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Forested ecosystems are essential in supporting the majority of terrestrial species on Earth. Forest products contribute significantly to the global economy as well as contributing in sequestering carbon as part of climate change mitigation.In British Columbia, conventional forest and range management has historically considered multiple-use landscape resources independently. We explored an opportunity to integrate the forest and ranching industries, in order to enhance both forestry and grazing practices, so that forest production and understory forage productivity can be fully realized. Silvopasture, which is the complementary use of land for forestry and range productivity for livestock, is a practice that integrates these two sectors. Previous research has shown that a successful integration of forage, cattle and timber management can provide significant economic, social and environmental benefits such as increasing forage yield and quality, tree growth, enhancing soil carbon storage, and increasing soil water availability.Our objective was to test the integration of forage and timber management to improve forage quantity, quality and to enhance soil carbon sequestration. Specifically, we tested two hypotheses: (H1) 20 m width strip–thinning will maximize forage yield and quality and (H2) 20 m width thinning will sequester more soil carbon than uncut control or 10 m and 15 m thinning. In British Columbia, Canada, a mid-rotation forest of planted 45-year old lodge pole pine was harvested July 2018 at 10 m, 15 m and 20 m width strips in three adjacent forest sites at an elevation range between 1340 –1400 m. Baseline data including tree stand density, understory plant species composition, and soil carbon and nitrogen were collected pre-harvest, June 2018. An agronomic seed mix was broadcast at 12 kg/ha: 30% Dactylis glomerata, 30% Bromus riparius, 30% Thinopyrum intermedium, and 10% Trifolium repenswas seeded in October 2018. Field experiments, laboratory analysis and remote sensing were used in the second and third phase of this research to monitor forage quality and quantity, soil total carbon, nitrogen and organic carbon as well as soil carbon sequestration. We found that all strip widths enhanced forage quality,but the 20m strips produced more yield than other treatment units. We found higher soil compaction and increased pH level in 20 m strips than other treatment units. However, a highe rsoil carbon and nitrogen was found in 15 m and 10 m strips than in 20 m. Our results provide evidence for optimizing land use in silvopasture.

Forest ecology -- British Columbia

Thompson Rivers University

2021-01-01T00:00:00Z