Katerina, Voronezh city

Tell me, when does the leaf fall period end for apple trees and rowan trees?

Leaf fall is a seasonal phenomenon in the life of trees and shrubs, which is observed in early autumn. By 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 times. This largely depends on weather conditions and the area where green spaces are grown, as well as the types of trees and their age.

It is difficult to unequivocally answer the question of when leaf fall ends. It has been noticed that poplars lose their leaves first, then oaks and rowan trees. Apple trees are slowly losing their leaves, and even in winter, single leaves on some trees continue to flutter in the cold wind.

Trees during leaf fall

Dropping leaves from trees serves another purpose - the crown under the snow cover has significant weight. Tree branches, especially young ones, are unable to withstand such a load. Fallen leaves help 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 are removed along with the fallen leaves with the beginning of leaf fall.

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 the foliage remains in the poplar crown. Poplar leaves are completely lost by mid-October. Young poplars remain green longer than older trees; they later turn yellow and shed their leaves.

Oak
Oak leaves begin to 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 turn brown, and ripe acorns fall off the tree along with the leaves.

Rowan in autumn: video

This happens because in addition to chlorophyll, the leaves also contain other coloring substances. It is especially abundant at the end of September and the first ten days of October. In what period does leaf fall begin and end in linden and birch?

As September approaches, the trees gradually begin to change their summer emerald green leaf color to autumn yellow. By mid-September, the birch leaves become ocher-golden and gradually begin to fall off.

For many trees, leaf fall occurs unevenly, that is, it occurs at different times. For example, after the first hard frost, leaves begin to fall on linden and maple trees. By this time the birch had already dropped most leaves.

It is difficult to unequivocally answer the question of when leaf fall ends. It has been noticed that poplars lose their leaves first, then oaks and rowan trees. Dropping leaves from trees serves another purpose - the crown under the snow cover has significant weight. Tree branches, especially young ones, are unable 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 are removed with the beginning of leaf fall along with fallen leaves.

Poplar During leaf fall, mature 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 the foliage remains in the poplar crown. Young poplars remain green longer than older trees; they later turn yellow and shed their leaves. Oak The fall of oak leaves begins in the first half of September; after about 30 days, the trees completely lose their leaves.

Oak leaves immediately turn brown, and ripe acorns fall off the tree along with the leaves. Rowan Autumn rowan is as if painted with watercolors, its leaves do not turn yellow, but acquire a pink color, the process of leaf fall begins around the beginning of October, and ends by November 1.

Leaf fall of apple trees begins in the third decade of September and ends in the second half of October. Birch is a whole genus of deciduous shrubs and trees of the Birch family, which is distributed throughout 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 don’t like this time of year because of the constant rain and slush, but without a doubt, early autumn is very beautiful due to the trees changing their color. For example, the same birch tree begins to change color around the 20th of August, although this, of course, also depends on the weather.

However, we repeat, everything 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 leaf fall begins almost immediately with the first frost. Remnants of leaves, which can remain on the trees even in the case of active leaf fall, usually fall off after the third or fourth severe frost and this applies to most trees.

Trees during leaf fall

Reprinting materials and using them in any form, including in electronic media, is possible only with a back active link to our website, not blocked from indexing by search engines. The autumn forest is beautiful when the leaves begin to fall. Forest glades were dressed in yellow colors, and river valleys were dressed in wine red and pink shades. In the second half of September, poplars also become multi-colored: some of them become lemon-yellow, others almost orange, some golden-yellow.

By the end of September, this strong, mighty tree also submits general laws nature - 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 become 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 occurs unevenly and sometimes lasts for several weeks. Here are several aspen, elm, elm, ash and apple trees standing almost naked, and not so far from them are 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 tree is the first to begin to play in the autumn rays of the still warm sun with the yellowness of its 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 whole and in individual branches.

Apparently it’s a combination of moisture, heat and daylight. 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 birch and rowan leaf fall is observed on October 14 on average. In October, whirligigs, warblers, shrikes, and corncrakes fly away from us. In the first days of the month, there is (on average) a massive migration of geese in the Tver and Yaroslavl regions.

Their mass flight 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 flight of starlings usually ends in last decade month. The mallard takes flight after the starlings. Some birds stay with us for the winter. And it’s not only rooks that spend the winter in our cities.

The beginning of autumn is 29 days: from August 26 to September 24. Birch leaf fall 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 to mid-October.

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, nitrogenous substances move in significant quantities 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 is responsible for 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 the fact that chlorophyll dissolves in 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 for 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, a remnant of which is the oak anemone, which currently lives under the canopy of a spruce forest that is alien to it. 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.

Let's start in order, as the questions are asked in the textbook, to fill out the observation diary. Just remember that for different areas, autumn changes occur at different terms.

The leaf fall of the linden ended on October 7, the leaf fall of birches almost ended on October 10, the last leaves fell from the poplars on October 1, the lilac retained its 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, almost every day flocks of ducks and geese fly south.

In September, you can still find hedgehogs, mice, and squirrels in the forest; if the day is warm, then snakes even crawl out onto the paths.

With the loss of foliage, the autumn forest becomes transparent, light and cold rains often fall, but a few mushroom pickers still roam the forest.

The world around us, grade 3: How to correctly fill out a diary of observations of autumn nature in a scientific diary?

1. Observe and write down (day of the month) when the first frost occurred.
2. When did the puddles first become covered with ice?
3. Write down when the first snow fell?
4. 4. Mark when the river, lake, pond became covered with ice?
5. Write down in which month the birch trees ended leaf fall __ , at the linden trees __, in other trees___ what are their names.
6. When did flocks of migratory birds appear?
7. What animals did you see in the fall?
8. Other observations?

How fortunate that today I can quite accurately fill in some of the columns of this observation diary.

For example, today, September 27, the puddles in the morning were covered with the first ice, although the first frosts began two days ago on September 25.

The situation with the first snow is even more curious; for us it fell on September 24 and it was very unexpected.

Rivers in our region become covered with ice only by the end of October, or even at the beginning of November, although lakes with standing water certainly become covered with ice earlier in mid-October.

The leaf fall of birches begins in early September, but finally ends only in October, let it be the 10th. Around the same time, linden trees lose their leaves. But aspen and poplar fly around by the end of September, on the 28th-30th.

The first flocks of migratory birds moved south in early September; these were swallows and swifts, and songbirds. Now, in the 20th of September, ducks fly south.

When I recently went for honey mushrooms, I discovered that the autumn forest was still alive. Mice were scurrying around in the fallen grass, it was warm and frogs were jumping, and once a chipmunk crawled out onto a stump and screamed shrilly, something of his own.

In September you can still pick mushrooms, although it is difficult to find boletuses and saffron milk caps under the fallen leaves, but honey mushrooms have occupied numerous stumps in the neighboring forest.

Each plant has its own duration of leaf fall, but leaf fall itself can be observed at different times depending on weather conditions in 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 the 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. Their 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!