This report is an update of a study initiated in 1971 to assess the effects of cattle grazing and seeding with a grass-legume the mix on survival and growth of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) seedlings, planted on a clearcut in the Engelmann spruce (Picea engelmanni Parry) - subalpine fir (Abies Lasiocarpa (Hook.) Nutt.) zone in southern British Columbia. Pine growth parameters, tree and shrub density, understory botanical composition, and forage production were measured 12 years after the grass mix was sown and 13 years after the pine was planted.
Seeding did not affect pine diameter at breast height, basal area, or volume, but height was moderately suppressed. Presence of grazing benefited pine growth, apparently by reducing competition from herbaceous vegetation. Pine growth was best on plots grazed but not seeded. Trembling aspen (Populus tremuloides Michx.) and willow (Salix spp.) had become major competitors with the pine saplings, and brush densities were high for all treatments. Seeded species occurred more frequently on the seeded plots, but their combined cover never exceeded 15 %. Total forage production had declined only slightly since the first years following seeding, but composition of production had shifted away from grasses toward shrubs and forbs.
Cattle grazing and seeding were compatible with lodgepole pine regeneration. Factors contributing to this compatibility included the establishment of lodgepole pine prior to grass seeding, and good grazing management which promoted even utilization of forage and minimized seedling injury.
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Updated June 02, 2009