The Agroforestry Project

The Hollies is an organic holding of forty acres in North Shropshire which, until 1996, was a dairy farm, subsequently carried a beef herd, and since 2014 has reared youngstock for a dairy farm in the neighbouring village. A system of silvopastoral agroforestry is practised which is a method of land-use whereby trees, perennial ground cover crops (in this case grasses, clovers and herbs) and livestock (in this case bovines) are produced on the same piece of land. 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 other parts of the world, most especially Asia. Therefore a landscape had to be created in order to study the many uses of trees and their interaction with cattle.

Bovines are usually regarded as exclusively grazing animals but, if given the opportunity, will browse trees and shrubs often in preference to grazing pasture – browse lines along hedgerows and under field trees are a distinctive sight in the countryside 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tree for livestock but, after its demise in the second half of the twentieth century, this role has been largely superseded by the ash, although cattle will browse on most deciduous trees, especially the young foliage thereof and a rich and varied diet naturally leads to healthier and more disease resistant animals.

Cattle browsing Elms

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, little has been done in an agricultural situation and it is becoming increasingly obvious that farmers have to control their own climates as far as it is possible so to do; 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, for example by lowering 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 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 being dependent on growth rates and ground conditions. The alleys are rotationally grazed to allow the pasture to rest and recover continually. An opportunistic grazing system is employed whereby the cattle graze if there is fodder available whatever the time of year and, critically, if ground conditions are suitable – the increasingly frequent weather “events” of recent years (ie. high rainfall in short periods of time) result in grassland management becoming more difficult.

Aerial photograph, August 2015, during a very dry summer, hence parched alleys. Courtesy of “Highobs”.

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 prominent with collections of walnut, hickory, sweet chestnut, almond, maidenhair and hazel. Almonds, despite good growth rates and reasonable fruiting, have not been a success and over half have been removed owing to disease. Maidenhair trees (Gingko spp.) have been extremely slow growing with no vertical growth in some years. 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). It had been suspected before planting that their hardiness might be an issue and therefore young trees and seed were purchased 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. Once well-established, however, the Araucarias have grown well.

Mowing In Alleys July 2012

Late-leafing tree species are essential in agroforestry systems as they allow the ground cover crop to grow well before the partial tree canopy is formed. The foxglove tree (Paulownia spp.)is pivotal in Asian agroforestry systems combining both high growth rates and late-leaf emergence, the timber and foliage having numerous uses. Seven species have been trialled here but only  P. Fortunei has thrived. 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 some of 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

As the landscape has developed there is now much more birdlife and this has probably been the solution to previously observed 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. In effect the rows of trees become longitudinal “sink holes” within the land. The impact of small mammal burrows on drainage is an area which needs far more research. A few 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. Occasional direct drilling into the existing swards has taken place, otherwise natural sward reseeding is encouraged. In the early stages of a project such as this it would have been far easier 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.

Left picture: slurry applied lightly to trees in rows deters rabbit damage in winter; middle picture, bark stripping damage above electric fence damage above damage by trailed mower; right picture, electric fence damage on hornbeam. 

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 tree foliage browsed increases as seemingly does the neck lengths of the animals as they graze below and above the electric fence. Only Araucarias, Gingkos and Phellodendron have never been browsed. Cattle will even damage astringent walnut leaves if they are hungry enough.

There is much more work to be done. For example grasses rapidly go to seed and become unpalateable under shade and so different species 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. A concept of total farming is being developed whereby the component parts- the pasture, the tree crops, the livestock and even the gardens- work together as a whole. And the project progresses 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.

Visits in 2017:
Sunday 2nd April 11am, visit by SEPNET.
Wednesday 21st June, visit by Pasture-Fed Livestock Association

Contact details;
Peter Aspin 01948 840073
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. Click here to open google maps close up of the farm in a new tab.

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