Category Archives: Bioenergy from Wood

Compression

If biomass needs to be compressed into pellets or briquettes, they need to be further comminuted into particles of a few millimetre lengths. This happens with refining mills that grind the biomass between serrated disks. These particles are then compressed in a pellet or briquette press to particles of uniform size and density. The heat produced during pressing degrades the […]

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Water Use

Large-scale changes in land-use, such as those proposed for intensive biomass production, constitute a change in the structure, functioning, species composition and management of the vegetation growing on the land. This, in turn, signifies a change in how water is intercepted, infiltrated, transpired and evaporated from the land surface. The resultant impacts on the availability and quality of water in […]

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Heteroskedasticity

An apparent challenge in the modelling of biomass is heteroskedasticity. This effect of growing variance with growing dimension of trees is characteristic of tree data. The problem is that heteroskedasticity (in-homogeneity of variances) violates a basic assumption of ordinary least squares regression (van Laar and Akga 2007).

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Biomass Harvesting and Logistics

Pierre Ackerman, Bruce Talbot, and Bo Dahlin 6.1 Introduction As with conventional timber harvesting and transport, the selection of machine systems for biomass production is often based on local availability, traditional harvesting methods and systems and the innovative spirit of entrepreneurs. However, piecing together an optimal biomass harvesting and transport systems to fulfil sustainable biomass supply requires substantial knowledge and […]

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Direct Liquefaction

Thermal conversion of biomass to liquids can proceed via non-pyrolytic processes, in which the feedstock is directly heated in a liquid medium that may or may not interact with the biomass (Cheng et al. 2010; Klass 1998; Titirici et al. 2007). Low temperature and atmospheric pressure in the presence of a solvent with acidic or basic catalysts can be used, […]

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Ash Content

Ash is the inorganic residue such as silica, potassium, calcium, sulphur and chlorine that remains after combustion at high temperatures and constitutes between 0.2 and 20 % of the biomass weight. In general most biomass contains similar levels of C, H and O, but the amounts of Si, Ca, Mg, K, P, S, Cl, Al, Fe and Mn, or heavy […]

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Nutrient Input-Output Budgets and an Index of Nutritional Sustainability

A simple index of nutritional sustainability has been proposed by du Toit and Scholes (2002) to gauge the nutritional sustainability of a variety of management regimes across different site types. While this is a fairly coarse indicator (it does not take transformations within the system into account) it is comparatively easy to use because it requires estimates of only (a) […]

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Remote Sensing Methods Using LiDAR or Photogrammetry to Estimate Tree or Stand Parameters

Remote sensing is based on the principle of measuring reflected electromagnetic energy from a target under investigation. The source of the energy can either be energy (photons) from the sun or an artificial source, like a laser pulse in the case of a LiDAR instrument. However, the energy measured by the sensor interacted with the target, as well as having […]

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Productivity Potential in the Different Biomes with Case Study Data from the Sub-region

Many parameters may be used to express productive potential of biomes. Produc­tivity may be expressed in terms of stocking, mass per unit area and basal area. However, not many studies have been conducted for estimating total biomass and therefore productivity of Southern African vegetation. Partly, this could be attributed to the fact that the ecoregion has too many species with […]

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