摘要 : Red fir (Abies magnifica) clear felled areas of various ages were sampled to identify site factors that predict successful regeneration. During 3 field seasons, 113 clear felled areas were sampled in 5 national forests along the w... 展开 Red fir (Abies magnifica) clear felled areas of various ages were sampled to identify site factors that predict successful regeneration. During 3 field seasons, 113 clear felled areas were sampled in 5 national forests along the western slope of theSierra Nevada between latitudes 37 and 40鳱. They were 4-32 yr old and 2028 ha in area, had slopes of 3-30?that cumulatively faced in all directions, and were situated on slope faces that ranged from concave, convex and constant to mixed. Records weremade of the cover of all herbs, shrubs, and tree saplings, and of the density of saplings by age class. A total of 208 taxa were encountered. Both red fir regeneration (represented by sapling cover) and invasiveness (the reciprocal of clear felled area age minus average red fir sapling age) were maximum on gentle, NE-facing, concave slopes, in clear felled areas with maximum edge (the ratio of perimeter to area), and at relatively high latitudes and relatively low altitudes. Both shrub and herb cover were positively correlated with red fir regeneration, indicating that management suppression of these species is not necessary. Microclimate models showed that regeneration, invasiveness, and canopy growth were most negatively correlated with daily summerinsolation and most positively correlated with late snow melt, the latter resulting from deep snowpacks and/or late snow melt on N.-facing slopes. In general, abundant natural red fir regeneration occurred only after a post-logging lag phase of 12 yr. 收起