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Sasha K. (Belogorsk)
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. A little more time will pass and all the golden foliage will rush to the ground. Watching nature, people often ask themselves the question - when does the leaf fall end for birch, linden, maple and other favorite yellowing trees? Let's try to answer this question.
When the leaves turn yellow
Foliage begins to change color long before the first frost. As a rule, this happens at the end of August, when the day has already noticeably decreased and it has become a little colder, and lasts for 14-20 days. At first, only single gray-yellow patches are visible on the branches, but day by day there are more and more of them.
By mid-September, birch leaves become ocher-gold and gradually begin to fall off. Maple branches are no less beautiful at this time. The crowns of the tree are covered with foliage of yellow, brick red, red and even purple hues. The foliage of the linden, which is only half yellowed, stands out noticeably.
The beginning of leaf fall
For many trees, leaf fall is uneven, that is, it happens in different time. 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. Her leaf fall begins in the first decade of September and lasts 15-20 days.
Important! The beginning of leaf fall depends on the weather. Dry sunny weather and windless days delay the golden decoration of trees.
Leaf fall is especially abundant after the third frost. The leaves fall to the ground very densely, forming a thick bedding on the ground. Birch drops about 30 kg of leaves in autumn. In an adult linden and maple, this amount reaches 40-50 kg.
End of leaf fall
The end of leaf fall, as a rule, is accompanied by a significant cooling, deterioration weather conditions, frequent rain and strong gusts of wind. By October 7-10, lindens and birches lose their last yellow leaves. Maples are exposed much later, only by October 20. Single leaves can be kept on the branches until mid-November, reminding passers-by of the past golden season.
Observations of nature during leaf fall
The period of active leaf fall is accompanied by a significant cooling and the arrival of night frosts. Summer white clouds are replaced by a solid gray veil. It is often foggy in the morning. The first flocks of migratory birds fly into the sky.
The end of leaf fall in lindens and maples is accompanied by gloomy rainy weather, frost on the still green grass and thin ice on the puddles. Rooks gather in flocks and fly south. Gradually the earth cools down and nature falls asleep.
Autumn leaf fall: video
According to the calendar, autumn begins on September 1, but astronomers believe that from September 21 on the day autumn equinox. Phenologists, on the other hand, believe that autumn begins with the appearance of the first yellow leaves on the trees of the warty birch or drooping birch. This is usually noticeable on August 23rd. But I first noticed the appearance of yellow leaves on August 18 on birches, and on lindens on August 24. After the first frost, there were even more yellowing leaves, and leaf fall began near birch, linden, and aspen. And already on October 4, during the excursion, we noted that there were no leaves on the poplars at all, the leaves on the birches were preserved in very small quantities. Partially there were still leaves on the oak near the school, on the maples. But the Canadian Norway maple has already completely lost its bright red outfit. We noticed that there are still a lot of leaves in the willow, in the lilac. They are still quite green. Full coloration of the leaves occurs when the bulk of the leaves have changed from green to color. For example, rowan on September 18, maple on September 20. The beginning of leaf fall is the day when the leaves fall even in calm weather or from touching a branch. For example, maple has September 14th. Massive leaf fall occurs when about half of the trees of each species shed their leaves. Full leaf fall is recorded when the trees lose all their leaves. Individual leaves are not taken into account. For example, bird cherry - September 22, linden - September 24, aspen - October 5, maple and birch around October 14. Ash, Canadian maple, poplar, alder, aspen can shed their leaves in one day. The sequence of leaf fall different trees different: the oak does not part with the leaves for the longest time, but the leaves appear on it later. There are oak trees that do not shed their leaves at all. So far, scientists have not been able to explain this phenomenon.
Leaf fall is not the same not only for different breeds trees, but even among representatives of the same species, depending on the growth conditions and individual features. The timing of leaf fall is affected by the age and condition of the tree. Young plants shed their leaves much later than ripe and overmature ones. Sick trees affected by heart rot, as well as those affected by man or beast, lose leaves faster than healthy ones. In trees growing on the edge, in swampy and flooded places, leaf fall passes faster than in plants in dense forest. Needle-shaped leaves of pine, spruce have a small surface, their needles are hard, covered with a wax coating and therefore slightly evaporate water. They successfully endure winter drought, are very cold-resistant. In larch, the opposite is true, so it sheds its needles annually, as well as deciduous trees. In evergreens - lingonberries, cranberries, the change of leaves occurs in the spring. Cowberry leaves are hard, their stomata are only on the underside and near the curved edges of the leaf, so evaporation is negligible. At the wild rosemary, the leaf is pubescent from below, besides, the bushes hide under the snow in winter.
But for trees located close to electric lights, leaf fall begins later, since they have longer daylight hours.
Causes of falling leaves
Trees prepare for leaf fall in advance. Even in summer, a bud is born in the axil of the leaf petiole, and organic substances are deposited in the wood cells. Spring will come and due to these reserves, the bud will develop into a young shoot with leaves. By autumn, a layer of cells forms at the leaf petiole, which separates the leaf petiole from the branch; in autumn, the leaf easily separates from the branch and falls off.
Fall value
Leaf fall is the adaptation of plants to winter conditions. By dropping leaves for the winter, trees protect themselves from mechanical damage. Often in winter, during snowfalls, even large branches of trees break under the pressure of snow. There would be even more such breakdowns if the leaves did not fall off and trap snow on their surface. Leaf fall contributes to the removal of various mineral salts, a large amount of which accumulates in the leaves in the fall and becomes harmful to the plant. Leaf fall returns mineral salts to the soil. The leaves rot, and the mineral salts are reused to feed the plants. Hence, 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. Where is the beginning of the phenomenon of leaf fall? From additional literature, we learned that such a peculiar adaptation of nature began to take shape. About 60 million years ago, when warm and humid climate of our places began to gradually give way to seasonal, with cold and snowy winter. Under the new conditions, only those trees and shrubs survived that went into winter with fewer leaves. So from generation to generation this important property of the leaf has developed.
Is it worth burning leaves in autumn?
The soil is covered with a layer of fallen leaves, branches, bark, dead grass. This layer is called the forest floor. AT deciduous forest litter annually is about 4 tons, and in pine forest– up to 3.5 tons per 1 ha. The forest floor has great importance in the life of the forest. The accumulation of humus and minerals in the soil, the development of biological processes depend on it. Loose litter easily decomposes and allows water to enter the soil, dense litter rots for a long time and has a sour smell. The bedding protects the soil and plant roots from freezing. The humus stains the soil dark colors, so these soils warm up better sunbeams, slowly cool down and thus create favorable conditions for life in the soil of beneficial microorganisms and plant roots. Cleaning leaf litter reduces planting growth by 11%.
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.
When the days become shorter, and the sun no longer generously shares its warmth with the earth, one of the most beautiful seasons of the year comes - autumn. She, like a mysterious sorceress, changes the world around and fills it with rich and unusual colors. Most notably, these miracles occur with plants and shrubs. They are among the first to respond to weather changes and the onset of autumn. They have three whole months ahead of them to prepare for winter and part with their main decorations - leaves. However, at first, the trees will certainly please everyone around with tints of color and frenzy of colors, and the fallen leaves will carefully cover the earth with their veil and protect its smallest inhabitants from severe frosts.
Autumn changes with trees and shrubs, the causes of these phenomena
In autumn, one of the most important changes in the life of trees and shrubs occurs: a change in the color of the foliage and leaf fall. Each of these phenomena helps them prepare for winter and survive such a harsh season.
For deciduous trees and shrubs, one of the main problems in winter time year is a lack of moisture, so in the fall all useful substances begin to accumulate in the roots and core, and the leaves fall off. Leaf fall helps not only to increase moisture reserves, but also to save them. The fact is that the leaves evaporate the liquid very strongly, which is very wasteful in winter. Coniferous trees, in turn, can afford to show off with needles in the cold season, since the evaporation of liquid from them is very slow.
Another reason for leaf fall is the high risk for branches to be broken under the pressure of a snow cap. If fluffy snow lay down not only on the branches themselves, but also on their leaves, they could not withstand such a heavy burden.
In addition, many harmful substances accumulate in the leaves over time, which can only be eliminated during leaf fall.
One of the recently uncovered mysteries is the fact that deciduous trees placed in a warm environment, and therefore not in need of preparation for cold weather, also shed their leaves. This suggests that leaf fall is associated not so much with the change of seasons and preparation for winter, but is an important part of life cycle trees and shrubs.
Why do leaves change color in autumn?
With the onset of autumn, trees and shrubs decide to change the emerald color of their leaves to brighter and more unusual colors. At the same time, each tree has its own set of pigments - "paints". These changes are due to the fact that the leaves contain a special substance, chlorophyll, which converts light into nutrients and gives the foliage green color. When a tree or shrub begins to store moisture, and it no longer reaches the emerald leaves, and the sunny day becomes much shorter, chlorophyll begins to break down into other pigments, which give the autumn world crimson and golden tones.
The brightness of autumn colors depends on the weather conditions. If the street is sunny and relatively warm weather, then autumn leaves will be bright and colorful, and if often it's raining then brown or dull yellow.
How the leaves of different trees and shrubs change color in autumn
A riot of colors and their unearthly beauty autumn is due to the fact that the foliage of all trees has different combinations of colors and shades. The most common purple color of the leaves. Maple and aspen can boast of crimson color. These trees are very beautiful in autumn.
Birch leaves become light yellow, and oak, ash, linden, hornbeam and hazel - brownish yellow.
Hazel (hazel)
Poplar quickly sheds its foliage, it is just beginning to gain yellowness and has already fallen.
Shrubs also delight with the variety and brightness of colors. Their foliage turns yellow, purple or red. Grape leaves (grape - shrub) acquire a unique dark purple color.
The leaves of barberry and cherry stand out against the general background with a crimson-red tint.
Barberry
From yellow to red, rowan leaves can be in autumn.
The leaves of the viburnum turn red along with the berries.
Euonymus dresses in purple clothes.
Red and purple shades of foliage determines the pigment anthocyanin. An interesting fact is that it is completely absent in the composition of the leaves and can only be formed under the influence of cold. This means that than colder days, the more crimson will be the surrounding leafy world.
However, there are plants that, not only in autumn, but also in winter, retain their foliage and remain green. Thanks to such trees and shrubs, the winter landscape comes to life, and many animals and birds find their home in them. In the northern regions, such trees include trees: pine, spruce and cedar. To the south, the number of such plants is even greater. Among them, trees and shrubs are distinguished: juniper, myrtle, thuja, barberry, cypress, boxwood, mountain laurel, abelia.
Evergreen tree - spruce
Some deciduous shrubs also do not part with their emerald clothes. These include cranberries and cranberries. On the Far East there is interesting plant wild rosemary, the leaves of which do not change color in autumn, but roll up into a tube in autumn and fall off.
Why do the leaves fall, but there are no needles?
Leaves play an important role in the life of trees and shrubs. They help create and store nutrients, as well as accumulate mineral components. However, in winter, when there is an acute shortage of light, and, therefore, nutrition, the leaves only increase the consumption of useful components and cause excessive evaporation of moisture.
Coniferous plants, which most often grow in areas with a rather harsh climate, are in great need of nutrition, so they do not shed their needles that act as leaves. The needles are perfectly adapted to the cold. The needles contain a lot of chlorophyll pigment, which converts nutrients from light. In addition, they have a small area, which significantly reduces the evaporation from their surface of much-needed moisture in winter. From the cold, the needles are protected by a special wax coating, and thanks to the substance they contain, they do not freeze even in very coldy. The air that the needles capture creates a kind of insulating layer around the tree.
The only coniferous plant that leaves its needles for the winter is larch. It appeared in ancient times, when summers were very hot and winters were incredibly frosty. This feature of the climate led to the fact that the larch began to shed its needles and it was not necessary to protect them from the cold.
Leaf fall, as a seasonal phenomenon, occurs for each plant at its own specific time. It depends on the type of tree, its age and climate.
First of all, poplar and oak part with their leaves, then the time of mountain ash comes. The apple tree is one of the last to shed its leaves, and even in winter, it may still have a few leaves.
Poplar leaf fall begins at the end of September, and by mid-October it completely ends. Young trees retain their foliage longer and turn yellow later.
Oak begins to lose its leaves in early September and completely loses its crown in a month. If frosts begin earlier, then leaf fall occurs much faster. Along with oak leaves, acorns also begin to crumble.
Mountain ash begins its leaf fall in early October and continues to delight with its pink leaves until November 1. It is believed that after the mountain ash parted with the last leaves, dank chilly days begin.
The leaves on the apple tree begin to turn golden by September 20. By the end of this month, leaf fall begins. The last leaves fall from the apple tree in the second half of October.
Evergreens and shrubs do not lose their foliage even with the onset of cold weather, as ordinary hardwoods do. Permanent leaf cover allows them to survive any weather conditions and maintain maximum storage. nutrients. Of course, such trees and shrubs renew their leaves, but this process occurs gradually and almost imperceptibly.
Evergreens do not shed all their leaves at once for several reasons. Firstly, then they do not have to spend large reserves of nutrients and energy to grow young leaves in the spring, and secondly, their constant presence ensures uninterrupted nutrition of the trunk and roots. Most often, evergreen trees and shrubs grow in areas with a mild and warm climate, where the weather is warm even in winter, however, they are also found in harsh climatic conditions. These plants are most common in tropical rainforests.
Evergreens such as cypresses, spruces, eucalyptus, some types of evergreen oaks, rhodendron can be found in a wide area from harsh Siberia to the forests of South America.
One of the most beautiful evergreens is the blue fan palm, which is native to California.
The Mediterranean oleander shrub is distinguished by an unusual appearance and a height of more than 3 meters.
Another evergreen shrub is gardenia jasmine. Her homeland is China.
Autumn is one of the most beautiful and colorful seasons. Flashes of purple and gold leaves, preparing to cover the ground with a multi-colored carpet, coniferous trees, penetrating the first snow with their thin needles and evergreens, always pleasing to the eye, make the autumn world even more delightful and unforgettable. Nature is gradually preparing for winter and does not even suspect how fascinating these preparations are to the eye.
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 is observed from 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 in different trees begins and ends at different times. This largely depends on weather conditions and the area where green spaces grow, as well as the types of trees 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
