Shelterbelts provide many farm benefits
Winter is traditionally a good time for planting trees as soil temperatures are low and the roots can more easily acclimatise to any new environment they’re planted in.
So it’s timely to talk about how using trees to create shelterbelts on farms can provide a range of environmental, economic and animal welfare benefits.
Bad weather is a key cause of animal suffering and providing shelter where none naturally exists is something farmers can do to help stop it.
Shelterbelts also help to reduce evaporation of soil moisture and transpiration from plants due to wind. Live shelter is particularly helpful in retaining soil moisture in prolonged dry spells, thereby supporting pasture growth for longer periods.
And shelterbelts improve the microclimate of plants and soil by improving plant-water relations, conserving heat and reducing wind damage to grass leaves, which can stunt grass growth.
Erosion prevention is another benefit of shelterbelts as they help control the removal of topsoil by the wind, especially when used alongside other sustainable land use practices such as minimum tillage.
Other benefits of shelter trees include the fact they can be a haven for native birds, give shelter to homes, buildings and stockyards, be aesthetically pleasing, increase the tree species in an area, and support a range of insect life. Using native plants, particularly those naturally occurring in the locality, helps preserve local character.
Shelter can also screen noise and reduce odours associated with livestock operations.
When establishing a shelterbelt, consideration needs to be given to site selection and the tree species to be used. Terrain, weather conditions and livestock behaviour are factors to take into account. Strategic planting is likely to be more worthwhile than blanket planting.
Shelter is most effective when sited at the right angles to the eroding wind. If east-west belts are required they should include deciduous species to lessen the winter shading of pastures.
The density of the trees in the shelterbelt helps determine the wind behaviour on the leeward side of the shelterbelt and also, to a some extent, on the windward side. Practical experience shows belts of medium density produce a much more even windflow over a much wider area. The correct density can be achieved by careful species choice, recommended spacing between the trees and ongoing management. If belts are too dense, this can create turbulence either side of the prevailing wind. But if gaps in a shelterbelt are too big this can cause the wind to funnel through at excessive speed.
Generally speaking, the longer the windbreak, the better the protection for stock and pasture. Finally, tall shelter gives the most economic protection as the area protected is directly related to the height of the windbreak.
As always, it can pay to get professional advice on shelterbelts to help ensure farms get the maximum benefits from any spend on tree planting.
Bala Tikkisetty is a sustainable agriculture co-ordinator at Waikato Regional Council. For further information on shelterbelts, contact him on 0800 800 401 or at bala.tikkisetty@waikatoregion .govt.nz.
TREE PLANTING: Now is the best time.