Published Date
Energy September 2010, Vol.35(9):3717–3721,doi:10.1016/j.energy.2010.05.017 Author
Lauri Vesa a
Teijo Palander b,,
aForestCalc Consulting Oy Ltd., 80230 Joensuu, Finland
bSchool of Forest Sciences, University of Eastern Finland, 80100 Joensuu, Finland
Received 21 January 2010. Revised 5 May 2010. Accepted 8 May 2010. Available online 11 June 2010.
Abstract The value and volumes of industrial stump fuel supply are increasing for energy production. Accurate estimates of aboveground and belowground biomass of trees are important when estimating the potential of stumps as a bioenergy source. In this study two stump biomass equations were adapted and tested using them as calibrated stump biomass models computed as the cumulative sum by a local stand. In addition, variables derived from stem measurements of the forest harvester data were examined to predict stump biomass of a stand by applying regression analysis. The true stump yield (dry weight) was used as the reference data in the study. Both biomass models performed well (adjustedR2 ˜ 0.84) and no advance was found in using other stem dimensions as independent variables in the model. The stand-level model can be used in innovative stump biomass prediction tools for increasing efficiency of energy wood procurement planning to stands within a certain area. In practice, wood procurement managers would need to adapt developed system and decide whether the degree of accuracy/precision provided by the models is acceptable in their local stand harvesting conditions. Keywords
Energy wood
Planning system
Forest harvester
Adaptive methods
Nomenclature
Bstump
total yield of stump biomass, kg/stand (dry weight)
Published Date
Forest Ecology and Management 1 June 2011, Vol.261(11):1919–1927,doi:10.1016/j.foreco.2011.02.015
Author
Heljä-Sisko Helmisaari a,,
Kjersti Holt Hanssen b,
Staffan Jacobson c,
Mikko Kukkola d,
Jukka Luiro d,
Anna Saarsalmi d,
Pekka Tamminen d,
Bjørn Tveite b,
aUniversity of Helsinki, Dept. of Forest Sciences, P.O. Box 27, FI-00014 Helsinki, Finland
bNorwegian Forest and Landscape Institute, P.O. Box 115, NO-1430 Ås, Norway
cForestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden
dFinnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland
Received 31 October 2010. Revised 1 January 2011. Accepted 11 February 2011. Available online 5 March 2011.
Abstract The aim of this study was to determine the effect of whole-tree harvesting (WTH) on the growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies(L.)Karst.) as compared to conventional stem harvesting (CH) over 10 and 20 years. Compensatory (WTH + CoF) and normal nitrogen-based (CH + F or WTH + F) fertilisation were also studied. A series of 22 field experiments were established during 1977–1987, representing a range of site types and climatic conditions in Finland, Norway and Sweden. The treatments were performed at the time of establishment and were repeated after 10–13 years at 11 experimental sites. Seven experiments were followed for 25 years. Volume increment was on average significantly lower after WTH than after CH in both 10-year periods in the spruce stands. In the pine stands thinned only once, the WTH induced growth reduction was significant during the second 10-year period, indicating a long-term response. Volume increment of pine stands was 4 and 8% and that of spruce stands 5 and 13% lower on the WTH plots than on CH during the first and the second 10-year period, respectively. For the second 10-year period the relative volume increment of the whole-tree harvested plots tended to be negatively correlated with the amount of logging residue. Accordingly, the relative volume increment decreased more, the more logging residue was harvested, stressing the importance of developing methods for leaving the nutrient-rich needles on site. If nutrient (N, P, K) losses with the removed logging residues were compensated with fertiliser (WTH + CoF), the volume increment was equal to that in the CH plots. Nitrogen (150–180 kg ha−1) or N + P fertilisation increased tree growth in all experiments except in one very productive spruce stand. Pine stands fertilised only once had a normal positive growth response during the first 10-year period, on average 13 m3ha−1, followed by a negative response of 5 m3ha−1during the second 10-year period. The fertilisation effect of WTH + F and WTH + CoF on basal area increment was both smaller and shorter than with CH + F. Research highlights ► 22 logging residue experiments in the Nordic countries were followed for 20 years. ► Whole-tree harvest after thinning significantly decreased stem volume increment. ► Decrease in volume increment continued and deepened in the second 10-year period. ► The more logging residue was harvested, the lower was the relative volume increment. ► Removal of nutrients, especially N, was the most probable cause for the growth losses. Keywords
Aspen (Populus tremuloides Michx.) is a clonal tree species that commonly regenerates via root suckering after disturbance. This paper reviews the literature and identifies critical gaps in our understanding of the dynamics of aspen root suckering. The role of plant growth regulators (e.g., hormones, carbohydrates), environmental conditions (e.g., soil moisture, temperature, nutrient availability), overstory disturbance (e.g., harvesting, wildfire), ground disturbance (e.g., soil compaction, wounding or severing of roots), vegetation competition, predisturbance stand condition, and clonal (genetic) differences are discussed as they relate to sucker initiation, sucker growth, and (or) patterns of site establishment. The paper presents a series of conceptual figures summarizing our knowledge of the factors controlling suckering dynamics and identifies areas of future research.
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The impacts of partial cut systems on nutrient availability and understory vegetation are poorly understood. To examine these responses, white spruce dominated stands in the boreal mixedwood of Alberta were clear-cut or partial-cut and the forest floor treated by slash burning, mixing, mounding, or scalping in a split-plot design. Soil nutrient availability (ion exchange resin), net N mineralization (in situ incubations), and vegetation (density and cover) responses were assessed. With the exception of higher Mg availability in the clearcuts, differences in nutrient availability were driven by forest floor disturbance and not harvest method. Relative to controls, burning increased availability of NH4+, NO3–, and P, and scalping increased Ca and Mg but diminished K. Controls had low levels of NO3–. The mixing treatment substantially reduced net N mineralization. In terms of vegetation, partial cuts reduced root suckering by Populus spp. (Populus tremuloides Michx., Populus balsamifera L.) relative to clearcuts. Burning and mounding stimulated fireweed (Epilobium angustifolium L.) cover, while scalping increased Populus spp. sucker density. In contrast, mixing largely reduced vegetation establishment, likely because of the destruction of roots and rhizomes and reduced N supply. Nutrient availability and vegetation establishment were more strongly controlled by forest floor disturbance than by partial canopy retention.
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Samples from the n trees nearest to a point or plot center are sometimes used to estimate per-tree values such as age or growth from increment cores. Clutter et al. (J.L. Clutter, J.C. Fortson, L.V. Pienaar, G.H. Brister, and R.L. Bailey. 1983. Timber management: a quantitative approach. John Wiley & Sons, New York) indicated that this procedure can be biased because it is more likely to sample large trees occupying large amounts of space. This sampling procedure falls into the category of n-tree distance sampling in which the nth closest tree to a point defines a plot radius that can be used to estimate number of trees or amount of volume per hectare. When a ratio of n-tree per-hectare estimates is used to estimate per-tree attributes, the resulting estimator is a weighted average in which weights are the inverse of the n-tree sampling plot size. Since this ratio estimator essentially weights observations inversely with plot size, it is not subject to the objections of Clutter et al. (1983). This estimator is used to estimate age by diameter at breast height class for eastern cottonwood (Populus deltoides Bartr. ex Marsh.) on the Cimarron National Grassland.
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The recent practice of planting broad-leaved trees at wide spacing (3 × 3 m) in Britain has generated debate concerning the effects of initial spacing on early growth (up to 5 years old) and form. The experiments described investigated the effects of spacing on the early growth of common ash (Fraxinus excelsior L.) using two replicate Nelder experiments at two sites, with spacings in the range 0.77–4.86 m. In both experiments, height, stem diameter, and stem volume decreased with increasing spacing; at one site, shoot and root dry mass also showed the same trend. These results suggest that better growth at closer spacings may be a silvicultural characteristic of ash. Analysis of the data showed that there was no intraspecific competition, and a number of hypotheses were examined that may explain the observed results.
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Industrial roundwood is the raw material produced from harvested trees that is used to manufacture a wide range of wood products. Roundwood is harvested from the forest and is transported to primary manufacturing facilities to be processed into primary and secondary wood products. Roundwood includes sawlogs that are processed into dimensional lumber, veneer logs peeled into plywood and panels, pulpwood chipped for pulp and paper products, composite logs chipped for oriented strand board panels, and fuelwood that is converted into a variety ofenergy products.
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Perry, Charles H.; Nelson, Mark D.; Piva, Ronald J. 2010. Imports and exports of roundwood in the upper Midwestern United States. Chapter 2. In: Eredics, Peter, ed. Mapping Forestry. Redlands, CA: ESRI Press: 5-8.
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