The most affected plants by the wind are the ones that are planted in exposed sites. Woody plants, exposed continuously to strong winds will have their top-growth unbalanced, giving the plants a one-sided appearance. The exposed shoot tips are also likely to be damaged or scorched. Trees that grow on hill tops and on exposed, coastal sites, are also examples of plants that are going to be damaged by strong winds.
Strong winds and gales
The greater the velocity of wind, the more damage it causes. In high winds, shoots and stems of plants may be broken. In gale force conditions, trees may be uprooted or their root systems seriously weakened.
Strong winds will not only affect the garden plants, but it will also cause damage to fences, greenhouses and other structures in the garden. On sandy or peat soil, the wind may course soil erosion.
High temperatures combined with strong winds will increase the rate at which water is lost from plants, leading to desiccation of leaves and shoots. Similar wind damage will occur if temperatures are too low. In these conditions plants cannot replace lost moisture if soil water is frozen.
Effects of topography
The severity of the winds depends to a large extent on topography. Coastal sites often have no natural protection from halt-laden winds coming in from the sea. Hill-top sites may be equally exposed, because the wind gusts around and over the hill.
Wind funnels are created by the channeling of air between hillsides and along valleys, through corridors of established trees, or between adjacent buildings. This has the effect of intensifying wind speed and strength. So if possible you must avoid planting in these areas.
Windbreaks are an effective means of providing shelter from wind. They may be either artificial, such as fences or screens, or natural, such as tree or shrub hedges.
How a windbreak works
It does not matter what kind of windbreak your use, but you have to make sure that is about 50 per cent permeable. Solid wind barriers will deflect the wind upwards, causing turbulence behind them. Fences or screens need to be up to 4 m high in order to offer maximum protection as a garden boundary, but if they are used only as a wind barrier they may be as low as 50 cm for low-growing plants like vegetables or strawberries. If you want to achieve the greatest benefit across a large area, you should place the windbreaks at regular intervals roughly equal to ten times their height.