Regeneration and Resource Sharing : A model to simulate uneven-aged forest stands dynamic
Irstea, Research Unit on Forest Ecosystem (EFNO), 45290 Nogent-sur-Vernisson, France, firstname.lastname@example.org
INRA, UMR547 PIAF, 63100 Clermont-Ferrand, France, email@example.com
INRA, UMR AMAP, 34398 Montpellier, France, firstname.lastname@example.org
Objectives and content
Currently, there is a strong trend to turn forest management towards silviculture in accordance with natural processes. Modelling forest dynamics is a key tool to assist the management of complex uneven-aged forest stands.
The RReShar model (Regeneration and Resource Sharing) is a functional - structural model. Stand structure is described, including all the strata of the forest ecosystem, i.e. adult trees, suppressed trees, saplings and seedlings growing in the understorey (regeneration) and herbaceous/shrubby vegetation. Growth processes of all those components are based on the interactions with light and water.
The simulated scene is a 1 ha plot divided into square cells of a chosen size (a few meters). Adult trees are explicitly spatialised on the plot, whereas understorey vegetation and regeneration are considered as a multi-species layer whose characteristics vary at the cell level. Vegetation is described by its height and cover. Tree regeneration, i.e. seedlings and saplings, are initialised as cohorts characterized by a diameter and height distribution. The overstorey and understorey growth time step is annual, whereas within this annual loop, the light interception and water cycle (interception, evapotranspiration and soil water content) processes are simulated, respectively, monthly and daily.
Currently, RReShar is calibrated with data coming from uneven-aged mixed Quercus petraea – Pinus sylvestris stands with an understorey colonised by Calluna vulgaris, Pteridium aquilinum and Molinia caerulea in temperate conditions. However, the model was built to be as generic as possible and can be easily run with other species and climatic conditions.