ForestMAS - A single tree based secondary succession model employing Ellenberg indicator values
Authored by Simon Kolmanic, Nikola Guid, Jurij Diaci
Date Published: 2014
DOI: 10.1016/j.ecolmodel.2014.02.016
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Abstract
Over recent decades farmland abandonment has affected large areas of the
landscape. To better predict the changes associated with this process, we developed a secondary succession model based on Ellenberg indicator
values describing the ecological niche of a tree along environmental
gradients. These values are compared with local ecological factors
dependent on terrain conditions. The terrain is represented by a Digital
Terrain Model, where the local conditions are represented by a light
availability model, climate data, soil properties, and a combination of
a water flow model and average annual rainfall data. Each tree in our
model is associated with its immediate circular ecological neighbourhood
and is treated individually from the seedling stage through to its
decay. Each year, tree heights, actual vigour, and neighbourhood radii
were calculated. When two radii intersected, the vigour of both trees
was compared. The weaker of the two became dominated, leading to
stress-related mortality. When a tree reached the adult stage, it
produced seeds that established new seedlings that competed for light
and nutrition. To start the simulation, the initial amount of seed was
planted on bare ground. It was possible to monitor the succession phases
either visually or statistically. 3D tree models were used to visualize
a tree at any age, generating realistic landscape images useful for
demonstrating long-term changes in the cultural landscape to
non-experts. The results were compared with those from previous field
studies in various areas of Slovenia. Apart from predicting landscape
changes after farmland abandonment, the model can be used for
forecasting the regeneration process after clearcutting or natural
disasters. (c) 2014 Elsevier B.V. All rights reserved.
Tags
Dynamics
growth
Simulation-models
Discontinuous canopies
Species composition
Radiative-transfer
Plant-populations
Asymmetric crowns
Vegetation
model
Seed production