• Lautenschlager, R.A.
  

Red raspberry (Rubus idaeus L.) seeds from one to four years old germinated only after harsh scarification with concentrated sulfuric acid. Germination of recently collected seed was not enhanced by: (1) short-term intermittent soaking in dilute hydrochloric acid; (2) passage through the digestive tracts of bears, coyotes or birds; (3) physical perturbations such as nicking, mechanical scarification, repeated freezing and thawing, and/or five years of natural exposure; (4) light; (5) increased temperatures or temperature fluctuations; or (6) addition of nitrogen (N).

Interactive effects among shade, moisture, and nutrients on seedling growth of raspberry were common. Raspberry biomass increased with moisture and nutrients, and with N level when N was the only nutrient manipulated. Raspberry biomass production was reduced under 73% shade, while production under 30% shade was similar to that under full sun. Raspberry shoot/root ratio increased with increasing nutrients and shade, but decreased with age. Biomass and shoot/root ratio increased in high-N plots, as did interspecific competition; however, in the field experiment, raspberry shoot/root ration decreased with shade.

White spruce [Picea glauca (Moench) Voss] height growth was not affected by shade or added N. However, spruce diameter and mass production decreased with intra- and interspecific competition and increased with growing space, and in low-N plots, where raspberry was less common. Spruce shoot/root ratio also increased in low-N shaded plots.

In recent clearcuts, conifers, hardwoods, and raspberry cover in the upper stratum (0.5-1.5m above ground) and within 0.5 m of planted spruces consistently decreased spruce growth. Hardwoods caused the largest growth reductions. Fireweed (Epilobium angustifolium L.), grasses and sedges, and raspberry cover in the lower stratum (<0.5m) were positively correlated with spruce growth; however, their cover in the upper stratum showed a negative correlation. Spruce grew better on the well drained than on the somewhat poorly drained site. Competitive vegetation was more abundant on the well drained site and it affected spruce growth to a greater degree there. Paperpot seedlings suffered more from competition than did 2+2 transplants. Herbicide technology presently offers the only economically effective control of raspberry and other forest brush. Herbicide treatments provide forest crops a respite from all but conifer competition, during which crops gain resources and structure,