Crown development of Scots pine trees following thinning and nitrogen fertilization

The effects of thinning and nitrogen fertilization, singly and in combination, on the growth of 45-year-old Scots pine (Pinus sylvestris L.) trees in northern Sweden, were studied from 1983-1988 inclusive. Sixteen trees were examined each year for crown development. The number of branches, shoot axes and buds produced, branch elongation on main axes, and dry weight production of shoot axes, needles, buds, cones, and dead material on live branches, were determined destructively on four trees per treatment. Both thinning and fertilization influenced the number of crown components produced annually. Branch elongation was increased by fertilization, and decreased by thinning. The weights of the components studied were increased more by fertilization than by thinning. Thinning promoted the distribution of growth to the lower crown, while fertilization promoted growth in the upper crown. Combined thinning and fertilization increased the weight of shoot axes, needles and buds more rapidly than did thinning or fertilization applied individually.

[1]  H. Brix.  Effects of thinning and nitrogen fertilization on branch and foliage production in Douglas-fir , 1981 .

[2]  A model for the relationship between branch number and biomass in Pinus sylvestris crowns and the effect of crown shape and stand density on branch and stem biomass , 1986 .

[3]  W. McGill,et al.  Dynamics of foliar N in Douglas-fir after spring and fall application of ammonium nitrate and urea , 1990 .

[4]  E. Valinger.  Effects of thinning and nitrogen fertilization on stem growth and stem form of Pinus sylvestris trees , 1992 .

[5]  J. Landsberg.  Crop physiology of forest trees , 1987 .

[6]  Manfred Näslund.  Funktioner och tabeller för kubering av stående träd , 1940 .

[7]  D. F. Forward,et al.  GROWTH AND MORPHOGENESIS IN THE CANADIAN FOREST SPECIES: IV. RADIAL GROWTH IN BRANCHES AND MAIN AXIS OF PINUS RESINOSA AIT. UNDER CONDITIONS OF OPEN GROWTH, SUPPRESSION, AND RELEASE , 1961 .

[8]  O. Junttila.  Effects of temperature on shoot growth in northern provenances of Pinus sylvestris L. , 1986, Tree physiology.

[9]  E. Valinger.  Effects of thinning and nitrogen fertilization on growth of Scots pine trees: total annual biomass increment, needle efficiency, and aboveground allocation of biomass increment , 1993 .

[10]  L. J. Heidmann.  Fertilization increases cone production in a 55-year-old ponderosa pine stand in central Arizona , 1984 .

[11]  T. Kira,et al.  Structure of forest canopies as related to their primary productivity , 1969 .