Modelling the structural growth of Scots pine with implications for wood quality

• Published in: Ecological modelling 1999-10, Vol.122 (1), p.117-134
• Main Authors: Kellomäki, Seppo, Ikonen, Veli-Pekka, Peltola, Heli, Kolström, Taneli
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Biological and medical sciences; Forestry; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; Heartwood; Knots; Light interception; Methods and techniques (sampling, tagging, trapping, modelling...); Modelling; Pinus sylvestris; Quality of wood and forest products; Scots pine; Tree structure; Wood density; Wood quality
• ISSN: 0304-3800; 1872-7026
• DOI: 10.1016/S0304-3800(99)00086-1

A model for simulating the growth and development of individual Scots pines ( Pinus sylvestris L.) is presented in terms of three-dimensional structure of the tree as determined by the influence of local light conditions on branch growth, with implications for the properties of the wood. The basic computational unit for structural growth is the shoot. Each shoot produces new shoots with dimensions related to the amount of direct and diffuse radiation intercepted in the parent shoot and supplied by other shoots in the crown. The calculation procedure utilises the spatial distribution of shoots produced by the growth process (location, azimuth, inclination), and the structure of the shoots determined in terms of the density, angle and length of the needles. The allocation of tree biomass amongst the needles, branches and stem is basically related to the allocation of the growth of forming shoots between the shoot axis and the needles under the control of the hierarchical position of the parent shoot, branch age and the height of the tree. The growth, death and pruning-off of shoots and branches are modelled over the life span of the tree using time step of 1 year, taking special care to identify the location of green and dead knots in the wood. The properties of the stem are further described in terms of the stem form, wood density and heartwood, which are modelled in the context of the overall growth of the tree. The computation produces the three-dimensional distribution of ring widths, density and heartwood in the stem, i.e. from the pith to stem surface and from the stem base to tree top. The model produces quite a realistic crown and stem structure for simulated Scots pines regardless of the life span of the tree. Furthermore, the model is capable of calculating quite accurately, e.g. average wood density values for any section of wood within a tree.