Seedling response following partial cutting in lodgepole pine forests on caribou winter range in west-central British Columbia

Abstract

Group selection and irregular group shelterwood silvicultural systems were applied to older lodgepole pine (Pinus contorta var. latifolia) forests in west-central British Columbia to determine their potential for maintaining northern caribou (Rangifer tarandus caribou) habitat. These silvicultural systems created small openings 15-30 m wide, which were planted with lodgepole pine and interior spruce (Picea glauca x Picea engelmannii) seedlings. Fifth-year survival and growth results indicate that either species could adequately regenerate the small openings created by partial cutting. Pine survival in the partial cuts (93-95%) was comparable to the clearcuts (94%). Pine height and height growth did not vary significantly between treatments; however, diameters were significantly larger in the clearcuts. After five years across all treatments, pine seedlings were 38-42 cm tall with diameters ranging from 7-11 mm. Spruce survival varied considerably between the clearcuts (35-98%) but was more consistent in the partial cuts (66-97%). Total height and height growth differed significantly among treatments, with the shortest spruce seedlings found in the clearcuts. Seedling diameter did not differ among treatments. Average fifth-year height ranged from 31 cm to 44 cm and diameters ranged from 7 mm to 9 mm. To maintain caribou habitat, species should be planted in similar proportions to the pre-harvest stand composition to avoid potential impacts on the terrestrial and arboreal lichens, which are important caribou forage.