Two M.Sc. projects and one Ph.D. project on the growth, physiology and carbon dynamics of short intensive cultures of willow grown for bioenergy
For more than 15 years, Sweden has been succesfully using short rotation intentive cultures (SRIC) of willow for energy production purposes. Willows (Salix spp.) are especially well adapted to cool and wet climatic conditions and to poorly drained clayey soils. These systems are initiated from cuttings which are planted at a high spatial density (15,000 to 18,000 plants per hectare). Aboveground biomass is harvested every two to three years while preserving the root system to promote new growth from sprouting after each harvest. The production system is thus a renewable one, which operates on short rotations for at least 25 years. This type of system also favours the use of organic residues (e.g. liquid manures and slurries). Commercial systems could assure the long term production of would fiber for solid and liquid biofuels (e.g. granules, cellulosic ethanol) or wood products. SRIC of willow can also play a major role in water purification as well as in conserving biodiversity and soil fertility in agricultural settings. They are also used for other environmental purposes such as phytoremediation of contaminated soils and the construction of sound barriers. Under our latitudes, SRIC of willow constitutes one of the most productive agricultural system. In Quebec, it is estimated that SRIC of willow can produce between 8 and 20 tons per hectare per year of dry biomass for its aboveground component only. However, climatic and soil conditions that favour maximum yields are not well elucidated. Also, we only have preliminary data on root biomass production and soil carbon accumulation. Currently, entrepreneurs interested in developing willow bioenergy plantations do not have the required tools to identify the sites that are conducive to the short rotation intensive culture of willow trees and to determine the potential of the plantations to sequester carbon. This is a problem when starting such a business because of the uncertainties about returns associated to biomass sales and carbon credits. For the last 15 years, our team has contributed to the establishment of many SRIC of willow across the province. With the help of producers, we estimate that more than 300 hectares of SRIC of willow are under production from Huntingdon in the Southwest of Montreal to Abitibi in the North and Rivière-du-Loup in the East. Thus, our team benefits from a tremendous network of plantations with various willow species, different ages, and established under an array of soil and climatic conditions. The general objective of this project is thus to maximize the use of this network of plantations to bring knowledge on the role of willow plantations to sequester carbon. More specifically, the study will allow to : (i) quantify the amount of carbon sequestered in aboveground and belwoground biomass in plantations with contrasted growth, (ii) build models to identify the best sites for growing willow systems by establishing functional relationships between (a) hydroclimatic conditions, soil physical and chemical properties, nutrient status of plants (foliar) and gaz exchange, and (b) biomass production and sequestered carbon; (iii) calibrate and validate mathematical models to predict the potential for carbon sequestration and its long term dynamics in aboveground biomass and soil, and (iv) develop simple tools to quickly and precisely account for carbon content in aboveground biomass and roots. The latter objective aims at quickly and precicely measuring the amounts of carbon sequestered for the need of carbon accounting in the context of a carbon credit market. These questions will be investigated by two fully funded M. Sc. students (objectives i, ii and iv) and one fully funded Ph.D. candidate (objective iii) located at the Center for Forest Research, at the Université du Québec à Montréal, under the supervision of Nicolas Bélanger and co-supervisions with either Christian Messier, Michel Labrecque and François Courchesne. The ideal M. Sc. candidates will have completed a B.Sc in biology or geography whereas the Ph.D. candidate will have a graduate degree in pedology, ecology, biogeochemistry or microbiology. For full information, please contact Dr. Nicolas Bélanger, Center for Forest Research, Université du Québec à Montréal, by email: [email protected] or phone: (514) 987-3000 ext. 0900#.
