Basic Density in Norway Spruce, Part III. Development From Pith Outwards

Håkan Lindström


A change in forest management using intensive silviculture is gradually transforming the conifer raw material base of the Swedish forest industry. As the end-use properties of forest products greatly depend on wood characteristics, such as tracheid length, tracheid diameter, microfibril angle, and basic density, there is increasing concern to foresee how silvicultural regulation of growth conditions alters wood properties.

In this study, a fertilization trial near Strasan, central Sweden, six net parcels of Norway spruce (Picea abies), planted in 1957 and clear-felled in the winter of 1989/1990, were used to evaluate the influence of varying growth conditions on basic density. Growth rate of each parcel had been regulated by annual dressings of nitrogen, phosphorus, potassium, and micronutrients.

The basic density, kg/m3, of individual growth rings at breast height, from pith outwards, using suppressed, intermediate, and dominant trees sampled from each parcel, was evaluated in different modeling approaches. In a modeling attempt based on growth conditions, site quality, initial stand density, thinning, tree class, climate, and cambial age were, separately or in interaction, found significant for basic density development with r2 = 0.46-0.63. These results suggest that crown development at stand and tree level over time will affect basic density.


<i>Picea abies</i>;tree class;silviculture;wood formation;basic density;wood density;wood characteristics;crown development;models

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