Stem taper functions for Betula platyphylla in the Daxing’an Mountains, northeast China

Abstract

Accurate prediction of stem diameter is an important prerequisite of forest management. In this study, an appropriate stem taper function was developed for upper stem diameter estimation of white birch (Betula platyphylla Sukaczev) in ten sub-regions of the Daxing’an Mountains, northeast China. Three commonly used taper functions were assessed using a diameter and height dataset comprising 1344 trees. A first-order continuous-time error structure accounted for the inherent autocorrelation. The segmented model of Max and Burkhart (For Sci 22:283–289, 1976. 10.1093/forestscience/22.3.283) and the variable exponent taper function of Kozak (For Chron 80:507–515, 2004. 10.5558/tfc80507-4) described the data accurately. Owing to its lower multicollinearity, the Max and Burkhart (1976) model is recommended for diameter estimation at specific heights along the stem for the ten sub-regions. After comparison, the Max and Burkhart (1976) model was refitted using nonlinear mixed-effects techniques. Mixed-effects models would be used only when additional upper stem diameter measurements are available for calibration. Differences in region-specific taper functions were indicated by the method of the non-linear extra sum of squares. Therefore, the particular taper function should be adjusted accordingly for each sub-region in the Daxing’an Mountains.

Predicting the upper stem diameters and volume of a tropical dominant tree species

“…Several other studies have reported the better performance of variable exponent taper function in comparison to a single form and segmented taper functions (Sharma and Zhang 2004;Rojo et al 2005;Duan et al 2016). In contrast, other studies have shown that segmented taper functions are better than variable exponent taper functions (Crecente-Campo et al 2009;Özçelik and Crecente-Campo 2016;Shahzad et al 2021), suggesting that a particular form of the taper function may not be universally applicable.…”

“…Several studies have shown that variable exponent taper functions predict upper stem diameters more accurately than the other two types of taper functions (Sharma and Zhang 2004;Rojo et al 2005;Duan et al 2016). However, other studies have also reported that better performance of segmented taper functions over variable exponent taper functions (Crecente-Campo et al 2009;Özçelik and Crecente-Campo 2016;Shahzad et al 2021). Several studies have been carried out on tree tapers in different areas of the world (Candy 1989;Fang and Bailey 1999;Kozak 2004;Sharma and Patron 2009;Arias-Rodil et al 2015;Poudel et al 2018;Silwal et al 2018;Alkan and Özçelik 2020;Shahzad et al2021)…”

“…of studies have taken place in North America (Max and Burkhart 1976;Shaw et al 2003;Sharma and Patron 2009;Li and Weiskittel 2010;Poudel et al2018), in Europe (Arias-Rodil et al 2015Socha et al 2020), Asia (Fang and Bailey 1999;Tang et al 2016;Lumbres et al 2017;Silwal et al 2018;Shahzad et al 2021;Koirala et al 2021) and relatively a lower number in Australia (Gordon 1983;Bi and Turner 1994;Bi 2000), South America (Nunes and Görgens 2016;Beltran et al 2017) and Africa (Mabvurira and Eerikäinen 2002;Gomat et al 2011). To our knowledge, only two taper functions have been developed in Nepal and these were developed for S. robusta C.F.…”

Comparison of Modeling Approaches for the Height–diameter Relationship: An Example with Planted Mongolian Pine (Pinus sylvestris var. mongolica) Trees in Northeast China

“…We incorporated Rd into the asymptote parameter as well. Additionally, the independence of all the variables (i.e., D, HDOM, and RD) was further tested by using the CN indictor, which would influence the inferences made about significance and parameter estimates [71,72]. It was found that the CN of the GM was smaller than 30, which suggested that there was no multicollinearity.…”

The Effect of Age on the Evolution of the Stem Profile and Heartwood Proportion of Teak Clonal Trees in the Brazilian Amazon

“…Their importance lies in the possibility of estimating the diameter at a given height, as well as the volume of sections and portions along the profile. This analysis allows us to know the various uses of the stem that can be assigned to its different parts, allowing for greater yield and use of production [12][13][14].…”