Effect of altitude and slope on the germination and growth of blue pine (Pinus wallichiana A. B. Jacks.) in reference to stratified and non-stratified seeds

During the present study, the impact of cold stratification at different elevations and angles on the germination and growth characteristics of white pine ( Pinus wallichiana A. B. Jacks.) seedlings were examined. In the years 2019–20, seeds were gathered in Himachal Pradesh from several altitudinal ranges [1800–2100 (A 1 ), 2100–2400 (A 2 ), 2400–2700 (A 3 ), and > 2700 (A 4 ) m.a.s.l] and aspects [southern aspect (As 1 ), eastern aspect (As 2 ), and south-eastern aspect (As 3 )]. The nursery was established in 2020 at the Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan (HP), Department of Silviculture and Agroforestry Forest Nursery. After being sun-dried, the cones were manually shaken and twisted to release the seeds. To break their dormancy, seeds were stratified with various layers of sand and moss for around 60 days before sowing. Seed viability (78.9% in S, 63.1 in NS), germination percentage (84.3% in S, 80.8 in NS), seedling height (11.7 in S, 9.22 cm in NS), survival percentage (71.3% in S, 59.6% in NS), and other growth traits of stratified (S) and non-stratified (NS) seeds were found to be significantly higher in stratified seeds collected from lower altitudinal ranges. Based on the findings, it was concluded that cold stratification of seeds obtained from lower altitude sites was suitable for extensive planting owing to their higher vitality and overall superior health.