Trees In An Urban Setting. The Causes Of Diseases In Trees And Their Distribution. Pests. Care. Parks. Gardens. A Photo

Trees In An Urban Setting. The Causes Of Diseases In Trees And Their Distribution. Pests. Care. Parks. Gardens. A Photo
Trees In An Urban Setting. The Causes Of Diseases In Trees And Their Distribution. Pests. Care. Parks. Gardens. A Photo

Video: Trees In An Urban Setting. The Causes Of Diseases In Trees And Their Distribution. Pests. Care. Parks. Gardens. A Photo

Отличия серверных жестких дисков от десктопных
Video: How To Protect Trees From Wood Boring Insects 2023, January
Anonim

In urban environments, there are specific detrimental effects on growing conditions that worsen the condition of trees and contribute to the spread of a number of diseases and injuries. The first feature is chemical effects. Poisoning of tree roots is very widespread when faulty sewerage systems, cesspools, sewers and ditches, gas pipes are located close to them, as well as if there is garbage or materials containing toxic substances nearby. Poisonous substances partially go into the soil and cause root poisoning. Inorganic substances directly poison the roots, and organic, decomposing, emit gases poisonous to the roots or contribute to the development of harmful microflora. As a result of prolonged poisoning, the roots die off, then the tops dry out, and later the tree dies.

Trees in the city
Trees in the city

Roots can also be poisoned by gases in the air. Usually, these gases poison the leaves, but when they accumulate in large quantities they enter the soil in the form of poisonous solutions with atmospheric precipitation. This process can be enhanced if factories, factories, power plants, railway stations, etc. are located near green spaces. The smoke coming out of the pipes can contain various toxic substances in a gaseous state: sulfuric anhydride, acids, chlorine, hydrocarbons (methane, ethane, etc.) and resinous substances. These gases act on the outer covers and penetrate through the stomata of leaves or directly through the epidermis if the concentration of acids is high. Poisoning of leaf cells occurs and, as a result, disruption of the activity of the plant as a whole. Smoke is also harmful because large particles (soot, etc.)) cover the leaf surface and disrupt normal assimilation, which weakens the tree. On average, from 300 to 1000 tons of solid particles fall out of the air per 1 square kilometer of the territory of large cities per year. As a result of air pollution, the intensity of sunlight decreases, the air becomes less transparent and ultraviolet radiation drops sharply (by 30-40%). High concentrations of gases and their prolonged exposure to the tree cause the death of buds, branches, flowers and leaves, which become a substrate for the development of various fungi and their conductor into the trunk.the air becomes less transparent and ultraviolet radiation drops sharply (by 30-40%). High concentrations of gases and their prolonged exposure to the tree cause the death of buds, branches, flowers and leaves, which become a substrate for the development of various fungi and their conductor into the trunk.the air becomes less transparent and ultraviolet radiation drops sharply (by 30-40%). High concentrations of gases and their prolonged exposure to the tree cause the death of buds, branches, flowers and leaves, which become a substrate for the development of various fungi and their conductor into the trunk.

The second feature is soil compaction by vehicles and pedestrians, as well as various soil coverings (asphalt, concrete, cobblestone, etc.). Prolonged soil compaction disrupts the normal gas exchange of the soil, the roots die off and in the future are usually affected by root rot.

Trees in the city
Trees in the city

The third feature is work related to the laying of sewerage, gas pipelines and other urban amenities. During these works, ditches of various depths and widths are usually dug and very often at a distance of no more than 1 meter from trees or next to trees. When laying ditches, parts of the roots, and sometimes the entire root system, are often cut off or chopped off, which leads to the rapid drying of trees. The fourth feature is the variegated composition of the soil on which the green objects are located. Typically, the composition of the soil is poor or unfavorable for tree growth as a result of renovation work, when the lower layers of the soil are moving up and the upper ones down, as well as when trees are planted in former landfills. The fifth feature is extremely widespread mechanical damage to trees: disturbances in the bark (obstructions, hammering nails, cutting out inscriptions, etc.),breaking off branches and twigs, wounding trunks during repairs and other work, wrapping wire around the trunks and other damage. These injuries are especially dangerous, as they are usually not treated or treated incorrectly, which facilitates the penetration of various pathogenic organisms through them. It should also be noted that planting material often has numerous wounds resulting from the formation of crowns, pruning of diseased and dead branches, etc. As a result of the combination of the action of this complex of unfavorable factors, a very difficult situation is created that requires versatile knowledge and the ability to correctly identify the leading factors in the unfavorable state of green spaces from green building workers. Under natural conditions, tree species grow in tree stands, which are characterized by certain moisture regimes,temperature and other growth conditions. When trees are exposed to open space (for example, in boulevard and other plantings), their growth changes dramatically: the trees take on a typical squat and spreading shape, a large crown is formed with a mass of branches, foliage or needles. However, assimilation in these cases does not increase, it remains relatively weaker than in small tree crowns in stands. From the point of view of a phytopathologist, this can reduce the resistance of needles and leaves to diseases, especially since they are in different lighting and temperature conditions compared to the forest situation.However, assimilation in these cases does not increase, it remains relatively weaker than in small tree crowns in stands. From the point of view of a phytopathologist, this can reduce the resistance of needles and leaves to diseases, especially since they are in different lighting and temperature conditions compared to the forest situation.However, assimilation in these cases does not increase, it remains relatively weaker than in small tree crowns in stands. From the point of view of a phytopathologist, this can reduce the resistance of needles and leaves to diseases, especially since they are in different lighting and temperature conditions compared to the forest situation.

Trees in the city
Trees in the city

Insolation in cities is greater per unit area, but the intensity of light can be sharply reduced by smoke and dust in the atmosphere of the city, as well as by continuous and dense fogs and clouds. The intensity of the light affects the thickness of the leaves, the number of stomata, etc. Changes in sunlight intensity and duration for many breeds are a factor that strongly influences their physiological functions, in particular photosynthesis. Disruption of normal photosynthesis causes a number of metabolic disorders. In cities, the air temperature is 5-10 ° higher than in the forest, and the relative humidity is 25% lower, which is explained by the strong heating of the air from stone buildings, structures, bridges, asphalt pavements, sidewalks, etc. An increase in air temperature leads to a decrease in the relative humidity of the air,which can drop in cities up to 35%. Accordingly, the temperature and humidity of the soil in cities change: the topsoil can be heated up to 30 ° and more, while the humidity drops to 10-15%.

Trees in the city
Trees in the city

As a result, an increase in air and soil temperature with a simultaneous decrease in air and soil humidity has an adverse effect on the condition of trees, their growth, functions and resistance to diseases. In cities, trees are exposed to more intense cold temperatures than in natural forests, where temperature fluctuations are reduced. A decrease in temperature reduces physiological activity, and a sudden drop in temperature causes serious damage due to freezing or dehydration of tissues. In severe frosts, the trunks crack and the bark burns, as well as the roots die off. In cities, this is a common occurrence due to soil compaction and other reasons. Soil moisture in cities is often lower than that required by many tree species, with disastrous consequences: due to wilting,by weakening of growth and physiological processes, there is an intense attack of insects and damage by infectious and non-infectious diseases.

Trees in the city
Trees in the city

Low soil moisture affects tree nutrition. Nutrients enter the tree with a normal flow of water in its plumbing system. Water flows from the soil - an area of ​​low salt concentration - into the tree, whose cells contain higher salt solutions. Excessive concentration of salts in the soil near the roots with low soil moisture, excessive fertilization and in other cases can disrupt the process of water absorption by the tree and even lead to the release of water to the soil. This causes a loss of cell turgor and subsequent wilting of leaves and the plant as a whole. The oxygen content of the soil is essential for the normal growth of trees. In a forest setting, this is regulated by the looseness of the soil and in other ways. Lack of oxygen can cause the cessation of root growth and their death.In parks and forest parks, this is noted especially often when trampling the soil, flooding green spaces, covering the soil with asphalt or concrete, etc. Dense soil disrupts the normal diffusion process of gases between the soil and the atmosphere and simultaneously deprives the soil of its normal water permeability. Although the need of tree species for soil aeration is different: peach, cherry and other species die with a lack of oxygen in the soil, and many species grow even in swamps or on very wet soils. Damage, death of roots, as well as delayed formation of new ones associated with poor aeration, reduces the absorbing surface, as a result of which the intensity of absorption of minerals decreases, i.e. starvation of the tree sets in. Poor aeration often induces anaerobic root respiration, followed by the accumulation of by-products,which in large quantities can be poisonous to the roots.

Trees in the city
Trees in the city

In birch, beech and alder, at the age of 50, the roots spread to the sides for a distance of up to 8 meters. The roots of trees at the edge of the forest often spread up to 20 meters or more. In pine, the lateral roots, in contrast to spruce and beech, reach a larger distribution area at a young age. At the age of 14 years in a closed forest stand, the feeding area can be up to 7.5 m., At the age of 60 years - 8.75, and at the age of 80 years - 2.8 due to the death of lateral roots and their replacement by roots of a higher order. Root hairs are of great importance. Young pine has 24 times more of them than fir, and 5-12 times more than spruce. A large number of root hairs allows pine to grow on soils where fir and spruce are starving, since the pine uses a larger volume of soil with a scarce supply of nutrients and water.In urban conditions, salinization of soils is noted: the installation of skating rinks in wide alleys, the pouring of saline solutions by ice cream sellers right at the base of trees and bushes, etc. This can cause either a malfunction or the death of trees and shrubs, since the permissible percentage of salt in soil moisture is only 0.1%. It should briefly dwell on the sharp change in environmental conditions by man. Lack of awareness of the requirements for the growth conditions of tree species often leads to the fact that agrotechnical measures carried out by humans give the opposite results - they harm the tree. So, improper planting (for example, with bending of the roots) disfigures the seedlings, disrupts their functions or causes dying off. An incorrectly made trunk circle can cause suffocation of the roots,incorrect pruning of branches or roots - the cause of deterioration in tree growth and diseases, improper treatment of wounds and hollows worsens their condition, etc.

Trees in the city
Trees in the city

Very widespread and harmful plantings along streets and roads after laying the sewer system, telephone cables, etc. These works dramatically change the conditions for tree growth: infertile soil is removed to the surface, soil is contaminated with various poisonous materials extracted upward, the structure of the soil is disturbed (voids, compaction, etc.). In some cases, roots, trunks and branches are damaged, and wound care measures are not followed. Large damage is caused by pruning branches for various purposes, but without treating the sections or without spraying them with an antiseptic. So, there are cases when, when pinching and pruning branches in nurseries without proper measures to protect the cuts and without disinfecting the instrument, acute epidemics of fire blight were caused, spreading throughout the forest and leading to death,destruction and mutilation of many thousands of planting material. This condition also contributes to the spread of a number of fungi: cytospores, nectria and others. There are cases when, when creating a shady arch over the sidewalks, vaults were cut in the crowns of trees, and the mass of branches that were pruned was not sprayed with fungicides. As a result, all branches, and then trees, were attacked by the nectria fungus. In many parks, the norm of visitor load is not observed, which leads to a sharp deterioration in the conditions for the growth of trees and shrubs (trampling of the soil, etc.), as well as to numerous damage. Finally, it should be noted the undoubted harm caused to green spaces (parks, gardens, boulevards) by raking fallen leaves, seeds, fruits and twigs without compensating for the loss of this source of nutrition with fertilizers.Removing this debris deprives the soil of its natural replenishment of nutrients, and the soils become unfavorable for tree species growth. The depressing effect of soil depletion in nutrients does not appear immediately, but gradually, shortening the life of trees and weakening their growth.

Trees in the city
Trees in the city

As a result of the deteriorated conditions for tree growth and heterogeneous harmful effects on green spaces in cities and industrial centers, the resistance of woody vegetation to infectious and non-infectious diseases is greatly reduced. The consequence of this is a very short life span of trees, which is often half of their normal longevity in natural conditions. The resistance of trees to diseases and unfavorable environmental factors can be innate and acquired. It is not enough to hope for both, it is necessary to create such conditions for the life of trees in cities and industrial centers, which would increase their natural stability or eliminate harmful effects. More attention should be paid to the biology of tree species and to their individual features.In urban conditions, it is also necessary to pay attention to the need of trees for fertilizers, watering and washing of crowns. These three measures will greatly improve their growth and condition, as well as increase their resistance to disease.

Popular by topic