Fig. 3
The classification tree model for S. borealis. Start from the top node of the tree. If the data meet the climatic condition of the node, go left, otherwise go right. The number of terminal nodes after pruning was 20 from A to T. The numbers written beneath each node show the occurrence probability and n under the climatic conditions of each node. The terminal nodes enclosed by the solid line indicate suitable habitat and those enclosed by the dashed line show marginal habitat. Other terminal nodes are considered non-habitat. The numbers in parentheses show the number of data points classified into the node