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Abstract

Interest in utilizing trees for bio-energy production has increased drastically in recent decades. In Sweden, hybrid poplar has been in focus as future biofuel supplier and has been planted on former farmland (on limited areas, ca 1000 ha A study of the biomass production was carried out for each alternative. The stump and root study was made in six poplar ( The aims of the present studies were to measure the biomass of poplar stumps (incl. root system) and the sprouting capacity from above clear cut poplar plantations. Thereafter present biomass estimation functions for stumps (and roots) and sprouting production as well as some practical implications.-1, mainly for research and demonstration). To improve the management of the first generation of poplar (Populus sp.) plantations in Sweden, equations for calculating aboveground biomass, stem taper, and stem volume have recently been published. After harvest, there are at least two alternatives for the site: (1) Extract the stumps with or without parts of the root system to allow subsequent re-planting of trees or cultivation of cereals; and (2) Utilize the sprouting capacity of the poplar stumps. The sprouts can be harvested in a 5–10-year rotation or thinned for later harvest of pulp wood. Populus sp.) stands and the sprouting study in ten poplar stands, on former farmland in Sweden, situated between latitudes 55 and 60° N. At time for clear cut, the mean age of the poplar stands in the first study was 20 years (range 16-23), the mean stand density 1151 stems ha-1 (range 361-3279), and the mean DBH (diameter at breast height) 288 mm (range 81-574). For the second study the mean age of the poplar stand was 17 years (range 8-21), the mean stand density 1050 stems ha-1 (range 361-2143), and the mean DBH 244 mm (range 68-574). The mean dry mass weight for the 72 excavated stumps was 45±39 kg (1-185) and 14±16 kg (0.2-87) for roots ≥50 mm. Dry mean stump weight represented 21% by dry weight for the stem. The mean total dry weight per hectare for stumps was 34.9±21.8 (12.9-66.9) tons and 12.0±9.6 (4.7-10.9) tons for roots. The excavation of below-ground biomass can either focus on the stump or stump with parts of the root system. Depending on the soil type and moisture, the cleaning of stumps and roots might be more or less heavy. The studied sprouts were 1-7 years old. Stump sprouting was observed in all studied stands. The number of sprouts per living stump varied depending on sprout age and decreased as sprout age increased. The mean dry mass of all sprouts per stump-1 was 16.1±14.0 (range 3.3-37.2) kg. The mean total sprout weight per hectare for sprouts amounted to 16.9±14.6 (range 1.2-41.3) tons ha-1 when calculated for the actual living stumps in the studied areas. Keywords: bio-energy, biomass equation, excavation, root, stump, sprouting.

Published in

International Poplar Commission Working Paper
2012, number: IPC/11, pages: 81-81
Title: Improving lives with poplar and willows : Abstracts of submitted papers
Publisher: Food and Agriculture Organization of the United Nations (FAO)

Conference

24th Session of the International Poplar Commission

SLU Authors

UKÄ Subject classification

Forest Science

Permanent link to this page (URI)

https://res.slu.se/id/publ/53584