Neighborhood effects and size‐asymmetric competition in a tree plantation varying in diversity

Abstract

Abstract. A plantation of native trees was established in Panama in 2001 to study the relationship between biodiversity and ecosystem functioning. Five years later, mixed-species plots had experienced enhanced tree growth compared with monocultures. Searching for underlying mechanisms, we developed a neighborhood model isolating size and identity effects. We found that the size of neighbors is, by far, the largest source of variation in individual-tree diameter and height. Size-asymmetric competition appears as a structuring factor in the plantation. The relative growth rate of small trees was significantly lower than that of large trees, and their height and basal diameter were most variable. The 50 smallest trees of the plantation suffered a disproportionate amount of death, and the proportion of small trees was highest in monoculture. Increased biomass allocation to branches for trees growing in three-species plots suggests that competition for light might be taking place. Clearly, local neighborhood plays a central role in determining productivity, suggesting that scale needs to be incorporated in the theoretical development and analysis of biodiversity and ecosystem functioning.

Species-site matching in mixed species plantations of native trees in tropical Australia

“…Mixed species tree plantations may also provide benefits of product diversification, improved risk management and increased productivity when compared to monocultures (del Rio and Sterba 2009;Potvin and Dutilleul 2009;Amoroso and Turnblom 2006;Forrester et al 2004). Despite mounting interest in mixed species plantations over the last decade , trials of mixtures of native timber species in Brazil (Yamada andGholz 2002), Costa Rica (Montagnini et al 2003), Thailand (Elliott et al 2003), Australia Vanclay 2006a) and China (Jian-min et al 2003) have failed to produce plantation models for adoption by landholders or commercial timber growers on a large scale.…”

“…Studies documenting mixed species systems with productive advantages over monocultures (Amoroso and Turnblom 2006;del Rio and Sterba 2009;Erickson et al 2009;Forrester et al 2004;Potvin and Dutilleul 2009) have attempted to generalise design characteristics important for success. However, in many situations mixed species systems offer no change, or a reduced productivity compared to monocultures (Cavard et al 2010;Chen et al 2003;Erickson et al 2009;Forrester et al 2005;Hunt et al 2006) and it is acknowledged that a mechanistic understanding of the underlying processes is required to enable better predictive ability for situations where mixtures can be successful (Forrester et al 2005;Manson et al 2006).…”

“…Reduced productivity in mixtures has often been associated with asymmetric competition between species as plantations develop (Cavard et al 2010;Hunt et al 2006;Chen et al 2003). Whilst studies investigating neighbourhood effects have identified the inter-specific competitive effects in mixtures (Canham et al 2004;Bristow et al 2006), others have found the size of neighbours, rather than species identity, as the largest source of variation in individual tree diameter and height (Erickson et al 2009;Potvin and Dutilleul 2009).…”

A high‐resolution approach for the spatiotemporal analysis of forest canopy space using terrestrial laser scanning data

“…However, such studies with multitemporal point cloud data analyses are rare, mainly focusing on standard tree dendrometrics or wood volume estimations (Liang et al., 2012; Srinivasan et al., 2014). Our new method is, thus, a very promising approach which should lead to important advances in several aspects of forest ecological research, such as investigations on crown growth, morphology and plasticity (Longuetaud, Piboule, Wernsdörfer, & Collet, 2013; Schröter, Härdtle, & von Oheimb, 2012), canopy structures and canopy packing (Jucker, Bouriaud, Coomes, & Baltzer, 2015; Morin, 2015; Pretzsch, 2014), crown‐related tree interactions and competition (Fichtner, Sturm, Rickert, von Oheimb, & Härdtle, 2013; Lang et al., 2012; Potvin & Dutilleul, 2009; Thorpe, Astrup, Trowbridge, & Coates, 2010), and niche differentiation and spatial complementarity (Ishii & Asano, 2010; Sapijanskas, Paquette, Potvin, Kunert, & Loreau, 2014; Williams, Paquette, Cavender‐Bares, Messier, & Reich, 2017), including changes over time.…”

“…The outcome of competition for canopy space is, thus, strongly affected by tree interactions at the local neighborhood level (Fichtner et al., 2018). Furthermore, these tree neighborhood interactions constitute a key factor determining a tree's architecture and, ultimately, growth, and productivity patterns (Fichtner et al., 2017; Potvin & Dutilleul, 2009; Pretzsch, 2014; von Oheimb et al., 2011). …”