Relationships between radial growth rates and lifespan within North American tree species

We conducted a meta-analysis of tree-ring data to quantify relationships between growth and lifespan in 4 North American tree species: Tsuga canadensis, Quercus alba, Pinus ponderosa, and Pseudotsuga menziesii. Data sets were compiled from across the range of each species and included a total of 14 341 measured time series. For each species we calculated the age at which each tree was sampled and pooled all trees into 50-y bins. Within each of these 50-y bins, we calculated mean ring width and mean basal area increment in 50-y intervals according to cambial age. Thus, ring widths formed during the same time period in the trees' life stage could be compared across trees sampled at increasing ages. In all 4 species the longest-lived trees experienced slower growth rates than trees sampled at relatively young ages. Furthermore, long-lived trees with slow growth rates appear to mix with shorter-lived, fast-growing trees in the same forests. Such a relationship between growth and lifespan within species may be an important component of biodiversity that holds implications for old-growth forest development and long-term management.