iCONic tree trail – Part 1
This is the first in a six-part series about how Perthshire Big Tree Country is helping to save internationally threatened species of conifers. Felicity Martin explores the global crisis that led to the iCONic project and visits Gleneagles, where the first iCONic tree was planted.
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30 March 2014
Introduction
A global role for ‘Big Tree Country’
Perthshire is a living museum of trees. It contains both native woodlands, comprised of species that colonised Scotland after the last ice age, and a great range of exotic species discovered all over the world by plant hunters, many of whom originated locally. A tradition among Perthshire landowners of planting and nurturing these introduced species has created a picturesque landscape endowed with a great diversity of trees, including many record breaking specimens.
The Perthshire Big Tree Country initiative works to conserve, promote and interpret this natural and cultural heritage, but its partners recognise that the living landscape cannot be frozen in time, as Charlie Taylor, Forestry Commission Scotland’s local Forest District Manger, explains:
“Introduced conifers are a distinctive feature of Perthshire and provide a striking contrast to our native broadleaved trees, particularly where they have been grown together to enhance the landscape. But specimens planted in the 18th and 19th centuries are ageing. If we want our descendants to enjoy a similar landscape to what we have now, we need to plant a new generation of trees.
“However, the world has changed from when these species were discovered 150 to 250 years ago, growing in pristine old growth forests in the Americas and elsewhere. Most of those forests have been chopped down and the remaining trees are being depleted by other threats, such as pests and diseases.
“Over a third of the world’s 615 known conifer species are listed by the World Conservation Union as being threatened. So now, rather than simply beautifying the landscape, we want to help save threatened trees from becoming extinct. We’ve begun doing that with the iCONic project, through which Perthshire is playing a role in global conservation.”
Growing problems for the world’s conifers
The acronym iCONic stands for Internationally threatened CONIFERS In our Care and represents a remarkable synergy between Perthshire and the work of the Royal Botanic Garden Edinburgh’s International Conifer Conservation Programme (ICCP), co-ordinated by Martin Gardner MBE.
One of the species the ICCP is trying to preserve rivals Perthshire’s famous Fortingall Yew for longevity. Recently scientists counted the rings on some massive dead stumps of Fitzroya cupressoides and found that the trees were over 5000 years old. Known in its native Chile as Alerce, Fitzroya is endangered in the wild. Martin explains the problems that threaten its survival.
“Chile has undergone more rapid loss of temperate rain forest than anywhere else in the world.
“For more than three centuries Alerce has suffered from over-exploitation due to its highly prized wood. As well as logging, human-set fires and the conversion of forest to pasture land has significantly reduced its range.
“Another big threat, is encroachment from plantations into national parks by the non native Monterey pine, as this commercial species is bred to be very competitive and fast growing.
“Alerce was introduced to Britain in 1849 and proved a popular ornamental tree. When we started the International Conifer Conservation Programme in 1991, we thought that so many people grew it that its genetic diversity would be represented in gardens, even if the ancient cathedral-like groves disappeared in Chile. We knew that we needed a broad genetic base if we were ever to restore depleted populations in wild; it’s no good just having one individual, as it probably won’t work.
“To check this, we designed a project to prove that we had many different genetic types in cultivation. An advert in Royal Horticultural Society journal resulted in 28 different tree samples. When we tested them in the lab we found that everyone was growing the same clone. Even worse, Alerce has separate male and female trees and we discovered that we had only had one female tree in cultivation since 1849.
“So we started to integrate the growing of plants in the UK with the conservation of plants in the wild. By testing trees in the wild we found out where the main centres of genetic diversity were so that we could advise conservation managers about most valuable areas needing protection. We also made sure that we collected seed from a wide range of wild trees. Now we are cultivating 200 trees of Fitzroya of different genotypes in our Network across the UK and Ireland, including sites in the iCONic project.
“We have learnt a lot about this plant including what conditions they will tolerate. In their native habitat they receive 5 metres of rain a year, but we are growing them successfully in Perthshire, which has much less rainfall.”
A safe haven for iconic species
The iCONic project was launched with the planting of an Alerce at Gleneagles Hotel by Gleneagles Chairman, Peter Lederer CBE in September 2008. This venue was chosen because of the innovative voluntary contribution scheme that the hotel established to support Perthshire Big Tree Country’s work in enhancing and preserving the beautiful countryside.
Since then other specimen trees from around the world have been planted in the grounds, including a Japanese umbrella pine, which is one of Japan’s most threatened trees. One of the ‘flagship’ species selected by the iCONic project, it is naturally rare with a fragmented distribution. Pressure of logging means that is now highly threatened in the wild. Perthshire provides a suitable habitat for this unusual looking species, but up until now it has rarely been cultivated in Britain. Increased planting of it here will help safeguard its future in the wild.
Another site for tree planting is on Kinnoull Hill by Perth, where the Aitken Arboretum was established thanks to a generous bequest by the late James Aitken, a well-known Perth landscape gardener. The theme of the arboretum is “From the forest to the garden”. Sheltered by tall mature conifers, it features both large growing specimens and groups of smaller trees which can be planted in a normal garden.
The Aitken Arboretum is now home to ten King William pines, a species endemic to Tasmania. The species has suffered historically from logging and fire, with about a third of its habitat burnt during the 20th century. The planted saplings are enclosed in deer proof fences to protect them in their early years and can be seen from the path that winds up through the arboretum.
In next month’s article we will look at the historic legacy that Perthshire’s ‘planting lairds’ have left and explore how a new generation of plant hunters are collecting seed and propagating trees for tomorrow.