The RIC Good Wood Guide

Living Structures

LIVING FENCES

­ adapted from an article by Kurt Herran (originally published in Permaculture Journal, no. 8)

[See also Pleaching]

This article by Kurt Herran was first published in Czechoslovakia in 1933, and was updated by the author in 1955 when the section on wind protection was added. As you will see, this is as much a how-to article as it is an explanation of the technique.

CONTENTS AT A GLANCE...
Introduction
Live wattle fences as a natural construction method
The live wattle fence
The training of the live wattle fence
Selection of tree species
Method of growing hedges
Growing a live wattle fence in situ
Planting distances
Height of plants
The interlacing of hedges
Shapes of the hedge crown
Old and damaged hedges
Various uses of live wattle fences
The fencing-in of pastures by means of live wattle fences
The problem of wind protection
Summary

Introduction

Often the first thing a building owner will do after fencing an area with conventional materials is attempt to disguise the harsh appearance of the new fence and/or obtain some privacy by planting trees or bushes. Usually climbing plants, shrubs, etc are planted along the fence line. Unfortunately, any plants growing over or in contact with fences often contribute to their rapid demise. Wooden fences can be prone to rotting because climbers growing over them prevent their access to air and sun and thereby thwart the seasoning of the timber. Things are similar with wire netting fences, and in addition the plants growing in front of them hamper painting or the application of anti-rust compounds which are necessary every few years.

Live wattle 1 fences on the other hand, can ensure year-round privacy and security. In addition, maintenance is minimal, and the fences are usually sufficiently aesthetically pleasing so as to not need any other plantings to screen or disguise them.

The growing/construction process for living fences is fairly straightforward:

  • Well developed young trees are planted at suitable distances from one another.
  • Branches from each tree or bush are woven into those of its neighbours and the points of contact (intersections) are secured with tape, which results in the plants growing together permanently.
  • As soon as diameter growth starts, the young trees gradually grow together firmly (occlude 2) at the points of intersection. According to tree species it is usually no longer possible after 1 or 2 years to separate the branches at the joins ­ even by force.
  • The formerly separate young saplings have now been transformed into one long, low-growing tree with many root systems through which the sap circulates continuously. No individual tree in the row can die-off because each is supported by the 'network'. Even if one or several of the trees is cut with a saw close to the ground they cannot perish. Only the short stem running from the first intersection to the saw cut would die off. Above the intersection however, the wood will continue to live and grow, because it is nourished by all other stems and roots.

    The living fence method has been able to remove the greatest drawback of conventional hedges in that there need never be any holes or gaps appearing due to individual plants dying off. Perhaps the greatest asset of living fences is that all tree species without exception, both coniferous and and deciduous, can be used. In this manner, it is possible to create natural structures of all kinds. No longer are we limited to the small number of so-called 'hedge' plants, but we are able to choose from all the tree species available. Nor does the natural construction method mean interference with the creative forces of Nature, which merely guides them and trains them into suitable shapes in the service of human need.

    A fence planted in accordance with the live wattle fence method will soon secure privacy. According to soil, moisture and care, it will soon provide a barrier against small animals. In special cases where it is desired to make the live fence animal-proof from the beginning, it is possible to tie some old wire netting to the the fence in some places which will then grow right into the growing hedge. This wire netting will hardly be visible in a few years. Barbed wire could also be used on the top of the live fence, if thought necessary.

    The lasting qualities of a live wattle fence as against an ordinary fence should be stressed. A wooden fence will last, according to the timber used, 10­15 years 3; in high rainfall areas, this may only be 5 years or less. A wire fence (which must be painted to prevent it from rusting every 2­3 years) will last no more than 30 years, and even concrete or brick fences start to weather as the years go by. On the other hand, a live wattle fence will last as long as the tree species of which it is made ­ that is to say, for several generations. If regarded from this perspective, the original cost of a living fence needs hardly be considered, and it is cheaper than any other fence built from whatever conventional materials. While an ordinary fence deteriorates year after year, a living fence does the opposite: it becomes stronger year by year, constantly increasing in value because it is supported by life itself.

    It should also be mentioned that the natural construction method has now been developed to such a stage that it is possible to grow parts of a live wattle fence in suitable lengths in tree nurseries. The grown sections can then be delivered to the final site, planted out, then joined. It is possible to install a living fence in any desired spot as if it were 'ready-made', just like a fence built of conventional materials.

    Live wattle fences as a natural construction method

    This method, patented in four countries, makes it possible to grow living fences. Summer houses, espaliers, trellises and other structures can be constructed from live tree-plants.

    Note that these fences are not made of plaited twigs as has been tried in many countries and regions in the past. Such espaliers were called 'Belgian hedges', which today are little known in horticultural circles. With live wattle fences the little stems are interlaced in various shapes so that they may become joined. This wattle formation continuously grows together; with espaliers the fruit wood is suitable trained and with live fences crowns can be developed ­ wide at the bottom and narrow at the top.

    In order to obtain the necessary width with espaliers, the fruit trees are allowed to grow together close to the ground or at any desired height. Arbours or summer houses erected by means of the live wattle fence method form one stable, cohesive whole which later needs no support to sustain the arch.

    The live wattle fence

    As the name implies, a live wattle fence is at the same time a fence and a hedge. This fact is of the greatest importance when fences and windbreaks are erected, because these characteristics in conjunction provide the almost ideal enclosure. An uninterrupted live fence gains in strength from year to year and hedge formation becomes ever more dense so that a reliable enclosure is produced, protecting the section against wind and snow drifts. If the trees or bushes were grown together in a hedge formation but without them forming joins with their neighbours, then there would be no little or no advantage over a fence made from conventional materials.

    The principle is that a live wattle fence does not consist of individual plants which grow closely together in hedge formation and fight each other for the space necessary for their development above and below ground, but rather form a closely knit unit, as if they were one single dwarf tree with a long crown close to the ground. Once the young tree plants have grown together, they no longer behave as separate and individual plants.

    While normally one fells the growing tree and constructs conventional fences, etc, from the dead timber, which is doomed to rot, we are now able to produce these structures from live tree plants.

    All these live structures fulfil their tasks at least as well as those built from conventional materials, but being part of Nature are much more durable, since they are supported by the life inherent in them. Every protective structure built from conventional materials starts to decay from the moment it is erected, although this may be delayed by ongoing maintenance measures such as painting and impregnation with preservatives, etc. In contrast, live protective structures increase in value and lasting qualities for decades. These structures pulsate with life itself and fulfil their purpose for generations without requiring undue amounts of time, effort or money to maintain them.

    Owners of houses are now able to fence-in their sections to suit their ideals. The purpose of a garden is not only to provide food, but it should be an extension of the living area ­ a kind of open air home. Universally, attempts are made to design a garden which is an extension of the home in both purpose and effect in order to make it part of the home. The garden fence must also support this undertaking. It must keep out cold winds and provide privacy. Such an enclosure should not be like a foreign body but should provide a feeling of intimate association with nature and of cosy domesticity, and for that reason it should be also be part of Nature. A live wattle fence fulfils all these requirements in the best possible manner. In order to subdivide the garden purposefully and aesthetically, we should above all use espaliers erected according to the live wattle fence method.

    Let us here counter an objection which might be raised against a live fence of this nature. It might be feared that crops might suffer by the shade and root formation of the hedge. These slight disadvantages can be easily overcome by letting the garden path run around the inside of the live fence. A path running around the whole garden has other advantages as well, and in any case the shade will now extend only over the path yet under it the roots have enough space to extend and develop.

    With garden plots, protection against cold and drying winds is very useful. We find in practice that cold and drying winds greatly retard even the hardier plants and some crops are destroyed completely. Thus, it is imperative to provide for sufficient and effective windbreaks.

    The training of the live wattle fence

    Young tree plants are planted to form a lattice shape or other suitable shapes with interbranch contact, or crosswise by means of pressure discs on one axis. A thin pin can be pushed through the intersections or points of contact. Patented counter-discs are placed on both protruding ends and pushed on as far as the wood itself. The plants put together in the lattice shape or some other suitable shape will thus be firmly connected. The counter-discs mentioned cannot slip back. The great pressure of diameter increment of the wood soon causes the growing together of the plants joined in the manner described. In this way we can obtain live wattle fences growing increasingly stronger and denser, which on the outside are clad in pleasing green foliage.

    The tree plants grow in most cases quite a bit in good soil, but also in poorer but well prepared soil during the first year after planting out. Thus it is possible to use plants 140­160 cm if need be for wattle fences. Tree species whose stems are as a rule comparatively thin towards the top, such as birch, should not be too short. At first the tops which are still too thin should not be interlaced, and the top parts should be interlaced later. It is best when the tree plants are suffiently high and thick to interlace the whole fence at once.

    It is not recommended to grow tree plants directly from seed because in most cases it is too difficult for the layperson to achieve sufficient quantities of uniform size and vigour.

    If there is enough time and space available, very young seedlings could be purchased from the nursery and grown-on until the plants reach a suitable size for planting out. However, unless a very large quantity of plants is required, the savings will be minimal because of the time and effort involved in looking after the seedlings and the high attrition rate. At least double the number of plants required for the fence would have to be purchased and cared for this way.

    When plants of uneven size, shape and degree of health are planted out, some of the seedlings will die and others will lag behind in growth, so that no more than half of the seedlings transplanted originally are likely to survive.

    Even where saplings are purchased at optimum size, the number required should be increased by 5­6% and the surplus plants should be planted out close by. This is in order to have spare plants available should any of the original plants in the row fail to strike, remain stunted or be otherwise unsuitable. If no spares are kept on hand, it would almost certainly be necessary to order more from the tree nursery, which may only be able to be done in spring or autumn. On the other hand, available spare plants can be carefully lifted during wet weather from where they were planted and then replanted, with as much soil around their roots as possible, in the position from which the failed plants were removed. In most cases these will continue to grow without trouble.

    The roots of plants are very sensitive to atmospheric effects when lifted from the soil. For this reason, the roots should be weed protected during transit. Once unpacked and planted out, they should be heeled-in as quickly as possible, watered, and sheltered against wind and sun. Before heeling-in, the plants should be sorted if possible into uniform thicknesses. The very thin and the very thick ones should be placed in separate lots and heeled-in separately. In this manner everything is prepared for planting out and time is saved later on during the planting process.

    Selection of tree species

    When selecting a tree species for a live fence, the decisive considerations are climatic conditions, soil and site condtions and the ultimate purpose of the live fence. As far as possible preference should be given to species growing quickly during the initial years, which later do not produce too many shoots or too much wood, but which are apt to flower and fruit profusely. It hardly matters under normal conditions whether a species can reach an age of 100 or 500 years or even more, but the timber characteristics are of importance. Timber species with soft wood should be chosen carefully because such wood is often attacked by the goat moth, a very destructive pest. There are certain means by which this pest can be effectively controlled, but the whole live fence would have to be examined periodically and carefully in order to ascertain whether it has become affected and to carry out control measures.

    For live fences it is advisable to use low-growing species, and for very low fences, dwarf varieties. With arbours and high hedges, more vigorous species may be selected. It is advisable to select such species which have the characteristics best suited for the purpose. For normal live fences it is not wise to choose species which produce a large amount of wood and which take almost a generation to form large crowns. It is better to pick a species best suited for the purpose, and in consideration of the dictates of Nature which humanity has studied for thousands of years. The plants needed for live fences should always be purchased from a reputable tree nursery and they must be be planted out as saplings. So-called self-sown (wildling) trees taken from the forest are entirely unsuitable for live fences. They very likely have grown in poor, cramped conditions, are often growing crookedly, and rarely make suitable hedge plants, even after years of good care and careful trimming. It is very important to make sure that hedge plants are bought from a proper source if failures are to be avoided. Badly grown hedge plants are the most expensive ones. While with afforestation schemes it is not important that every plant should strike, every component of a live fence must be of good quality.

    The various Mountain Ash species (Rowan, Service, Whitebeam) as well as Birch, Fly Honeysuckle, Cornelian Cherry, Privet and similar fruiting low-growing trees, or rather trees with small crowns, have proved themselves very suitable for living fences. Wild Pear trees, Crab Apple trees, fruit trees, Hornbeam and above all, Silver Maple, are successful. Beekeepers often prefer to plant Limes or other nectar-producing trees for live fences. In many cases it will be possible to grow species which not only perform the requisite functions of shelter and protection, but which also have pleasing aesthetic and/or fruit-bearing properties. This is the case with Rowan trees whose ornamental berries adorn the top of the hedge. If these are not harvested but left for the birds, they will remain on the hedge until far into the winter. Species with long thorns such as Crataegus, Holly and others have the additional advantage of providing a barbed wire effect. The long thorns stop cats and other animals from robbing nests and present an effective obstacle for man and beast.

    Method of growing hedges

    A live fence can be grown either on the site proper or can be planted out in sections, as if it were prefabricated. Such sections raised in tree nurseries will have already grown together and be showing advanced hedge formation. After planting out, each section is joined (once their roots are established and the foliage is beginning to grow). The sections are shaped in such a way that there is no difficulty in joining them on the final site, nor will this show at all. Today, the natural construction method has ben developed to the stage where it is possible to plant out complete live wattle fences, which is a considerable added advantage. In many cases, we do not wish to grow an enclosure in situ, but prefer to plant only the finished product. It may even be difficult, if not impossible, to grow a live wattle fence at the site in some cases. We now have the capability of constructing the hedge just as quickly as any other kind of fence. It is obvious, of course, that such hedges, which must be grown in a tree nursery for at least two years before they have suffiently grown together and are thick enough, must be more expensive than a live wattle fence grown from individual plants on the site. For this reason the latter method will probably be preferred as a rule. It will be described hereunder.

    Growing a live wattle fence in situ

    The natural construction method should use only tree plants of sound growth and development. It is not possible to try and interlace plants immediately after they have been planted out. We must bear in mind that some plants won't strike and will have to be replaced; also it is a law of nature that the young trees must at first remain in an upright position so that they can strike and they will settle as the loosened ground settles. It is easy to see that at this stage we cannot expect them to grow together before they have struck and before they have started to grow again.

    Planting distances

    For a live wattle fence of 120 ­180 cm in height, distances on planting out are as a rule 12.5 cm; ie, there are 8 plants to one running metre. The planting distance may be increased to about 17 cm. Or else, with hedges intended to remain below 120 cm in height the distance can be reduced to 10 cm so that sufficient intersections are made by interlacing. In such cases dwarf varieties should be used where possible. With river bank protection schemes, cattle paddocks, etc, and with summer houses the trees should be not less than 20 cm apart. With summer houses the distances can be even somewhat greater, but the young trees are allowed to fork at the tops.

    With espaliers the distances can be greater still. Here we seldom plant closer than 40 cm, but the trees are allowed to fork straight above the ground or at a convenient height to avoid undue width of mesh of the lattice. If there is need to provide protection from prevailing crosswinds, some of the trees can be planted 40 cm one either side of the line of the hedge at intervals of 125 cm and growing towards the row at a right-angle. When the whole hedge is interlaced, these trees can also then be incorporated into the hedgerow so that they serve as cross-struts. In this manner, they will protect the hedge against lateral wind pressure.

    Height of plants

    It might be assumed that it is possible to grow the tree plants on the spot from seeds or to plant out small seedlings in order to save the expense of larger plants. However, experience shows that is necessary to use plants which are of approximately the same height as the completed live fence, if we want to produce from them an entirely uniform hedge. Small plants, even with the best of care, never grow uniformly enough for a live fence. When interlacing is being carried out, it is advisable to have available as many saplings as possible of uniform thickness and sufficient height. Interlacing may be carried out only up to a height where the trees still have a diameter of about 8 mm and for this reason the plants must be of sufficient height when bought. After interlacing they are topped as soon as the desired height is reached. If it is necessary to stop interlacing before that, the thin tips are left and these can then be interlaced a year later.

    For a live fence required to be 130­160 cm in height, trees 160­180 cm high should be ordered, which, before planting out, are sorted into equal thicknesses so that the eventual lattice will be as uniform as possible. With live fences intended to grow very high, we still need not as a rule plant trees higher than 180­200 cm, unless we place greater emphasis on the lattice formation than on a wide and thick crown. In cases where very high fences are needed it is better to let the crown form to some extent and then permit shoots to continue to grow on the top at suitable intervals, which are then likewise interlaced. In the case of arbours or summer houses however, very tall young trees may be planted as long as they are supplied by the tree nursery fairly slender and with sound root systems. With summer houses, etc, we require as a rule no wide crown, but merely protection against sun, wind and provision of some privacy. In general with summer houses trees we use trees between 140­160 cm, or 160­180 cm. These are pruned at a suitable height above two lateral buds and are then allowed to fork and grow from there. Interlacing takes place above the forks.

    The interlacing of hedges

    Interlacing is best carried out when there is no foliage. It should not be done during frost because frozen wood will break on being handled. In poor soils when plants have not reached the desired height or where conditions are otherwise unfavourable, it is better to wait two summer seasons before interlacing the saplings.

    The saplings are tied to a horizontal wire and already form a pleasant green wall. It should be decided in each case by rule of thumb whether to wait another year ­ but in general interlacing should start as soon as the saplings have struck well and are showing some growth. If we find however that towards the end of summer the plants have still not yet recovered from transplanting, it is better to wait another year before interlacing.

    If the plants have been sorted into equal thicknesses and were planted at exact distances, the wattle fence will have a completely uniform mesh. Saplings which did not strike well or are of stunted growth should be replaced during wet weather by spares, or these are removed towards the autumn while the summer foliage makes a clear distinction possible and strong spare plants should be planted before interlacing.

     An alternate means of creating hedgerows is to wait until plants are two years old then cuts are made no more than one-third of the way through each stem so that they can be bent and intertwined. The weaving and plaiting is aided by stakes every 60 cm, around which the branches can be twined. In its early years a hedge must not be allowed to grow up more than it grows sideways. Cutting back should begin in the second year after planting and for the first five or six years. Upward growth should be restricted to no more than 15­16 cm annually.

    Shapes of the hedge crown

    In order to achieve the growing together of the pinned-together tree plants, as well as uniform thickness from top to bottom while at the same time shaping the crown, further growth and crown formation at the top should be retarded. The lateral shoots at the bottom should be left alone until a crown has formed which is close to the ground, wide at the bottom and narrow at the top.

    Once the conical shape has been achieved the hedge should not be trimmed straight by means of hedge clippers in the case of fruit-bearing species. Trimming should be done in such a manner that shoot formation on the top is retarded. Individual branches tending to grow beyond the pyramidal crown should be cut individually with pruning shears. With tree species which naturally form small crowns the fruit wood and the so-called terminal buds are not trimmed off and there should be no further difficulty with pruning.

    Only where unsuitable species have been chosen, or if after the hedge crown has formed the flowering and fruiting organs are foolishly removed time and again, will it be necessary to counteract excess growth of wood by cutting. It is quite easy to promote either the formation of wood or fruiting. Once the hedge crown has been formed, it will be found that a hedge of this nature is favoured by birds for nesting, and since there is no trimming, the birds are not disturbed when hatching. Along roads and railway embankments and wherever else possible, it is wise to select tree species for live fences which offer not only good nesting possibilities for birds ­ which are the best means of controlling pests ­ but also some food, particularly during the winter.

    Old and damaged hedges

    Where old hedges which are no longer serviceable are to be replaced by live wattle fences, the latter should be planted early enough for the old hedge to offer some protection during the growth and establishment phase. Where it is not possible in exposed situations to grow a new live fence and where it is not desired to plant 'prefabricated' sections, posts and old wire netting can provide provisional protection.

    Where old hedges exist, it is at times possible to saw off the old plants cleanly close to the gound and to produce slender new shoots which can then be used for making a live fence; ie, to use the new growth from existing old plants to create the hedge. This can always be done with Hawthorn for instance. The new shoots should be pruned early, towards the end of May (Northern Hemisphere) and the strongest of them left to grow at regular intervals without laterals. In this manner we can obtain during one summer season straight shoots up to 2 m high. Where there are some larger gaps, we insert fresh plants 160­180 cm high when the old wood is being sawn off.

    If a live wattle fence is subsequently damaged either by an accident or in some other manner, the damaged parts should be cleanly cut back. The new shoots appearing are then pruned until we have the required number to enable them to grow strong and be interlaced. If this method does not produce any success, we plant slender saplings from a tree nursery alongside the old hedge, which are then interlaced after striking.

    If it is desired to obtain a close mesh, in particular close to the ground very early on, the plants should never be put in more closely than has been stated. Nothing would be achieved by close planting and even an adverse effect might be produced, because the lattice formation would remain weaker if the plants were too close. The mesh of the lattice close to the ground can be easily reduced in size without closer planting. Almost all tree species grow vertical suckers from the root collar which are cut back fairly short as soon as they are noticed, in order to force them to form branches. These suckers can now be placed over the adjoining mesh and kept in place by thin brass pins (15 mm long), after which the sucker is cut off above it. However, in most cases the hedge crown will soon be so dense that such measures are necessary only in special cases.

    Various uses of live wattle fences

    Live wattle fences can be used not only for fencing-in houses and sections, paddocks and whole farms, but also for cemeteries, public parks, reserves, sports grounds, railway stations, roads and anywhere where a durable enclosure or protective hedge is needed. Live wattle fences are also useful for protecting river banks and stopping erosion along roads and railway embankments. They also give excellent protection against snowdrifts and fires.

    During grass fires a live fence whose conical crown starts at ground level is not endangered by the flames. Since no grass can grow under the hedge, flames cannot shoot from the ground up and the worst that can happen is that the outer shoots are singed. In locations where there is a fire risk or where a live fence is designed as protection against grass fires, we should not use tree species which keep their dry foliage during the winter months, such as is the case with Oak and Beech.

    The fencing-in of pastures by means of live wattle fences

    Pastures can be enclosed cheaply and efficiently with live fences with a useful life-span of many human generations. This is done in the following manner:

  • Species are used which are cheapest to procure.
  • Distances could be at least twice as great as with standard fences, and in this manner only half the normal number of plants needs to be used per fence. The height of 120 cm should be sufficient for a fence of this nature. The increased distance between the plants and the limited height also requires only half the normal quantity of discs and pins for joining branches.
  • It is possible during the same working period needed for completing one running metre of standard live fence, to erect at least double the length,that is to say, two running metres of paddock fencing. Thus the total cost of a paddock fence will be much less that that of a standard live fence.
  • If we take into consideration also that annual repairs including timber requirements for wooden fences are no longer necessary with live fences, in addition to which the useful life of the latter is several generations, it is obvious that live interlaced fences are vastly superior to ordinary wooden fences in every respect.
  • It is possible to select species for live fences which are not eaten by the farm animals and there is no need to worry about this aspect.
  • The problem of wind protection

    I intend to state here the most important factors to enable the reader to recognise the advantages offered by hedges and to show you that the planting of hedges can help decisively in the solution of important wind protection problems as well as in landscaping.

    At the turn of the century the total number of hedges (in Europe) started to decline. The removal of existing hedges and the fact that no new ones were planted is a consequence of utilitarian economic thought, which considered every plant not producing a direct return to be a weed; ie, as an object taking nourishment from the soil, obstructing the view and preventing the use of farm machinery. This attitude is met with even today.

    Not until the end of last century did we discover that regions planted with hedges fulfil far more important purposes than keeping farm animals away from fields or supplying firewood. Above all, hedges offer protection and food to many useful animals: (in Europe) weasels, hedgehogs, toads, lizards, common grass snakes, etc. All of these greatly contribute to keeping down the pest populations in the whole neighbourhood, certainly far more so than would be possible by the use of chemicals.

    Wind, which would strongly dry out the ground is either deflected or filtered by hedges so that it is no longer able to carry away any dry soil made friable by frost. Nor can hedge-impeded remove the important carbon dioxide close to the ground. Strong evaporation from the soil is particularly detrimental at high wind velocities in spring and summer, during a period when the plants are already very active, and/or during the middle of the day when the air humidity is at its lowest and evaporation greatest.

    Detrimental wind effects are likewise expressed by the fact that more water is being given off by the leaves, which forces the plant to greater activity while suffering from growth-retarding chill due to increased evaporation. The low air humidity in turn causes increased evaporation of moisture from the ground on windy days ­ almost twice as much compared with calm days. The danger of drying out is greatest immediately after rain; ie, at a time when the water has not yet penetrated the soil. At this time a windbreak is most effective. Science has proved that about half the amount of annual precipitation evaporates due to wind action, and the wind takes more moisture from the soil than any crop.

    In America, whole regions have lost their humus and been turned into deserts through the impoverishing effect of soil and wind erosion. In Austria too, there are some regions which largely have no protection against the wind and which are deprived of more of their agricultural soil every year. How valuable windbreaks are can be gauged from the fact that a hedge of only 2 metres in height provides protection over a downwind distance of 100 metres.

    Schleswig-Holstein in Germany is one of the classical hedge regions, with its well known 'rampart' hedges which are cut down every 6­8 years. Here the land taken up by hedges is about 5% of the entire area, which therefore cannot be used for farming and is set aside for wood production. Schleswig-Holstein has less forest than any other part of Germany, but despite this every farmer has their own firewood which they can take every year from the hedges around their fields. The freshly cut wood is not used until the year after, so that the firewood used is fully air dried; this has three times the heating value because when burnt it is not necessary to evaporate the large volume of water which would be retained by unseasoned green wood.

    The most important benefit of a hedge in farming is the increased yield produced on the fields which it surrounds. This is due to the following:

  • The permeable hedge has a braking effect on the wind which directly benefits plant growth. The decreased movement of the crops due to wind makes possible the uninterrupted activity of the roots and hence results in more vigorous growth.
  • The reduction of the wind force due to the presence of hedges reduces the evaporation of water present in the soil. We know that more snow accumulates behind a hedge than on an open space, due to a decrease in the force of the wind, and the same applies to rain. This accumulated water results in increased growth in the summer and droughts are more easily overcome.
  • Thus, the presence of hedges results in higher crop yields. The plants need above all carbon dioxide which they transform into sugar starch with aid of water. Carbon dioxide is present in the air and is produced all the time through the decomposition of inorganic compounds of humus. It rises slowly from above the ground. If all other substances necessary for the growth of a plant are present, the carbon dioxide greatly promotes its growth. However, if the wind is able to remove this carbon dioxide, the plant lacks a substance necessary for its growth, and consequently it is less able to absorb all other factors it requires in order to thrive. However, if hedges break the wind force, carbon dioxide remains above the ground and can be absorbed by plants. Carbon dioxide is used in horticulture also and is produced artifically in glasshouses by means of smoke cartridges. It is used for fertilisation purposes and results in more vigorous plant growth.

    To a certain extent, hedges influence the macro-climate, as as has been proved by observation and measurement.

    Another important advantage of hedges is that they reduce the growth of weeds in their vicinity. Every piece of agricultural land grows a greater or lesser number of weeds whose seeds are carried by the wind over long distances. Every windbreak, however, catches a number of seeds which will then grow close to the windbreak and perish, either because they grow so closely together or because of the lack of light.

    People often get the erroneous idea that hedges promote an increase of field mice numbers. This is not borne out by observation, however. It is a fact that hedges planted as windbreaks are always avoided by field mice, for the following reasons:

  • As has been stated before, hedges provide food and shelter for the enemies of field mice, e.g. hedgehogs, weasels and grass snakes, and at the same time providing these with cover and strong points for hunting.
  • Research into the ecological requirements of field mice as to temperature and humidity show that field mice prefer warm and dry conditions. For this reason, they must be classed as 'prairie animals'. Therefore the so-called 'cultivated prairie' can be regarded as the optimum environment for field mice, not hedges. The climate close to the soil beneath hedges has stable temperature and humidity ­ and can be described as 'attenuated forest soil climate'. It is therefore not a suitable environment for field mice.
  • It has been proved that in particular, useful bird species favour hedges for nesting, and it needs hardly be stressed to what extent birds keep down insect pest populations. Since birds cover very long distances when searching for food for their young, even distant windbreaks fulfil a useful purpose within a region. Let us here mention another inconspicuous and quiet helper in the struggle against insect pests ­ the spiders, which by way of their webs woven into windbreaks, catch and consume a huge number of insects.

    Hedges serving as windbreaks are also of importance because they provide shade for farm animals. During the hottest hours of the day in mid-summer, the pasturing animals spend this period lying in the shade while they chew the cud. It has been proven that this rest in the shade increases the yield of milk, compared with cows that have to spend the time of greatest heat on pastures without any shade. Finally, hedges provide food for bees, if tree species are used which flower at different times, such as Maple, Mountain Ash, Lime trees, Acacia, Hawthorn, Elder, Blackthorn and others.

    Summarising, we can say that the planting of windbreaks has the following advantages:

  • Heat storage, and thus earlier harvesting
  • Increases of precipitation in dry areas
  • Increased dew formation
  • Better nourishment of plants
  • Mitigation of frosts
  • Protection of pasturing animals against biting winds and the heat of the sun
  • Destruction of wind-borne seeds of noxious weeds
  • Protection against snow drifts along roads and embankments
  • Stabilisation of slopes and hillsides
  • Supply of firewood from prunings
  • ­ and many other favourable characteristics.

     

    1. Wattle:­ Rods or stakes interwoven with twigs or branches of trees, used for making fences, walls, roofs, etc. From the Old English 'watul' ­ covering; and waetla ­ bandage. (Macquarie Dictionary)

    (Australian wattle trees [acacia spp.] possibly got their name from their suitability for fence-making.)

    2. Occlusion:­ To close, shut, or stop up ­ a passage, etc. (Macquarie Dictionary)

    3. This applies for CCA-treated pine as well.



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