Alternative tree-cover states of the boreal ecosystem: a conceptual model

Aim: Previous analyses of remotely-sensed data detected the multimodality of the tree-cover distribution of the boreal forest, and identified areas with potentially alternative tree-cover states. This paper aims at investigating the causes of multimodality and multistability of the boreal forest, their influence on the asymmetric tree-species distribution between Eurasia and North America, and whether multistability could be associated with recent greening trends in LAI/NDVI. Location: Eurasian and North American boreal forests. Time period: 2000--2010. Major taxa studied: Boreal forest plant functional types. Methods: We employ a conceptual model based on tree-species competition to simulate the sensitivity of tree cover to stochastic disturbances and to changes in environmental factors. We include different plant functional types based on survival adaptations, and force the model with remotely-sensed environmental data. We analyse the model as a dynamical system. We use metrics fr...