Woodland Management

A Practical Guide - Second Edition

Chris Starr

• Editore: Crowood
• Anno: 2013
• ISBN:
  9781847976185
• Argomento: Tecnología e ingeniería
• Categoria: Silvicultura

Now in full colour, this is the second edition of this highly acclaimed book. Woodland Management is essential reading for anyone with an interest in trees and woodlands, whether they simply enjoy walking in the woods, are considering buying woodland, or wish to gain a greater understanding of the history and management of Britain's woodland. The book begins with a look at how our woodlands have developed and a discussion of the different types of woodland, and then explores, in a non-technical way, all aspects of management. It considers: broadleaf and conifer woodlands; factors influencing the choice of tree species; surveying and mapping; the seasonal cycle and the operations that occur at different times of the year; conservation and biodiversity; planting new woodland; natural regeneration; coppicing; the types of site; ground preparation; protecting ancient trees; growing trees for timber; thinning and felling; methods of selling timber; generating revenue from timber production and other sources; the factors involved in buying and owning woodlands; where to find grants; how to write a management plan; who to contact for further information; and much more. An indispensable guide for all those interested in maintaining our rich woodland heritage. Now in full colour, this is the second edition of this highly acclaimed book, which is illustrated with 86 colour photographs and 37 diagrams.

CHAPTER 1

Woodlands: Past, Present and Future

In the absence of people, Britain and, indeed, many other countries throughout the world, would be substantially covered in woodland. The highest mountains and the estuaries aside, woodland would stretch from sea level to above 600m, forming what is often referred to as ‘mixed oak forest’. In reality, this would have been a complex mosaic, consisting mainly of broad leaved species, with open spaces and, in places, grazed pasture woodland. Only in the more northerly regions and on some of the poorer soils in the south would Scots pine have flourished. The species composition of this mosaic would have varied in response to the local climate, soils and the degree of exposure. Although Britain is a small island, it exhibits a wide range of microclimates, and the woodland would have reflected this.

The Wildwood

Oliver Rackham, the eminent woodland historian, evocatively refers to our prehistoric forests as the ‘wildwood’, reflecting the diverse nature and primitive hold they have on us. We have a strong affinity with this wildwood and it is reflected in our fables, our literature and in our deepest desires and fears. It is easy to forget that not so long ago large mammals roamed our woodlands. The wild boar, wolf, beaver and elk all lived in Britain’s woodland before hunting drove them to extinction. The last wolf was killed in Scotland as recently as 1743. The only large mammals now found wild are deer. Today, the reintroduction of some of these mammals is under serious consideration, particularly in the more remote parts of Britain. A private landowner is currently considering plans to convert some 10,000 hectares of land in the Highlands of Scotland into a reserve stocked with long-extinct mammals such as the bison, wolf and lynx as part of an ecological restoration project.

Forest Types

On a broad scale, Britain lies within what is known as the deciduous summer or temperate forest. This stretches across Europe and into Asia, covering vast areas as far north as Scandinavia and as far south as the Mediterranean. Although primarily made up of broadleaved species, it also contains some conifers, particularly at higher altitudes. Across much of Europe the climate is continental, exhibiting greater extremes of temperature with warmer summers and colder winters than our own.

In Britain, by contrast, the effects of the close proximity to the sea are felt everywhere and this is why even at quite high altitudes broadleaves grow well here. Only in the far north do British woodlands merge into another large-scale forest type, the northern or boreal coniferous forest that stretches across Scandinavia and Russia; in fact, most of Siberia is conifer forest. These are the native pinewoods dominated by Scots pine, and sometimes referred to as the Caledonian Forest. Now restricted to the Highlands of Scotland, often in quite isolated groups, considerable effort is under way to regenerate these pinewoods, using local seedlings protected from the effects of grazing.

Ancient westerly ‘Atlantic’ oak woodland growing on steep-sided valley slopes at Culbone in north Somerset, bordering the Bristol Channel and Exmoor. This represents something approaching the natural woodland that would have covered parts of the region in the past. The woodland has been worked for tan bark and coppice, so oak is probably more common than it would have been. The effects of wind and salt spray cause the trees to become stunted towards the shoreline.

Native Tree Species

Native tree species are those that colonized Britain naturally after the last ice age and before the formation of the English Channel some 8,000 years ago. These native species gradually moved back from mainland Europe as the climate warmed and the ice retreated. It is possible that one or two might have survived during the ice age in isolated refugia, but we cannot be sure of this.

These native tree species – of which there are about thirty-three – are listed in Table 1. In the past, they made up the complex woodland cover of Britain and are of the utmost importance for nature conservation and the maintenance of our remaining semi-natural woodlands. Today, they are supplemented by species introduced at various stages over the last 8,000 or so years, including some that would have arrived naturally had the Channel not prevented them.

Table 1 lists the native species in the generally accepted order of arrival – the wind-pollinated pioneer species followed by those with heavier seed. As they arrived, they migrated northwards, colonizing regions where the climate and soils were suitable. Some of the later arrivals, notably beech, reached only as far as the south of Britain naturally. Note that nearly all the species are broadleaved, a clear indication of our place within the temperate forest ecosystem of the northern hemisphere.

Wood Pasture and High Forest

In recent years the Dutch ecologist Hans Vera has challenged some of our notions of what the natural forest in Britain and much of Europe would have looked like after the last ice age. Rather than being dense high forest, he proposes that some of it was more like wood pasture, with widely spaced trees browsed by larger mammals. He suggests that as the ice melted, the larger grazing mammals, including the now extinct wild ox, together with the wild cattle and the wild horse, moved into Britain ahead of the trees. These ungulates had a major effect on the spread and regeneration of the woodland, resulting in more of the light-demanding species such as oak and hazel being present (a fact observed from the pollen record).

Table 1: The native tree species of Britain
Common name	Botanical name	Notes
Common juniper	Juniperus communis	Now restricted to small isolated upland and heathland sites
Downy birch	Betula pubescens	Typical pioneer species, with local adaptations to site
Silver birch	Betula pendula	Typical pioneer species, with local adaptations to site
Aspen	Populus tremula
Scots pine	Pinus sylvestris	Once native in southern England when the climate was cooler than it is today
Bay willow	Salix pentandra	Native willows important for insects
Common alder	Alnus glutinosa
Hazel	Corylus avellana
Small-leaved lime	Tilia cordata
Bird cherry	Prunus padus
Goat willow	Salix caprea
Wych elm	Ulmus glabra
Rowan	Sorbus aucuparia
Sessile oak	Quercus petraea	Important for insects and lichens
Ash	Fraxinus excelsior
Holly	Ilex aquifolium
English oak	Quercus robur
Hawthorn	Crataegus monogyna
Crack willow	Salix fragilis
Black poplar	Populus nigra var. betulifolia	Quite rare. Not to be confused with the introduced hybrid black poplars
Yew	Taxus baccata	Poor for wildlife but of high cultural value
Whitebeam	Sorbus aria
Midland thorn	Crataegus laevigata
Crab apple	Malus sylvestris
Wild cherry (Gean)	Prunus avium
Strawberry tree	Arbutus unedo
White willow	Salix alba
Field maple	Acer campestre
Wild service tree	Sorbus torminalis
Large-leaved lime	Tilia platyphyllos
Beech	Fagus sylvatica
Hornbeam	Carpinus betulus
Box	Buxus sempervirens	Restricted to southern England, this was the last tree to cross from Europe before the English Channel formed

The woodlands that developed did so with more open pasture woodlands forming a mosaic of grazed grassland and scrub, and areas of more closed woodland composed primarily of light-demanding species. In many ways, these would have looked much like parkland. These wooded pastures, which have been well documented in England for over 1,000 years, would have been rich in a range of different habitats including deadwood, natural pollards and grassland.

Research is currently under way to assess the sorts of grazing regimes, animal density and tree responses to grazing under conditions likely to have been found in the past. While we are still unsure of quite what the wildwood would have looked like, and the variations that might have occurred across Britain, it is likely that the role played by large grazing mammals in our woodland history and development has been understated.

The Changing Face of Woodland

Following the retreat of the ice sheet after the last ice age, the climate gradually warmed up and plants gradually returned, culminating in woodland. As the climate changed, so the species composition changed, with the pioneer species such as alder and birch giving way to the longer-lived, large seed-bearing trees such as the ...