Bark functional ecology: evidence for tradeoffs, functional coordination, and environment producing bark diversity

Abstract

SummaryThe causes underlying bark diversity are unclear. Variation has been frequently attributed to environmental differences across sites. However, variation may also result from tradeoffs and coordination between bark's multiple functions. Bark traits may also covary with wood and leaf traits as part of major dimensions of plant variation.To assess hypotheses regarding tradeoffs and functional coordination, we measured bark traits reflecting protection, storage, mechanics, and photosynthesis in branches of 90 species spanning a wide phylogenetic and environmental range. We also tested associations between bark, wood, and leaf traits. We partitioned trait variation within species, and within and across communities to quantify variation associated with across-site differences.We observed associations between bark mechanics and storage, density and thickness, and thickness and photosynthetic activity. Increasing bark thickness contributed significantly to stiffer stems and greater water storage. Bark density, water content, and mechanics covaried strongly with the equivalent wood traits, and to a lesser degree with leaf size, xylem conductivity, and vessel diameter. Most variation was observed within sites and had low phylogenetic signal.Compared with relatively minor across-site differences, tradeoffs and coordination among functions of bark, leaves, and wood are likely to be major and overlooked factors shaping bark ecology and evolution.

Tree growth, wood and bark water content of 28 Amazonian tree species in response to variations in rainfall and wood density

“…1). One explanation can be related to leaf phenology of trees in central Amazonia, since production of leaves and bark water content seem to be interrelated (Clark & Gibbs 1957, Rossel et al 2014. In central Amazonia the production of litter tends to increase in the dry season (Luizão & Schubart 1987), which suggests that the production of new leaves can follow a similar pattern (Doughty & Goulden 2008).…”

“…In Amazonian trees, Nogueira et al (2008) reported wood water content in the range of 22 to 67% (mean of 33.9%), with moisture increasing toward the tip of the tree. Variations in water content of wood and bark have been attributed to environmental and phylogenetic factors, with higher water contents often associated with thicker barks (Rossel et al 2014). In temperate and tropical forests, tree water content of poles and branches can vary seasonally (Gibbs 1958, Chapotin et al 2006).…”

Effect of Drying on the Antioxidant Capacity and Concentration of Phenolic Compounds in Different Parts of the Erythrina americana Tree

“…The moisture content in the leaves is higher and more stable than in the tree bark. This is because in the tree bark, the water and solutes may buffer the daily or seasonal fluctuations in water availability in the tree tissues (Rosell et al 2014).…”

Periodicidade do crescimento de espécies arbóreas da Floresta Estacional Semidecidual no Sul do Brasil

“…Considerando-se que uma das funções da casca é o armazenamento de água (ROSELL et al, 2014), os valores negativos observados da taxa de incremento podem ser atribuídos ao uso dessa reserva hídrica pela planta durante o período mais desfavorável. Adicionalmente, a variação da umidade relativa do ar leva a oscilação da largura da casca, já que ela está em contato direto com o ambiente (ZWEIFEL et al, 2000;STAHL et al, 2010).…”