When my time comes I will hop the twig a happy man, in the knowledge that during my lifetime I have been instrumental in the planting of thousands of trees. I do not want to sound conceited; it makes me happy to think that I shall leave many beautiful trees that future generations can enjoy.
Before sailing heavenward on a soft, leafy bed to that great nursery in the sky, I have every intention of planting many more trees. I encourage clients to plant hardwoods because they are longer-lived. It helps, too, if they are indigenous (those that have lived on the site of present Britain for the last three million years or so, since the post glacial period), which includes of course the oak, yew, lime, elm, hornbeam, Scots pine and juniper. A beech will seldom live for more than 200 years. I am not including Roman introductions such as horse chestnut.
Of course we grow many trees from other continents, but they usually live longer, and are more likely to achieve their full stature, in their country of origin. Look at those vast wellingtonias (Sequoiadendron giganteum) from the mountainous forest areas of California. Will they ever grow to the same size in the UK? Since they were introduced to this country only in 1860, we must wait and see. Yet some of the first cedar of Lebanon (Cedrus libani), introduced to our shores in about 1650, have matured into fine specimens, matching the statuesque proportions of their distant cousins in their country of origin, the west Himalayas and the Mediterranean.
Oaks are famous for long life. Some wonderful specimens, believed to be between 600 and 800 years old, can be seen at Blenheim Palace in Oxfordshire and at Chatsworth House in Derbyshire. Some of the oaks in Windsor Great Park are believed to be more than 1000 years old. Coln Crosby, the superintendent of woody ornamental plants at RHS Wisley, told me, 'Oaks grow for 300 years and then slowly dies back for another 300.'
Should we be worried about the spread of 'Sudden Death' disease, which has begun to affect oaks and other trees? Worst affected so far is beech, but the good news is that this disease, introduced on imported wood (probably from China) like the devastating elm disease (introduced from North America), has been contained in small pockets of Cornwall. There is still hope that it will be eradiated altogether before it spreads further.
The longest-lived tree in Britain is a yew (Taxus baccata) growing at Fortingall in Perthshire, first recorded by Thomas Pennant in 1769 as having a girth of 56ft 6in. It is reckoned to be about 5000 years old. As a sapling it was busy getting its roots down some 3000 years before anybody had heard of Jesus Christ. But of course yew is a primordial tree, believed to date back some 200 million years. There are several fascinating types of yew. If you are looking for an excellent green up right form, you can do no better than to plant Taxus baccata 'Fastigiata Robusta' (the 'robusta' addition to the name is so reassuring).
Then there is the statuesque Spanish or sweet chestnut (Castanea sativa), which, as a mature specimen, has deeply furrowed, light grey bark and those marvellous shiny leaves a top. At Shrubland Hall in Suffolk, the house was turned into a clinic, there is an avenue of these beauties, reckoned to be between 800 and 1000 years old.
The spacing of trees can be difficult to get right. Having planted a few parkland trees in what was once open space, I have come to the conclusion that if they look too far apart to begin with, you have got it right. I believe in planting small. The 'instant' effect achieved by planting semi-mature trees at enormous expense does not pay in the long run. If you plant a 3ft tall tree and a 10ft tall tree, three or four years later both will be 10ft tall.
The biggest killer of trees is planting them too deep. Always plant them so that the 'root flare' is level with, or even proud of the surrounding soil. It is better to plant an inch too high than an inch too deep. Trees like company, so when you plant a hardwood, surround it, if you can, with shorter-lived softwoods such as silver birch and prunus species (the flowering cherries) to encourage the 'posterity' tree to grow tall and straight initially. This is how they all start their lives in the wild. 'If you observe Nature you will have half the answer,' Colin Crosby of the RHS wisely observed.
He further told me that the popularly conceived fact that the root run mirrors the leaf canopy above is incorrect. The truth is that the root run is twice as wide as the canopy, or more. This is an important consideration when planning a garden. Initial shaping of a tree is very important, especially when a side shoots at a decent angle. Such forks often result in the death of a tree before its prime because water sits in them and eventually seeps down into the hardwood, causing rot.
My nine 'posterity' trees are: native oak (Quercus robur); cedar of Lebanon (Cedrus libani); Scot's pine (Pinus sylvestris); dawn redwood (Metasequoia gyptotroboides); Spanish or sweet chestnut (Castanea sativa); walnut (Juglans nigra or J regia); Mulberry (Morus nigra); Ginkgo biloba, a relatively recent introduction to our shores; and wellingtonia (Sequoiadendron giganteum).
If you are worried about diseased trees, contact the Disease Diagnostic and Advistory Service, Forest Research, Alice Holt Lodge, Wrecclesham, Farnham, Surry GU10 4LH, 01420 23000 (www.forestresearch.gov.uk).