How can soil erosion affect trees?

Soil erosion can significantly impact trees, primarily by exposing their roots. This exposure happens when the soil that normally covers and protects the roots is worn away by wind, water, or human activity. When roots are exposed, the stability of the tree is compromised, making it more susceptible to being uprooted, especially during storms or high winds.

Furthermore, exposed roots can lead to increased stress on the tree. The roots are vital for anchoring the tree and absorbing water and nutrients from the soil. When they are left unprotected, they become more vulnerable to environmental factors such as extreme temperatures, dehydration, and diseases. This combination of decreased stability and increased stress can ultimately affect the overall health and longevity of the tree.

The other options suggest conditions that would not typically arise from soil erosion. For example, erosion does not aid in root spread or improve nutrient availability; rather, it often diminishes the nutrient-rich layer of soil that supports tree health. Additionally, erosion would generally reduce, not enhance, water retention, as it removes the soil structure needed to hold moisture effectively.