摘要
【目的】树冠结构影响光能截获能力从而直接影响生物量的积累。杨树冠形特征参数的研究能够为杨树优良品种的选育提供有力的选择依据,但是因为杨树的树型高达,树冠结构复杂,树冠结构特征参数难以直接观测。【方法】建立了利用三维扫描技术获取树冠结构特征参数的方法,并测量了高密度(2 m×3 m)人工林中6年生杨树03-04-171的冠形特征参数,包括不同生长单元早发枝和同期枝一级枝的枝长、分枝角度、方位角、枝条曲率及弯曲度。对直接测量(砍伐)与三维扫描方法测量的胸径、树高进行回归分析,检测三维扫描测量的精度。【结果】回归分析结果表明:胸径的回归系数分别为R2=0.967 72,显著值为P=8.26×10-13,树高回归系数为R2=0.965 27,显著值为P=1.440 29×10-12。结果说明三维扫描方法具有较高的测量精度,可以应用于树冠结构特征的测量。扫描参数结果显示,树冠上每一个生长单元的上部枝条长度较长,分枝角度较小,曲率较大,数量少,为早发枝;中下部枝条数量多,短而平直,为同期枝,这与已有的研究结果一致。【结论】三维扫描技术可以应用于树冠结构特征的研究。
Objectives]Crown architecture is one of important determinants of productivity and yield of plantations since it comprises branches and leaves orientation and distribution,thereby affecting canopy density,light interception and carbon assimilation. Identifying and quantifying the underlying factors contributing to crown architecture are therefore important for a better understanding and optimization of stand productivity. However,the measurement of crown architecture of a tree is difficulty and consuming. [Method]To make the crown architecture measurement work easier,more precision and less consuming,a new method of obtaining architecture character parameters with 3 D laser scanner was studied. To analyze precision of the method,the diameter at breast height （ DBH ） and height of poplar 03-04-171 （（Populus deltoides cl.‘55/65’ × P. deltoides cl.‘2KEN8’） × （P. nigra‘Brummen’× P. nigra‘Piccarolo’） ） in a 6-year-old forest planted in a stand density of 2 m × 3 m were measured with direct （ harvest） and scanner method. The crown architecture parameters （ the primary branch length, branch angle, azimuth, branch curvature and ratio of branch bow to string of proletpic branch and sylleptic branch ） were measured to analyze the feasibility of the new method. Regression analysis was used to compare the method of direct measurement （ harvest） and indirect （ 3 D laser scanner） measurement of the crown architecture parameters. [Result]The results showed that the 3 D laser scanner had a high precision（DBH： R^2 =0. 967 72,P=8. 26 × 10^-13; Height： R^2 =0. 965 27,P=1. 440 29 × 10^-12 ） in measuring the crown architecture parameters and could be used in crown architecture measurements. The scanned results showed that the primer branch length,branch angle and branch azimuth had a similar rhyme in each growth unit （ the aboveground part that the temperate trees growth in one year） of the trunk,and the six-years-old tree had five growth unit. The branch was short in the bottom of the growth unit and longer in upper side of each growth unit. The branch angle in the lower and middle side of growth unit was larger than that in the upper side. The azimuth was larger in the middle part of growth unit,however smaller in lower and upper site of the growth unit. The proleptic branch distributed in upper side of each growth unit while the sylleptic branch distributed in middle and lower side. Proleptic branches accounted for 1/3 of the total number of crown branches. In conclusion,in each growth unit of stem,branches in the top of growth unit （ proleptic branch） were longer and upstanding,while the branches in the middle of growth unit （ sylleptic branch） were relatively short and had a large branch angle. The branches in the top of crown were short and erect,the branches in the middle crown had a larger angle in origin,and the lower branches had a lager azimuth. The ratio of bow and string branches was steady in all branches of the crown. [Condusion]The obtained results through 3D laser scanner were consistent with other measured results,suggesting that the 3 D laser scanner method could be used in measuring and analyzing crown structure.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2015年第5期108-116,共9页
Scientia Silvae Sinicae
基金
国家"十二五"科技支撑计划:超高产优质杨树速生材新品种选育(2012BAD01B03)
关键词
三维激光扫描
杨树
树冠结构
枝长
分枝角度
方位角
3D laser scanner
Populous
crown architecture
branch length
branch angle
branch azimuth
