4.3 Stronger provenance effects in fast vs. slow growth species
Provenance trials are highly resource-intensive (Sork et al. 2013), often restricting investigations to a single species. However, local adaptation can be highly species- and context-dependent, which limits the broad applicability of climate-matching provenance strategies in tropical systems with high species diversity. We differentiated between species that generally grow slower, live longer, and invest more resources into defences than those that grow fast and have a more rapid lifecycle using the fundamental plant trait wood density (Poorteret al. 2008, Wright et al. 2010). We found that species-level wood density was negatively associated with the mean performance of provenances grown in sympatry vs those grown for survival and growth (height increment). This supports our hypothesis that faster-growing species with shorter generation times are more likely to exhibit local adaptation, with slower-growing species potentially more likely to be maladapted. However, this was not the case for inherent growth rate. It is likely that after only 1.5 years of measurements, provenance variation is observable primarily in faster-growing species or at sites where resource limitations do not obscure growth potential, and so it remains unclear whether the observed provenance differences are due to higher rates of molecular evolution in faster-growing species (Smith & Donoghue 2008).