An increase in the demand for wood results in improved recovery and less residual biomass in the forests. Paradoxically, interest in forest residue as a renewable source of raw material seems to be in a reverse ratio to its availability in a certain area. Finland and Sweden are probably more dependent on forestry and forest in dustries than any other developed countries in the world. A sufficiency of raw ma terial for integrated forest industries is vital for the national economy of both countries, and a great deal of attention is being paid to the long-term potential of unutilized biomass left behind in logging operations. Furthermore, since these countries possess no reserves of fossil fuels, and since their per-capita consump tion of primary energy is exceptionally high, they also consider unmerchantable forest biomass a realistic source of indigenous energy. A joint Nordic research project on harvesting and utilization of logging residue was carried out in 1969-1976 under the auspices of the Nordic Research Council on Forest Operations. This fruitful cooperation soon gave rise to related national projects in Sweden, Finland, Norway, and Denmark, stimulating further research and producing practical applications. Concurrently, particularly after the worldwide energy crisis in 1973, research on all aspects of utilization of forest bio mass mushroomed in the United States, Canada, and the Soviet Union. An ex plosive increase occurred in both the number and diversity of biomass studies.

Klappentext

The first world-wide energy crisis in the early 1970s resulted in an explosive increase in both the number and diversity of studies on unmerchantable tree components such as tops, branches, foliage, stumps, and roots, and on whole small-sized trees. Here is a synopsis and the latest information on forest biomass utilization and the potential of this renewable raw material resource, presented from an interdisciplinary viewpoint. This balanced review of scientific literature as well as recent practical developments and experience in forest biomass utilization covers various aspects - quantity and properties of the resource, - harvesting and transport, - ecological consequences of intensive biomass recovery, - comminution and upgrading, - utilization for pulp, paper, composite boards, fodder, and energy in solid, liquid, or gaseous form.

Inhalt
1 Introduction.- 2 Residual Forest Biomass as a Raw Material Reserve.- 2.1 Biomass Components of a Tree.- 2.2 Composition of Whole-Tree Biomass.- 2.3 Biomass of an Entire Stand.- 2.4 Forest Biomass Inventory.- 2.5 Quantity of Residue in Practical Logging Operations.- 3 Technical Properties of Residual Tree Components.- 3.1 Anatomical Structure of Residual Tree Components.- 3.2 Cell Dimensions in Residual Tree Components.- 3.3 Chemical Composition of Residual Tree Components.- 3.4 Basic Density of Wood and Bark in Residual Tree Components.- 3.5 Heating Value of Residual Tree Components.- 4 Recovery of Residual Forest Biomass.- 4.1 Harvesting Whole Trees.- 4.2 Relogging Slash from Cutovers.- 4.3 Continuously Progressing Swath Harvesters.- 4.4 Harvesting Stump and Root Mass.- 5 Comminution of Residual Forest Biomass.- 5.1 The Purpose of Comminution.- 5.2 The Techniques of Comminution.- 5.3 Energy and Power Requirement in Comminution.- 5.4 Position of Comminution in the Harvesting Schedule.- 6 Trucking Residual Forest Biomass.- 6.1 Transport-Technical Characteristics of Residual Biomass.- 6.2 Improvement of Bulk Density by Compaction.- 6.3 Trucking Unlimbed Timber.- 6.4 Trucking Unprocessed Logging Residue.- 6.5 Trucking Comminuted Biomass.- 6.6 Alternatives to Trucking.- 7 Examples of Biomass Harvesting Systems.- 7.1 Whole-Tree Chipping Systems.- 7.2 Systems for Chipping Slash.- 7.3 Systems for Integrated Recovery of Crown Mass and Conventional Timber.- 7.4 Systems, for Harvesting Stump and Root Mass.- 8 Utilization of Residual Forest Biomass.- 8.1 Use of Chips as a Solid Fuel.- 8.2 Use of Residual Biomass for Pulp and Paper Products.- 8.3 Use of Residual Biomass for Panel Products.- 8.4 Use of Residual Biomass as a Feedstock for Chemicals.- 8.5 Use of Residual Forest Biomass for Fodder.- 8.6 Upgrading Residual Forest Biomass.- 9 Ecological Consequences of Residue Removal.- 9.1 Effect of Residue Removal on Nutrient Balance.- 9.2 Effect of Residue Removal on Regeneration and Growth.- 9.3 Effect of Residue Removal on Forest Health and Environment.- 9.4 Returning Nutrients to Forest Soil.- Scientific and Common Names of Tree Species.- Equivalents and Conversion Factors.- References.