Forest modeling involves the representation of processes occurring in forests through mathematical models (functions and systems of equations). The goal of forest modeling is to develop models for the distribution, dynamics, and relationships between forest attributes such as tree and stand characteristics (height, diameter, stem volume, etc.), as well as more complex forest-related measures (e.g., forest value—both monetary and ecological, health condition, deadwood volume and structure, etc.), in order to accurately simulate and predict stand growth and tree mortality based on the site conditions, current state, and management practices. Reliable forest models, along with data that statistically reflect forest resources objectively, are crucial for forest management decision-making and for both short-term and long-term forecasting of Estonia's forest resources.
Forest models are created at various levels, ranging from relatively simple tree or stand growth equations to complex forest simulation models. The accuracy of these models largely depends on the quality of forest data, making it essential to systematically collect and maintain forest data, especially through long-term permanent sample plots. In 1995, the establishment of a permanent sample plot network for forest growth dynamics (KKPRT) began, which now includes over a thousand plots across Estonia. These plots have measured the coordinates of all trees, allowing for measurements of the same trees at five-year intervals. Initially established for creating stand growth models based on individual tree growth and mortality equations, the sample plot network has evolved into a comprehensive data acquisition system for monitoring stand growth and condition, including data on stand development, regeneration, deadwood volume, naturalness, and more. Numerous studies have been conducted and are ongoing using the KKPRT database, focusing on the following topics:
- Modeling of individual tree growth
- Modeling of tree mortality
- Modeling of competition between trees
- Modeling of relationships between tree height and diameter
- Modeling of tree diameter distributions
- Modeling of stand growth and increment
- Modeling of stand structure and diversity
- Modeling of dominant height and its dynamics
- Investigating measurement errors and statistical outliers
- Modeling of causes of tree mortality
- Modeling of stand naturalness
- Modeling of stand growth dynamics under extreme growth conditions
- Investigating the use of innovative methods (e.g., tomography, resistograph)
- Research on the restoration of forest ecosystems
- Various studies on protected forests
Doctoral thesis:
Toomas Tarmu, (juh) Diana Laarmann, Andres Kiviste, Puude väljalangevuse modelleerimine sõltuvalt metsamajanduslikest võtetest (Assessment and modelling of individual tree mortality depending on forest management decisions), Eesti Maaülikool
Larger and longer-term projects:
Re-measurement of the Forest Growth Permanent Sample Plot Network
