Orchards – groups of trees cultivated to produce food – have a long history in the British Isles, which may stretch back as far as the Neolithic period.
The recognition of traditional orchards as biodiversity hotspots led to the creation of a Habitat Action Plan for orchards in 2007, and they are of increasing interest to scientists.
Why study organisms growing in orchards?
OPAL scientists are particularly interested in the lichens and mosses which grow on orchard trees and want to get more people involved in surveying them.
Woodlands in the UK are habitats of international importance for the conservation of these organisms and orchards may be equally important.
If you are planting a new orchard, lichens and mosses can show you how biodiversity develops over time and how these organisms colonise the new habitat.
In well-established orchards, they can contribute to knowledge about orchard ecosystems and demonstrate how changes in management affect the species in it.
What are lichens and why are they important?
Lichens are made up of two or more different organisms living together, a fungus and an alga.
Almost all fruit trees, even young ones, have lichens on their bark and mature orchards can contain many species.
Lichen diversity was devastated by the pollution of the Industrial Revolution. But in past decades, levels of sulphur dioxide pollution have fallen dramatically and there has been a spectacular re-colonisation by lichens.
They are indicators of pollution and monitoring the changes in the spread of lichens is important for understanding how our environment is changing.
What are mosses and why are they important?
Mosses are small green plants that may grow on tree trunks or branches, as well as on soil and buildings. They are visible all-year round, unlike many flowering plants.
Mosses are often used to monitor the presence of heavy metals such as lead because they accumulate high levels of these substances within their leaves in polluted habitats.
Surveying the mosses in orchards can also show us interesting things about how mosses spread and colonise. Some species, for example, are normally found in much damper habitats and scientists are investigating why they grow in orchards.
Useful links and further reading
Surveying orchard biodiversity (PDF, 466KB)
Orchard Network – the Habitat Action Plan (HAP) group for traditional orchards
British Bryological Society – organisation which promotes the study of mosses and liverworts
British Lichen Society – organisation which promotes the study of lichens
National Biodiversity Network Gateway – explore UK biodiversity data online