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Long term changes in stand structure and biomass production in short rotation willow coppice

Nordh, Nils-Erik (2005). Long term changes in stand structure and biomass production in short rotation willow coppice. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2005:120
ISBN 91-576-6919-8
[Doctoral thesis]

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Abstract

Short rotation willow coppice (SRWC) is a recently commercialised agricultural crop in Sweden, producing biomass for energy. The expected lifespan of a SRWC plantation is more than 20 years, or at least 5 harvests. Consequently, understanding of long term stand development in relation to management, plant material and site characteristics is of great importance. The focus of this thesis is on SRWC biomass production during later cutting cycles. Long term development and dynamics have been studied during three cutting cycles by means of annual census of individual stools, scaled up to stand level. Methods for non-destructive biomass assessment, by means of allometric relations, have been developed and validated for different clones. A method for predicting willow shoot growth in field trials, under different nutrient and water conditions, based on characteristics found in pot-grown plants under corresponding conditions, has also been investigated. The best non-destructive method for assessing shoot weight of clones with bow-shaped and branching stems was found to be shoot dry weight related to the sum of the cross sectional areas of all shoots. In straight, un-branched clones, the measuring height could be elevated to 105 cm above stem base without loosing precision. A comparison of a destructive and a non-destructive method, applied on 12 different clones, showed a mean deviation of 2.5%. Stool mortality during the 1st cutting cycle was non-density dependent. Biomass production increased in the 2nd cutting cycle but high density dependent stool mortality at the end of the 2nd cutting cycle negatively influenced the production in the 3rd cutting cycle, which was lower than both the 1st and 2nd cutting cycle. A stool size hierarchy was established early and prevailed through all cutting cycles. Stool mortality occurred mainly among small stools. In the beginning of the 4th cutting cycle, biomass production stabilised due to compensatory growth of the remaining stools. Total leaf area and total nitrogen pool of pot-grown plants were good clone-specific characters for predicting shoot biomass growth in the field during the first cutting cycle and may be used for shortening the time needed to characterise new clones. The results suggest that sustainability in SRWC systems is enhanced by matching clone and site and adapting fertilisation and harvest timing to actual stand development.

Authors/Creators:Nordh, Nils-Erik
Title:Long term changes in stand structure and biomass production in short rotation willow coppice
Year of publishing :December 2005
Volume:2005:120
Number of Pages:26
Papers/manuscripts:
NumberReferences
ALLI. Verwijst, T. and Nordh, N-E. 1992. Non-destructive estimation of biomass of Salix dasyclados. Bioresource Technology 41: 59-63. II. Nordh, N-E. and Verwijst, T. 2004. Above-ground biomass assessments and first cutting cycle production in willow (Salix sp.) coppice – a comparison between destructive and non-destructive methods. Biomass and Bioenergy 27: 1-8. III. Weih, M. and Nordh, N-E. 2005. Determinants of biomass production in hybrid willows and prediction of field performance from pot studies. Tree Physiology 25: 1197-1206. IV. Nordh, N-E. and Verwijst, T. 2005. Biomass production and population dynamics of 12 willow (Salix) clones grown in three short rotations during 14 years (manuscript).
Place of Publication:Uppsala
ISBN for printed version:91-576-6919-8
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P06 Renewable energy resources
K Forestry > K10 Forestry production
P Natural resources > P05 Energy resources management
Subjects:Not in use, please see Agris categories
Agrovoc terms:salix, biofuels, production, energy resources, biomass, fertilizer application, nitrogen, shoots, leaf area, growth, measurement, felling cycle, sweden
Keywords:Allometry, cutting cycle, fertilisation, harvest, leaf area, mortality, nitrogen pool, Salix, shoot, size hierarchy, stand dynamics, stool, Sweden.
URN:NBN:urn:nbn:se:slu:epsilon-842
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-842
ID Code:1001
Department:(NL, NJ) > Dept. of Crop Production Ecology
Deposited By: Nils-Erik Nordh
Deposited On:02 Dec 2005 00:00
Metadata Last Modified:02 Dec 2014 10:08

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