Dr Gabriel E Hemery and Dr Peter Savill
We have always thought that the old mantra “The right tree in the right place” needs an extra qualification: “For the Right Reason”. The additional qualification ensures that any tree planting or management is appropriate. For example, we should not advocate planting trees that have been genetically selected for timber production in ancient semi-natural woodland, or equally plant “locally native” when you want quality timber. Although not mutually exclusive, local provenances only very rarely include tested and improved material.
The decision about which species to plant is one of the most important of all in forestry because of the long cycles involved.
An incorrect choice can result in poor health or growth, and even the failure of a crop, and certainly failing to fulfil the objectives of the planting scheme. The stresses imposed by droughts, gales, frosts, and fires, some of which will inevitably occur over a rotation of up to 150 years, could lead to serious diseases or pest outbreaks or even death if species are not well matched to the site. The one or more species selected for planting must therefore be those whose requirements throughout life are likely to be satisfied by the site and climate in question. They must also fulfil the objectives of the planting scheme. The process of species selection is done in three stages:
- The Right Place: determining the characteristics of the planting site in terms of climate, soil, and other factors such as risks of browsing by deer as well as any legal and financial constraints. These characteristics are then matched to:
- The Right Tree: deciding which species are likely to thrive in such conditions. Care should be taken to consider the quality of the planting stock and its origin. For example, a hybrid Walnut (non-native and genetically selected) would not be an appropriate choice in some locations, despite admirably meeting a final objective of growing a valuable timber. From among suitable species, those selected for planting must be chosen for:
- The Right Reason: deciding which of one or more species satisfy the objectives of the planting scheme. Often the reasons why trees are planted are manifold. For example, you might, perhaps, be planting a landscape screen as well as providing game cover, and simultaneously growing a valuable timber crop.
The considerations to be taken into account are summarised in the diagram:The process of selecting species for planting entails matching possible species to the characteristics of the site. Then, from among possible species, choosing those that fulfil the objectives of the planting scheme.