Modelling aboveground biomass and fuel load components at stand level in shrub communities in NW Spain

•Novel stand-level biomass models developed for 9 shrubland types, by groups and all together.•Nonlinear iterative seemingly unrelated regression used to fit systems of integrated additive equations.•Models were also developed for standing fuel loads by size and condition, and litter.•Predictor variables were stand height alone or with stand cover and litter depth.•Generally, models performed reasonably well even those based on height alone.