Geographic variation in Douglas-fir from the coastal ranges of California

181 wind-pollinated families of Douglas-fir from through-out the coastal ranges of northern California were raised in a nursery at Corvallis, Oregon and assessed for growth, phenology, cold hardiness, and response to moisture stress. Variation patterns for seed weight, germination rate and cotyledon number were also determined. All characters varied genetically, and with the exception of date of bud burst the most significant contrast was between samples from the coastal fog-belt and those from the interior ranges. Coastal seed was relatively small and germinated more slowly, and seedlings had fewer cotyledons, less hypocotyl, but greater epicotyl growth; grew for a longer period before setting buds; showed less capacity to set buds in response to moisture stress; and were less cold hardy. Lesser variation patterns were associated with elevation and latitude. In spite of broad similarities in variation patterns, the distribution of variation among sampling levels was not the same for all characters. For example, time of bud set and epicotyl growth were closely associated with the regional difference in climate, the ratio of geographic:within stand variation being > 10, compared with values <1 for seed-related characters. Cold hardiness variation was also predominantly regional. Such differences indicate a variable complex of selection pressure gradients, and militate against any systematic distinction of the coastal and interior range populations.