iLand includes serotiny, i.e. the ability to store seeds in a canopy seedbank that is released in the event of a fire, as a functional trait for specific tree species.
Serotinous lodgepole pine (Pinus contorta) only drop seeds in the year following a fire. When trees are serotinous, the amount of seed released is a multiple of the seeds produced by a non-serotinous tree, representing the accumulation of cones over multiple years.
Serotiny is controlled by two species parameters serotinyFormula and serotinyFecundity.
serotinyFormula decides for each individual tree, if the tree is serotinous or not. The result of the function is interpretated as a probability, and the variable of the function is tree age. For example, polygon(x,20,0,140,1), would define a linear increase of probability between 20 and 140 years.
serotinyFecundity is a multiplier that increases the fecundity for post-fire seed rain of serotinous species
Hansen, W.D., Braziunas, K.H., Rammer, W., Seidl, R. and Turner, M.G. (2018), It takes a few to tango: changing climate and fire regimes can cause regeneration failure of two subalpine conifers. Ecology, 99: 966-977. https://doi.org/10.1002/ecy.2181