.48	6.01 ± 0.32	0.41 ± 0.001	0.53 ± 0.001	0.25 ± 0.001	1.15 ± 0.005	0.22 ± 0.000 3	69.65 ± 0.28	68.80 ± 0.31	3.61 ± 0.02	3.60 × 10^-3 ± 2.77 × 10^-5

枝叶性状 Twig and leaf traits	不同竞争梯度 Different competitive gradient
枝叶性状 Twig and leaf traits	竞争区优势枝 Superior branch in competitive zone	竞争区劣势枝 Inferior branch in competitive zone	非竞争区枝 Branch in non-competitive zone
叶厚 LT (mm)	0.42 ± 0.01^a	0.39 ± 0.03^a	0.41 ± 0.01^a
叶干物质含量 LDMC (g·g^-1)	0.56 ± 0.01^a	0.52 ± 0.02^b	0.52 ± 0.01^b
叶面积 LA (cm²)	0.23 ± 0.01^a	0.24 ± 0.02^a	0.26 ± 0.01^a
叶长 LL (cm)	1.13 ± 0.04^a	1.15 ± 0.09^a	1.20 ± 0.04^a
叶宽 LW (cm)	0.221 ± 0.004^a	0.224 ± 0.003^a	0.227 ± 0.004^a
比叶面积 SLA (cm²·g^-1)	61.91 ± 2.07^b	76.18 ± 8.06^a	70.84 ± 3.90^a
末端枝含水率 TTWC (%)	0.66 ± 0.09^a	0.72 ± 0.08^a	0.68 ± 0.11^a
末端枝直径 TTD (mm)	3.78 ± 0.16^a	3.40 ± 0.42^a	3.64 ± 0.18^a
叶干质量 LDM (g)	3.88 × 10^-3 ± 0.21 × 10^-3a	3.18 × 10^-3 ± 0.14 × 10^-3b	3.73 × 10^-3 ± 0.16 × 10^-3a

枝叶性状 Twig and leaf traits	不同竞争梯度 Different competitive gradient
枝叶性状 Twig and leaf traits	竞争区优势枝 Superior branch in competitive zone	竞争区劣势枝 Inferior branch in competitive zone	非竞争区枝 Branch in non-competitive zone
叶厚 LT (mm)	0.42 ± 0.01^a	0.39 ± 0.03^a	0.41 ± 0.01^a
叶干物质含量 LDMC (g·g^-1)	0.56 ± 0.01^a	0.52 ± 0.02^b	0.52 ± 0.01^b
叶面积 LA (cm²)	0.23 ± 0.01^a	0.24 ± 0.02^a	0.26 ± 0.01^a
叶长 LL (cm)	1.13 ± 0.04^a	1.15 ± 0.09^a	1.20 ± 0.04^a
叶宽 LW (cm)	0.221 ± 0.004^a	0.224 ± 0.003^a	0.227 ± 0.004^a
比叶面积 SLA (cm²·g^-1)	61.91 ± 2.07^b	76.18 ± 8.06^a	70.84 ± 3.90^a
末端枝含水率 TTWC (%)	0.66 ± 0.09^a	0.72 ± 0.08^a	0.68 ± 0.11^a
末端枝直径 TTD (mm)	3.78 ± 0.16^a	3.40 ± 0.42^a	3.64 ± 0.18^a
叶干质量 LDM (g)	3.88 × 10^-3 ± 0.21 × 10^-3a	3.18 × 10^-3 ± 0.14 × 10^-3b	3.73 × 10^-3 ± 0.16 × 10^-3a