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SiTree - Norway model

Status: In development | Version: v1.0.0 (2026-08-28)

General description

  • Description: Dynamic individual-tree model for Norwegian forest stands.
  • Target Species: spruce, pine, beech, others (codes: 1, 2, 3, 4)
  • Application Region: Norway

Technical characteristics

  • Model Level: Individual tree
  • Allows Projection: Yes
  • Projection Time Step: 5 years

To view the step-by-step sequence of initialization, projection, and harvest, see the individual-tree model calculation flow diagram.

Required variables

To run this model in SIMANFOR, the initial inventory must include the following minimum data:

Plot level (Plots sheet)

  • Inventory and plot IDs
  • latitude

Tree level (Trees sheet)

  • Inventory, plot and tree IDs
  • species
  • expansion factor
  • dbh
  • total height or site index

Sample inventories

You can download the following sample inventories in Excel format to test this model:

Modules and equations

Breakdown of simulated biological processes and their methodological references:

  • Site index / Stand productivity: Antón-Fernández et al. (2016)
  • Growth: BollandsÃ¥s & Næsset (2009)
  • Survival and/or mortality: BollandsÃ¥s (2007)
  • Ingrowth (trees of inventoriable size): BollandsÃ¥s et al. (2008)
  • Height-diameter relationship / height estimation: et al. ()
  • Tree volume and taper: Braastad (1966), Brantseg (1967), Vestjordet (1967)
  • Biomass: Marklund (1988), Petersson & StÃ¥hl (2006), Smith et al. (2014)
  • Diversity indexes: Omoro et al. (2010), Simpson (1949), Ulanowicz (2001), Bray & Curtis (1957)
  • Structural and size indexes: Varga et al. (2005), Moreno-Fernández & others (2025), Barbeito (2009)

References and documentation

  • How to Cite this Model:

SIMANFOR, 2026. Dynamic individual-tree model for Norwegian forest stands. (v1.0.0). https://www.simanfor.es

  • SIMANFOR Citation:

Bravo, F., Ordóñez, C., Vázquez-Veloso, A., Michalakopoulos, S., 2025. SIMANFOR cloud Decision Support System: Structure, content, and applications. Ecological Modelling 499, 110912. https://doi.org/10.1016/j.ecolmodel.2024.110912

  • Technical Documentation: SIMANFOR Models Repository (GitHub)

  • Model Bibliography:

  • Antón-Fernández, Clara, Mola-Yudego, Blas, Dalsgaard, Lise, Astrup, Rasmus (2016). Climate-sensitive site index models for Norway. Canadian Journal of Forest Research, 46(6), 794-803. 10.1139/cjfr-2015-0155
  • Barbeito, I. (2009). Natural regeneration dynamics of Pinus sylvestris L. in Central Spain.
  • BollandsÃ¥s, Ole, Buongiorno, Joseph, Gobakken, Terje (2008). Predicting the growth of stands of trees of mixed species and size: A matrix model for Norway. Scandinavian Journal of Forest Research, 23(2), 167-178. 10.1080/02827580801995315
  • BollandsÃ¥s, Ole Martin, Næsset, Erik (2009). Weibull models for single-tree increment of Norway spruce, Scots pine, birch and other broadleaves in Norway. Scandinavian Journal of Forest Research, 24(1), 54-66. 10.1080/02827580802477875
  • BollandsÃ¥s, Ole (2007). Uneven-aged forestry in Norway: inventory and management models. Norwegian University of Life Sciences, https://static02.nmbu.no/mina/forskning/drgrader/2007-Bollandsas.pdf
  • Braastad, Helge (1966). Volumtabeller for bjørk [Volume tables for birch]. Meddelelser fra Det norske Skogforsøksvesen, 21, 23-78.
  • Brantseg, Alf (1967). Furu sønnafjells. Kubering av stÃ¥ende skog. Funksjoner og tabeller [Volume functions and tables for Scots pine. South Norway]. Meddelelser fra Det norske Skogforsøksvesen, 22, 695-739.
  • Bray, J. R., Curtis, J. T. (1957). An Ordination of the Upland Forest Communities of Southern Wisconsin. Ecological Monographs.
  • Marklund, L. G. (1988). Biomassafunktioner för tall, gran och björk i Sverige [Biomass functions for pine, spruce and birch in Sweden].
  • Moreno-Fernández, D., others (2025). Structural diversity indices in managed forests.
  • (). sitree/R/height.korf.R at master · cantonfe/sitree. GitHub. https://github.com/cantonfe/sitree/blob/master/R/height.korf.R
  • Omoro, L. M. A., Starr, M., Pellikka, P. K. E. (2010). Tree biomass and soil carbon stocks in Taita Hills, Kenya. African Journal of Ecology.
  • Petersson, Hans, StÃ¥hl, Göran (2006). Functions for below-ground biomass of Pinus sylvestris, Picea abies, Betula pendula and Betula pubescens in Sweden. Scandinavian Journal of Forest Research, 21(S7), 84-93. 10.1080/14004080500486864
  • Simpson, E. H. (1949). Measurement of Diversity. Nature, 163, 688.
  • Smith, Aaron, Granhus, Aksel, Astrup, Rasmus, BollandsÃ¥s, Ole Martin, Petersson, Hans (2014). Functions for estimating aboveground biomass of birch in Norway. Scandinavian Journal of Forest Research, 29(6), 565-578. 10.1080/02827581.2014.951389
  • Ulanowicz, R. E. (2001). Information theory in ecology. Computers & Chemistry.
  • Varga, P., Chen, H. Y., Klinka, K. (2005). Tree-size diversity in progression of stand development in Douglas-fir forests. Forest Ecology and Management.
  • Vestjordet, Egil (1967). Funksjoner og tabeller for kubering av stÃ¥ende gran [Functions and tables for volume of standing trees. Norway spruce]. Meddelelser fra Det norske Skogforsøksvesen, 22, 539-574.