If your new orchard is in an area which is exposed to a strong prevailing wind, you should consider a windbreak as part of the orchard design. This will make a substantial difference to the quality of the fruit grown in the productive part of your orchard.
There are two key features of a windbreak. Firstly it must be a semi-permeable barrier, rather than a solid barrier. This means it allows the wind through, but slows it considerably at the same time.
Secondly, the extent of the area which is sheltered by the windbreak is largely determined by the height. A windbreak will typically shelter an area behind it which is 10x to 15x the height of the windbreak. Thus a 3m / 10ft high windbreak can be used to protect an area of 30m / 100ft or more behind it.
Windbreaks can be constructed either from living materials, i.e. trees or shrubs, or from building materials such as wooden fencing. In the latter case it is very important to use an open framework with plenty of gaps to allow the wind through.
In practice most small orchards (and many large ones) use living windbreaks, formed from trees which naturally have fairly dense foliage. When planted close together such trees are highly effective at braking the speed of the wind.
Tree varieties for orchard windbreaks
Whilst any tree species can be used for the purpose, orchard windbreaks traditionally use Alder species. Alder is ideal for a number of reasons:
- It grows quite quickly to a height of about 4m - 6m / 14ft - 20ft. You can expect young alder trees to gain about 2m of height in 2-3 years, so if planted at the same time as a new orchard they will out-pace the orchard trees and provide a good level of shelter within a few years.
- Alder grows happily in a wide range of conditions, and will tolerate much tougher conditions than most orchard fruit trees.
- Alder produces a good density of leaves, early in spring - before most orchard trees - and retains them well into autumn, thereby providing shelter throughout the growing season.
- Alder trees can be maintained easily, if the trees get too tall they can be safely cut or coppiced.
- Finally, an important point, Alder is not a natural home or host for the insect and fungal pests which can affect orchard trees.
Planting Alder trees
Young Alder trees are usually supplied about 60cm-80cm high and can be planted about 60cm - 1m apart.
There are several species of Alder:
- Italian Alder (Alnus cordata)
- Common Alder (Alnus glutinosa). This is native to the UK.
- Grey Alder (Alnus incana).
When designing your windbreak, be careful not to shade the orchard trees, because sunlight is vital for producing high-quality fruit. This can often be a balancing act since in many parts of the UK the prevailing winds, and maximum sunlight, are both from the south-west.
We can supply most Alder species, particularly useful if you are also considering one of our orchard packs.