Shropshire 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 ignored 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tree for livestock but, after the elm’s decline in the second half of the twentieth century, this role has been largely superseded by the ash, although cattle will browse on most deciduous trees, especially the young foliage thereof and a rich and varied diet naturally leads to healthier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.

Windrowing for silage in June 2022

Though some work has been done 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. In warm weather in an open landscape with few trees it is significant how livestock congregate wherever they can find shade or shelter and it is the weaker or less aggressive animals which are left in the most exposed situations inevitably impacting negatively on their health and well-being.

One of the first tasks on taking over the farm in 1982 was to allow the boundary hedges to thicken and heighten thus providing shelter for the livestock. Like so many hedgerows then, and even now, they were narrow and short and often stunted by the effect of spray drift- aerial crop spraying on neighbouring farms was not discontinued until several years later. It has become obvious that many of the trees planted within the effective shelter zone of the hedgerows have grown taller and straighter than those beyond it. Few farmers realise that by creating substantial hedgerows and therefore shelter for livestock, their food demand is significantly reduced which has a positive effect on profits. Similarly, in an arable or horticultural situation, hedgerows reduce the dessicating effect of wind on growing crops, thereby increasing yields. This is one of the principles of forest gardening which was an important influence on the research here.

The inherited field system here has been completely redesigned to create a rectilinear landscape with long strips of land based on the selions or quillets of the open-field system of the past. These strips, known as alleys, are, in this case, 20metres in width and divided by rows of trees, these being spaced at 5 metres intervals within the row. The whole system runs 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-like landscape and also 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 result in grassland management becoming more difficult. Even at the height of summer, if rainfall is extremely heavy it can be necessary to keep the cattle indoors for a short period of time in order not to damage the pastures through poaching and compaction which is expensive to rectify.

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 cause of this appears to be two-fold; firstly the emerging leaves are very susceptible to field slugs as most definitely are leguminous trees; secondly, they prefer to be in a sheltered situation, indeed growth rate in the garden is significantly faster. 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 the larger seeded pines. The Araucaria, an immensely important and productive nut tree, is a viciously-spined conifer obviously not browsed 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 from rabbit damage in winter with young trees affected. Ring-barking to depth is commonplace without protection as is leaf(spine)-nibbling. Once established, however, the Araucarias have grown well and because of their distinctive aerodynamic habit manage to grow vertically even in very exposed sites. The nut is one of the most nutritious foodstuffs known to man and has tremendous potential as an edible crop.

Windrows ready for baling in June 2022, note walnuts in left foreground not yet fully in leaf

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. Walnuts also leaf quite late and after that same winter some foliage did not emerge fully until early July. Any regular visitor to a timber yard or builder’s merchant will know that wood stocks are increasingly under pressure so different methods of production other than dense woodland need to be trialled. And so too do different species. For example although high value tropical hardwoods such as ebony will not survive, Diospyros (persimmons) which are members of the same Family are growing well here and fruiting.

Other predation has not been a problem, at least to date. In the past the biggest disincentive for squirrels has been buzzards nesting in the south-west corner of the farm, 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. As more than one visitor has said, the creation of a tree alley/parkland system creates a perfect hunting ground for birds of prey. 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, again probably as a result of the “parkland” nature of the farm. The farm is divided almost exactly in two halves by a busy B-road with the agroforestry project to the west and to the east traditional pastureland with just a handful of mature oaks and their adjacent lynchets providing evidence of the previous field pattern. The difference in wildlife between the two halves is striking: rabbits, and to a much lesser extent hares, present on the former are rarely seen to the east of the road; snipe have become frequent autumn/winter visitors to the east but never appear amongst the agroforestry planting; huge murmurations of Lapwings (and associated golden Plovers) of well into four figures were present between 2017 and 2020 and in neighbouring fields but again they never land in the agroforestry landscape- this phenomenon was temporary as in previous years there were murmurations of starlings which are now absent. Other migratory bird species such as Fieldfares and Redwings are not so particular and will alight anywhere. The fact that some grass cover is left on the fields throughout the winter provides wildlife with food and shelter as well as encouraging drainage of winter rainfall and early spring regrowth of the pasture since a “blanket” of grass maintains slightly higher soil temperatures.

First heavy tree pruning after 22 years, 30th November 2022

One of the main problems the UK has faced in recent years is flooding. Since the ground along the tree rows is not compacted by machinery or livestock, in the case here for twenty years now, they become, in effect, longitudinal field drains. Conventional civil engineering land drainage dictates that precipitation is removed as fast as possible which simply makes flooding downstream much more likely. The ground’s ability to absorb moisture must be increased so that it is available during more frequent dry periods. And as the alleys are grazed rotationally, they absorb significantly more precipitation between grazings as invertebrates aerate the soil between short periods of compaction by cattle often referred to as mob stocking though I find the term unsatisfactory. In places there are small ant-hills in the rows between the trees and indeed occasionally within the tree guards but never in the alleys where the soil is compacted. Similarly, rabbit digging is a minor problem but only beneath the boundary hedgerows and within the tree rows where there is no soil compaction. Badger digging has become a much more serious problem in recent years as on so many grassland farms occurring mainly in autumn but once local dairy farms open their maize silage pits their winter food source is determined and the problem disappears.

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 to establish the trees 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 so as to mimic, as far as possible, how trees establish themselves naturally. Inevitably because of this competition, growth rates in the early years can be low. This, however, is preferable to excessive “luxury” growth which can cause trees to be top-heavy and lean away from the prevailing wind.

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 because shade is available. The system is further modulating micro-climate as convection currents are being created by warm air in the centre of alleys rising thus drawing in the cooler air from beneath the trees. During arid spells, as exemplified by the summer of 2022, it is often commented how green the farm appears. 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 as the odour of the foliage is a strong deterrent. Observations on cattle browsing continue to interest. Even if they are on excellent grazing, they will often browse tree foliage in preference, most especially elm and ash. Trees such as Robinias and English Elm provide suckers in the pasture from late spring to early autumn which are readily consumed by the cattle. 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 eat astringent walnut leaves if they are hungry enough, though this is a significant indicator that more forage needs to be provided.

Yields of walnuts in 2022 have been very high with even some small trees producing light crops much earlier than normal. There has been some predation in the fields by squirrels but none at all in the forest garden. Sweet Chestnuts have yielded very well with a high proportion of fat edible nuts especially the variety Belle Epine and almost no predation. Hazelnut yields have also been higher than normal, again with no predation whatsoever in the forest garden. After twenty years there has been a very light crop of Butternuts (Juglans Cinerea) and, after twenty-one, the first Black Walnuts (Juglans Nigra).

There is much more work to be done. For example grasses go to seed more rapidly 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. The two most important crops of all, both directly and indirectly for mankind, are tree seed and honey and the work is based with this in mind- there is a tree or shrub flowering throughout the year. 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.

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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