The Hollies is a small organic farm in North Shropshire which until the mid-nineties carried a dairy herd but now has about sixty head of beef and dairy cattle. Silvopastoral agroforestry is a system of land-use whereby three crops are produced on the same area and at the same time, namely livestock, ground cover (in this case perennial grass and clover) and trees grown for a wide variety of purposes. The nature of this project is designed to bring elements of the open-field system of agriculture widespread in lowland Britain until the Enclosure Acts of the Middle Ages together with the agroforestry practices of Europe and, especially,Asia. Therefore a landscape had to be created in order to study the many uses of trees and their interaction with livestock, in this case bovines.
It has long fascinated me how cattle browse certain species of trees often in preference to grazing pasture, and this knowledge seems to have been largely lost in Britain in the last century as farming has intensified. Since its introduction by the Romans, the English elm had become the dominant browsing tree for livestock but after its demise in the late twentieth century this role has been taken over by the ash. However, cattle will browse on most deciduous trees,especially the young foliage thereof, as well as some conifers such as Metasequoia and Taxodium, and obviously a rich and varied diet leads to healthier and more disease resistant animals
|Cattle browsing Elms July2012|
Though much work has been done in both Britain and the U.S. in how to use trees to moderate climate in an urban setting, none has been done in an agricultural situation; as the climate becomes more extreme and the whole idea of having cattle in an uncontrolled environment (ie. outside) becomes more problematic, then it becomes necessary to create new fieldscapes in which livestock can thrive; by reducing maximum summer temperatures, increasing minimum winter temperatures, minimising diurnal temperature fluctuations, increasing humidity and reducing transpiration through shading and leaf condensation, reducing wind velocity and controlling wind direction and not least absorbing pollutants exhaled by the cattle. The high summer temperatures of July and August 2013 caused severe problems for livestock where no tree shade was available.
The previous field system here has been completely redesigned to create a rectilinear landscape with long strips of land based on the selions of the open-field system of old. These strips, known as alleys, are 20metres in width and divided by rows of trees, these being spaced at 5 metres intervals within the row. The whole system runs due North to South to allow the maximum amount of sunlight to reach the growing crop between the rows of trees for as long a period as possible. Alongside the rows, electric fences are used to protect the tree trunks from damage such as bark-stripping, but allowing the cattle to browse above this level which thus creates a parkland landscape and again encourages light to reach the understorey crop. Manual pruning is essential in the first few years but once the trees get beyond 2.5 metres in height, then the livestock are largely in control. The distance of the fence from the tree is absolutely critical and very much a case of trial and error.
As well as there being many species of tree for browsing such as ash, elm, zelkova, sweetgum, honey locust, black locust, hackberries,hawthorns and so on, there are numerous other families of tree represented embracing every purpose from cork to root beer production. However, nut trees are also prominent with collections of walnut, hickory, sweet chestnut, almond, maidenhair and hazel. The hardiness of most tree species has not been a problem, though owing to frost damage following the severe winter of 2010-2011, the holm oaks had to be coppiced. The other failure of that winter were the Araucarias (monkey-puzzles),. I had suspected before planting that their hardiness might be an issue and therefore bought young trees and seed from a number of sources, but of two dozen planted, 30% were lost with only a couple resprouting from the base. The tap roots of those dug up went to a considerable depth but then again so did the frost that winter and it was decided to replant with a small collection of pines.The Araucaria, a viciously-spined conifer obviously not damaged by cattle and therefore an ideal tree in certain strategic sites in a planting such as this, for example adjacent to cattle tracks, does suffer considerably from rabbits in winter with young trees damaged both above and below ground level. Ring-barking to depth is commonplace without protection as is leaf-(spine)nibbling.
|Mowing In Alleys July 2012|
Another tree species which has proved not to be successful in this project is the Paulownia. The foxglove tree is pivotal in Asian agroforestry systems combining high growth rates and late-leafing with the timber and foliage having numerous uses. Seven species have been trialled here but only P. Fortunei has survived. However, growth rate has been slow and woodpeckers inflicted severe damage in the extreme winter of 2010-2011. The climate here can be an issue as the nearby RAF Station at Shawbury often has the coldest winter lowland temperatures in England.
Other predation has not been a problem, at least to date. The biggest disincentive for squirrels have been buzzards nesting in the south-west corner of the farm. They have been attracted by the variety of pasture depth with at any one time between zero and 60 days growth of forage and all stages in between in the alleys providing perfect habitats for their food source, as well as numerous perching sites. Rabbits are only a problem in winter, but the solution has been to prune ash branches in late autumn and leave them on the ground. The rabbits will readily bark-strip these and avoid more destructive damage. Most satisfyingly, hares have begun to appear on the farm in recent years,probably as a result of the “parkland” nature of the farm.
|View down alley from high level, August 2012|
As the landscape has developed there is now much more birdlife and this has probably been the solution to previously noted foliage defoliation of young trees by caterpillars. There is now a proliferation of small ant-hills in the rows between the trees and indeed occasionally in the tree guards. This is because there is no compaction in the rows by either cattle or machinery and this has a beneficial effect on the drainage. Two summers ago a water burst in the adjoining road flooded the neighbouring garden and the adjacent alleys but largely dissipated in the first row of trees and disappeared in the second.
In an agroforestry system such as this permanent crops are preferable to annual ones as ploughing and cultivation close to tree roots is not advantageous. No ploughing has been done for almost ten years and none is envisaged for the future. Soil is too precious a commodity. Occasional direct drilling takes place, otherwise natural sward reseeding is encouraged. In the early stages it would be much easier to create such a system in an arable setting without the handicap of livestock. This has not been possible here and so at times much damage has been done to young trees which have had to be drastically pruned or replaced. Establishment has been very variable depending largely on spring and summer rainfall with the trees being planted into grass and clover swards with little or no mulching or watering. Inevitably because of this competition, growth rates in the early years are low.
Although it is only early in the project, the effects are becoming apparent. In previous years on hot summer days the cattle often spent much time in the buildings, but now they are much more content outside. Farmers visiting at the height of summer are amazed that the cattle are not bothered by biting/nuisance flies when grazing alongside the walnut trees. During arid spells it is often commented how green the farm appears. Observations on cattle browsing continue to interest. If they are on excellent fodder only the most palatable are taken. As the quality of fodder diminishes, then the variety of trees taken increases as seemingly does the neck lengths of the animals as they graze below and above the fence. Only Araucarias, Gingkos and Phellodendron have never been browsed. Cattle will even damage very astringent walnuts if desperately hungry.
There is much more work to be done. For example grasses rapidly go to seed and become unpalateable under shade and so different varieties will have to be trialled to suit a system such as this. Strategies are constantly being rethought and reworked and some trees which have not proved suitable are still being replaced. And the project develops without any grants or subsidies or payments of any sort which would inevitably compromise and inhibit the work.
The farm is open to group visits by prior appointment. A large variety of tree species is available for sale during visits, though numbers are small.
Peter Aspin 01948840073
Address The Hollies, Soulton,Wem,Shropshire, SY4 5RT
E-mail address [email protected]
Directions: The Hollies is situated on the B5065 half a mile south of the junction with the A49, between Shrewsbury and Whitchurch.