Description: War Thunder is a next generation military MMO game dedicated to...
Let's start in order, as the questions are asked in the textbook, to fill in the diary of observations. Just remember that for different terrain autumn changes come at different times.
Leaf fall near linden ended on October 7, leaf fall near birches almost ended on October 10, the last leaves fell from poplars on October 1, lilac retained foliage until October 24.
On September 10, a flock of swifts flew south, and the river became unusually quiet. From September 20 to October 10, flocks of ducks and geese fly south almost every day.
In September, you can still meet a hedgehog, mice, squirrels in the forest, if the day is warm, then snakes even crawl out onto the paths.
The autumn forest becomes transparent with the loss of foliage, there are often small and cold rains, but a few mushroom pickers still roam the forest.
The world around Grade 3: How to fill out a diary of observations of autumn nature in a scientific diary?
- Observe and write down (day of the month) when the first frosts were.
- When were puddles first covered with ice?
- Write down when the first snow fell?
- 4. Mark when the river, lake, pond was covered with ice?
- Write down in what month the leaf fall at the birches ended __ , at linden __, in other trees___ what are their names.
- When did flocks of migratory birds appear?
- What animals did you manage to see in autumn?
- Other observations?
How lucky that today I can quite accurately fill in some columns of this diary of observations.
For example, today, September 27, the puddles were covered with the first ice in the morning, although the first frosts began two days ago on September 25.
Even more curious is the situation with the first snow, it fell on September 24th and it was very unexpected.
The rivers in our area are covered with ice only towards the end of October, or even at the beginning of November, although lakes with stagnant water certainly become covered with ice earlier in mid-October.
Leaf fall at birches begins in early September, but finally ends only in October, let it be the 10th. Around the same time, leaves and lindens are lost. But aspen and poplar fly around by the end of September, this is the 28-30th.
The first flocks of migratory birds stretched south in early September, they were swallows and swifts, songbirds. Now, in the 20th of September, ducks fly south.
When I recently went for honey mushrooms, I found that autumn forest still alive. Mice are bustling around in the fallen grass, it was warm and frogs were jumping, and once a chipmunk crawled out onto a stump and shrillly shouted something of its own chipmunk.
In September, you can still pick mushrooms, although it is difficult to find boletus and saffron mushrooms under the fallen leaves, but honey mushrooms have occupied numerous stumps in the neighboring forest.
Autumn is coming ... the leaves on the trees and shrubs turn yellow, turn red, change their green color. The golden time is coming. Yellow spots interspersed in the cosmos of birches and green cascades of lindens. Why are the leaves turning yellow?
LEAF FALL
Leaf fall is one of the most characteristic phenomena autumn nature. It most clearly expresses the seasonal periodicity in the development flora our latitudes. Every year it repeats itself, first delighting our eyes with the countless tones and colors that the forest dresses up in, and then inducing involuntary sadness with the dull look of bare trees and the melancholy rustle of fallen leaves. Autumn has long been considered a boring time, a dead season in nature.
Poets compare it with old age, they 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, many things can be noticed in nature, many incomprehensible things can be explained. Many manifestations spring nature without corresponding autumn observations will seem mysterious to us. Spring and autumn are inextricably linked - these are separate stages of a single life cycle nature of our temperate latitudes.
CAUSES OF LEAF FALL
What are the causes of leaf fall? What causes our deciduous trees and shrubs to shed their leaves every year in order to be clothed with it again at the end of harsh winter? To answer this question, it is necessary first of all to find out whether leaf fall is a biological phenomenon due to the vital activity of the plant, or whether it is caused by a drop in temperature and the onset of autumn bad weather. If we transplant some young tree, for example, an oak or a maple, into a pot with earth in the summer or - even better - from the spring, and put it in a room or in a 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 dropping of leaves is not a direct consequence of the onset of adverse conditions. It, together with the winter dormant period, is included in 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 in the place where the petiole is attached to the stem, forming the so-called "leaf pad". Under a microscope on a cut, it is easy to see the formation of a special separating (cork) layer.
The cells of this layer have smooth walls and are easily isolated 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 the vascular bundles, which, like the smallest "water pipes", connect the leaf with the rest of the plant. Vascular bundles can be easily seen with the naked eye on leaf scars in the form of three, five or more large dots. They serve to conduct water and mineral salts from the root to the leaves (upward current) and nutrients- carbohydrates produced by the leaves in the process of assimilation (descending current). However, there comes a point when this last connection between the petiole and the mother plant is also broken. Often the slightest gust of wind is enough for this, sometimes the leaves fall even in completely calm weather as a result of sharp fluctuations in temperature, freezing or thawing, or directly under the influence of the gravity of the leaf blade, weighed down by settled dew. Have you ever been in the forest in the midst of leaf fall, when in clear weather it gets very cold in the evening, but there is complete calm? At this time, the uninterrupted rustle of falling leaves is surprisingly quiet and distinctly heard in the forest. The formation of a cork layer in the leaf petioles indicates to us that the leaf fall is preceded by a long preparation in the plant.
WHAT GIVES THE PLANT DISCHARGE OF LEAVES FOR THE WINTER
Leaf fall is an adaptation of plants to the conditions of winter - not only the cold, but also the dry season. If our deciduous trees remained for the winter in their green cover, they would inevitably die as a result of a 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 temperatures are fairly high throughout the year but humidity fluctuates widely, trees shed their leaves every year when a drought sets in. Thus, the trees of the African savannas are exposed for several months, the grasses of which are also burned out by the sun, until heavy rains again revive the vegetation of the savannahs. The value of leaf fall in our lives deciduous trees especially noticeable when compared with conifers. Conifers - spruce and especially pine - are drought-resistant plants. Their needles evaporate many times less water than the foliage of our hardwoods. Because of this, they are able to overwinter in a green form. It is believed that under conditions of poor water supply, the amount of moisture evaporated by conifers is related to the amount of moisture evaporated by deciduous species as 1:10, while under conditions of increased water supply, as 1:6. Oak per 100 g of dry matter of leaves evaporates 54.6 kg of water over the summer, birches - 81.4 kg, ash - 85.6 kg, pine is only 9.4 kg. It is interesting to note that larch in this respect behaves like hardwood and evaporates moisture 10 times more than pine, and five times more than spruce. This ability to save moisture is achieved by our conifers by the special structure of their needles. Not to mention the much smaller surface, the needles have a number of drought-resistant adaptations: a thick skin that surrounds the needles on all sides, and a bluish wax coating, which also reduces evaporation; great importance also has an arrangement of stomata in special depressions. After all, stomata are pores, a kind of vents through which gas exchange occurs in the plant and moisture transpiration occurs; immersing them in leaf tissue significantly reduces transpiration. On the contrary, 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 foliage, they thereby protect themselves from mechanical damage under the weight of snow. Often in winter one 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 phenomenon catastrophic. The above is far from limited to the biological significance of leaf fall. It also plays another role in the life of trees. It helps to remove waste, various mineral salts, a large amount of which accumulates in the leaves in the fall and becomes harmful to the plant.
If you take the leaves of a tree and examine how much ash they contain in spring, in the middle of summer and in autumn, before leaf fall, then the result will be a sharp increase in ash with the age of the leaves. 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 many as in spring. How does the accumulation of such a significant amount of minerals in the leaves occur during the summer? The fact is that the leaf evaporates water intensively throughout its life. To replace this evaporated moisture, a new one continuously enters it, which is sucked in by the roots from the soil. However, as we know, the plant receives from the soil not clean water, and solutions of various salts. These salts, passing along with water through the whole 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 it were, mineralized, abundantly saturated with salts, the deposits of which in some cases can even be examined under a microscope. A large amount of mineral salts deposited in the leaves by autumn disrupts their normal operation and becomes harmful to the plant; therefore, dropping 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 in autumn only about 1.5% ash in its needles, while larch, which in terms of evaporation approaches hardwood, accumulates in soft needles up to 2.5% of mineral salts. The need to get rid of harmful waste accumulated in the leaves causes leaf fall in trees in wet conditions. tropical climate. At first it was believed that in tropical regions, where the climate remains more or less uniform throughout the year, leaf fall does not exist at all. However, more careful observations made on the island of Java in the famous tropical botanical garden at Buthenzorg and in India showed that leaf fall is a common occurrence in the tropics as well. True, the fall of leaves in different trees does not occur here simultaneously, and even different specimens of the same species have leaf fall in different ways. time. As a result, the period of dormancy in a humid tropical climate often lasts for a tree or part of a tree for only a few days. The plant discards 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 causes, that is, it becomes necessary as a result of the vital activity of the plant itself.
WHAT IS 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. Remarkably, fallen leaves are much richer in carbohydrates than young ones. Thus, the plant, by shedding foliage every year, is deprived of a certain amount of nutrients that do not have time to completely pass into the stem. However, such extravagance does not bring much harm to the plant. Carbohydrates are substances that can be obtained by a plant from the air in any quantity. Plants absorb nitrogen only from the soil in the form of dissolved salts. And nitrogen is often not enough for the plant. Therefore, it turns out that before leaf fall, nitrogenous substances move in significant quantities to the trunk, where they overwinter or are consumed by the plant during the winter; together with nitrogenous substances, other mineral salts valuable for the plant are also removed from the leaves; nevertheless, 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 soil broadleaf forest does not freeze in winter due to the significant content of humus and this makes it possible spring plants grow under the snow. One hectare of oak forest receives more than 5000 kg of waste (dry weight of leaves, brushwood, etc.), which yields approximately 520 kg of ash. From this it is clear that the collection of fallen leaves and the general removal of forest litter in the forest adversely affect the life of trees. So, for example, in one experimental German forestry, where the collection of forest litter was practiced for a number of years, the increase in planting fell by 11%. The leaves of some trees contain tannins. They are found in small quantities in oak leaves, but they are especially abundant in the leaves of the noble chestnut, a tree that is 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 THE LEAVES TURN YELLOW IN AUTUMN
Plants appear green to us from a 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 is short lived. Capturing the solar energy necessary for the assimilation process, chlorophyll is destroyed under the influence of light and re-created in the plant, and its formation can also occur only in the light. However, chlorophyll is not the only coloring principle 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 causes the characteristic color of the carrot root, where it is found in very large quantities. Yellow pigments are always present in the green 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 distinguish with the help of 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 the chlorophyll dissolving in the alcohol, and especially quickly when the alcohol is heated or even gently boiled in a water tank.
A strong alcohol extract from green leaves, when viewed in transmitted light, looks emerald green, but in reflected light it fluoresces (shines) with a cherry red tint. Together with chlorophyll, yellow pigments also pass into alcohol. To separate them, pour a little gasoline into the hood. After shaking the mixture, after a while, you can notice that gasoline, as it is lighter, will float to the top, while the layer of alcohol 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 pigments of the leaf remaining in it - xanthophylls and carotenes. The separation of chlorophyll from yellow pigments is based on the fact that it has a 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; destruction of chlorophyll under the influence sunlight continues. As a result, the leaf loses its green color, and yellow pigments, imperceptible until this time, are suddenly revealed. Therefore, however, it must be added that not only xanthophylls and carotenes cause the yellow color of leaves in autumn; at present, other yellow pigments have also been found that are absent in the living tissues of the leaf and appear only when they die off at the time of leaf fall. Since the destruction of chlorophyll proceeds more rapidly in bright light in sunny weather, it becomes clear why in cloudy rainy autumn the leaves retain their green color longer and why, two or three clear sunny days, which have replaced the bad weather that has been standing so far, immediately decorate the crowns of trees in bright golden colors of autumn.
PURPLE TREE COLOR
The autumn coloring of the leaves is especially attractive with its crimson tones. However, these tones are not found in all trees. Crowns of maples and aspens are removed in crimson; an elegant, pinkish color is taken by the foliage of the euonymus; garlands of wild grapes turn dark purple. Along with this, lindens, oaks and birches are devoid of red shades, they are cast only in various yellow and golden tones. What causes the red color of autumn leaves? It is caused by a special coloring matter, 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 rarely occurs as small crystals. Anthocyanins are very easy to extract from any red or blue parts of the plant. If you boil a certain amount of beets or red cabbage, then the water turns from anthocyanin into a lilac or dirty red color. 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 causes blue and pinkish flowers. The numerous colors of roses, the fiery color of poppies, the sky-blue shades of forget-me-nots, the purple color of violets and bluebells - all this is the result of the presence of anthocyanin in cell sap. The fact is that anthocyanin, depending on the environment in which it is located - in acidic or alkaline, is able to quickly change its shade. Like litmus paper, it has a pinkish color when it is acidic, and turns blue when it is alkaline. In this regard, some plants have a remarkable ability to change the color of their flowers with age. We have already mentioned this phenomenon in the flowers of the lungwort, which at the time of flowering have a pinkish corolla, which later acquires a purple and then a blue color. The same is observed in the inflorescences of another inhabitant of the broad-leaved forest - the nomadic. In its graceful racemes, the lower, older flowers are blue in color, the upper, younger ones 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, then they gradually lose their acidity, and the anthocyanin dissolved in the cell sap turns blue. Using this property of anthocyanin, it is possible to arbitrarily 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 cap 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 stigmas of female hazel flowers in purple and pink color. Here it can play the role of some additional heat ray trap, 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. With a decrease in temperature, 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 delay in the foliage of nutrients received by the plant as a result of assimilation. This is especially noticeable with various wounds of plants. Carbohydrates accumulate above the cut site, and then the corresponding part of the plant takes on an intense anthocyanin color. Prof. Molisz, who first drew attention to this, describes such a case.
While walking through a vineyard one day, he was struck by the fact that on some branches of the vines the leaves were red, while others had normal foliage. Intrigued by the cause of this phenomenon, he began to carefully examine the reddened parts of the branches and found that they were all damaged in such a way that the movement of juices was hindered, but not stopped. In order 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 or three weeks, all the affected parts of the branches above the incision took on a bright anthocyanin color. It can be thought that in autumn leaves where damage easily occurs in vascular system, the flow of carbohydrates is inhibited, which contributes to the formation of anthocyanins. Thus, the crimson shades in which the trees are painted during leaf fall are not some special adaptation. They testify only to the ongoing attenuation of vital activity in the leaves in connection with the preparation of plants for the winter dormant period.
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 the snow falls, despite the fact that they have long been killed by frost. In aspen, leaf fall begins when the leaves are still green, while autumn coloring comes later, when part of the tree is already exposed. The duration of leaf fall in different trees, as well as the period of yellowing of foliage, is extremely different. Of our trees, leaf fall seems to be the longest in birch: it lasts about two months, while linden has time 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 cause of this phenomenon does not always lie in external conditions. Often two trees growing in the neighborhood differ for a whole week in the time of yellowing and falling of their leaves, and these features of the 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 stand in their autumn dress throughout the winter. Despite the fact that the leaves on such oaks have been dead for a long time, they hang firmly on the branches, withstanding winter blizzards and snowstorms, and fall off only at the beginning of spring, shortly before the development of young leaves begins. These peculiar trees are a special form of oak, known as "late oak", while specimens that normally shed their leaves are early oak. Both of these forms seem to be hereditary, although this still needs to be verified.
In addition to the features of leaf fall, late oak differs from early oak in later flowering and bud break, which is 2-3 weeks late. In spring, such oaks are still 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 with us, is characterized by a wider spreading crown, less regular trunk and lighter wood, while late oak has a more compressed crown, 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 the "summer oak", or simply "oak", and the late - "winter oak", or "oak". At present, most authors believe that the late, or winter, oak is more adapted to our climatic conditions, and therefore, over time, should gain a wider distribution. 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 true, then from this we can conclude that our climate has now deteriorated compared to the past, which, however, is confirmed by some other data. Recall, for example, the wider distribution in our past deciduous forests, the remnant of which is the oak anemone, which currently lives under a canopy of a spruce forest alien to it. Despite the great scientific and silvicultural interest that the early and late forms of oak represent, they are far from being studied enough. It is interesting to conduct more detailed observations of them in various conditions and in different years and to find out if there is a confinement of any form to certain habitats. It is very interesting to establish also whether any other tree species similar early and late forms. We have already pointed out the ability of larch under certain conditions to retain its needles for a very long time; late forms of beech and chestnut are often found in the Caucasus, but they have not yet been studied in this respect.
A common tree in Russia, it has beautiful curly leaves with five sharp ends. The tree is very picturesque, especially noticeable in autumn, when the foliage takes on many shades of golden and red. And when the leaves fall, it is so nice to collect bright autumn bouquets from them.
In this article we will talk about the maple itself, about its features and types, as well as about when the maple leaf fall begins and ends, on what conditions the timing of this depends. natural phenomenon.
Why does a tree need leaf fall?
With the onset of the first signs of a cold snap in the tree trunk, the delivery of nutrients through the stem vessels slows down. It is in the root system that these substances are stored, and each leaf of a tree is a small laboratory for their production. From the incoming water with minerals dissolved in it, under the action of photosynthesis (that is, with the help of sun rays) cells of a green leaf produce everything necessary for the life of a plant.
But now the sun and heat are getting smaller, the days are getting shorter, and the tree, as if realizing that winter will come soon with cloudy days and frosts, it is accepted to store the necessary substances at the root. During the preparation of the plant for winter dormancy, the leaves change color and fly around. This is how the fall begins.
special maple
Maple - in many ways unique tree. It is frost-resistant, one of the first to “wake up” in spring, and easily tolerate drought in summer. It is avoided by insect pests common to other trees, rodents and moose do not like young foliage and bark because of the bitter taste. That is why maple leaves often remain intact until autumn, without flaws and wormholes.
Mushroom lovers know that it is useless to look for them under this tree.
Bees actively fly to the flowering maple. They like to feast on winged maple seeds and squirrel flowers, field mice and some birds such as bullfinches and nuthatches. The seeds, by the way, only ripen late autumn when the maple ends falling leaves, and fall to the snow-covered ground.
Maples look great in parks and gardens - they have a light, thanks to long petioles, fluttering crown with curly leaves, beautiful wood color and bright autumn foliage colors.
From some types of maple (sugar, black, red, holly), when the trunk is cut in the spring, maple sap is obtained, which is then boiled down to syrup. Maple syrup has a special taste. It is often used as an additive to confectionery.
Maple types
Maple is widely distributed throughout the earth, mainly in the Northern Hemisphere. There are 20 species of maples growing in Russia. The most famous of them are: holly (or plane-shaped), Tatar, white, field.
Holly has five leaf lobes. From three to five ends of a field maple leaf.
On the Far East there is a Japanese maple. He has seven-, nine-pointed leaves and a bizarre bend in the trunk. This species is listed in the Red Book.
Individual specimens of maples, for example, white maple, can reach a height of 40 meters, while the usual height of Norway maple is 28-30 meters. There are shrubby maples, in which individual trunks can be ten meters high.
Maple leaf fall dates
Maple, as mentioned above, easily tolerates cold. Active leaf drop begins after the first frost, and this is the average on September 27th. By this time everything Maple leaves are already painted in autumn colors.
In October, it is time for strong leaf fall for most trees. It is impossible to say exactly when the leaf fall of the maple ends, but usually by the middle or end of the month the tree loses its foliage.
It is clear that the average date is inaccurate. Because if you live in southern regions, the end of the leaf fall of the maple may shift for a month or more - and the leaf fall will end only by mid-November. But if in the north - on the contrary, the first frosts can descend in these parts even at the end of August.
Another time when the leaf fall of the maple ends depends on the particular winter. It happens that autumn is protracted, not cold, frosts come later than usual, and the leaf fall comes and ends later.
Much depends on the conditions in which the tree grows. For example, in open and flooded or wetlands, a tree loses leaves faster than in a dense forest.
It is interesting that trees growing near street lamps shed their leaves later - after all, the daylight hours for them are increased.
Also, the period of leaf shedding depends on the age of the plant. How younger tree, the later it loses leaves.
In order to know exactly what kind of “routine” plants and animals live in your area, you need to observe changes in wildlife. It's informative and interesting.
Katerina, city of Voronezh
Tell me, when does the period of leaf fall end at the apple tree, as well as mountain ash?
Leaf fall is a seasonal phenomenon in the life of trees and shrubs, which has been observed since early autumn. Getting rid of leaves before the onset of winter cold, trees regulate the process of moisture consumption, significantly reducing its need. The process of leaf fall different trees starts and ends at different time. This largely depends on weather conditions and areas of growth of green spaces, as well as tree species and their age.
It is difficult to unequivocally answer the question when the time of leaf fall ends. It is noticed that first poplar leaves are lost, then oaks and mountain ash. Apple trees are slowly shedding their leaves, and even in winter on some trees, single leaves continue to flutter in the cold wind.
Trees at the time of leaf fall
Dropping leaves from trees serves another purpose - the crown under the snow cover has a significant weight. The branches of trees, especially young ones, are not able to withstand such a load. Fallen leaves can reduce the load on the skeletal branches of the tree, protecting the crown from damage.
Thanks to the process of photosynthesis, a large amount of harmful substances accumulate in the leaves by the beginning of autumn, which, with the onset of leaf fall, are removed along with fallen leaves.
The end of leaf fall in different tree species
Poplar
During the period of leaf fall, adult poplar trees lose a third of their leaves in the period from September 15 to 20, in the first ten days of October, up to 10% of foliage remains in the poplar crown. Completely lose poplar leaves by mid-October. Young poplars remain green longer than old trees, they turn yellow later and shed their leaves.
Oak
Oak leaves fall off in the first half of September, after about 30 days the trees completely lose their leaves. With early frosts, the timing of the end of leaf fall on oaks is reduced - trees quickly lose leaves at sub-zero temperatures. oak leaves immediately acquire a brown color, along with the leaves, ripe acorns fall from the tree.
Mountain ash in autumn: video
This happens because, in addition to chlorophyll, there are other coloring substances in the leaves. It is especially abundant at the end of September and the first decade of October. In what period does the leaf fall of linden and birch begin and end?
With the onset of September, the trees gradually begin to change the summer emerald green color of the leaves to autumn yellow. By mid-September, birch leaves become ocher-gold and gradually begin to fall off.
For many trees, leaf fall is uneven, that is, it happens at different times. For example, after the first severe frost, leaf fall begins in linden and maples. By this time, the birch had already dropped most of the leaves.
It is difficult to unequivocally answer the question when the time of leaf fall ends. It is noticed that first poplar leaves are lost, then oaks and mountain ash. Dropping leaves from trees serves another purpose - the crown under the snow cover has a significant weight. The branches of trees, especially young ones, are not able to withstand such a load. Thanks to the process of photosynthesis, a large amount of harmful substances accumulate in the leaves by the beginning of autumn, which, with the onset of leaf fall, are removed along with fallen leaves.
Poplar During the period of leaf fall, adult poplar trees lose a third of their leaves in the period from September 15 to 20, in the first ten days of October, up to 10% of foliage remains in the poplar crown. Young poplars remain green longer than old trees, they turn yellow later and shed their leaves. Oak Oak leaves fall off in the first half of September, after about 30 days the trees completely lose their leaves.
Oak leaves immediately acquire a brown color, along with the leaves, ripe acorns fall from the tree. Rowan Autumn rowan seems to be painted with watercolors, its leaves do not turn yellow, but acquire pink coloration, the process of leaf fall begins around the beginning of October, and ends by November 1.
The fall of apple trees begins in the third decade of September and ends in the second half of October. Birch is a genus of deciduous shrubs and trees of the Birch family, which is distributed in almost the entire Northern Hemisphere. Birch is better known to us as a tree up to 45 meters high and with a girth of up to one and a half meters.
Yes, many of us dislike this time of year because of the constant rain and sleet, but without a doubt - early autumn very beautiful due to the changing color of the trees. For example, the same birch begins to change color around the 20th of August, although this, of course, also depends on the weather.
However, we repeat, it all depends on the weather in the region. If, for some reason, the weather has changed so much that the temperature drops from the usual +20°C to -5°C, then the leaf fall begins almost immediately with the first frost. The remains of the leaves, which can remain on the trees even in the case of active leaf fall, usually fall off after the third or fourth hard frost, and this applies to most trees.
Trees at the time of leaf fall
Reprinting of materials and their use in any form, including in electronic media, is possible only with a back active link to our site, which is not closed from indexing by search engines. The autumn forest is beautiful when the leaf fall begins. Forest glades dressed in yellow colors, a river valleys- in wine red and pink shades. In the second half of September, poplars are also multi-colored: some of them become lemon yellow, others almost orange, some golden yellow.
By the end of September, even this strong, mighty tree obeys the general laws of nature - it becomes straw-yellow. True, poplar and birch shed their leaves long before the general cold snap. In aspen, leaf fall ends 5-6 days earlier than in birch. By September 15-20, old poplars are bare by a third, and by October 10, no more than 10-12% of the leaves remain on the trees.
Features of leaf fall
The leaf fall of different trees is uneven and sometimes lasts for several weeks. Here are a few aspens, elms, elms, ash and apple trees standing almost naked, and not so far from them - trees of the same age, but with rustling foliage still almost completely preserved.
September - the first signs of the coming autumn are already visible on the trees. The birch is the first to play in the autumn rays of the still warm sun with the yellowness of the leaves, the crowns of the trees are covered with the first noticeable gilding. On August 23, 2016, along the roads in the suburbs of St. Petersburg (specifically Oselki, Leskolovo, Ekaterinovka), I observed crimson maples in their entirety and in separate branches.
Apparently it's a combination of moisture, heat and daylight hours. The summer was very rainy and moderately warm. And by the middle of the month, the forests are bare. In the Leningrad, Pskov and Novgorod regions, the end of leaf fall of birch and mountain ash is observed on average on October 14. In October, the little warblers, warblers, shrikes, and corncrakes fly away from us. In the first days of the month, there is (on average) a mass passage of geese in the Tver and Yaroslavl regions.
Their mass departure is observed in the Tver region on October 18, in the Moscow region - on October 6, in the Vladimir and Oryol regions - on October 8-9. The departure of starlings ends, as a rule, in the last decade of the month. The mallard flies behind the starlings. Some birds stay with us for the winter. And not only rooks winter in our cities.
The beginning of autumn - 29 days: from August 26 to September 24. Leaf fall at the birch begins around the first half of September and lasts for another 20 days, that is, this tree completely falls off by the end of September-mid-October.
