Treesearch

Humans have converted forest to agricultural and urban uses, exploited species, fragmented wildlands, changed the demographic structure of forests, altered habitat, degraded the environment with atmospheric and soil pollutants, introduced exotic pests and competitors, and domesticated favored species. None of they activities is new; perhaps with the exception of atmospheric poilution, they date back to prehistory. All have impacted genetic diversity (i.e., species diversity and genetic diversity within species) by their influence on the evolutionary processes of extinction, selection,...

Sixty-two Douglas-fir/hardwood stands ranging from 40 to 560 years old were used to characterize the density; diameter, and height class distributions of canopy hardwoods and conifers in young (40 -100 yr), mature (101 - 200 yr) and old-growth (>200 yr) forests. The crown, bole, disease, disturbance, and cavity conditions of canopy conifers and hardwoods were also described. A series multivariate and univariate analyses were used to determine which tree conditions differed significantly among the age-classes. Stepwise discriminant analysis was used to identify variables with significant...