The orchard habitat
Steve Oram, Orchard Biodiversity Officer, PTES
People’s Trust for Endangered Species is working closely with orchard owners, groups and projects across the UK because of their significant value to wildlife. The unique way fruit trees age creates an indispensable habitat for a wide range of rare and interesting species, including various priority species, such as the noble chafer beetle and many others classed as nationally rare or scarce. This is because orchards comprise several different habitats, incorporating elements of woodland edge, meadow grassland, hedgerows, and wood pasture. This hosts a diverse flora of specialised plants such as fungi, mosses, liverworts and lichens through to veteran hedgerow trees, supporting an array of insect, bird, bat and mammal life. Other beneficial characteristics are that orchard soils are rarely ploughed or disturbed. There’s little, if any, chemical use; dead wood and rot holes in ageing fruit trees provide nest and roost sites; they provide a great nectar and pollen source in late spring; and an abundance of fruit forage in the autumn and winter. In short, they provide food and refuge for species that are in decline and struggling to survive in an ever-intensified farmed and urban landscape.
PTES created and maintains the official habitat inventory of traditional orchards, mapping and surveying to assess their condition. Through this work we have discovered that 90% of traditional orchards have been lost since the 1950s. Furthermore, nearly half of the remaining orchards surveyed were found to be in declining condition as a habitat, further threatening the species that orchards support.
When trees reach a certain age, they develop cavities and hollows as the heartwood dies and rots or is eaten, pecked, gnawed or otherwise removed over time. In fruit trees this happens at a relatively young age, around 40 or 50 years, but in most tree species it takes centuries. Due to woodland management, harvesting, development, and health and safety only a very few trees make it to the veteran stage. Ancient trees are normally found in wood pasture and parklands, but they are far and few between, whereas orchard trees, although not ancient by comparison, contain all the crucial veteran characteristics that make them such an astonishingly valuable habitat.
The most common reason for an orchard to be considered in decline is lack of replacement replanting. Orchards are a man-made habitat, and with the relatively short life span of fruit trees, even if they survive the changing winds of modern agriculture and garden-grabbing development, if no replanting is done, these old orchards will quickly disappear.
One major area of traditional orchard resurrection is the proliferation of community orchards. They’re a relatively recent phenomenon, kick-started in the 1990s by Common Ground. They come about in several ways, most often as a neighbourhood initiative, but can be part of an allotment, school, healthcare centre, or restoration project, and are becoming the de facto greenspace in development applications. Many of these are new plantations, but where the opportunity arises, communities have taken on old forgotten orchards and restored them to their former glory. Restoring the remaining trees and planting new trees in gaps will provide continuity of habitat – crucial to many slow to establish species.
Anyone wishing to set up a community orchard would do well to start with a copy of the Common Ground Community Orchard Handbook. But once you’re in possession of the land, the management is up to you. Restoration of old trees can take some planning and needs to be done over a number of years. Here are a few pointers.
Management of veteran trees
The old trees are key to biodiversity, so their retention and preservation is imperative. They give an orchard a sense of place that can be lacking in a new plantation. There is a tendency of land managers towards over-tidiness, and it takes a certain type to consider a rotting old stump with a scraggy wind-blown toupée of growth as beautiful. But these senescent relicts hold the seeds to future biodiversity, not only in the deadwood habitat above ground, but in the fungal associations below.
There’s little that can be done to revive a tree that is near the end of its natural life but gentle pruning can allow it to see its days out productively. When dealing with a tall tree, remove the highest parts so low growth can flourish. This has the dual benefits of reducing the chance of catastrophic mechanical failure or wind-throw and making it safe for people to work around it and gather a harvest. If in doubt, prop limbs up and put a temporary fence around the perimeter of the crown.
Restoring neglected trees
Apple and pear trees need to be pruned for the best results. Their natural tendency is a more bushy structure that produces lots of small fruits. In evolutionary terms this would lead to more seeds so increasing its dispersal opportunities. For our purposes, we want full sized clean fruit that is easy to harvest so we have to engineer growth to our desired shape. Unmanaged trees will have reverted to type, with lots of intertwining and crossing branches and a preference for top growth which shades out and eventually kills lower branches.
Major restoration work is best done in winter, but a vigorous healthy tree can be quite heavily pruned in the late summer with little risk to its health. A rule of thumb is to not remove more than a third of the living crown in any one year. Start by reducing the length of the highest branches, or any that look likely to break imminently. In the first year this may be the only cut you make. The ‘dead, damaged and diseased’ rule as applied to arboricultural work is not quite right for veteran trees. The exposed canopy deadwood is an important habitat for lots of wood-boring insects and their predators, so don’t be too hasty to cut it all out. You might even want to ring bark some branches and use coronet cuts (several angled ‘v’ cuts at the end of a branch) to artificially introduce veteran features.
During works, always keep an eye on the tree’s balance. Removing a large bough will change the centre of gravity, so either cut evenly on either side, or consider using a cut branch to make a sturdy prop.
Replanting with trees on vigorous rootstocks is critical to continuity of habitat. New trees shouldn’t be planted directly in the same spot as a recently removed tree of the same species. Either leave the soil fallow for a few years, or replace some of the topsoil. This reduces the chances of replant disease, although it’s quite poorly understood and occurs inconsistently. Or you could instead plant stone fruit (cherries, plums etc.) in place of pip fruit (apples, pears etc.) and vice versa to avoid the risk.
Finally, don’t neglect the ground. Removal of arisings after cutting will stop a build-up of nutrients and broaden the species mix. The more diverse the ground flora the more different types of insect will be attracted. Very few community orchards are grazed, so tailor the mowing regime to include a few frequently cut pathways, a percentage of uncut low scrub but a majority cut once or twice a year, generally done midsummer after the annuals have seeded and again just before harvest. Rotate the different areas so no one part becomes permanent scrub or pathway.
There’s lots more detail about all of the above on the PTES.org/orchards website, including video tutorials, bibliography and downloads. There is also a map with around 850 community orchards listed. Tell us about yours to get it included.