Annikki Mäkelä, Veli-Pekka Ikonen, Petteri Vanninen. (1997). An application of process-based modelling to the development of branchiness in Scots pine. Silva Fennica vol. 31 no. 3 article id 5632. https://doi.org/10.14214/sf.a8534

Original keywords: puutavara; mänty; kasvu; hiili; läpimitta; biomassa; oksat; laatu; latvus; simulointi; kasvumallit; mallit; hiilitase; oksaisus

English keywords: Pinus sylvestris; carbon balance; simulation; pipe model; timber quality; growth model; branching; crown structure; whorl

Abstract | View details | Full text in PDF | Author Info

A process-oriented tree and stand growth model is extended to be applicable to the analysis of timber quality, and how it is influenced by silvicultural treatments. The tree-level model is based on the carbon balance and it incorporates the dynamics of five biomass variables as well as tree height, crown base, and breast height diameter. Allocation of carbon is based on the conservation of structural relationships, in particular, the pipe model. The pipe-model relationships are extended to the whorl level, but in order to avoid a 3-dimensional model of entire crown structure, the branch module is largely stochastic and aggregated. In model construction, a top-down hierarchy is used where at each step down, the upper level sets constraints for the lower level. Some advantages of this approach are model consistency and efficiency of calculations, but probably at the cost of reduced flexibility. The detailed structure related with the branching module is preliminary and will be improved when more data becomes available. Model parameters are identified for Scots pine (Pinus sylvestris L.) in Southern Finland, and example simulations are carried out to compare the development of quality characteristics in different stocking densities.

Mäkelä, E-mail: am@mm.unknown
Ikonen, E-mail: vi@mm.unknown
Vanninen, E-mail: pv@mm.unknown

Category : Research article

article id 425, category Research article

Petteri Vanninen. (2004). Allocation of above-ground growth in Pinus sylvestris – impacts of tree size and competition. Silva Fennica vol. 38 no. 2 article id 425. https://doi.org/10.14214/sf.425

Keywords: Scots pine; allocation; growth efficiency

Abstract | View details | Full text in PDF | Author Info

The effect of tree age, size and competition on above ground growth allocation was studied with 69 Pinus sylvestris trees. Competition was described by tree-level indicators (needle density, crown ratio and height-diameter ratio). The stem, branch and needle growth were determined by stem and branch radial increments and tree level biomass analysis. Combined growth of compartments was strongly correlated with needle mass. Furthermore, tree age, size and competition indicators affected the allocation of growth among the compartments. The allocation of growth to stem and needle increased with tree age and size while the allocation of growth to branch decreased. The increasing crown ratio increased allocation of growth to branches. The combined growth of the components and separate growth of needles, branches and stem were related to needle mass. However, competition and tree size were significant additional explanatory variables when the stem, branch and needle growth were estimated according to needle mass. The growth efficiency increased with relative tree height and decreased with increasing needle density.

Vanninen, University of Helsinki, Department of Forest Ecology; mailing address: SAIMA – Centre for Environmental Sciences, Linnankatu 11, FIN-57130 Savonlinna, Finland E-mail: petteri.vanninen@helsinki.fi

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