Windthrow

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Windthrow

In forestry, windthrow refers to trees uprooted by wind, or to other phenomena that cause uprooting. breakage of the tree bole instead of uprooting it is called windsnap.

1 Ecological Effects
2 Causes
3 Popular Culture
4 External links
5 References

[edit] Ecological Effects

Windthrow disturbance generates a variety of unique ecological resources on which certain forest processes are highly dependent. Thus windthrow can act as a rejuvenating process whereby regeneration is made possible with new resource availability.

Severe uprooting opens bare patches of mineral soil that can act as seed sinks. These patches have been shown, in the Pacific Northwest of the United States, to have higher biodiversity than the surrounding forest floor. Additionally, the gap created in the forest canopy when windthrow occurs yields an increase in light, moisture, and nutrient availability in near proximity to the disturbance.

[edit] Causes

Windthrow in a British plantation, caused by the adjacent clearfell

Windthrow is commonly the end result of tree senescence, where multiple factors contributing to the declining health of a tree increase its susceptibility to windthrow.

Windthrow can also result from logging, especially in young forests managed specifically for timber. The removal of certain trees at a forest's edge increases the exposure of the remaining trees to the wind. The resulting damage can be a significant factor in the evolution of a forest.

Forest stands adjacent to lakes or other natural edge-creating features develop rooting strength through growth feedback with wind movement. If a tree does not experience much wind movement during the stem exclusion phase of stand succession, it is not likely to develop a resistance to wind. Thus, when a fully or partially developed stand is bisected by a clearcut, the seed trees and forest edges adjacent to the clearcut may not be capable of withstanding forces in which they didn't develop.

Trees with heavy growths of ivy, wisteria, or kudzu are already stressed and may be more susceptible to windthrow, the additional foliage acts as a sail to the wind.

[edit] Popular Culture

The term blowdown is a slang term used by hikers, hunters, mountaineers, rangers, and other outdoors people to describe a tree knocked over by the wind. The term is often used where the fallen tree (or trees) has become an obstruction to travel.