Admittedly, the wood is perishable. In fact, if this were not so, our forests would soon be cluttered with unsuitable skeletons of dead trees. Unfortunately, tree bugs and fungi are not able to distinguish between forest waste and wood for useful use. In the past, wood was used mainly in forest areas where it is readily available, therefore need termite damage repair. They agreed with a deterioration in quality, however, the replacement was relatively simple and inexpensive. In contrast, wood is now a valuable item and is transported over considerable distances between the forest and its place of use. To conserve world resources, the efficient use of wood is essential. One of the adequate methods of effective use is to increase its duration, protecting the wood from factors that destroy the tree, i.e. insects, fungi, fire, atmospheric and chemical effects, dry rot repair. For many centuries, wood has been a useful commodity, and the high cost of transportation in the past was justified only for the most valuable types of wood.
Even building wood imported into the UK in the nineteenth century was mainly wood of long-growing species, and its sapwood was removed. Dwindling resources and increased demand have led to stricter forest management practices to maximize production by producing fast-growing trees with wide annual rings, mainly consisting of precocious wood. Since the trees were cut when they had a relatively small diameter, sapwood prevails in the composition of the wood. For example, Swedish pine is currently at 50%. consists of sapwood. Although wide annual rings and a high percentage of sapwood do not significantly affect the strength properties of wood, such wood is less solid than wood of long-growing trees, widely used in the past and having a high percentage of core. Natural wood pests use wood mainly as a food source and shelter, or as a place to incubate their young. However, not all of them find wood attractive for these purposes. All living organisms have many absolutely specific requirements for survival:
• Source of power
• Certain moisture content
• air
• Suitable temperature
If any of these factors is missed, the risk of exposure to this agent will be eliminated. For example, parts of the raw wood used to build Scott’s capital camp during his expedition to the South Pole were not damaged, which discovered the expedition of Dr. Fuchs after 50 years. They also found that raw wood materials from the tombs of the pharaohs in Egypt were not damaged by insects or fungi after 4000 years. In both cases, extreme temperatures and dry air were so high that it ruled out the possibility of any decomposition organisms. The next example is the Iron Age canoes carved from wood, found in swamps in Denmark, and the remains of Marie Rose thrown onto land on the south coast of England, where the absence of rot was caused by a lack of oxygen. The problem is that controlling temperature, oxygen content and humidity with modern construction methods can be extremely difficult. The only way that can prevent the growth of wood-destroying organisms is to limit their food intake. This can be achieved by using inedible substances such as stone or steel, or in the case of wood, treating it with chemicals that have a toxic effect on these organisms, thus turning the wood into an unattractive source of nutrition.
Organisms destroying wood
Organisms that destroy wood can be divided into three main categories:
1. Fungi
2. Insects
3. Sea wood breech
Fungus repair
Fungi are living plants that differ from flowering plants only in the absence of chlorophyll in them, and the inability to synthesize their food, and therefore depend on the nutrients contained in other plants and animals. Their life cycle is similar to the life cycle of other plants, in which they begin life as a grain (or, in this case, as a tiny spore), which, under suitable conditions, emerges and takes root (or hyphae) that penetrate the wood and grow there . The enzymes released by hyphae that decompose wood absorb it, use it as energy and spread further, eventually forming a branchy mycelium or mycelium. When the fungi reach a sufficiently large size and have accumulated a sufficiently large amount of nutrients, the fungi, like any other plant, form a fruiting body (or sporophore), which is similar to the process taking place in flowers and seeds. Sporophores such as ,, toadstool “,” fungus-tinder fungus “and” fungus-raincoat “have external characteristics characteristic of fungi. It is important to distinguish wood rot fungi that cause wood rot from fungi that only feed on the contents of the cells, forming spots.
The first of these fungi eliminate certain components of the cell walls, causing the destruction of wood, and the last of these fungi leave the cell structure unchanged, eliminating only the nutrients of the tree that are in the cavities of the cells. stains fungi can affect wood when the tree has just been cut down in the forest (blue fungus) or can appear on wood during its use in high humidity conditions (staining or blue). When an infection occurs, stains are almost always associated with a change in the color of the wood surface, caused by mold, forming greenish or black, sometimes yellow, powdery growths that can be easily brushed off or sanded. Re-infection can be avoided by eliminating the source of moisture. Wood rot fungus seriously impairs wood and can significantly devalue it. On the other hand, the blue fungus does not affect the strength properties of wood, and is not a preliminary stage of decay, as many people suggest. However, this fungus spoils the appearance of the wood and makes it unacceptable if the appearance of the wood is important.
Fungi that destroy wood can be divided into three groups:
- Brown Rot (Basidiomycetes)
- White rot (Basidiomycetes)
- Soft rot (Ascomycetes)
• Dry rot (Serpula lacrymans)
Fungi that have a reputation for causing severe damage to building structures are probably dry rot fungi (Serpula lacrymans). Spores of dry rot germinate only at suitable atmospheric humidity, usually due to accidental moisture caused by possible leakage of pipes or damage to the roof when the wood gets very wet. The optimal conditions for the appearance of Serpula lacrymans vary in the range of air temperature from 21 ° C to 25 ° C, and wood humidity over 22%, but not excessive humidity. The fungus is sensitive to temperatures above 50 oC. The star-shaped hyphae formed during germination of the fungus penetrate the wood, diverging in circles from the point of germination, and branch there, so that the damaged area is covered with soft white shoots, similar to cotton wool. The shoots will not be limited only to wood, it will creep up on plastic, a brick wall, masonry and concrete, trying to find more wood for food. Of course, this overgrown shoot should be provided with food from nearby wood affected by fungi, and their hyphae will turn into rhizomorphic or conductive strings, supplying overgrown growth of food and water from places where they are in sufficient quantity.
Fungi use water to form a drop on the surface of the shoots, which in case of insufficient ventilation will maintain humidity at the optimum level for growth. This phenomenon of the formation of “tears” on the surface of the shoots explains the Latin name of the fungus “acrymans” and the description in the Old Testament book of Levitte “wash leprosy out of the house.” Preference for dry rot in unventilated rooms with a high level of humidity is ensured by the fact that the fungus is usually invisible and the first signs damage to the wood will be the curvature and cracking of the painted surface, by which time the infection with the fungus can already be very extensive, possibly spreading along the masonry and walls in its search means spacing in all directions: If food supplies run low or moisture levels suddenly drop, the fungus can spread over hidden plastic or wooden surfaces and form sporophores (Figure 2), causing millions of red-brown spores, in an attempt to infect all nearby wood. Dry rot is very complex, expensive and consists in removing all the wooden parts that are around the source of infection, disinfecting everything around the masonry and brickwork and, and replacing all damaged wood with wood that has undergone pressure treatment.
Insects
In order to fully understand the damage of this species, it is necessary to consider the typical life cycle of tree bugs. This cycle can be divided into four stages:
- Egg
- Larva (larva, worm or caterpillar)
- Pupa (arnica)
- Adult insect
A female beetle can lay its eggs in cracks, wormholes, or bumps in a freshly cut tree or dried wood. When a larva emerges from an egg, it gnaws a tunnel in the wood, and in some tree species it can continue to lay a tunnel for up to 10 years. When the larva has fully developed, it can move to the surface of the wood, then it will hibernate or the stage of the pupa, during which it will completely change its shape and shape to exit the pupa in the form of a fully developed beetle. After that, the beetle gnaws its way out of the tree outward, leaving an outlet for itself, and flies away for mating. Then the female lays eggs, thus repeating the life cycle.
Termite damage
In most cases, caterpillars damage the wood. Types of insects causing the most damage to wood in the United Kingdom (summarized in table 1):
• Furniture grinder (Anobium punctatum)
It is one of the most common causes of insect damage in the United Kingdom, and is commonly known as the “Woodworm.” It affects both hardwood and softwood, usually damaging sapwood. There is some evidence of damage to wood used outdoors, but it is more likely to affect indoor wood. It is best known for damage to furniture, but this insect also causes harm to wooden structures and carpentry, and if its presence is not eliminated in time, it can lead to a serious decrease in the strength of wood. It is easy to recognize him by the rows of dimples that are on his elytra, due to which he got his name “punctatum”.
Termites
Although, as can be seen on the map (Figure 5), termites are not found in the United Kingdom, in 1994 a colony of flying termites of the Reticulitermes species built an anthill in the North Devon resort of Saonton. These termites were destroyed. Termites are very significant in warmer regions of the world, and do much more damage than other tree bugs. In recent years, when new markets for the export of timber products appeared – the Middle East and Africa, termites have attracted more attention. Termites live in colonies and show a high level of social development. A typical colony consists of a queen laying egg, fertilizing the king and a huge number of sterile workers and military ants, each of which plays a role, as their names attest.
There are four main types of termites:
- Termites living underground or in soil
- Termites living in dry wood
- Termites living in wet wood
- Forest termites (These insects feed on leaves and plant debris in the soil, and do not harm the wood).
There are many signs by which underground termites can be distinguished from aboveground termites. Underground termites have no wings, and they need moist conditions to survive. They build closed entrances or shelters from the ground to the tree, often above the foundation of the building. If the tree rises above the ground and access to it along the moves is impossible, termites attach towers to them, consisting of a mixture of earth, wood and insect excrement. On the contrary, termites living in dry and wet wood may never reach the ground. Dry wood termites can live in very dry wood, the moisture content of which can reach 5-6%, raw and decaying wood is a suitable shelter for the kind of termites living in wet wood. Wood that has been attacked by any kind of termite does not seem to indicate much damage by termites, and any holes that might appear as a result of termite gnawing are quickly blocked.
Damage control by underground termites can be carried out in various ways. Termite metal sheets have been created that are used to prevent colonies from building tunnels in the mud, between food and a water source. Etching the soil around protected structures is also an effective method, however, it must be repeated every five years, and also in some places it is regulated by laws against environmental pollution. Termites of many other types, especially termites living in dry wood, are able to fly, and in reality, cannot be controlled by a system of physical obstacles. If the wood needs to be used for structures that are subject to termites, it must have natural resistance or be properly treated with an antiseptic. Wood treatment with an antiseptic is also desirable in places where there is a risk of hitting underground termites, since it is proved that the “triple” method, consisting of physical obstruction, pickling the soil and treating wood with an antiseptic, is the most effective form of protection. The best home remodeling companies.