Recent FLMs have improved the formulation of site-scale pro-cesses by adding quantitative information (e.g. tree numbers andbiomass) at each site. For example, LANDIS II adds biomass to eachspecies’ age cohort and uses a ratio of actual biomass to poten-tial biomass to quantify resource availability at each site, assumingage-cohort biomass by species implicitly incorporates tree densityinformation (Scheller et al., 2007, 2011). LANDCLIM also replacesthe presence/absence of species’ cohorts in the LANDIS modelwith species’ biomass dynamics, which tracks numbers of treesand biomass by species’ age cohort. Site-scale resource competi-tion is determined by growth- and density-dependent mortalitydriven by maximum stand biomass (Schumacher et al., 2004). InTreeMig, reproduction is modeled in a detailed way, including seedproduction by adult trees, seed dispersal, seed bank dynamics, ger-mination, and sapling development. Moreover, TreeMig accountsfor within-cell structure in terms of horizontal and vertical hetero-geneity within the forest stand (Lischke et al., 2006). In addition,LANDMOD is scaled up from a gap model to accelerate the com-putation efficiency (Garman, 2004), where growth and mortalityfunctions and bioclimatic values are fitted by meta-modeling tomodel gap simulations (Urban et al., 1999).