Dangerous trees. Reasons why trees fall during hurricanes New from users

A fallen tree is not so a rare event. It can damage a nearby house, car, gazebo, fence, electrical wires, collection of favorite plants... There are cases when people suffer and even die when trees fall... How to recognize and protect damaged trees?

Sad statistics

Trees fall in different ways - they can fall entirely, turning their roots out of the ground, their trunk can be crushed almost anywhere, a large branch or part of the crown can collapse... Any of these falls can cause a lot of trouble or even bring disaster. Let us give just two sad examples. In May 2013, in Moscow, a huge branch fell off from a tree growing near house No. 74 on Leningradsky Prospekt and crushed two children playing on the playground. The children were taken to the hospital with soft tissue bruises. In June, a real tragedy unfolded in the Bitsevsky Forest Park - a two-year-old boy died as a result of a falling tree.

Most often, fallen trees are left behind by stormy winds, but a tree can collapse completely unexpectedly in calm weather. Why do they fall? There are reasons for this; not a single tree will fall down just like that. Moreover, a healthy, properly formed tree can withstand severe external loads and withstand strong squally winds. A tree is a complex living organism, its stability largely depends on how it grows and develops.

Why are they falling?

There are four main reasons for the fall of trees and (or) their destruction: significant damage to the trunk by rot, violation of the integrity of the root system, severe tilt of the trunk, and improperly developed crown. Let's look at these reasons in more detail.

Roots, among other things, perform an anchor function. Without them, the trees would not be able to maintain a vertical position for long and would fall at the first gust of wind. The stability of a tree can be seriously affected by the severe development of root and butt-root rot, as well as by significant mechanical damage to the root system (for example, when digging trenches in the immediate vicinity of the trunk or when “rolling” the tree into asphalt with preliminary removal of a thick layer of soil).

Trees with a strongly inclined trunk fall for purely physical reasons, obeying the laws of universal gravitation. Such trees become especially dangerous if stem rot develops or the root system is damaged.

Incorrectly developed crown is formed in the absence of timely and qualified tree care, when they act on a very popular principle: plant it and forget, maybe it will grow somehow. Tree trees need competent, systematic care from the moment of planting to old age. In addition, in Russia the vicious practice of planting trees not from a nursery, but from the forest is still used, where in cramped conditions, due to competition, the branches of deciduous trees form a crown, being unevenly located. With unskilled care, improperly growing branches (not corresponding to the crown architecture) are not pruned in a timely manner, which subsequently leads to the collapse of parts of the tree.

There are four main reasons for the fall of trees and (or) their destruction: significant damage to the trunk by rot, violation of the integrity of the root system, severe tilt of the trunk, and improperly developed crown.

Detect in time

An emergency tree must be identified before it falls and causes damage. The presence of rot in the trunk can be indicated by dry sides, hollows, swellings of the trunk, fruiting bodies of mushrooms, etc. But sometimes these signs are there, but there is no developed rot. It also happens the other way around - rot in the trunk does not manifest itself with external symptoms. Identifying rot is quite difficult, and estimating its size is even more difficult. An error in this matter may result in the fact that either the abandoned emergency tree will fall or a non-dangerous instance will be deleted.

The old-fashioned method of identifying rotten trees by tapping is unreliable. And the use of a pulse hammer does not show a complete picture of the internal condition of the barrel. I am glad that at present in Russia there is an increasing spread of devices that allow one to “look” inside a tree without causing virtually any harm to it. Instrumental diagnostics of the internal state of trees is a modern scientifically based approach to solving this problem.

Device Resistograph® produced by a German company Rinntech® drills wood with a thin (only 1.5 mm in diameter and 45 cm long) drill made of special elastic steel. At the same time, sensors record the density of the wood (resistance to drilling). On one tree, samples are taken in several places: at different heights and in different directions. Using a computer program, the obtained data (resistograms) are processed by a specialist, and a picture of the internal state of the barrel is revealed.

Arbotom® device produced by the same German company Rinntech® is a pulse tomograph, the operating principle of which is based on measuring the speed of sound pulses passing through wood. In this case, from 2 to 24 sensors are installed on the tree under inspection at the required height along the circumference of the trunk, and a light blow is applied to the impact pin of each sensor in turn with a hammer. After each impact, sensors record incoming impulses. All data is transferred to the computer, and as a result, the program builds a planar model of the internal state of the tree trunk (tomogram). Plots with high speed sound passages (not affected by rot) are painted in blue and green tones, areas with average speed sound (with rot at the initial stage of development) - in yellow and orange, areas with low speed (with developed rot) - in red and purple. The program allows you to change the settings and use other color solutions, including black and white.

An emergency tree must be identified before it falls and causes damage.

Additional modules of the arbotome program expand its capabilities. The 3D module allows you to conduct research and obtain data on internal state tree trunk not in one plane, but immediately in the selected volume (cylinder (“cut” of the trunk) of the required height). Module Arboradix allows you to identify the location of first-order roots in space, as well as evaluate their qualitative condition (rotten or not). Module Mechanic Graph allows you to determine the direction of the likely fall of a tree, taking into account the rot present in the trunk and the geometry of the cross-section of the trunk.

The most important thing is that these devices are certified and successfully pass annual certification in Rostest, which indicates their reliability and reliability of the research results produced.

The decision to remove or preserve a tree is made by a specialist not only on the basis of data obtained as a result of instrumental diagnostics, but also taking into account biological features tree species, geometry and inclination of the trunk, crown architectonics, the nature of nearby objects and some other factors. Therefore, if there is a large tree growing near your private home, parking lot, playground or recreational area and you are afraid that it may collapse one day and cause significant damage, invite a qualified and experienced expert with certified equipment.

Urban tree problem

But what to do if a dangerous tree grows not on private, but on city territory? In this case, on your side Guidelines on assessing the viability of trees and the rules for their selection and appointment for cutting and replanting. In the capital, they were approved three years ago - by Moscow Government Decree No. 822-PP dated September 30, 2010. According to this document, the following categories of trees are subject to removal:

• “Old and overmature, large-sized trees with dried out, broken large branches with a diameter of more than 8 cm or with dry branches of any size, making up more than a quarter of the crown.
• Trees heavily affected by rot, with the presence of fruiting bodies of wood-destroying fungi, with large hollows, dry sides, and withered skeletal branches.
• Trees with a trunk angle of 45 degrees or more.
• Trees located at a distance of less than 5 m from buildings and structures (in accordance with SNiP).” In addition, dead and drying trees must be removed; to a certain extent affected by vascular, necrosis-cancer and rot diseases and pests (coccids, bark beetles, longhorned beetles, borers, etc.), as well as falling into the construction zone of buildings, structures and roads with subsequent compensatory plantings. It is necessary to ensure that city utilities remove dangerous trees in a timely manner. You can report these to your district government or write to the environmental management department, including through the department’s website in the “Question and Answer” section.

Identifying rot is quite difficult, and assessing its size and extent is even more difficult. An error in this matter may result in the fact that either the abandoned emergency tree will fall or a non-dangerous instance will be deleted.

You need to choose a parking spot as far away from trees as possible. If there are still trees near the parking lot, avoid poplars: they rot and fall more often than any other species, and in Germany it is even legally prohibited to plant them in cities. In addition, they have brittle wood, so there are frequent cases of large branches falling on cars. IN mature age in most cases, aspen, willow, and linden have rot.

Oaks, elms, ash trees, maples, and pines are affected by rot in much to a lesser extent, although among them there are emergency specimens.

Before leaving the car in the parking lot, inspect nearby trees: do they have a strong slope towards the car, are there any signs of stem rot (dry hump, swelling, hollow). Only after this can you calmly go about your business.

What to do if a tree or large branch falls on your car?

First of all, don’t worry: practice shows that you can compensate for the material and moral damage is quite real. If your car has a comprehensive insurance policy that provides compensation for damage in this case, you are in luck.

If you do not have such a policy, in addition to calling the police to the place where the tree fell, whose representatives will draw up a report, you must take a photo or video of the fallen tree yourself. In this case, you should start shooting by tying the fallen tree to the area, i.e., capture it against the background of nearby buildings, a fence, etc. Then you need to shoot close-up the break point on the fallen part of the tree and on the remaining one. Even if all parts of the tree are subsequently removed and the stump is removed, an expert will be able to determine the cause of the tree’s fall from photographs or video materials. The court orders and accepts such examinations without any problems.

Notify DEZ about the incident; the operator who accepted the application must provide its registration number. Next, invite an expert to assess the material damage and find out which organization is responsible for the maintenance of green spaces. Send her a claim demanding compensation for the material damage caused by the fallen tree, attaching copies of all documents. If the organization does not pay the damage within the period specified by you, sue it. When filing a claim, all available documents, photographs and videos must be recorded on a CD; they will be included in the case materials. Then you should petition the court to order a forensic biological examination to establish the reasons for the fall of the tree and provide the expert with the materials of the court case.

This summer was generous with rain showers, at which time the ground was soaked through. As a result, some fruit trees began to noticeably deviate from their natural vertical position. What to do in

Some trees in our gardens have just begun to lean, while others are almost falling to one side. Strong slopes (photo 1) are always dangerous due to the roots being turned out of the soil. The roots are torn off, exposed and dry, and in winter they also freeze.

You can prevent this disaster if you know the causes of tilts, eliminate them in a timely manner, and, if possible, help falling trees “get back on their feet.”

6 Reasons for Tilt fruit trees:

1. Most often, trees on vegetatively propagated (clonal) rootstocks bend, especially on their dwarf varieties in apple trees. Dwarf rootstocks allow you to grow short trees with all their advantages. But they also have significant shortcomings, in particular, poor “anchoring” (that is, insufficient fixation in the soil), since the root system of dwarf rootstocks does not have tap roots and occupies a small volume of soil. In this case, the architectonics (the nature of the structure) of the tree is violated: it turns out that the supporting area of ​​the foundation located in the ground (that is, the roots) is less than the diameter of the crown. Such a discrepancy inevitably leads to the collapse of trees both from the weight of the harvest and from various “surprises” of the weather. Therefore, in production plantings for dwarf trees, an indispensable condition is their trellis cultivation, that is, attachment to a strong vertical and horizontal support (photo 2).

In home gardens, you can use individual fastenings, but not to flimsy pegs that are unable to hold a tree (photo 3), but to solid stakes (photo 4).

2. Poor anchoring also occurs in trees on vigorous clonal rootstocks with shallow roots in the soil. Cherry trees especially suffer from this, which already grow intensively in the first years, giving large (up to 1.5 m) growth with large leaves characteristic of this crop. It is difficult for young roots that do not have time to grow quickly to support the huge vegetative mass of the crown. Besides big size the leaves increase their windage and the trees often lean towards the prevailing winds in the area. IN middle lane Cherry is still a new crop (meaning new varieties adapted here), and specialists are selecting special rootstocks for it. In the meantime, to grow it, you also need to provide strong support immediately after planting.

3. Sometimes young pear trees also bend, if the seedlings had weakly branched roots and they had not yet had time to get stronger. Then the roots will grow both in breadth and depth, and the tree will stand firmly on the ground. But the slope will remain and even intensify due to the weight of the harvest if it is not corrected in a timely manner. Therefore, before it’s too late, carefully pull the barrel to a firmly driven stake, placed as a counterbalance to the tilt.

5. Another common reason for tilting is the unevenness of the crown around the circumference, which causes it to skew towards the most branched part due to the weight of the fruits and leaves. This usually happens because of the notorious recommendation - to plant by grafting to the north (or south). You need to focus not on the location of the graft, but on the structure of the crown. It is necessary to plant so that its bare parts are in the most illuminated place (south or east). In this case, the crown will level out faster, “fluff” on all sides and tilting will not occur.

6. Trees that are quite healthy, but planted too close to a pedestrian path or flower (vegetable garden, strawberry, etc.) plot, can also fall to one side. At first the seedlings seem so small, but soon they grow, and now their branches interfere with the free passage or shade other valuable plants. The owners either pull up such branches or constantly cut them off, which also leads to crown asymmetry and tilting.

Consider all this when choosing a landing site.

What to do if a tree falls?

Don't start leaning trees, correct the situation immediately. First, to make work easier, carefully remove upper layer soil around the trunk. Then, on the side opposite to the slope, drive a strong stake deeply at a distance of approximately 0.5 m from the stem. To prevent the roots from coming off when you pull up a tree, you need to dig them up, cut some of them, and then knock down the soil from below as much as is needed to level the tree. Of course, all this should be accompanied by appropriate watering to fill the voids between the roots, additional filling them with soil and surface mulching, as when planting.

Tie the leveled tree with a figure eight to the stake in 2-3 places, using a strong rope. If necessary, the tree can be secured with guy ropes to 2-3 stakes. This procedure for leveling a tree is almost equivalent to replanting, so it is better to perform it in the spring. In winter, you should try to secure the tree with supports, since the weight of the snow may increase the tilt.

Trees and shrubs, including forest ones, decorate a personal plot, make it more beautiful and comfortable, create a favorable ecological environment around the house, thereby increasing its material value. It is worth noting that the removal of at least one tree violates the integrity of the tree stand on the personal territory, leading to its thinning, which can, in turn, lead to the collapse of this planting, especially if it is ripe or overmature. Therefore, the decision to remove a particular tree or shrub must be made justifiably, with good reasons. In order not to make a mistake in culling trees for cutting down, you must definitely invite a specialist who professionally deals with tree removal.

In this short essay we will look at cases in which tree removal is desirable or necessary. We will try to talk about the signs that indicate trees should be removed.

In what cases is it necessary to call a specialist to inspect green spaces on your territory:

1.Fallen tree
– if one of the trees on your territory for some reason, for example from a strong gust of wind, fell to the ground, although this tree did not have obvious signs drying out or illness. This situation means that not everything is normal with the tree stand on your site, that many trees in it are sick. A root sponge can have such an effect on a tree stand. Also, this tree itself is subject to mandatory removal from your territory, since it can itself pose a threat to people and animals, and also, after some time, tree diseases and pests will breed on it.

2.Drying of trees
- on your personal plot without visible reasons One or more trees have begun to dry out. This is your signal to call a tree removal specialist. When one or more trees in a tree stand on your territory dry out, removing trees that have begun to dry out is a necessary measure. We will substantiate this statement in this article a little later. Drying of trees or shrubs can be caused by for various reasons: hydrological, natural decay, infestation with diseases and forest pests. In every special case It is necessary to carry out different measures to preserve the planting, and, accordingly, different amounts of work to remove trees.

3.Construction work– at the beginning of construction work on the territory of a personal plot, you need to decide in which places you need to remove trees and bushes to clear the area for construction work. This same case can also include measures for redevelopment of a site, when growing trees and shrubs interfere with the placement of new objects, for example, for establishing lawns and flower beds, installing garden furniture.

What could be the reason for tree removal:

1.Drying
– is the reason for the mandatory removal of a tree for a number of reasons: a withered tree loses its aesthetic qualities and disfigures the appearance of the area. Due to the fact that a shriveled tree loses its stability, it begins to threaten the life and health of people located near it, and can also destroy nearby buildings and structures when it falls.

2. Windfall after hurricanes and snowfalls
– it is necessary to remove trees after hurricanes and snowfalls. Trees that have fallen in this way must be disposed of from the territory of the personal plot for the same reasons as when they dry out, namely: disfigurement appearance territory, danger to people and animals, as well as to nearby buildings and structures. Also, on fallen trees that are still alive, diseases and forest pests begin to multiply, dangerous for healthy trees and shrubs growing nearby.

3. Strongly leaning trees.
An overall trunk tilt of more than 10 degrees may be a reason to remove the tree for safety reasons. Such a tree has a very high risk that in a strong gust of wind it will be uprooted and fall, causing damage to the structures located at the site of its fall, and, God forbid, to people. You need to get rid of such trees on your site.

5. The presence of a hollow or rotten dry shoulder on the tree trunk.
A hollow or rotten dry hole on the trunk of a healthy tree is formed as a result of infection of this tree with some diseases, for example, various types of necrosis. For this reason, such a plant, even if it is still alive, carries the risk of becoming infected with these tree diseases. woody plants located nearby. Also, the strength of the trunk of such a tree is very weakened. It can fall to the ground at any moment and cause varying degrees of destruction and harm to the health of people who may be near this tree at the time of the fall. For these reasons, it is imperative to remove trees with hollows and rotten dry sides.

6. There are cracks on the tree trunk.
Cracks in a tree trunk, such as frost cracks, lead to a decrease in the strength of the tree trunk, which increases the risk of it falling. Also, through cracks in the trunk, various microorganisms can penetrate into the woody tissue of the tree, causing plant disease and then its death. For these reasons, it is necessary to remove a tree whose trunk has cracks, even if it is still alive.

7.Old big trees. An old, large, spreading tree takes up too much space on the site. The crown of such a tree shades the garden area, which creates unfavourable conditions for the growth and development of other plants on the site. On the other hand, an old tree, due to its volume and mass, can significantly lose its stability. This leads to the risk of it falling and causing significant damage. An overmature tree has a high risk of becoming infected with wood diseases and pests, and subsequently drying out. Removing trees that are large and old from the garden plot is highly desirable.

8. Trees with a damaged root system.
Often, during construction work involving digging pits and trenches, for example, laying communication routes or utility networks, the root system of trees located in the immediate vicinity of the soil sampling site is damaged. Such trees have a risk that after some time they may begin to weaken, become infected with diseases and pests, and, as a result, dry out. Since such trees will subsequently, after completion of construction, grow in close proximity to buildings, when they dry out and fall, they pose a direct threat to the constructed structures. Thus, removing trees with damaged root systems from the garden area is very desirable.

conclusions

In this article, we have listed cases in which tree removal is necessary or highly desirable. However, culling of trees and shrubs for removal and subsequent disposal from a personal plot must be done with the help of a specialist who professionally deals with tree removal. Unprofessional approach to solving this important issue, how the choice of trees for removal and disposal on a personal plot can lead to the fact that healthy ones are cut down, valuable trees and bushes, but sick, dangerous ones will remain and threaten damage when they fall.

A collection of interesting problems and questions

A.

Thin tall tree cut down at the root and falls (Fig. 40). Where does the tree trunk bend when it falls: convex down or up?

Rice. 40.

To avoid confusing the picture with extraneous circumstances, we will assume that, firstly, the tree trunk has been sawn completely, down to the last fiber, and, secondly, there is no air resistance to the falling tree (otherwise you would be distracted from the direction of the task by the fact that branches and leaves, the components of the crown, like a parachute, support the top of the tree, and, therefore, under the influence of its own gravity, the trunk bends down).

B.

Look at the root!

Kozma Prutkov. “Thoughts and aphorisms”, No. 5.

- Uh-uh, you can’t fool us! - this is the answer received from many of those to whom the author proposed this problem. - We know that the falling body is in a state of weightlessness. And if a tree trunk weighs nothing, then why will it bend? Moreover, in the absence of an atmosphere, the state of weightlessness of a falling object is ideal!

This answer is too hasty. Only free the falling body is in a state of weightlessness, and the cut tree is not free-falling, since it (look at the root!) rests its butt* on a stump or on the ground.

*Butt – part of the tree adjacent to the root

IN.

Let's imagine that the butt of a falling tree is attached to the stump by a hinge, around which the tree rotates as it falls. And even though there is no earth where the tree is about to fall, the trunk, having passed through a horizontal position, continues to rotate further. This allows us to view it as a pendulum. And we know the behavior of a pendulum well. Let us now imagine, instead of a trunk, a set of mathematical pendulums 01 , 02 , 03 , ..., 08 of different lengths, each of which is fixed at the same suspension point 0 (Fig. 41). As you know, a mathematical pendulum is a point mass suspended on a weightless rod. For such a pendulum, it is known that the longer the pendulum, the longer its period of oscillation. The shortest pendulum 01 will have the shortest period of oscillation, each subsequent period will have a longer period.

Rice. 41.

Let all pendulums initially make the same angle α 0 with respect to the vertical. Let's release all the pendulums at the same time and photograph them after the period of time during which the pendulum 08 will have time to turn at a noticeable angle α 8 . Since the period of oscillation of a pendulum 07 in short, then during the same period of time it will rotate through a larger angle α 7 . Angle of rotation α 6 of the pendulum 06 even more, etc. As a result, the pendulums in the picture will be located along a curve 01"2"3"...8" , which is convexly facing down. Now it is clear that the whole trunk will also fall convexly downwards, only the elastic forces connecting the individual “pendulums” together will tend to straighten the curve, which is why the deflection will be much less than shown. When a thin, tall trunk falls, this deflection is clearly noticeable.

If a tree, falling, touches the neighboring one or begins to fall before the trunk is completely sawed (“with a crunch”), then vibrations will be superimposed on the considered deflection, gradually attenuating. It would seem that these vibrations should also occur when the tree is completely cut due to the fact that while the tree was standing, it was compressed (or even bent) by its own weight, and when it begins to fall, it is released from tension. This would be the case if the weight of the tree was removed instantly. This happens in an electric oscillatory circuit if it is instantly connected (or disconnected) to an emf source. (shock excitation of the circuit). But a falling tree is unloaded from its weight (and unloads the stump) gradually, and vibrations do not occur.

Five cars were seriously damaged on the 5th street of Yamskoye Pole. A large maple tree fell on the cars. Owners of wrecked cars believe that the weather is not to blame. It was raining, but strong wind did not have. But there are questions for public utilities. They landscaped the lawn and cut down the roots of the maple tree. So the old tree found a foothold on the other side of the roadway.

Utility services are urgently cleaning up the lawn. Fall asleep new land, sowing grass. In general, they are eliminating the consequences of a completely unpleasant story - both for the five car owners and for the engineering service of the Begovaya district. On Tuesday at ten o'clock in the evening a huge maple tree fell here, not from a hurricane. The weather, although rainy, was completely calm.

The tree stood and at some point simply fell on its side, by a lucky coincidence, crushing only cars and not hitting people. The one-way 5th Street of Yamskoye Pole has become a dead end. Drivers, approaching the barricade, turned around and drove back in front of the police. Clearly like a brick. No one was deprived of their rights for this.

Work to clear the rubble lasted half the night. And in the morning the realization came that for some reason the tree had fallen on its own, and it was unclear who would pay for the broken cars. The council said that they carried out work here to lower the ground level.

“In order to ensure that in the event of heavy rains that may occur, the soil does not wash out onto the roadway,” explains Viktor Yuryev, deputy head of the improvement department of the Northern Administrative District of Moscow.

Experts explain that the technology removes the top fifteen centimeter layer of soil. Instead, a layer of soil ten centimeters thick is poured. And the roots of the trees are not affected. Yuri Grudzinsky is ready to argue with this statement. He explains that the tree that fell on his car - "ash maple" - has a superficial root system. That is, the roots of the tree do not grow deep into the ground, but to the sides. Depth - from zero to half a meter. If you cut off the roots, the tree will fall.

“I am a builder by training and a lawyer by training. Therefore, I can say. - That is, you can’t do this? - You can’t do this. We will prove this in court, if necessary,” says Yuri Grudzinsky, the victim.

The fallen tree also turned out to be almost rotten through and through. This is indicated by the dark core - it is visible on the cut. There is dust in the center of the trunk.

“The root system that is in constant contact with over-compacted soil, with the asphalt zone where overheating occurs, begins to slowly die. And through the dead roots, rot passes into the base of the trunk and leads to the tree either being uprooted or breaking ", explains Dmitry Kuharkin, forest pathologist.

True, this process is not quick and can last for decades. But could working with the lawn cause, even if not the rotting of the tree, then at least the weakening of its root system.

“If we are talking about creating a lawn, then this is usually a bedding. And the tree’s roots penetrate into this bedding after 4-5 years. Therefore, if we change the lawn every 4-5 years, then we definitely cut off the upper root system,” continues Dmitry Kuharkin , forest pathologist.

Moreover, neighboring trees also recently found themselves in the center of landscaping. Using a special tool, we examine maple wood. Both trees showed signs of rotting. The age of the rot is at least ten years. That is, the conclusion is obvious - trees can fall. When is unknown. Whether their roots are damaged is also unclear. But most likely there are no botanists in the government. Lawn gardeners are not like them either. Therefore, they are unlikely to study trees.