When are trees more susceptible to windthrow?

Trees are more susceptible to windthrow when the soil is saturated and shallow-rooted. This is primarily because saturated soil cannot provide strong support to the roots of a tree. When the ground is saturated with water, it can lose its cohesion and stability, leading to reduced anchorage for trees. Shallow-rooted trees, in particular, are vulnerable since their root systems do not extend deep enough to access more stable soil layers. As a result, when strong winds occur, these trees may easily be uprooted or toppled.

In contrast, during winter months, many trees are dormant, which can make them less prone to windthrow. In drought conditions, roots may be more concentrated in search of moisture and thus can be relatively more stable. When trees are fully leafed out in summer, they do have a larger surface area to catch wind, but if the soil conditions are favorable, their strong anchorage can help withstand wind stress better than during periods of saturated soil.