Woodland is an integral part of our lives. It provides fuel, food for farm stock and materials from which we build shelters, fences and tools. This may have started as random harvesting of material but silviculture, the management of trees, soon developed into various forms of woodland management.
In the UK, woodland has been defined as ‘land under stands of trees with a canopy cover of at least 20% (or having the potential to achieve this), including integral open space, and including felled areas that are awaiting restocking.’ That’s an area largely taken up by trees and associated clearings which when viewed horizontally appears to be homogenous.
You will all know from your own garden that vegetation is constantly trying to change into something else. This process is known as ‘natural succession’. During the last ice age (10,000 years ago), the northern part of the area we now know as The British Isles was covered in an ice sheet with temperatures permanently below freezing and glaciers scouring the landscape. To the south, we had Tundra, an area subject to long winters below freezing but with short summers enabling thawing. It is in Tundra that vegetation can begin to develop and take hold. Tundra is known for large stretches of bare ground and rock and for patchy mantles of low vegetation made up of ‘pioneer species’ such as mosses, lichens, herbs, and small shrubs. As the climate warmed, the bare ground revealed was colonised by these pioneer species and vegetation began to develop and change. This process of change continued until the climate settled and the ‘climax vegetation’ was established. Over most of what is now lowland Britain the climax vegetation will be a type of woodland.
As the climate improved and the vegetation developed, so the fauna changed as insects and animals took advantage of the new opportunities revealed. The fauna that explored and established itself as a result of these new opportunities included primitive, hunter-gatherer, nomadic humans and they colonised what was a largely wooded landscape. Human activity soon began to affect that landscape and some of the earliest changes and examples of silviculture would have been clearings artificially created to attract grazing animals to hunt. Approximately 6,000 years ago, Neolithic culture spread into Britain. The people lived in settled communities whose lifestyle was largely based on farming and was powered by flint tools. Flint was no longer utilised as ‘found’ nodules but was actively mined by sinking shafts into our chalk landscape to harvest the seams of flint below. It can be claimed that the first ‘industry’ in Britain was flint mining and the production of stone tools (bi-facial axes) with large complexes of shafts in places such as Grimes Graves in Norfolk and Cissbury, Church Hill, Harrow Hill and Blackpatch near Findon.
Neolithic farmers cleared the well-drained, relatively shallow soils on our chalk downs. They were wooded and beneath the tree cover was a layer of fertile ‘forest brown earth’ soils overlaying the chalk. The Neolithic farmers were probably ignorant of all but very basic soil husbandry techniques and these soils were quickly depleted and eroded, leaving a few inches of nutrient-poor free draining soil (rendzina) which probably led to those fields being abandoned in favour of newly cleared plots leaving the old arable areas to colonise with local plants and be utilised for rough grazing. The colonising plants that were best able to survive the grazing pressures formed the basis of what is now our chalk downland.
Woodland was still an integral part of the lives of these Neolithic communities; it provided fuel and food for the settlers and their farm stock together with materials from which they built shelters, fences and tools, etc. This probably started as random harvesting of material but then developed into what we now call silviculture various forms of woodland management.
Felling
By felling, I mean the simplest and most basic harvesting of the timber by cutting through the tree’s trunk just above ground level. Once felled, the branches and trunk of the tree are accessible and can be utilised for their various purposes.
Shredding
Woodland was a source of fodder for grazing animals and one of the earliest examples of silviculture. This form of silviculture was known as ‘shredding’. This is the process of stripping the side branches from a tree so that they can be fed to farmed animals who would eat the leaves, tender shoots and the bark. What they couldn’t eat could later be utilised as firewood and the tree could be left to grow on upwards for later felling.
Coppicing
‘Coppicing’ is the silviculture technique whereby a tree is cut off just above ground level leaving a stump or ‘stool’. The following spring, the stool will sprout new shoots and because they are being fed by an established and relatively extensive root system they will grow quickly and vigorously, competing one with another as they grow towards the sunlight. This has the benefit of making the grain of the new wood straighter than slower grown timber and, consequently, it will cleave or split more readily. This is very useful for converting the harvested poles for their various uses as the heavier poles can be readily broken down into smaller sections by splitting or ‘cleaving’. The shoots are left to grow for a varying number of years, depending upon the species of tree and the intended use of the poles. Today we will be most familiar with Chestnut poles, usually cut on a ten to twenty-five year cycle, used cleft or whole for fence stakes, or split down into ‘pales’ for Chestnut paling fencing. On a smaller scale and a shorter cycle, Hazel is used for woven Hazel hurdles or bean poles and occasionally as thatching spars. Many hardwood trees will respond to coppicing although not all produce useful timber. Oak and Hornbeam have been extensively coppiced to produce firewood or charcoal especially in the iron working areas of the Weald, and Willows are coppiced or pollarded to be harvested as ‘withies’ for basketry.
A coppice worker can only cut so much timber in a season and they usually plan their work so that the area of coppice (a copse) is split into a number of sections or ‘coups’ so that, as they work from coup to coup in a circular fashion year on year, they find themselves back at the place they started when the stools are ready for harvesting again. This has significant wildlife benefits. The clearing of a coup leaves relatively bare ground, flooded with new light and perfect for woodland-floor plants to thrive and to be colonised by the animals and insects from the adjoining, albeit one year older, coup. In this way the varying wildlife interests are cycled around and around the copse.
Trees being coppiced don’t die of old age as coppicing maintains the tree at a juvenile stage, allowing them to reach immense ages. The age of a stool may be estimated from its diameter; some grow so large — as much as 5.5 metres (18 ft) across — that they are thought to have been continually coppiced for centuries.
We are beginning to see a resurgence in the interest in silviculture with the establishment of coppices with fast-growing species such as Willow, Alder and Poplar for ‘energy wood’ which is then mechanically harvested and used to fuel electricity generation.
Pollarding
One of the problems with coppicing is that grazing animals can cause serious problems by browsing on the coppice regrowth. The coppice worker attempts to reduce the damage by stacking the less useful ‘twiggy bits’ over the freshly cut stool to keep animals away but this is not always 100% successful. They can fence out animals altogether but that can waste a potential grazing resource. The answer is ‘pollarding’ which silviculture defines as ‘coppicing at a height’. The cut is made about five feet from the ground, out of reach of most grazing animals. In this way the woodland can provide grazing and timber. This land use is known as ‘wood pasture’. The tree’s response to being cut is similar to a coppice stool with a new crop of vigorous shoots that could be harvested in a sequential rotation on the appropriate timescale.
As with coppicing, pollarding keeps a tree young and our most ancient trees in the UK are often old pollards. This longevity led to the use of pollards to mark important boundaries.
There can be an issue when the cropping cycle is abandoned. The harvesting cuts made when pollarding are wounds and, as such, susceptible to fungal infection and this often leads to the hollowing out of the main trunk. This is not a problem whilst the tree is being regularly cropped, as a tube is nearly as strong as a solid bar. However, when the regrowth is not harvested the heavier limbs developed can tear open the trunk in strong winds.
Glynn Jones
