An assessment of covariation among phenological, anatomical, and morphological traits of 50 tree species growing in urban conditions

The utility of trait-based ecology is limited by a lack of knowledge regarding the links between species' traits and performance, and by uncertainty about the nature of covariation among different traits. To advance the use of traits for predicting the performance of temperate tree species growing in urban environments, we explored covariation among leaf morphological traits, wood anatomy, and the phenology of canopy development and wood growth. By quantifying covariation among these functional traits, we aim to better understand how different tree species contribute to ecosystem services in urban environments, including shading, stormwater retention, and carbon sequestration. At an arboretum and cemetery in northeast Ohio, we monitored more than 200 individual trees, spanning 50 species. For each tree, canopy (i.e., leaf) phenology and radial growth (i.e., bole growth) were measured weekly from April through December. We expected that canopy phenology and bole growth would vary substantially among species, that the timing and rate of wood growth would be constrained by canopy phenology, and that both canopy phenology and wood growth would be constrained by wood anatomy and leaf morphology. Preliminary results show substantial interspecific variation in the phenology of bole growth and leaf development. Compared to leaf and canopy traits, bole growth varied less predictably among species. Tree species with longer periods of canopy greenness and later leaf senescence tended to have low rates of bole growth, suggesting there might be a tradeoff between traits that maximize shade production and stormwater retention (late leaf senescence) and traits that maximize carbon sequestration (bole growth). Wood anatomy (e.g., diffuse porous vs. ring porous species) strongly constrained the phenology of leaf development and wood growth. Leaf dry matter content (LDMC) was weakly correlated with leaf and wood phenology, while leaf mass per area (LMA) varied independently of phenology.