Leaf fall is a unique phenomenon in the life of trees and shrubs. To answer the question of when leaf fall begins and ends in rowan, birch, aspen, maple or any other plant, several factors must be taken into account. The region where trees and shrubs grow, the type of weather conditions of a particular time of year and some other features are very important. Leaf fall plays an important role not only in the life of specific plant species, but also in all of nature.

The meaning of leaf fall in nature

Thanks to it, trees and shrubs regulate the evaporation process and the level of moisture consumption. During the cold season root system cannot absorb from the soil the amount of liquid that would provide adequate nutrition for plants. To avoid death in winter, trees are forced to get rid of leaves. Since it is this part of the plant that requires the largest number water.

On branches freed from leaves, much snow will not accumulate in winter. The branches and trunk will not suffer under its weight. Fallen trees, shrubs, and dead parts of herbaceous plants are important elements in the process of soil formation. A large amount accumulates in the leaf blades of plants. toxic substances. Liberation from elements harmful to growth and development occurs when the leaves fall.
In rowan, birch, aspen, spruce, pine and any other plant, this phenomenon occurs in its own way. Phenological observations provide enormous material for studying the deciduous phenomenon.

When does autumn begin in the life of a plant?

As you know, the year is divided into four seasons. According to the calendar, autumn is the period from September 1 to November 30. It must be said that the division is arbitrary, and in life these deadlines are never met.

This happens for the reason that shift periods for each type are set separately. For example, when leaf fall ends for the rowan tree and it is preparing for the conditions of survival in winter, by this time all of them have already completed their growth cycle, without having lived to see the calendar autumn.

in nature

The onset of autumn is marked by certain signs. They can be seen in both living and inanimate nature.

A decrease in day length and a decrease in average daily air temperature is one of the main indicators affecting the life of wildlife. Air temperature from plus 15 degrees with a gradual decrease to zero refers to the autumn period. It is at these indicators that changes begin to occur in the life of most plants. So the average daily temperature regime indicates when leaf fall begins in rowan, birch, oak, aspen and other deciduous plants.

Folk signs

Based on centuries-old observations of nature carried out by people, signs have been compiled. Using them, you can predict the nature of the upcoming season, the amount of harvest of vegetables, fruits, and grain crops. It must be said that the reliability of many signs is very high, and today scientists can explain and substantiate their essence. When the leaf fall of the mountain ash ends, bright red berries are very noticeable on its branches. One of the signs says that a rich rowan harvest means a harsh winter. But this same fact also indicates that when the tree bloomed, the weather was excellent, and nothing prevented the bees from pollinating its flowers.
It is popularly believed that when the leaf fall of rowan and lilac ends, the pre-winter period begins. There are only a few days left before the onset of winter.

Everything interesting

Information for children regarding certain knowledge must be selected taking into account its simplicity and ease of assimilation: children must understand perfectly what is being discussed. Otherwise, it will not benefit either the child or his parents. Knowledge -…

To protect plants from frost, it is recommended to cover them with the arrival of the first cold weather. You can use a variety of materials for this. The most in a simple way protection of heat-loving plants is to cover them with a layer of fallen leaves. They are great...

The leaf is one of the main parts of the shoot. Its main functions are photosynthesis (the formation of organic substances from inorganic substances in the light), gas exchange and evaporation of water. Similarities and differences between leaves of different plantsLeaves of different plants...

Everyone loves autumn leaf fall, when the birch trees are carved with yellow
sparkle in the blue azure." But what is leaf fall from a biological point of view, and what is its significance in plant life? Leaf fall from a biological point of view
In places where...

Trees in a snow-covered forest appear dead and completely lifeless. However, this is not the case. Even in severe bitter frosts, life does not leave these majestic plants. During the winter, trees rest and accumulate energy to…

Autumn comes, the days become shorter, the leaves on the trees turn yellow, redden and curl, and then completely fall off. Leaf fall is a very beautiful phenomenon, but why do trees shed their clothes every autumn? The fact is that this way wood saves...

Autumn is rich in harvests. Cereals are ripening in the fields, mushrooms are appearing in the forest, and the harvest in the gardens is ripening, and rowan is no exception. This tree is often used for landscaping; it is especially attractive in the spring - during flowering, and…

In order to draw a rowan branch, it is necessary to reflect in the drawing the structural features of the shoots and leaves of this tree and depict clusters of berries. The branches are drawn first, the berries are depicted last. Instructions 1Start drawing...

The plant world is preparing for the winter cold, just like humans. But it has more advantages. By certain changes in the movement of air or stars, plants sense how soon the cold will come and how strong it will be. They themselves know about it and...

Folk signs of autumn helped our ancestors determine whether the next year would be fruitful and what weather to expect in winter or spring. Modern people have lost the ability to independently forecast the weather, as they monitor climate change and...

What is the importance of leaf fall in plant life? Big. The leaves have done their job of providing the tree with nutrients throughout the spring and summer and can now leave. What is the importance of leaf fall in plant life? Important. If the leaves...

For the comprehensive development of preschool children in kindergarten and younger schoolchildren, it is extremely necessary to pay attention to the natural changes of the seasons: spring, summer, autumn, winter. For example, with the beginning of autumn and new school year can you teach a lesson...

Already in the first days of September, the trees clearly show characteristic features another time of year. They are carried by the inevitably approaching autumn. Leaf fall occurs in each type of tree at its own time. Peculiarities of leaf fallWatching the trees,…

Everyone knows the common rowan - a tree without which it is hard to imagine the front garden of a house, a shady corner of a park, an alley on a city boulevard. However, the life expectancy of rowan along with the characteristics of its growth, as well as useful and…

What should an essay on the topic “ Autumn leaf fall"? Definitely descriptive, since here it is important to depict a picture in your own words, to reproduce the landscape. And this is only possible by choosing the right words. Well, let's talk about it...

Starting in late autumn and then throughout the winter, the tree and shrub species of the flora of our region remain dormant. Such winter phenomena in the life of plants are caused by many reasons. Among them is a significant decrease...

Autumn is coming... the leaves on the trees and bushes turn yellow, red, and change their green color. The golden time is coming. Yellow spots are interspersed among the bushes of birch trees and green cascades of linden trees. Why do the leaves turn yellow?

LEAF FALL

Leaf fall is one of the most characteristic phenomena of autumn nature. It most clearly expresses the seasonal periodicity in development flora our latitudes. Every year it repeats itself, first delighting our eyes with the countless tones and colors in which the forest is dressed up, and then inducing involuntary sadness with the dull appearance of naked trees and the melancholic rustle of fallen leaves. Autumn has long been considered a boring time, a dead season in nature.

Poets compare it with old age and are sad about its approach. For a naturalist, autumn is the most interesting time of the year, a time of intensive research and observation, when the numerous adaptations of the animal and plant world to the conditions of an unfavorable season are most clearly revealed. At this time, it is possible to notice a lot in nature and explain a lot of incomprehensible things. Many manifestations of spring nature will seem mysterious to us without corresponding autumn observations. Spring and autumn are inextricably linked - these are separate stages of a single life cycle of nature in our temperate latitudes.

CAUSES OF LEAF FALL

What are the causes of leaf fall? What makes our deciduous trees and shrubs shed their foliage every year in order to be clothed with it again at the end of the harsh winter? To answer this question, it is necessary first of all to find out whether leaf fall is a biological phenomenon caused by the life of the plant, or whether it is caused by a drop in temperature and the onset of autumn bad weather. If in the summer or - even better - in the spring, we transplant some young tree, for example, oak or maple, into a pot of soil, and put it in a room or greenhouse, in the fall it will inevitably shed its leaves, despite the best care. Autumn bad weather does not penetrate into the room or behind the glass of the greenhouse, there are no frosts here, nevertheless, leaf fall will appear here with sufficient regularity. This indicates to us that the autumn shedding of leaves is not a direct consequence of the unfavorable conditions that have occurred. It, together with the winter dormant period, enters into the very cycle of plant development. There is another way to make sure that leaf fall is a biological process. At the end of summer, a cut is made through the base of the leaf petiole of a tree at the place where the petiole attaches to the stem, forming the so-called “leaf pad.” Under a microscope, it is easy to see the formation of a special separating (cork) layer on the section.

The cells of this layer have smooth walls and are easily separated from each other. By the beginning of leaf fall, the connection between them is broken in some place, and the leaf remains hanging on the tree only thanks to vascular bundles, which, like the smallest “water pipes,” connect the leaf with the rest of the plant. Vascular bundles can easily be seen with the naked eye on leaf scars in the form of three, five or more large points. They serve to conduct water and mineral salts from the root to the leaves (upward current) and nutrients - carbohydrates produced by the leaves during the process of assimilation (downward current). However, there comes a moment when this last connection between the leaf petiole and the mother plant is broken. Often the most insignificant gust of wind is enough for this, but sometimes leaves fall even in completely calm weather as a result of sharp fluctuations in temperature, freezing or thawing, or directly under the influence of gravity of the leaf blade, aggravated by settled dew. Have you ever been in the forest at the height of leaf fall, when in clear weather it gets very cold in the evening, but there is complete calm? At this time, the forest is surprisingly quiet and the continuous rustle of falling leaves can be clearly heard. The formation of a cork layer in leaf petioles indicates to us that leaf fall is preceded by long-term preparation in the plant.

WHAT DOES DROPING FOLIAGE FOR THE WINTER GIVE A PLANT?

Leaf fall is an adaptation of plants to winter conditions - not only the cold, but also the dry season. If our deciduous trees remained in their greenery for the winter, they would inevitably die as a result of lack of moisture, since the evaporation of water by their leaves would not stop, and the flow of water into the plant could almost completely stop. In many tropical and subtropical countries, where the temperature during all year round is quite high, but the humidity is subject to strong fluctuations; every year, when drought occurs, the trees shed their leaves. Thus, the trees of the African savannas are exposed for several months, the grasses of which are also burned by the sun, until heavy rains again bring the savannah vegetation back to life. The importance of leaf fall in our lives deciduous trees This is especially noticeable when comparing them with conifers. Conifers - spruce and especially pine - are drought-resistant plants. Their needles evaporate many times less water than the foliage of our hardwoods. Thanks to this, they are able to overwinter in a green form. It is believed that in conditions of poor water supply, the amount of moisture evaporated by conifers is related to the amount of moisture evaporated by deciduous trees as 1:10, and in conditions of increased water supply - as 1:6. Oak evaporates 54.6 kg of water per 100 grams of leaf dry matter over the summer, birch - 81.4 kg, ash - 85.6 kg, and pine only 9.4 kg. It is interesting to note that larch in this respect behaves like a deciduous tree and evaporates moisture 10 times more than pine and five times more than spruce. This ability to save moisture is achieved by our conifers due to the special structure of their needles. Not to mention their significantly smaller surface area, needles have a number of drought-resistant adaptations: a thick skin surrounding the needle on all sides, and a bluish waxy coating, which also reduces evaporation; great importance It also has stomata arranged in special recesses. After all, stomata are pores, a kind of windows through which gas exchange occurs in the plant and moisture transpiration occurs; immersing them in leaf tissue significantly reduces transpiration. In contrast, the leaves of our deciduous trees lack any special drought-resistant adaptations. They have a wide surface and thin skin. Speaking here about the importance of leaf fall in the life of our trees, one cannot help but pay attention to the fact that by shedding their leaves, they thereby protect themselves from mechanical damage under the weight of snow. Often in winter you can observe how, even in a leafless state, large branches of trees break under the pressure of snow; a wide leaf surface on which a lot of snow would settle would make this a catastrophic phenomenon. The biological significance of leaf fall is far from limited to the above. It also plays another role in the life of trees. It helps remove waste, various mineral salts, large quantities of which accumulate in the leaves in the fall and become harmful to the plant.

If you take the leaves of a tree and examine how much ash they contain in spring, mid-summer and autumn, before leaf fall, the result will be a sharp increase in ash as the leaves age. At the end of May, beech leaves contain 4.6% ash relative to dry weight, at the end of July - 7.4%, and at the end of October - 10.8%, i.e. more than twice as much as in spring. How does such a significant amount of minerals accumulate in the leaves during the summer? The fact is that the leaf intensively evaporates water throughout its life. To replace this evaporated moisture, new moisture continuously enters it, which is absorbed by the roots from the soil. However, as we know, the plant does not receive from the soil clean water, and solutions of various salts. These salts, passing along with water through the entire plant, also enter the leaves. Part of them goes to feed the plant, while the part that remains unused is deposited in the cells of the leaf. As a result, by autumn the leaves become as if mineralized, richly saturated with salts, the deposits of which in some cases can even be seen under a microscope. A large amount of mineral salts deposited in the leaves in the fall disrupts their normal functioning and becomes harmful to the plant; therefore, shedding old leaves is a necessary condition for its normal functioning. Since the deposition of mineral salts in the leaves is the result of evaporation, it is clear that the more moisture the leaves are able to evaporate, the more they mineralize by autumn. This is especially clearly seen when comparing the amount of ash deposited in the leaves of pine and larch. Pine, which, as we know, evaporates very little moisture during the summer, contains only about 1.5% ash in its needles in the fall, while larch, which in terms of evaporation is close to deciduous species, accumulates up to 2.5% in its soft needles. % mineral salts. The need to get rid of harmful waste accumulated in the leaves determines the fall of leaves in trees in a humid tropical climate. At first it was believed that in tropical areas, where the climate remains more or less uniform throughout the year, leaf fall did not exist at all. However, more careful observations made on the island of Java in the famous tropical botanical garden in Buitenzorg and in India showed that leaf fall is a common phenomenon in the tropics. True, the fall of leaves of different trees does not occur simultaneously here, and even different specimens of the same species have leaf fall at different times. time. As a result, the dormant period in a humid tropical climate often lasts only a few days for a tree or part of a tree. The plant sheds the old leaves that have become unnecessary ballast for it and immediately puts on a new green outfit. These facts indicate that leaf fall depends not only on external, but also on internal reasons, that is, it becomes necessary as a result of the life activity of the plant itself.

WHAT IS CONTAINED IN FALLEN LEAVES

Analyzes of fallen leaves showed that, in addition to a certain percentage of ash, they contained a significant amount of carbohydrates - organic substances containing carbon and produced by the leaf as a result of its absorption of carbon dioxide from the air. It is remarkable that fallen leaves are much richer in carbohydrates than young ones. Thus, the plant, annually shedding its leaves, is deprived of a certain amount of nutrients, which do not have time to completely pass into the stem. However, such extravagance does not cause much harm to the plant. Carbohydrates are substances that can be obtained by a plant from the air in any quantity. The plant absorbs nitrogen only from the soil in the form of dissolved salts. And the plant often lacks nitrogen. Therefore, it turns out that before leaf fall, significant quantities of nitrogenous substances move into the trunk, where they overwinter or are consumed by the plant during the winter; along with nitrogenous substances, other mineral salts valuable for the plant are removed from the leaves; however, it has been established that a significant part of them still remains in the falling leaves.

Fallen leaves are a very valuable fertilizer. Thanks to them, the soil in the forest is annually enriched with humus, acquiring a number of important properties. We know, for example, that the soil of a broad-leaved forest does not freeze in winter due to its significant humus content, and this allows spring plants to develop under the snow. One hectare of oak forest receives more than 5000 kg of waste (dry weight of leaves, brushwood, etc.), which produces approximately 520 kg of ash. From this it is clear that the collection of fallen leaves and, in general, the removal of forest litter in the forest have a negative impact on the life of trees. For example, in one experimental German forestry, where collection of forest litter was practiced for a number of years, the growth of plantings fell by 11%. The leaves of some trees contain tannins. They are found in small quantities in oak leaves, but there are especially many of them in the leaves of noble chestnut, a tree widespread in Western Transcaucasia. Fresh fallen leaves in chestnut forests contain up to 12% tannins, so collecting them to obtain tannic extract can be of industrial importance.

WHY LEAVES TURN YELLOW IN AUTUMN

Plants appear green to us because of the large number of tiny chlorophyll grains located in the cells of leaves and stems. We know that in the chlorophyll grain the process of decomposition of carbon dioxide takes place, as a result of which organic substances - carbohydrates - are created in the plant from inorganic compounds. The chlorophyll grain does not remain unchanged in the plant. It doesn't last long. Catching the solar energy necessary for the assimilation process, chlorophyll is destroyed under the influence of light and is created again in the plant, and its formation can also occur only in the light. However, chlorophyll is not the only coloring agent in plant tissues. Along with it, special pigments known as xanthophyll and carotene are constantly present. The first of them is pure yellow, the second has an orange tint; carotene determines the characteristic color of carrot roots, where it is found in very large quantities. Yellow pigments are always present in the greenery of the plant, but in summer they are completely invisible, as they are masked by the intense green color of chlorophyll; nevertheless, they are very easy to identify using the following simple experiment. Everyone probably knows that the green parts of plants, if thrown into strong alcohol, begin to turn pale, while alcohol, on the contrary, quickly turns green. This process of leaf discoloration is caused by chlorophyll dissolving into alcohol, and especially quickly when the alcohol is heated or even gently boiled in a tank of water.

A strong alcoholic extract from green leaves looks emerald green when viewed in transmitted light, but in reflected light it fluoresces (glows) with a cherry-red hue. Along with chlorophyll, yellow pigments also pass into alcohol. To separate them, pour a little gasoline into the hood. After shaking the mixture, after some time you will notice that gasoline, being lighter, will float to the top, while the alcohol layer will remain at the bottom. In this case, gasoline will have an emerald color, while alcohol will take on a golden-yellow color from the yellow leaf pigments remaining in it - xanthophyll and carotene. The separation of chlorophyll from yellow pigments is based on the fact that it has greater solubility in gasoline than in alcohol. In autumn, as the activity of the leaf fades due to the formation of a separating layer in its petiole, the formation of chlorophyll in it slows down and, in the end, completely stops; The destruction of chlorophyll under the influence of sunlight continues. As a result, the leaf loses its green color and yellow pigments, previously invisible, are suddenly revealed. Therefore, however, it must be added that not only xanthophyll and carotene determine the yellow color of leaves in autumn; Currently, other yellow pigments have been found that are absent in living leaf tissues and appear only when they die at the time of leaf fall. Since the destruction of chlorophyll occurs at a faster pace in bright light in sunny weather, it becomes clear why in a cloudy, rainy autumn the leaves retain their green color longer and why, two or three clear sunny days, having replaced the bad weather that had hitherto, immediately decorate the crowns of the trees in the bright golden colors of autumn.

PURPLE COLOR OF TREES

Autumn leaf color is especially attractive with its crimson tones. However, these tones are not found in all trees. The crowns of maples and aspens are hidden in crimson; the foliage of the euonymus takes on an elegant, pinkish color; Garlands of wild grapes turn dark purple. Along with this, lindens, oaks and birches are devoid of red shades; they cast only various yellow and golden tones. What causes the red color of autumn leaves? It is caused by a special coloring substance, anthocyanin, which is extremely widespread in plants. Unlike chlorophyll, anthocyanin is not associated with plastic formations inside the cell. It is dissolved in cell sap and is less commonly found in the form of small crystals. Anthocyanin is very easy to extract from any red or blue parts of the plant. If you boil a certain amount of beets or red cabbage, the water turns purple or dirty red from anthocyanin. It is enough to add a few drops of some acid, for example, acetic acid, to this solution, and it will immediately take on an intense red color. Anthocyanin also determines the blue and pinkish color of flowers. Numerous colors of roses, the fiery color of poppies, sky-blue shades of forget-me-nots, the purple color of violets and bells - all this is the result of the presence of anthocyanin in cell sap. The fact is that anthocyanin, depending on what environment it is in - acidic or alkaline, can quickly change its color. Like litmus paper, with an acidic reaction it has a pinkish color, with an alkaline reaction it turns blue. In this regard, some plants have the remarkable ability to change the color of their flowers with age. We have already mentioned above this phenomenon in lungwort flowers, which at the moment of flowering have a pinkish corolla, which later acquires a purple and then blue color. The same is observed in the inflorescences of another inhabitant of the broad-leaved forest - the compatriot. In its graceful clusters, the lower, older flowers are blue in color, while the upper, younger flowers are pinkish. A similar change in color with age can be seen on forget-me-nots. The flowers of all these plants are initially very rich in acids; subsequently they gradually lose their acidity, and the anthocyanin dissolved in the cell sap turns blue. Using this property of anthocyanin, it is possible to randomly change the color of some flowers without much difficulty.

If you hold on for a while blue flowers forget-me-nots or violets in an atmosphere of tobacco smoke, they soon begin to turn green under the influence of alkali, which is contained in tobacco smoke. The same result is obtained with the action of ammonia. If you place the flowers of the plant under a glass cover with fuming hydrochloric or acetic acid, they quickly turn pink. Anthocyanin is widely distributed in young growing parts of the plant. We indicated above that it colors female alder catkins and the stigmas of female hazel flowers purple and pink color. Here it can play the role of some additional heat ray catcher, absorbing the green and blue parts of the spectrum. What is the significance of anthocyanin in dying leaves? The appearance of anthocyanin in plant tissues depends to a certain extent on external conditions. When the temperature decreases, the amount of anthocyanin in the cell sap increases in the same way as in bright light. At the same time, the formation of anthocyanin is also stimulated by the stop or retention in the foliage of nutrients received by the plant as a result of assimilation. This is especially noticeable in case of various plant injuries. Carbohydrates accumulate above the cut site, and then the corresponding part of the plant takes on an intense anthocyanin color. Prof. Molisch, who first noticed this, describes such a case.

Walking through a vineyard one day, he was struck by the fact that some branches of the vines had red leaves, while others had normal foliage. Curious about the cause of this phenomenon, he began to carefully examine the reddened parts of the branches and discovered that they were all damaged in such a way that the movement of the juices was hampered, but not stopped. To finally make sure that it was the defeat and the resulting stagnation of nutrients that played a role here, he made numerous cuts on other bushes up to two-thirds of the wood. After two to three weeks, all the affected parts of the branches above the cut took on a bright anthocyanin color. One might think that in autumn leaves, where damage easily occurs in the vascular system, the flow of carbohydrates is inhibited, which promotes the formation of anthocyanin. Thus, the crimson shades that trees turn during leaf fall are not any special adaptation. They only indicate the ongoing attenuation of vital activity in the leaves in connection with the preparation of plants for winter period peace.

FEATURES OF LEAF FALL IN TREES AND SHRUBS

Autumn coloring of leaves is not observed in all trees. Alder leaves retain their green color during leaf fall and turn black only after frost. In the same way, lilac leaves do not change their color at all: they remain green on the branches until snow falls, despite the fact that they have long been killed by frost. In aspen, leaf fall begins when the leaves are still green, but autumn coloring occurs later, when part of the tree has already been exposed. The duration of leaf fall in different trees, as well as the period of yellowing of foliage, can be extremely different. Of our trees, leaf fall is apparently the longest in the birch: it lasts about two months, while the linden manages to shed its foliage in two weeks. It is not so easy to establish the timing of leaf fall in any tree species, since in different specimens of the same species it does not begin and end at the same time. It is interesting to note that the reason for this phenomenon does not always lie in external conditions. Often two trees growing in the same neighborhood differ by a whole week in the time of yellowing and falling of their leaves, and these characteristics of leaf fall of individual trees are repeated annually. Of particular interest are some specimens of oak, which do not shed their leaves for a very long time and remain in their autumn attire throughout the winter. Despite the fact that the leaves on such oaks have long been dead, they hang tightly on the branches, withstanding winter blizzards and snowstorms, and fall only in early spring, shortly before the development of young leaves begins. These peculiar trees represent a special form of oak known as "late oak", while those that normally shed their leaves are classified as early oak. Both of these forms appear to be hereditary, although this remains to be verified.

In addition to the characteristics of leaf fall, late oak differs from early oak in later flowering and bud opening, which is delayed by 2-3 weeks. In spring, such oaks still stand completely bare, while their neighbors are already covered with a green haze of young foliage. Despite such a sharp difference in development, both oaks do not differ significantly in the shape and size of their leaves and acorns. True, some authors point out that the early form of oak, which is generally more common among us, is characterized by a wider spreading crown, a less regular trunk and lighter wood, while the late oak has a more compressed crown, a full-wooded trunk and heavier wood; It is interesting that both forms of oaks are distinguished by the local population: the early oak is called “summer oak”, or simply “oak”, and the late one is called “winter oak”, or “oak”. Currently, most authors believe that late, or winter, oak is more adapted to our climatic conditions, and therefore should become more widespread over time. The fact is that young oak shoots are often damaged by spring frosts. In this regard, the late form of oak is in more favorable conditions. If this is indeed the case, then we can conclude that our climate has now worsened compared to the past, which, however, is confirmed by some other data. Let us recall, for example, the wider distribution of broad-leaved forests in our past, the remnant of which is the oak anemone, which currently lives under a canopy that is alien to it spruce forest. Despite the great scientific and silvicultural interest that early and late forms of oak represent, they have not yet been sufficiently studied. It would be interesting to conduct more detailed observations of them in different conditions and in different years and find out whether any form is confined to certain habitats. It is also very interesting to establish whether any other tree species of this kind have early and late forms. We have already pointed out the ability of larch to retain its needles for a very long time in some conditions; Late forms of beech and chestnut are often found in the Caucasus, but they have not yet been studied in this regard.

Each plant has its own duration of leaf fall, but leaf fall itself can be observed in different terms depending on the weather conditions late summer and autumn. The literature reports that in middle lane In Russia, the beginning of leaf fall is observed in the second half of September, and ends by mid-October. At the same time, there are trees that fall off literally in two weeks, for example, linden, and there are trees whose leaf fall is very long. For example, birch trees begin to color yellow at the end of August, the first birch leaves appear on the paths of parks, in forests, on the sidewalk in the city at the beginning of September, and after that the birch trees can retain their foliage until the end of October. The duration of leaf fall is about two months... Our observations also confirm the fact that under certain weather conditions a tree can fly around in a few hours. This fall we observed a massive fall of leaves on one very windy day; the next morning many of the observed trees flew off (maple, several birches).

This fall, we believe that the main leaf fall ended by the end of October, and not by the middle. The beginning of autumn was unusually warm. On October 28-29, most of the trees in our study area were leafless. Some birches, several poplars, and all types of willows retain their foliage. At the same time, it is interesting that the five-stamen willow does not yet acquire autumn color; its leaves fall green. The lilac leaves and cherry leaves did not fall off or change color (they are also still green on almost all trees). But the most interesting thing is the behavior of the European linden. For Moscow, this is an alien species. Unlike small-leaved linden - our local species, which turns yellow early and flies away quickly, foreign lindens are green, in full foliage. The leaves gradually fall off without changing color. Also, the larch leaves have not yet finished falling.

For example, this is what our yards look like now. The one that turns yellow far ahead is the birch tree.

In this photo, on the left side there is a group of larches and a lonely yellow and not falling chestnut tree (all the others in the area have long since flown around), and with right side- two birches.

Tell us about the timing of leaf fall in your region in the comments!

Already in the first days of September, the characteristic signs of the next season clearly appear on the trees. They are carried by the inevitably approaching autumn. Each type of tree falls at its own time.

Features of leaf fall

Watching the trees, you involuntarily begin to think, when does leaf fall end for linden, rowan, apple trees and other plants? Leaf fall is an uneven phenomenon, its duration is estimated at several weeks. Multi-colored foliage is in no hurry to leave the crowns. The colorful leaves seem to reluctantly leave the branches one by one.

Abundant leaf fall occurs at the end of September and beginning of October (until the first ten days have passed). Leaves, caught by the third and subsequent frosts, fall off en masse. Thick leaf fall covers the ground with a colorful carpet.

The leaves, flying vertically, gently fall to the ground, covering it with a thick litter that saves the rhizomes from freezing. The slantingly rushing leaves play bright And the picked up gusty wind, having had enough of a spin, they find a safe haven.

The beginning of leaf fall

The linden crowns begin to blaze with autumn colors long before the first frost arrives. In the last days of August, single strands colored in grayish-yellow tones can be seen among the branches. The proportion of colored leaves increases daily, and the color palette becomes more intense. A noticeable gilding creeps onto the crowns of the linden trees. And after 14-20 days the foliage begins to burn golden.

By this time, birches put on an ocher-yellow outfit. The foliage is red with red. Ash tree crowns shine with pale honey tones. Oak leaves are filled with brown colors. Pink leaves glow in the lacy crowns of rowan trees. And the rosehip thickets flash with a wine-red color scheme.

By the time the linden leaves fall, and this happens no earlier than September 23, the crowns of other trees are already actively exposed. The first leaves of birch, aspen, maple and hazel trees fell on September 14th. Intense leaf fall in linden trees occurs following the first frost that pierces the air, which usually happens on September 27th.

First, linden trees lose leaves from large branches located below. Then the foliage falls off from the middle of the crown. The tops of linden trees are the last to be exposed. In elm, ash and hazel trees, on the contrary, the upper branches are exposed first.

The end of leaf fall

By October 7, linden trees lose their last leaves. At the moment when the leaf fall of the linden tree ended, they didn’t even think about exposing their thick crowns together with the alder. Their leaves do not change color; they remain green until the first fluffy snow falls. Their foliage, caught in a strong frost, instantly turns black. It is difficult for crispy frozen leaves to stay on the branches; they quickly fall to the ground.

By the time the leaf fall ends at the linden tree, the elm and bird cherry trees are completely bare. Their leaf fall ends by September 24th. Aspens are ahead of linden trees; their leaf fall ends on October 5th. Birches, maples and hazel trees are in no hurry to part with their foliage. A few leaves remain on them until October 15.

Natural phenomena during linden leaf fall

The period of linden leaf fall is accompanied by the arrival of cold fronts and night frosts. Cumulus clouds replaced by a continuous veil and grayish haze. Flocks of birds appear in the sky, flying south. After September 27, cranes in slender flocks stretch across the sky in a southern direction.

And when the leaves of the linden tree end, the half-naked crowns of other trees blaze with the brightest contrasting colors. Rooks, huddled in friendly flocks, fly away to warmer climes. Snow dust swirls in the air. Falling snowflakes do not yet fall to the ground, do not dust its surface. The puddles are twitching with thin ice. The skies are dirty greyish shades, devoid of clouds, turning into a gloomy film of rain.

Birch trees are deciduous plants; every year they shed their leaves in order to again acquire fresh green “clothes” in the spring. When does leaf fall end for birch trees? Schoolchildren often ask this. Our material will help you understand this and learn a lot interesting facts about this seasonal phenomenon.

What is leaf fall?

The term, so familiar to everyone, refers to the biological process during which tree leaves that have lost chlorophyll are separated from the stems and fall to the ground. This process is characterized by the following features:

• In autumn, trees take on a variety of colorful colors, from yellow and orange to crimson and crimson red. This happens because before the leaves fall, chlorophyll, the pigment that gives them their green color, is destroyed.
• The leaves acquire the ability to easily separate from the branch even with a slight gust of wind due to the formation of a special separating layer that disrupts the connection between the leaf and its stem.
• Due to this seasonal phenomenon, trees are freed from those harmful substances that have accumulated in the leaves during the season of active growth.
• With the help of leaf fall, plants are protected from excessive loss of moisture, which becomes very difficult to extract from the soil in harsh winter times.

We examined the main signs of the most important seasonal change in the life of trees. Now let’s get acquainted with when birch leaf fall ends, as well as when it begins.

Birch

Early autumn is characterized by still warm weather conditions; the thermometer often has a positive value, but precipitation may occur in the form of drizzle and frost. The trees begin to turn yellow, playing stunningly beautiful colors in the rays of the already dim sun. In the first week of September, the thin-trunked tree begins to lose its foliage.

The average duration of leaf fall depends on weather conditions and can range from 15 to 20 days. The answer to the question of what month the leaf fall of birch trees ended can be given as follows: September ( last days this month) or October (its first half).

Process Features

Birch is one of the first trees to begin losing leaves, along with aspens, maples, and lindens. Considering when leaf fall ends for birches, it should be noted that by the end of October these beautiful trees standing completely naked. The fall of the plant's leaves begins on September 15, completion - approximately by October 5, but more exact date It’s impossible to name - it all depends on the natural conditions of each specific year. The main activity of the process begins after the first frost, which, as a rule, occurs in the last days of September (from about the 28th).

Folk signs

We looked at when leaf fall ends on a birch tree. Why do people need this knowledge? First of all, observing nature is interesting in itself. However, there are also several folk signs, which our distant ancestors used to predict the weather. Some of them are interesting in their own way:

• If leaves fall from birch and oak simultaneously and evenly, you should expect a mild winter.
• A severe winter is expected if oak and birch trees become bare at different times.
• The leaves turned yellow, but did not fall off by the deadline - there will be frosts.
• The leaves on the white-trunked tree did not fall in the first week of October - snow will fall late this year.
• The leaf fall is happening “according to the script”, the tree sheds its leaves on time - we can expect a long thaw at the end of January.

Unfortunately, it is impossible to accurately answer the question of what date leaf fall ends for birches, but everyone can determine an approximate time frame: the process of leaf fall for a traditional Russian tree ends by the end of September or the beginning (less often, the second half) of October.