FIBER LENGTH, TRACHEID DIAMETER, AND LATEWOOD PERCENTAGE IN NORWAY SPRUCE - DEVELOPMENT FROM PITH OUTWARDS

In a fertilization trial near Strasan, central Sweden, six net parcels of Norway spruce (Picea abies) planted in 1957 and clear-felled in th e winter of 1989/1990 were used to evaluate the influence of growth co nditions on wood characteristic development. The six parcels used in t he study represented two unfertilized, two medium, and two heavily fer tilized treatments. Suppressed, intermediate, and dominant trees were sampled from each parcel, and wood characteristics were determined fro m pith outwards on every second growth ring. Dependence of wood charac teristic development was evaluated in models built on a limited set of growth factors that had a high predictive capability, yet were simple . Tracheid length was found dependent on logarithm of cambial age and growth ring width, which gave an r(2) = 0.87. Earlywood radial trachei d diameter was found dependent on logarithm of cambial age, growth rin g width, and site quality, which gave an r(2) = 0.67. Earlywood tangen tial tracheid diameter was found dependent on logarithm of cambial age , growth ring width, and site quality, which gave an r(2) = 0.76. Late wood radial tracheid diameter was found dependent on logarithm of camb ial age and site quality, which gave an r(2) = 0.19. Latewood percenta ge was found dependent on logarithm of cambial age and growth ring wid th, which gave an r(2) = 0.53. Basic density was found dependent on la tewood percentage and the inverted value of earlywood radial tracheid diameter, which gave an r(2) = 0.80. Results indicate that changes in growth conditions over time, acting through crown development, will in fluence wood structure development of Picea abies.