The value of shelter and shade should not be underestimated when looking to improve profitability. Have a look at livestock in a paddock on a very hot day or on a very windy day.
Where do they congregate?
Where would you congregate if you had a choice?
Shelter and shade ameliorate the environment for livestock and improve growing conditions for most crops. One of the things to assess when you audit the resources of your farm is whether you have enough shade and shelter so that all stock can escape the direct midday sun and in the process sweat less, use less water and energy staying cool.
When considering shelter or shade, you first need to assess what benefit is being sought.
Is it shelter for a house, sheds or livestock?
Where do the critical winds come from?
Every District has its own patterns of winds and some are more damaging than others. On the Canterbury Plains in New Zealand, the dominant wind is the Nor-wester, a hot, dry wind that dries out the soil and causes wind erosion and makes both people and animals cranky if exposed to it for long periods of time.
Often the coldest winds are more important to protect against rather than the most frequent winds. Crop and pasture production is significantly increased by the reduction of soil moisture loss from strong or hot winds.
This diagram demonstrates the effectiveness and benefits of shelterbelts.
As can be seen from the graph at the top, the percentage gain in crop yields from effective shelter far outweighs the smaller losses from crop shading and competition for water and nutrients close to the shelterbelt.
Permeable shelter is preferable to dense windbreaks as they produce less turbulence but if a shelterbelt becomes too open near the ground, its effectiveness may be lost. Provided that a permeability of 40 - 50% can be maintained, shelter width is relatively unimportant. However, single rows of trees are vulnerable to strong draughts should trees die or blow over. A shelterbelt length of at least 12 times the tree height allows for maximum shelter value.
Trees provide a significant part of the protection of land from soil degradation factors such as fire, wind and water.
Trees are useful for soil conservation works - exotic species like willows and poplar have particularly good soil binding properties and have an important place in the planting of streamside and waterlogged areas.
Trees use much more water than pasture and areas identified as very high recharge areas are often usefully planted with trees at spacing of about twice the expected tree height for adequate recharge control.
Strategic shelterbelts of less flammable tree species can provide significant fire protection to strategic assets such as farm buildings. So yes shelter and shade belts are useful tools to improve profitability as well as to protect farm assetts from wind and fire.
