Ecological Diversity in North American Pines

Ecological groups were identified from 34 North American species of pine using multivariate analysis of 18 ecological traits. Five adaptive modes are described: 1) fire‐resistant species that are large, thick‐barked, and have large cones and long needles; 2) tall, fast‐growing mesophytic species with moderately high shade tolerance; 3) stress‐tolerant species with animal‐dispersed seeds, occurring mainly on cold or dry sites where fire is infrequent; 4) fire‐resilient species that are precocious reproducers with small seeds, often in serotinous cones; and 5) species of southern mesic sites with fast growth, strong, heavy wood and short persistence of needles. Intermediates between these modes exist. Convergent evolution has occasionally occurred, as shown by high ecological similarity of species in different taxonomic sections within Pinus. However, the analogies between species are imperfect, suggesting the importance of constraint by shared ancestry and divergence produced by a diversity of environments.