The effect of competition on individual tree basal area growth in mature stands of Pinus cooperi Blanco in Durango (Mexico)

Abstract

In this paper, we evaluated how well-selected distance-dependent and distance-independent competition indices explain individual tree basal area growth of trees, growing in mature and even-aged stands of Pinus cooperi Blanco. A total of 18 competition measures were analyzed of which six do not need tree location (distance-independent) and 12 that utilize tree location (distance-dependent). The competition situation of a stand and/or an individual tree was studied using 11 different competitor selection methods. The mean square error reduction relative to no-competition was used to judge the performance of each competition index. It was found that the best distance-independent competition indices performed as well as the best distance-dependent competition indices. It was concluded that the BAL-MOD-index would be a good competition index to be incorporated into further individual tree basal area growth models for the study area.

Neighbor identity and competition influence tree growth in Scots pine, Siberian larch, and silver birch

“…More than 30% of the variation usually remains unexplained when different formulations of CIs are used to explain growth (Rivas et al, 2005;Stadt et al, 2007;Tomé and Burkhart, 1989). However, the two explanations are functionally equivalent and suggest that to adequately predict growth responses of Scots pine, the structure and functioning of the surrounding stand must be estimated in more detail than using simple indices (see also Olano et al 2009).…”

“…Casper and Jackson, 1997;Goldberg and Barton, 1992), and has been demonstrated in many case studies in forestry (e.g. Canham et al, 2004;De Luis et al, 1998;Mielikäinen, 1980;Rivas et al, 2005). However, the practical value of this information has often been underrated, due to the commercial demands favoring monocultures (Kelty, 2006;Nichols et al, 2006).…”

Individual tree basal area growth models for Chir pine (Pinus roxberghii Sarg.) in western Nepal

“…The individual tree based growth models are usually developed to describe growth dynamics for structurally complex and heterogeneous stands (Wykoff 1990;Pretzsch 2002;Uzoh, Oliver 2006;Bollandsås, Naesset 2009). In these models, the potential growth of individual trees is reduced by competition in-dex (a measure of competition), which may be either distance dependent (Bella 1971;Biging, Dobbertin 1992;Ledermann, Stage 2001;Rivas et al 2005) or distance independent (Wykoff 1990;Uzoh, Oliver 2006;Bollandsås, Naesset 2009). Long-time growth series (longitudinal or radial growth) data of individual trees are needed to develop individual tree growth models.…”

“…Distance dependent or distance independent individual tree growth models can be developed using either of the two methods: indirect control over the growth with potential modification (Biging, Dobbertin 1992;Pretzsch 2002;Pommerening et al 2011;Sharma 2013) or direct estimation of growth by regression techniques (Wykoff 1990;Huang, Titus 1995;Rivas et al 2005;Uzoh, Oliver 2008;Subedi, Sharma 2011). With the indirect method, potential growth is expressed as a function of current size or age of the trees and site index, while competition index and measures of tree vigour are used as modifiers that reduce potential growth (Biging, Dobbertin 1992;Pretzsch 2002;Reed et al 2003;Pretzsch 2009).…”

“…With the indirect method, potential growth is expressed as a function of current size or age of the trees and site index, while competition index and measures of tree vigour are used as modifiers that reduce potential growth (Biging, Dobbertin 1992;Pretzsch 2002;Reed et al 2003;Pretzsch 2009). However, with the direct method, periodic tree growth is modelled as a function of tree size, site index, competition index, and mean stand characteristics by applying regression techniques (Wykoff 1990;Huang, Titus 1995;Mailly et al 2003;Rivas et al 2005;Uzoh, Oliver 2008). In this study, the direct method was applied by using tree size or tree age as independent variable, because potential growth data (i.e.…”