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

Abstract

Abstract• Previous studies on competitive interactions among silver birch, Scots pine, and Siberian larch have not addressed the direct importance of the species identity of nearby competitors.• We examined the joint importance of competition and species identity, using subject trees with a high local abundance of a single dominant neighboring species. Interspecific neighbors influenced annual height increment, shoot length, and branch number per unit crown length, especially in Scots pine. Silver birch and Siberian larch were predominantly affected by the level of competition alone, as estimated with competition indices.• In Scots pine, the effects may have been a direct consequence of the species identity of neighbors or they may have acted as a substitute for the effect of some non-measured variable associated with species-specific characteristics. These functionally equivalent alternatives suggest that simple indices are not adequate measures of the neighbor effect for Scots pine.• A simple extrapolation of individual tree growth to the stand level suggested that Scots pine and silver birch may grow faster in mixed than in pure stands. Siberian larch showed negative growth responses to interspecific neighbors, but the effects may be counterbalanced at the stand level by a corresponding increase in pine or birch growth.

Individual tree mortality of silver birch (Betula pendula Roth) in Estonia

“…Several studies reported that the competition and growth of silver birch trees, and consequently their survival prospects, are strongly related to the identity of neighboring species (Kaitaniemi & Lintunen 2010, Jõgiste 2010, Hynynen et al 2011. Their findings are consistent with our results, in that including sp to the best nonspatial mortality model definitely improved its fit.…”

Analysis of Individual Tree Competition on Diameter Growth of Silver Birch in Estonia

“…Despite the fact that the identity of neighbouring species is an important factor in the characterization of their competitive effects (Bella, 1971;Zhao et al, 2006;Kaitaniemi & Lintunen, 2010;Bošelá et al, 2013), no significant improvement appeared in recalculating the selected indices using Ellenberg's light values except for young trees. One possible explanation is that in our study plots about two-thirds of the trees analysed were birch with the same light factors.…”

“…In Estonia, birch is the second most abundant tree species in terms of forest cover (31.2%) and the coverage is expanding (Yearbook of Forest, 2013). A few attempts have been made to study birch growth related to the negative interaction of tree competitive status in stands (Jõgiste, 1998;Prévosto et al, 1999;Andreassen & Tomter, 2003;Damgaard & Weiner, 2008;Kaitaniemi & Lintunen, 2010).…”

Automatic Assessment of Crown Projection Area on Single Trees and Stand-Level, Based on Three-Dimensional Point Clouds Derived from Terrestrial Laser-Scanning

“…Competition among neighboring trees mainly depends on (1) the tree species; (2) the inter-tree distances formed by the overall spatial tree pattern in a forest stand; and (3) tree parameters like diameter at breast height (DBH), tree height, or crown projection area (CPA) [1][2][3][4]. The information needed to assess these aspects is much higher compared to data provided by large scale forest inventories, despite the fact that catalogues of key attributes surveyed in forest inventories have broadened and that modern survey networks were developed towards multi-purpose forest inventories [5][6][7].…”