Browsing by Author "Forcella, F."

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Berry production in three whitebark pine forest types
(1990) Weaver, T.; Kendall, K.; Forcella, F.
In the whitebark pine lwhortleberry (Pinus albicaulis/Vaccinium scoparium) habitat type of southwestern Montana, whortleberry plants produced seven to 69 berries I m• X yr in 1974. In subalpine fir (Abies lasiocarpa) habitat types of northwestern Montana, huckleberry plants (Vaccinium globulare) may produce from 13 to 228 berries I m2 X yr. While removal of competing trees increases production, thinning the understory apparently reduces berry production in direct proportion to the shrubs removed; there is no compensatory production indicative of shrub-shrub competition in fully vegetated plots. Fifty- to 100-fold variation in production among years in Vaccinium globulare berry production is attributed to variation in weather conditions.
Biomass and productivity of the subalpine Pinus albicaulis — Vaccinium scoparium association in Montana, USA
(1977-10) Forcella, F.; Weaver, T.
Biomass of fifty conifer forests and nutrient exports associated with their harvest
(1977) Weaver, T.; Forcella, F.
Biomasses of climax Rocky Mountain forests studied ranged from less than 50 to more than 300 tons/ha. Total biomass was approximately 1.5 times the biomass of normally merchantable boles. When compared with conventional bole harvest, the nutrient exports associated with harvest of all aboveground parts in these stands would apparently be at least three times higher for nitrogen, six times higher for phosphorus, four times higher for potassium, and three times higher for calcium.
Stand development in whitebark pine woodlands
(1990) Weaver, T.; Forcella, F.; Dale, D.
Analysis of density data from stands in the Northern Rocky Mountains shows that, while seedlings establish at the rate of over 1,000 I ha x year in whitebark pine-grouse whortleberry (Pinus albicaulis-Vaccinium scoparium) forests of all ages, stem numbers in the canopy thin to 400 at 30 years, 150 at 200 years, and 100 at 300 to 600 years. Indices of productive potential, cover, and total circumference rise to an asymptote at about 100 years. Total basal area rises from 0 to 60 m21 ha at about 200 years, the aggregate basal area of trees with diameters over 20 em rises from 0 to 40 m21 ha at about 250 years, and tree height maximizes (12 m) at 200 years. It is hypothesized that further growth in productive potential (that is leaf and I or root area) is prevented by limited supplies of water or a nutrient, further growth in basal area is prevented by lack of a nutrient (probably not carbon, hydrogen, oxygen, or nitrogen) and further growth in height is prevented by scarcity of water.