The Beechwoods, which are typical of the downland landscape of Wiltshire, are in many cases reaching maturity and degenerating in health. It is apparent that many landowners feel unable to maintain and regenerate them in view of the apparent cost and technical problems involved. The Wiltshire County Council are concerned that these important landscape features should not be allowed to become moribund and disappear. In order to allay some of these fears and to encourage landowners to actively manage these beechwoods the Wiltshire County Council have produced the following notes.
Historical evidence suggests that beech was uncommon as a natural species in Wiltshire and that the majority of the clumps and roundells of Beech on the downs today were artificially established in the 19th century. It would appear that many were for shelter but a proportion purely for their visual effect on the landscape. In most cases they were planted in mixture with a coniferous species, some of which are still alive today or, if dead, their stumps are still visible. Additionally there is evidence that banks surmounted by hawthorn around the perimeter gave added protection. There is no doubt that the problems associated with chalk downland afforestation were appreciated for reference is made in the literature of the time to the need for adequate weed control, shelter and even watering of young trees. It is most probable that these plantations received intensive care, for labour was cheap, until they were well established.
The Beech hangings, roundells, clumps and shelter belts are a typical feature of the chalk downland of Wiltshire. The hangings on the steep escarpments have been established on chalk and extend into the greensand at lower elevations. They tend to emphasise the landform vertically, when planted along dry re-entrant valley sides and to provide linear emphasis when planted continuously along escarpments.
The roundells and clumps are often situated in visually prominant positions on or near the summit of the scarp crests, and have become important landmarks. Generally the effect of exposure on these has rounded their outlines so that they mirror the smooth form of the down.
The value of shelter belts in landscape terms is more debatable than the foregoing. They have generally been linear and sited without relation to the underlying land form. Thus they can be seen aligned straight down galley sides and over ridges, though when mature they are not obviously cutting across all topographical features from every viewpoint. It is now generally accepted that tree planting can be sited so that it satisfies landscape, cultural and shelter criteria. The County Council hope that landowners will consult the Planning Department before establishing trees on bare ground, although there is no statutory obligation to do this.
In the past the establishment of beechwoods on chalk downland was primarily for visual effect or shelter or a combination of these functions. These woods can fulfill other functions; wildlife conservation, sporting, The object or objects of management must be established before operations commence as they influence choice of species, siting and cultural treatments.
(i) Introduction The restrictions to tree growth on Chalk Downland are Climate, Topography, Soil Vegetation. These factors limit the choice of species and are important in site selection.
(ii) Climate The average annual rainfall varies from 950mm (37.5 ins) in the west of Wiltshire to 760mm (30 ins) in the east. Temperature is not a significant limiting factor to tree growth.
(iii) Topography and local climate The elevation of the chalk downland ranges from 91 m (300 ft) to just below 304 m (1,000 ft) which is not high in absolute terms, but does make a large proportion of the area highly exposed, depending upon its relative elevation and aspect. Exposure to the prevailing S.W. wind will restrict height growth and also increase transpiration stresses in young trees, thus accentuating drought symptoms in young trees.
Aspect and slope are important in relation to moisture availability as it has been shown that the driest conditions occur on steep slopes to the south west and the moistest conditions on gentke slopes to the north east. Frost is an important factor in dry valleys between high downs. The downland sward can provide good conditions for radiation frosts in clear, still weather.
Geology and soils
The underlying geological formation of the Downs is Chalk. The overlying drift mantle is clay with flints of varying depth. The mantle tends to be deepest on flat topped downland but extends to less elevated chalk downland at depths of 30 cm (1 ft) to 60 cm (2 ft). The clay with flints is derived from the Tertiary Reading Beds and generally consists of loams or sandy clays with products of the chalk intermixed, due to the action of melting snow and ice, during the Pleistocene glaciations.
Fig. 1 The common superficial deposits in relation to topographic features.
Unless cultivated by man, they tend to contain little or no free lime and are somewhat acid in reaction. The acid reaction is also due in part to the presence of wind blown loess either deposited over the chalk, on the Clay with flints or mixed in the surface layers. From a forestry point of view the remaining soil type of importance is the Valley Gravel. This has been formed in dry valleys by the action of water removing most of the fine materials from the Coombe Deposits. See Fig. 1 for relationship of deposits in unglaciated chalk country.
Soils derived from the chalk itself as the parent material are called R;Indzenas. These are generally to be found on steep slopes or sharp ridges and consist of a shallow soil, usually not greater in depth than 250 mm (10 in), dark in colour and containing plentiful particles of chalk. The shallowness, extreme permeability and feee lime content of rendzenas renders them extremely difficult for afforestation and should therefore be avoided if at all possible.
To date no significant response in tree growth has been observed from the application of fertilizers to soils of the chalk downland though further experimental work is being carried out on this problem. The most significant feature of ehalk soils is the high lime content, in particular where there is no clay with flint cap, or where the underlying chalk has been incorporated with the surface soils by cultivation during historical times giving Ph values between 7 and 8. It appears that the proportion of free lime in the first 30 cm (1 ft) of soil is directly related to the chborotic symptoms that result. The symptoms of chlorosis are initially yellowing of the needles or leaves, reduction in annual height growth and sometimes resulting in death. It is thought that 'lime induced chlorosis' is attributal to the failure to take up, or make use of, certain minor elements, particularly iron and mangonese, in the presence of free lime. Chlorotic symptoms are far less likely to appear in trees planted on a shallow soil over chalk, with an acid reaction, than on a deeper soil that has free chalk incorporated throughout its profile. Vegetation
It is thought that during the Pleistocene age the downs would have supported a poor Arctic vegetation of dwarf willows and birches. During the pre-boreal period oack, birch, hazel, alder and pine appeared probably with beech appearing 41 the sub-boreal period, to form a lovi closed canopy woodland. Intensive cultivation from the early arrivals of man to the present day has resulted in the removal of most of the tree cover, with resultant erosion. Left uncultivated, the shallow soils support a specialised sward dominated by the Fescues (Festuda ovina and rubra). On the Clay-with-flint caps or on downwash soils in the valleys, where moisture retention is better, coarser grass species and large herbaceous vegetation occurs. The cessation of cultivation and the exclusion of grazing animals from chalkland areas normally result in the creation of a dense sward. Colonisation by yew and juniper takes place slowly on the driest sites while hawthorn, dogwood, blackthorns, hazel, privet, buckthorn, spindle, Wayfaring tree and elder colonise the moister sites. Oak and ash are the two likeliest species to form the tree cover with beech where the herbaceous weed groth is least. Seed availability is of course important in determining the proportion of each species.
As this booklet is primarily concerned with the rehabilitation and perpetuation of existing woodland it is not relevant to discuss in great detail the landscape implications of new planting. Nevertheless consideration of the immediate land form should be taken if establishing trees adjacent to existing woodland. As a general rule the planting boundaries should be irregular, within the bounds of practicability, taking account of the underlying landform i.e. not cutting across features, but complimenting them. The planting should follow the contours and when a conifer/hardwood mixture is used the planting pattern should attempt to ammteliorate the change in species. aoodland edges can be softened in outline by planting shrub species.
The following is a description of the current accepted method of establishment in the afforestation and reafforestation situation. There will, of course, be variations in these recommendations due to variable site conditions.
Reduce grass sward and herbaceous weeds with a tractor drawn "swipe".
Tractor mounted tine subsoiler drawn along planting line to minimum depth of 0.3m (12 in). Tines mounted on hydraulic drawbar attached to crawler tractor.
Rabbit and stock proof fence, 0.9m (3ft) high, using mild steel wire, or spring steel wire which is more efficient and cheaper. See Forestry Commission, Forest Record 80.
Insert plants in tine slots using Schlich spade; firm well. Rows 2m (6ft. 6in) apart, plants 2m (6ft 6in) apart in rows. Current experimental work indicates that plants grown in Japanese Paper Pots have a very high rate of survival in the field and that 1 1 Corsican Pine bare rooted transplants that have been cold stored for at least one month survive almost as well and are better than those lifted from the nurse and planted on the same day. This is attributed to the fact that stripped roots occlude over during cold storage.
In 'lanes' lm (3ft) wide, using reap hook.
spot application, lm (3ft), square around each plant, of Paraquat
using knapsack sprayer fitted with Arborgard or granular Dichlobenil and
Dalapon using a motorised knapsack applicator. The retention of any herbaceous weed growth between the rows is important as protection from wind dessication.
Regular maintenance of fences and possibly control of rabbits.
1. Preparation of Ground
Reduce herbaceous weed growth with a tractor drawn 'swipe'. The necessity of this will depend upon the intensity of the cover provided by the previous tree crop and in many instances may not be required.
Unlikely to be practical due to stumps of previous crop. It is probable that during the life of the crop the acidity of the top soil will have increased so that disturbance of this layer should be avoided.
As in I Afforestation.
As in Afforestation, but often without tine slots, therefore planting costs will be higher due to the difficulty of inserting the planting spade into unruptured soil.
5 Weeding, Protection & Costs as in Afforestation.
Some of the downland beechwoods have been well managed, but the greater portion have been neglected. Very rarely has thought been given to their replacement or improvement of their wildlife holding capacity.
Most downland beechwoods, have been widerthinned and become devoid of any shrub layer. A selective thinning preferably ca.ried out by a qualified Forester, would benefit the trees to be retained and the value of the timber can frequently more than offset the cost of the operation.
At the time of thinning, consideration should be given to the possibility of creating space within the woodlands for replacement planting. Alternatively new planting, preferably on the leeward side of the wood, should be considered. As many beechwoods have lost their side cover and shrub understorey and become very draughty the planting of shrub species oibon thiwg would be highly desirable to improve the habitat for game and wildlife.
The size of trees to be planted will be dependant upon the number required, Balanced against protection costs. It is quite likely that using larger plants with plastic sleeve protection will be cheaper when planting within an existing woodland matrix than erecting a rabbit proof ring fence. All clumps should be within a stock proof fence to encourage a reasonable ground flora and any natural regeneration of trees and shrub species.
It is County Council policy to encourage the planting of indigenous hardwoods wherever possible. The County Council recognise that it is culturally desireable to establish hardwoods within a conifer matrix. Typically Beech (Fagus sylvatica) has been established in mixture with Lawson Cypruss (Charaecyparis lawsoniana,) or Western Red Cedar (Thuja plicata) where some overhead cover already exists. In the afforestation situation Beech (Fagus sylvatica) has been established satisfactorily in mixture with Austrian Pine (Pinus nigra var nigra) or Corsican Pine (Pinus nigra var maritima) . There is no substantial evidence to suggest a change in this recommendation.
The shrub species suitable for these sites are listed below:-
B1ackthorn Prunus spinosa, Box Buxus sempervirenas, Buckthorn Rhamnus cathartica, Dogwood Thelycrania sanguinea, Elder Sambucus nigra , Guldel Rose Viburnum opulus , Hawthorn Crataegus monogyna, Hazel Corylus avellan , Field Maple Acer Campestre , Privet Ligustrum vulgare , Spindle tree Euonyomus europea, Wayfaring Tree Viburnum lantana,
It would not be realistic to quote costs as these show considerable variation from site to site and inflation would render them Quickly out of date.
The highest proportion of the total cost is likely to be for protection. The shape of new plantings have a direct bearing on this as a long narrow site will have a higher cost per unit area protected than a site that is nearer square. As mentioned in :.section 7 the possibility of using larger planting stock with plastic sleeve protection should be considered in the reafforestation situation.
It is important to allow for ongoing costs for a maintenance period of up to 5 years.
Grant aid is available for amenity tree plantin' in the countryside, from the Countryside Commission, and for commerci,11 planting from the Forestry Commission. (see Biblioraphy for sources of information).
Advice is readily available from qualified Forestry Consultants, the Forestry Commission and the Forester in the County Council Planning Department.
Chalk Downland Afforestation by R. F. Wood, B.A., B.Sc., and VI. Nimmo
F.C. Bulletin No. 34 H.M.S. 1962The Entopath News. Chemical Control. Oct 1973. Forest Research, Alice Holt
Wildlife Conservation in :Woodlands by R. C. Steele, B.Sc., F. C. Booklet 29 H.N..3.0. 1972
Forest Fencing by H. W. Pepper and L. A. Tee Forestry Commission Forest Record 80 H. M.S.O. 1972
Report on Forest Research 1973 Forestry Commission H.M.S.0.
The New Dedication Scheme (Basis III) Forestry Commission Leaflet July 74 H.M.S.O.
Grants to Local Authoritys and other public bodies for conservation and recreation in the Countryside - Countryside Commission for Lngland and dales ilay 1974.
John Dower House, Crescent Place, Cheltenham, Glos. GL50 3RA.