Biomass production of dense direct-seeded lodgepole pine (Pinus contorta) at short rotation periods

• Published in: Silva Fennica
• Main Authors: Backlund, Ingegerd, Bergsten, Urban
• Format: Article in Journal/Newspaper
• Language: English
• Published: Finnish Society of Forest Science 2012
• Subjects: Forestry; SD1-669.5; Northern Sweden
• Online Access: https://doi.org/10.14214/sf.914; https://doaj.org/article/4d84619983ed4f48b0579324e4924cb5

Lodgepole pine (Pinus contorta) is a fast-growing species that is suitable for producing woody biomass in Nordic countries. Direct seeding of this species is cheaper than planting and creates dense, stable stands. The objective of this study was to quantify the stem volume and biomass production of direct seeded lodgepole pine stands grown under different site conditions with different stem densities, at an age that would permit extensive harvesting of biomass. A circle-plot inventory was performed in 16 of the oldest direct seeded lodgepole pine stands in mid-northern Sweden. Stemwood production of almost 200 m/ha was achieved on average on the best sites, rising to about 300 m/ha for the best circle-plots within 30 years of direct seeding despite the fact that pre-commercial thinning was made once or twice. This corresponds to 100 and 140 tons of dry weight biomass/ha, respectively. Higher stand stem densities (â¥3000 st/ha) yielded more biomass with only slight reductions in diameter at breast height. The development of stem volume with respect to dominant height in direct seeded stands was becoming comparable to that in planted stands with similar spacing. It therefore seems that there is an unutilized potential for cost-effectively growing lodgepole pine in dense stands for biomass production after direct seeding. It may be possible to devise regimes for short(er) rotation forestry that would yield substantial amount of inexpensive biomass for biorefineries within a few decades.33