24433_HabitatLeaflet_ascophyllum leaflet 18/03/2010 16:46 Page 3 Design: rjpdesign.co.uk Managing trees in Scotland’s open habitats for lichens, bryophytes and fungi Front cover image: Avenue of lichen-covered wayside trees in Perthshire © Plantlife Back from the Brink Management Series 24433_HabitatLeaflet_ascophyllum leaflet 18/03/2010 16:46 Page 2 24433_HabitatLeaflet_ascophyllum leaflet 18/03/2010 16:46 Page 1 Back from the Brink Management Series This booklet will help land managers and conservationists who manage parkland and trees in open habitats. These trees are not only part of our well-loved natural and cultural heritage but provide important habitat for many organisms, including threatened species of international importance. This booklet explores the ecology of lichens, bryophytes and fungi that grow on these trees. It looks at threats to their survival and outlines management recommendations to encourage and conserve these special communities. Plantlife is the organisation that is Wild plants have been marginalised and speaking up for the nation’s wild plants. taken for granted for too long. We work hard to protect wild plants on the Please help us by supporting our work. ground and to build understanding of the vital role they play in everyone’s lives. Wild To find out more, please visit our website or plants are essential to life – they clean our contact us at the office below. air and water, provide food and shelter for our insects, birds and animals and are critical in Plantlife Scotland the fight against climate change. Balallan House Allan Park Plantlife carries out practical conservation Stirling work across Scotland, manages nature FK8 2QG reserves, influences policy and legislation, runs Tel. 01786 478509/01786 479382 events and activities that help people discover wild plants and works with others to promote www.plantlife.org.uk the conservation of wild plants for the benefit of all. 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[email protected] ᮤ Lichens and moss cushions on Rowan, Whitelee, South Lanarkshire © John Douglass 1 24433_HabitatLeaflet_ascophyllum leaflet 18/03/2010 16:46 Page 2 Back from the Brink Management Series Avenue of lichen-covered wayside trees in Perthshire © Plantlife Summary of management recommendations for trees of open habitat More detail is provided later on page 17 ● Maintain the number of mature and ● Explore alternative options to felling if veteran trees health and safety issues demand action ● Ensure future habitat continuity and a ● Consider using Tree Preservation Orders good age structure ● Consider the cultural and historical ● Where natural tree regeneration is not importance of veteran trees when planning possible, plant new trees from local native management intervention of any kind stock ● Avoid spreading fertiliser, slurry, pesticide ● Maintain high levels of native trees such as or herbicide within the vicinity of oak and ash in proportion to non-natives important trees, to prevent drift ● Maintain grazing at a sustainable level ● Where arable farming or ploughing and ● Control invasive non-native scrub reseeding cannot be avoided, leave a buffer ● Continue any existing pollarding where zone of 5m beyond the edge of the canopy appropriate ● Take measures to reduce access where ● Leave standing and lying dead wood in situ heavy use has compacted the soil above wherever possible the root plate ● Control levels of timber collection for ● Prevent and control fly tipping, littering firewood and fires in the vicinity of target trees ● Where conditions are not naturally damp, ● Seek specialist advice from lichenologists, allow vegetation to grow up immediately bryologists and mycologists if there is a around fallen dead wood to maintain proposed change in the management of an humidity important site ● Avoid sudden or dramatic changes in shade ● If you are aware of the presence of and humidity by carrying out work such as biodiverse trees of open habitat on your branch lopping of clear felling in adjacent land, ensure that any contractors and land areas in a gradual manner, perhaps over managers are made aware of their several years where important importance and vulnerability communities of lower plants and fungi are ● Ensure regular access for monitoring is already established maintained 2 24433_HabitatLeaflet_ascophyllum leaflet 18/03/2010 16:46 Page 3 Back from the Brink Management Series What do we mean by open habitat? designed landscape. A few parks date from Trees of open habitats are defined here as trees medieval times when sections of ancient in open wood-pasture, waysides, parklands, forest were fenced into deer-parks, but most farmland, churchyards, orchards and gardens, parks date from the eighteenth and where sunlight is plentiful. The lichen, nineteenth centuries. Wood-pasture and bryophyte and fungi communities associated parkland habitats exhibit a mosaic of with trees in these open habitats are often well grassland with large, open-canopied, developed and include rare and endangered spreading trees, that are isolated or in small species of international importance. groups and often associated with large amounts of fallen or standing dead wood. Wood-pasture and parkland Some of the best examples of old wood In Scotland, wood-pasture developed over pasture and parkland in Scotland can be time through the use of natural woodland as seen at Dalkeith Oakwood, Cadzow Oaks, pasture, and where animal grazing limited Glenlee Park, Taymouth Castle, Glen Finglas, woodland regeneration. In contrast, Rassal Ashwood, The Nest, Gannochy and parkland is usually part of a more recent Drummond Lochs. Cadzow Oaks, Hamilton High Parks SSSI, an example of a medieval hunting park © John Douglass 3 24433_HabitatLeaflet_ascophyllum leaflet 18/03/2010 16:46 Page 4 Back from the Brink Management Series Orchards Factors that affect bryophytes, lichens Old orchards can be good refuges for epiphytes and fungi of trees in open habitats and fungi, as the trees have not been subjected to biocides or high levels of fertilisers. Orchard Geographical distribution: trees are often pruned regularly, which The oceanic climate of western Britain is milder increases their lifespan and creates particular and wetter than the east. This influences veteran tree niche habitats ideal for some epiphytic and fungal community types. bryophytes (mosses, liverworts and hornworts), lichens or fungi. Orchards are often associated Underlying rocks and soils: with large estates near urban centres, such as The geology of an area will affect the those in the Clyde Valley. bryophyte, fungi and lichen communities by affecting both tree bark chemistry (see Wayside trees below) and drainage. Sites with poor Some wayside trees may be remnants from drainage and high humidity often support ancient forests while others were planted for good epiphytic and fungal communities. shelter-belts, pollards and timber production. These trees are either isolated individuals or Tree species: grow in small groups, rows or avenues. They Native deciduous trees including Ash, Oak, Elm provide predominantly well-lit, relatively and Field Maple normally provide the best open habitats for lower plants and fungi and habitats for bryophytes, lichens and fungi but are found: some exotic conifers, for example, larch, can support relatively luxuriant communities of ● by roads, tracks or paths lichens even though their species diversity ● along rivers and stream edges may be low. Exotic broadleaved plantings such ● in hedgerows or fields as Sycamore, Horse Chestnut, Lime, Tulip-tree, ● beside buildings or gates and Walnut can also support interest. ● in streets and gardens ● in churchyards Natural bark pH: Tree species naturally differ in bark pH, Wayside Ash at Whitelee, south of Glasgow which in turn influences the communities © John Douglass they can support. Bark pH will also vary according to levels and type of atmospheric pollution. Most bark is to some extent acidic. Conifer bark tends to be more acid than deciduous bark. pH 1 is highly acidic, pH 7 is neutral and pH 14 is highly alkaline. 4 24433_HabitatLeaflet_ascophyllum leaflet 18/03/2010 16:46 Page 5 Fallen logs, stumps and branches forming an important habitat for lichens, bryophytes and fungi in Dalkeith Oakwood SSSI, Lothian © John Douglass Table 1. Selected tree species and their high number of each of these niches is relative bark pH. available, the epiphytic and fungal diversity is likely to be high. Tree species Bark pH Pine 3.4 - 3.8 Growth form: Birch 3.2 - 5 The trunks and branches of trees in open Oak 3.8 – 5.7 habitats provide relatively stable, well-lit Ash 5.2 – 6.6 niches with differing exposures to wind and Elm 4.7 – 7.1 rain. Water seepage zones often contrast Taken from Orange (1994) with dry bark crevices and fissures. The smooth, young bark of twigs and small Ecological continuity: branches can differ greatly in their texture If ancient or veteran trees are present, they and therefore their moisture holding may be remnants of ancient woodland and capacity, and even their pH when compared are therefore more likely to support rare and with the main trunk. Different epiphytic and diverse epiphytic and fungal species. fungal communities will occupy these different niches. Dead wood: Dead wood in the form of snags (attached, Threats: dead wood and decorticate branches), Trees of open habitat are susceptible to a exposed lignum of standing trunks, fallen number of threats including pollution and branches and trunks or old stumps provide over-grazing. For more detail please see important habitats for many species. If a page 15. 5 24433_HabitatLeaflet_ascophyllum leaflet 18/03/2010 16:46 Page 6 Lichen communities of trees in open habitats Trees of open habitats provide a unique environment for a range of lichens that thrive on relatively high levels of light and lower levels of humidity than is found in damp shaded woodland. The Lobarion lichen community of large leafy lichens including Lobaria, Nephroma Textured Lungwort (Lobaria scrobiculata), a and Pannaria species is best developed in species found in ancient wood pasture and north-western Scotland in ancient wood parkland in north western Scotland pasture and parks.