This is the fifth in a six-part series about how Perthshire Big Tree Country is helping to save internationally threatened species of conifers. Felicity Martin explores why the Atholl Palace Hotel and Bonskeid Estate were chosen for different styles of planting, and looks at what happens once the trees are in the ground.
30 July 2014
Choosing sites and caring for trees
Propagating saplings from the collected seed of threatened conifers is only the beginning of the story. To secure the long-term future of this rare genetic material, a safe home is needed for the plants to grow into mature trees. Within Perthshire a variety of planting sites with different characteristics are being used.
The iCONic project works with a wide range of landowners in the public and private sectors to establish its tree collections. Several criteria are used in selecting participating sites.
They must have ready public access, with at least a path or a public right of way passing through or beside the site. And the sites need to provide a suitable environment for the species concerned. But perhaps most crucially, they need to have long-term continuity of ownership and management in order to provide a permanent and secure home for species that could live for a hundred years or more.
Two distinct styles of planting are being used, depending upon the nature of the site and the amount of space available.
Specimen tree planting
In existing gardens and arboreta, iCONic species are normally being planted as specimen trees, sometimes individually, or in groups of 3, 5, and so on. Often a diverse species mix is planted at one site, in keeping with how the established trees were planted in these often historic landscapes.
One such site is the Atholl Palace Hotel at Pitlochry, where specimens of Chilean Plum Yew, Nordman fir, Spanish fir and Cilician fir have been planted by the iCONic project.
The Cilician fir is quite rare in cultivation, unlike many of its close relatives. The species is ‘near-threatened’ in the wild due to its restricted natural distribution in Turkey, northern Syria and Lebanon. The montane areas where it grows are considered to be at high risk from climate change, with rising summer temperatures and declining annual rainfall.
As is typical of this style of planting, the setting that these new trees are going into is a mature designed landscape. The hotel grounds are laid out with ornamental ponds and many enormous specimen trees dating from the late 19th century. These include Douglas fir, noble fir, western red cedar, western hemlock, coast redwood and giant redwood.
On its introduction to Britain in 1853, the giant redwood was named Wellingtonia after the recently deceased Duke of Wellington. As elsewhere, it was planted widely in gardens and avenues around Perthshire. There is a very fine specimen, dating from about 1880, beside the Japanese Garden near the foot of the hotel drive.
In the wild, the species is restricted to the western slopes of the Sierra Nevada in California. The once mighty groves of giants have declined due to past logging and today the main threat is fire management regimes. The species is adapted to withstand frequent, but not very intense fires caused by lightening strikes, after which the trees release seed and regeneration occurs. However, human prevention of fire leads to the accumulation of a greater fuel load so that, when they eventually occur, fires burn more devastatingly.
Naturalistic grove planting
Several commercial forests in Perthshire are providing sites for naturalistic groves that contain many individuals of a single species. They are planted at a natural, random spacing that will give the groves an organic appearance as they develop. Growing a large number of individuals together in this way allows more genotypes to be conserved.
As well as the groups of various species planted at Forestry Commission sites around Tay Forest Park, a grove of Fraser fir were planted at Bonskeid Estate near Pitlochry in the spring of 2010. They are in a beautiful situation close to the Linn of Tummel.
The site can be accessed by taking the riverside path south from the Garry Bridge car park just north of Pitlochry. This path leads to the Linn of Tummel and an adjacent strip of wooded land gifted to the National Trust for Scotland (NTS) by Dr G F Barbour of Bonskeid in 1944. The area was originally part of a designed landscape, with some majestic stands of Douglas firs as well as mature oak and beech. The new Bonskeid grove of Fraser fir is above the Linn, near a way-marked path running uphill from the NTS property.
Please note that Bonskeid House is a private residence, separate from the estate, and is not open to the public. We would ask visitors to the Bonskeid Estate to respectfully bear this in mind.
Andrew Barbour, the present owner of Bonskeid Estate, believes that the estate has a clear stewardship responsibility for the land that includes actively protecting the environment and wildlife, and providing access so that people can enjoy the countryside.
“There are a lot of paths on the property that locals and tourists alike use and which form part of the wider path network around Pitlochry. And we work with conservation agencies on good management practices to care for the environment. For example, we use low-impact forestry systems, avoiding large clearfells, an approach that maintains the woodland structure and lends itself to the planting of naturalistic groves of iCONic species.
“The Fraser fir planted here is one of the world’s most popular Christmas trees, but it’s threatened with extinction in the wild. It comes from the Appalachian mountains of North America and is named after the Scottish botanist, John Fraser. Over 80 percent of mature trees in its natural range have been killed by an introduced insect, the Balsam woolly adelgid. Here these hardy conifers can thrive safe from that pest.”
Promoting healthy growth
Once a site is selected for iCONic plantings, the ground is prepared to ensure that conditions are optimum for the new arrivals. Trees are normally planted in autumn or spring and are protected from damage by rabbits or deer, or careless humans who may accidentally trample them. Individual specimen trees are usually planted within wooden cages, while large numbers of trees planted in a grove setting are guarded by simpler cages of wire netting.
After planting, they require continuing maintenance if they are to thrive. Competing vegetation needs to be weeded out from around the plants and any damage to them pruned away. Their care is often a team effort between local staff, the iCONic team and volunteers.
All the plants are carefully labelled and are closely monitored, often with two site visits during the first year after planting. They are measured annually for the first five years to check how well they are growing and to keep a record of their progress. All the information gathered is entered into the database of the Royal Botanic Garden Edinburgh that is used to monitor the collections. This knowledge bank will be used to inform future planting, and to help horticulturists and conservationists working to protect these species.
Together, the iCONic collections around Perthshire are preserving a wealth of genetic diversity that can be drawn on in the future to help restore depleted forests around the world.
In next month’s article we will look at the prospects – both in Perthshire and in their native habitat – for the tree species that the iCONic team is protecting, and explore the challenges for the future.
Find out more from the iCONic project website.