How do windblown snow and frost damage trees near the tree line?

Near the tree line in temperate mountain regions, trees face harsh environmental conditions that can damage or kill their shoots and trunks. These factors include:

• Windblown Snow: Crystals carried by the wind act as an abrasive, damaging the buds of trees.1
• Frost Damage: In temperate zones, the brevity of the growing season means that tree shoot tissues may not have sufficient time to harden before winter begins, making them susceptible to freezing. Additionally, rapid temperature drops can cause the water within a tree's sap and vascular tissues to freeze and expand. Because the outer bark contracts faster than the inner tissues, this creates mechanical stress that leads to "frost cracks"—ruptures in the trunk and branches that can leave the tree vulnerable to insects, fungi, and bacteria.1
• Desiccation and Exposure: Shoots exposed above the snowpack can suffer from desiccation due to direct and snow-reflected solar radiation, particularly late in the winter. Furthermore, if wind removes the insulating snow layer, the tree's roots may suffer from freezing injury.1

These stresses often result in the formation of krummholz—stunted, deformed, shrub-sized trees.1