Modeling Variation in Crown Profile with Tree Status and Cardinal Directions for Planted Larix olgensis Henry Trees in Northeast China

Crown profile models were developed for north, east, south, and west crown directions of dominant trees, intermediate trees, and suppressed trees in planted stands of Larix olgensis Henry in Northeast China. A total of 139 sample trees were randomly selected, and all branches of each tree were measured. A segmented power equation, segmented polynomial equation, modified Weibull equation, and Kozak equation were selected as the candidate models. A traditional approach that did not consider the differences between tree status and crown directions was also developed. Three steps were conducted to analyze the effect of tree status (dominant, intermediate, and suppressed tree) and crown direction (north, east, south, and west) on the crown profiles using a dummy variable approach. Step 1 considered only tree status, Step 2 considered only crown direction, and Step 3 took both tree status and crown direction into account. Nonlinear mixed-effects model was used to express the effect of individual tree level on crown shape, and was also compared to the ordinary least-squares and generalized least-squares model. The results demonstrated that the modified Kozak equation showed good performance in the crown profile description. The nonlinear mixed-effects model significantly improved the model performance compared to the ordinary least-squares and generalized least-squares model. There were differences among the crown profiles among the four directions of dominant, intermediate, and suppressed trees. South-oriented crowns had the tendency to be the largest, which is likely to be mainly a result of light conditions. The competition status of the subject tree was the main reason leading to an asymmetric crown. Individual trees with strong competition levels had smaller crowns.

[1]  Juan Gabriel Álvarez-González,et al.  Development of crown profile models for Pinus pinaster Ait. and Pinus sylvestris L. in northwestern Spain , 2013 .

[2]  Alexandre Piboule,et al.  Reconstructing crown shape from stem diameter and tree position to supply light models. I. Algorithms and comparison of light simulations , 2005 .

[3]  D. Maguire,et al.  Crown profile models based on branch attributes in coastal Douglas-fir , 1997 .

[4]  Paul J. Kramer,et al.  The Physiological Ecology of Woody Plants , 1991 .

[5]  G. Nigh,et al.  Effects of neighbours on crown length of Abies lasiocarpa and Picea engelmannii in two old-growth stands in British Columbia , 2010 .

[6]  S. Thomas.  Photosynthetic capacity peaks at intermediate size in temperate deciduous trees. , 2010, Tree physiology.

[7]  S. Pauleit,et al.  Crown size and growing space requirement of common tree species in urban centres, parks, and forests , 2015 .

[8]  H. Peltola,et al.  Effects of early thinning regime and tree status on the radial growth and wood density of Scots pine , 2007 .

[9]  R. Sharma,et al.  Individual tree crown width models for Norway spruce and European beech in Czech Republic , 2016 .

[10]  Douglas M. Bates,et al.  LINEAR AND NONLINEAR MIXED-EFFECTS MODELS , 1998 .

[11]  Stephan Getzin,et al.  Asymmetric tree growth at the stand level: Random crown patterns and the response to slope , 2007 .

[12]  W. Winner,et al.  Photosynthetic differences between saplings and adult trees: an integration of field results by meta-analysis. , 2002, Tree physiology.

[13]  Margarida Tomé,et al.  A tree crown ratio prediction equation for eucalypt plantations , 2001 .

[14]  Peter L. Marshall,et al.  Crown development in red pine stands. I. Absolute and relative growth measures , 1994 .

[15]  Bao-guo Wu,et al.  Study on crown profile models for Chinese fir (Cunninghamia lanceolata) in Fujian Province and its visualization simulation , 2016 .

[16]  D. Hann.  An adjustable predictor of crown profile for stand-grown Douglas-Fir trees , 1999 .

[17]  Zhanqing Hao,et al.  Vertical structure and spatial associations of dominant tree species in an old-growth temperate forest , 2007 .

[18]  Gregory S. Biging,et al.  Stochastic models for conifer tree crown profiles , 1997 .

[19]  Sean C. Thomas,et al.  Ontogenetic changes in leaf size in Malaysian rain forest trees , 1995 .

[20]  F. Houllier,et al.  Branchiness of Norway spruce in northeastern France: predicting the main crown characteristics from usual tree measurements , 1992 .

[21]  J. Kershaw,et al.  Modelling primary branch frequency and size for five conifer species in Maine, USA. , 2010 .

[22]  Peter L. Marshall,et al.  A crown profile model for Pinus radiata D. Don in northwestern Spain , 2009 .

[23]  H. Sterba,et al.  Derivation of compatible crown width equations for some important tree species of Spain , 2005 .

[24]  Hailemariam Temesgen,et al.  Tree crown ratio models for multi-species and multi-layered stands of southeastern British Columbia , 2005 .

[25]  D. Hann,et al.  Crown profile equations for stand-grown western hemlock trees in northwestern Oregon , 2003 .

[26]  E. Vonesh,et al.  Linear and Nonlinear Models for the Analysis of Repeated Measurements , 1996 .

[27]  J. Marshall,et al.  Family differences in height growth and photosynthetic traits in three conifers. , 2001, Tree physiology.

[28]  V C Baldwin,et al.  Predicting the crown shape of loblolly pine trees , 1997 .

[29]  David L. R. Affleck,et al.  Conifer crown profile models from terrestrial laser scanning , 2015 .

[30]  J. Kershaw,et al.  Species differences in total and vertical distribution of branch- and tree-level leaf area for the five primary conifer species in Maine, USA , 2009 .