Increased early-season freezing events in warmer climate on south-facing slopes.Seed-based treeline seedlings are vulnerable to increased freezing events.This suggests an explanation for unchanged treelines in the warming world.
► There is a general unimodal pattern of cushion plant cover along altitude. ► The pattern is related to an optimum combination of temperature and precipitation. ► There is a shift in limiting factors of plant growth between low and high altitudes.
