A wall of this nature is known from Dutch laid-open application 8801994, which shows a number of plastic tubes or tubes made from bamboo material which extend vertically and are arranged in a closely abutting manner. The intention is that plant material should extend through the interior of the tubes and, over the course of time, should grow over the top end of the tubes and then downwards. In this way, it is possible, for example, to obtain a soundproofing wall or some other form of wall.

However, it has been found that it takes a long time for the plants to grow from the bottom up through the tubes, while if the tubes are immediately filled with earth and plants are provided on the top side, insufficient moisture in dry periods means that these plants will inevitably die. Moreover, tubes of this kind require a comparatively high-quality material which has an acceptable external appearance.

Consequently, the costs of producing walls in this way are comparatively high, which is one of the reasons why walls of this kind have thus far not found a market.

Numerous alternatives are known for the production of soundproofing walls. One example is formed by concrete structures, but in the long term these have a less pleasant appearance. Walls made from wood require the use either of hardwood or of other types of wood which have been impregnated with agents which are not environmentally friendly.

Moreover, it is necessary to carry out maintenance work, such as mowing, on walls of this nature.

One object of the present invention is to provide a wall which is inexpensive to manufacture, i. e. has a lightweight structure, so that no special foundation measures are required. This is in contrast to the concrete walls described above, which at least require a foundation which, where the ground is relatively soft, moreover has to be pile- driven.

Another object of the present invention is to limit the maintenance which has to be carried out on walls of this nature, in contrast to wood-based walls, which always require maintenance.

The objects described above are achieved by means of a wall in which the tubes are provided on the outside with an irregular fibrous covering which extends around each of the said tubes.

The invention is based on the insight of allowing plant material to extend from the ground along the outer side of the tubes. A number of plants are particularly suitable for doing this. On the one hand, such plants are quick-growing, and on the other hand, they have no problems with moisture uptake. Moreover, these plants carry leaves for most of the year or are evergreen. Owing to the presence of a fibrous covering around the tube and, at a later stage, the plant growth, the appearance of the tube is less important. Moreover, there are particularly few demands placed on the strength of the tube, so that it can be made from a comparatively inexpensive material such as recycled plastic. Since the interior of the tube is not filled with earth, the entire structure is comparatively lightweight. As a result, there is no need to use a complex foundation structure. It has been found that a wall comprising tubes of this nature is completely covered by plant growth within one or two years. Since this plant growth forms part of the appearance of the wall, there is no need to carry out maintenance work, i. e. to mow it, etc.

The tubes used may comprise any material and be designed in any way which is conceivable in the prior art. They may be either solid or hollow, hollow generally being preferred for material and weight considerations. Particularly in the case of soundproofing walls, it may be important to limit the"sound box volume"of the tubes as far as possible. In such a case, it is sensible to fill the inside of the tubes, for example by filling them with foam produced from recycled plastic or waste material. The materials from which the tubes are produced may be either wood-like materials (such as bamboo) or stone-like ceramic materials. However, as indicated above, it is preferred to produce the tubes from plastic, and more particularly from recycled plastic.

The covering arranged on the tubes may comprise any material.

Under certain circumstances, it may be important for it to have a reasonable durability, although in general this will not be necessary, since the particular plants which have been placed on the outer side of the tubes, after they have climbed up along the wall with the aid of the fibrous material, will be able to adhere to the tubes by themselves.

Consideration may be given to flax, hemp and/or tiger grass for the material used. Plastic materials may also be employed. However, according to an advantageous embodiment, use is made of coir, which more particularly has been preserved.

The use of coir or other fibrous material provides a

soundproofing effect and prevents reflection of the sound as far as possible.

According to an advantageous embodiment of the invention, at least two sets of tubes are present, the bottom ends of each set being arranged in a line, with the result that two essentially parallel bottom lines which are at a distance from one another are formed, and the top ends of each set being arranged in a top line, the distance between the said top lines being shorter than the distance between the said bottom lines. In this way, it is possible to obtain a particularly stable "wigwam-like"structure. In the space between the two sides of the triangle, the supporting structure can be accommodated so that it is protected against the effects of weather and wind. Consequently, there are considerably lower demands placed on a supporting structure of this nature than when installing a vertical wall which is supported by props.

It is possible to position such a structure over a crash barrier and/or to use the foundation of a crash barrier for the foundation of the wall produced in this way. Increasingly, when trees and the like are pruned, banks of wood are being formed, i. e. the pruned branches are arranged horizontally and other greenery is allowed to develop between them, so that all kinds of animals can dwell in banks of wood of this kind.

The wall described above can be used not only as a soundproofing wall but also to screen the view, for example as an anti- dazzle wall where various roads run next to one another. Other applications of the wall described above will immediately be obvious to the person skilled in the art on reading this description.

The invention will be explained in more detail below with reference to exemplary embodiments which are illustrated in the drawing, in which: Fig. 1 shows a first embodiment of the wall according to the invention, in perspective view; Fig. 2 shows a second embodiment of a wall according to the invention, and Fig. 3 shows a tube according to the invention in detail.

A first embodiment of the wall according to the invention is denoted overall by 1 in Fig. 1. It comprises wall parts 9 and 10, each comprising a number of adjacent tubes 2 and 3. Tube 2 is a comparatively long tube and tube 3 a short tube.

Fig. 3 shows a detailed view of such a tube, which comprises a plastic tube 4 around which a fibrous material 5, such as coir, is

arranged. The plastic tube 4 may be hollow, solid or hollow and filled with foam. The plastic used is preferably a recycled plastic which may be of relatively low quality.

In Fig. 1, the long tubes extend beyond the intersection between the sets of tubes 9 and 10, while the short tubes 3 end at that intersection, resulting in a"wigwam"-like structure. Plants can grow upwards from the ground along the fibrous material 5 which is arranged on the outside of each of the pipes. These plants may be any variety which is known in the prior art, such as ivy (hardy) or cedum.

The structure shown in Fig. 1 is held together by a set of bars 8 which are connected to horizontal beams 7. The beams 7 which lie closest to the ground are connected to posts 6 which are arranged in the ground. They can be positioned in the ground in any way which is known from the prior art. For example, it is possible to use structures as employed in the construction of greenhouses, both for the posts and for the rest of the structure.

Further structures may be present within the space delimited by the wall parts 9 and 10 and the ground 16.

Fig. 2 shows an example of a vertical wall, which is denoted overall by 11. This wall too is provided with plants and is held upright by props 12.

The height of the wall, or the length of the tubes, is dependent on requirements. At any rate, it is possible, by adapting the length (and diameter) of the tubes, to achieve any desired height. In general, a height of up to about 4 metres will be particularly effective.

The plant material which extends upwards along the tubes in the coir or other fibres 5 can be put in place by being planted or sowed both on the ground and in the fibrous material. It has been found that a period of two years is generally easily sufficient for such walls to be completely grown over.

In the embodiment shown in Fig. 1, the soundproofing properties are particularly good. This results, on the one hand, from that part which extends beyond the intersection of the wall parts 9,10 and, on the other hand, from the presence of two walls. The sound is substantially absorbed and scarcely reflected owing to the fibrous coir material and the subsequent plant growth.

The structure described above does not require any maintenance, while the growing greenery can easily be mown along the limits of the wall if it takes up too much room.

The space shown in Fig. 1 above the top beam 7 may, if desired, be filled with earth, in which further plants, cables and the like can be arranged. It is also possible to position an irrigation installation here.

It should be understood that the invention is described above merely with reference to a preferred embodiment. The structure of the wall will be adapted to match the particular use. In addition to being used for soundproofing and as an anti-dazzle screen, the wall described above can also be employed to protect against wind or the movement of sand and dust. Such variants are all considered to lie within the scope of the appended claims.