Servicio de Información Comunitario sobre Investigación y Desarrollo - CORDIS

Data and knowledge on wood and fiber properties and their variation in European spruce forest resources. Classification of wood for mechanical pulp

Data and knowledge on wood and fiber properties and their variation in European spruce forest resources. Classification of wood for mechanical pulp.

Objectives of these tasks were:
- To build up data on wood and fiber properties in wood resources from different European regions, emphasizing spruce resources and properties important for paper production. And, based on these data:

- To analyse the variability of these properties within and between various types of stands and trees.

- To select suitable materials for the pilot plant and mill trials.

Norway spruce is the wood species most used in Europe for production of printing paper grades from mechanical pulp. Large volumes of Sitka spruce are also available soon. Prior to the project, there was only fragmented knowledge about the variability of Norway spruce grown at different European locations and even less information about Sitka spruce. The project has provided a fair basis in the form of data and models for assessing the value of a particular type of wood supplied to a specific mill. This is now being used for wood raw material optimisation.

Comprehensive sampling of wood materials was performed from stands of Norway spruce in Estonia, France, Norway and Sweden and of Sitka spruce in Great Britain. The sampling strategy was designed to provide data about the effects of the major sources of variation in the most important wood and fiber properties, as a structured basis for modelling (result 8880). The stands and trees were characterized. Sampled were taken at different heights in trees of various sizes from stands of different ages, climatic and growth conditions.

Sub-samples were prepared to provide data also on the radial variations from juvenile to mature wood. An arsenal of measurement methods was applied to determine wood and fiber properties for different parts of the trees, including growth ring widths, content of latewood, juvenile wood and heartwood, basic wood density, moisture content, fiber length, fiber width and fiber wall thickness. This way, information was obtained about internal growth patterns and variations in wood and fiber properties in the stems of the samples spruce trees.

The data were crosschecked for errors to improve the data quality. Individual widths of growth rings and latewood bands from pith to bark and property averages for radial sub-samples and full cross-sections were compiled into a comprehensive database. The procedures for sampling, measurements and the database structure were adapted from a previous project Forest-Pulp-Paper on softwood species in Sweden, which also provided some data on Swedish stands, but the EuroFiber database is unique in providing related information on properties of stands, trees, wood and fibers of Norway spruce and Sitka spruce on the European level.

Statistical analysis of the data showed large variations in fiber dimensions and wood density within each region. The differences between regions were limited compared to the variations within each region. This means that each mill will have to deal with, or has the opportunity to make use of the major part of the total variability.

Trials to relate raw material properties and process conditions to product properties and energy demand have often failed, due to difficulties to control the input material. Therefore, large efforts were made to provide selected materials with different but uniform properties for the trials and to monitor the materials carefully during the trials. For this selection, differences between industrially feasible wood classes were analysed based on the database. Parameters related to the functionality of the fibers in paper were estimated for all samples and subjected to multivariate data analysis. Fiber length and wood density were selected to describe the suitability of fibers in the samples for different products. (This result is not generally applicable but valid for the investigated spruce resources in Europe). The property-based selection rules were translated into forestry terms, defining suitable wood materials for the trials. The usefulness of selection by fiber length and wood density was proven in the following trials.

The database proved to be useful for the development of models for wood and fiber properties. Various types of models may be designed for different applications, for instance for new tools and practices in forestry planning and operation. The database is also a strong and unique basis for fundamental research on growth and properties of wood, trees and stands as well as for education.

The methods and practices used will be applied in other projects to other wood species and regions/countries, to address problems and possibilities also for other types of products as well as for research and education. The wood and fiber database is owned and managed by STFI but available to all project partners and will be made publicly available in 2005. It is being used in further research projects and in the development of applications.

Reported by

STFI-Packforsk
Drottning Kristinas vag 61
114 86 Stockholm
Sweden
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