Biomass and stem volume equations for tree species in Europe

A review of stem volume and biomass equations for tree species growing in Europe is presented. The mathematical forms of the empirical models, the associated statistical parameters and information about the size of the trees and the country of origin were collated from scientific articles and from technical reports. The total number of the compiled equations for biomass estimation was 607 and for stem volume prediction it was 230. The analysis indicated that most of the biomass equations were developed for aboveground tree components. A relatively small number of equations were developed for southern Europe. Most of the biomass equations were based on a few sampled sites with a very limited number of sampled trees. The volume equations were, in general, based on more representative data covering larger geographical regions. The volume equations were available for major tree species in Europe. The collected information provides a basic tool for estimation of carbon stocks and nutrient balance of forest ecosystems across Europe as well as for validation of theoretical models of biomass allocation.

Individual tree measurements by means of digital aerial photogrammetry

This study explores the plausibility of the use of multi-scale, CIR aerial photographs to conduct forest inventory at the individual tree level. Multiple digitised aerial photographs are used for manual and semi-automatic 3D positioning of tree tops, for species classification, and for measurements on tree height and crown width. A new tree top positioning algorithm is presented and tested. It incorporates template matching in a 3D search space. Also, a new method is presented for tree species classification. In it, a partition of the image space according to the continuously varying image-object-sun geometry of aerial views is performed. Discernibility of trees in aerial images is studied. The measurement accuracy and overall measurability of crown width by using manual image measurements is investigated. A simulation study is used to examine the combined effects of discernibility and photogrammetric measurement errors on stand variables. The study material contained large-scale colour and CIR image material and 7708 trees from 24 fully mapped plots in Southern Finland. The results of the discernibility analysis suggest that 88–100% of the total stem volume is measurable when using multiple aerial photographs. The structure and density of the forest were found to affect discernibility. The best hit-rates when using the semi-automatic tree top positioning algorithm ranged from 77 to 100% of the visually discernible trees. Systematic underestimation of the crown width was observed and the measurability of crown width was best near the image nadir. Species classification was tested in mixed stands of Scots pine, Norway spruce, and silver birch. The Kappa-coefficients ranged from 0.71 to 0.86. The results of the simulation suggest that very high accuracy at the individual tree level cannot be expected. However, if the photogrammetric measurements are unbiased, the aggregate stand variables can be very accurate. An accurate species recognition method is needed in the mixed stands in order to achieve unbiased estimates for the small strata.

Conflict cultures – Qualitative Comparative Analysis of environmental conflicts in forestry

Owing to the internationalisation of the forestry debate and forest policy, there is growing need to conduct comparative forest policy research at an international scale. This research compares environmental confl icts in forestry in seven cases during 1984–1995. The cases include Finland, France, Minnesota USA, Norway, Pacifi c Northwest USA, Sweden and West Germany. The research is based on the notion that each society has its own ‘cultural’ ways of producing and managing environmental confl icts in forestry, depending on the social, political, economic, and resource characteristics of the society. The purpose of the study is to describe these confl ict cultures, to identify and analyse the societal aspects that impact them, and to discuss the implications of understanding confl icts as cultural phenomena. The research is based on focused interviews of multiple actors related to forest management and protection. For the data analysis, a ‘hermeneutic’ (interpretative and understanding) approach is introduced to Qualitative Comparative Analysis, the use of which has been dominated by causal applications. As a result of the analysis, models of confl ict cultures and confl ict management strategies are constructed. The model of confl ict cultures indicates three basic dimensions of confl ict culture, and defi nes how they are related to each other. These dimensions are mild vs. intense confl icts, separatist vs. co-operative relations between actors and stability vs. change in forest resource policy and use. The model of confl ict management strategies indicates to what extent the different cases place emphasis on interactive vs. institutional confl ict management, and the management of confl icting (sub)cultures within the society vs. the confl ict culture of the society.

Birch as sawn timber and in mechanical further processing in Finland. A literature study

This study based on literature and restricted interviews of forest products companies is a compilation of current knowledge concerning utilisation of the wood of birch species growing in Finland, silver birch (Betula pendula) and pubescent birch (B. pubescens), for saw milling and further related processing. As the basis for this, the properties (morphological, anatomical, physical, mechanical and chemical) of birch wood are presented as well as the effects of cultivation and how growing conditions affect these properties. The issues cover resources and use of large- and small-dimensioned birch, current and potential importance of birch for saw milling as well as for furniture and joinery industries, quality and specifi c properties of birch timber for sawing and processing for special purposes, principles and methods of grading the quality of wood, how to improve and control quality, timber procurement, primary processing, machining and surfacing as well as semi- and end-products. Based on the available data, the principal needs for research and develop.