What explains the riot of colors during the leaf viewing season? Why do some trees turn yellow, others turn red, and then they turn brown.
The explanation lies in the replacement of chlorophyll with other substances: carotenoids and anthocyanins. In summer, trees have a lot of nutrients, but with the arrival of autumn, this supply gradually decreases. With the depletion of reserves, the synthesis of chlorophyll stops. And then other pigments that are present in the leaves, but overlapped by the green color - yellow and orange - become noticeable. These are the same pigments that determine, for example, the color of carrots - carotenoids.
Leaves with red hues are the result of the formation of anthocyanins. These pigments are absent in green leaves. They begin to form in the leaves of some plant species after the disappearance of chlorophyll. Anthocyanins are the same pigments that give radishes, geraniums, roses or cauliflower their color.
The brightness of the color of autumn leaves depends on the weather. Trees wear their most beautiful clothes in sunny, dry weather, at temperatures of 0 – 7 degrees Celsius. If the weather is cloudy and rainy, then the leaves do not burn, but turn into dull yellow shades or even turn brown.
As winter approaches, yellow and red leaves gradually lose their pigments. Brown leaves, which can be seen in late autumn, with the onset of severe cold, after snowfall, are leaves in which there are no pigments left at all, and the cell walls have become noticeable.
What color are the leaves of trees in autumn?
Birch leaves are yellow-golden in autumn
According to various sources, the oak family reaches 450...600 species. Representatives grow in different parts of the planet in temperate latitudes, where the climate suits the needs of the tree.
Russia is one of the most favorable countries for oak growth: territories with nutritious soil, open areas without shade, sufficient rainfall and optimal temperature conditions for the plant.
Interesting Facts
Many myths, legends, and stories are associated with centuries-old giants. For humans, oak is the personification of strength, power, and energy.
- Druids performed the ritual of “seducing lightning,” knowing that oak attracts lightning more often than other trees.
- 80 years of married life is called an “oak wedding.” The union is associated with the longevity and strength of oak.
- The most expensive mushrooms chose tree roots for their mycelium. These are truffles, a favorite delicacy of the French. Without nourishment from the oak tree, they die.
- Many trees have become famous due to their size and age. The oldest oak tree is located in France, its trunk girth is 9 meters. According to legend, the soldiers of Julius Caesar rested under it.
general description
Regardless of the type and variety of tree, oak has common distinctive features that determine its genus:
- The height of the individual is from 25 to 40 meters;
- Spreading deciduous or evergreen crown;
- The leaves of oaks of different varieties are lobed or serrated with pinnate venation;
- The bark is rough, with age-related cracks;
- The trunk in young individuals is thin, in older ones it is noticeably thickened and massive.
Many species bloom at the same time their leaves emerge . Female and male flowers are on the same tree:
- The female ones are located in the leaf axils at the tops of young shoots (as in the photo). Perianth in 3 sections, poorly developed;
- Male flowers are collected in earrings at the base of the shoots. The perianth is divided into 5-7 sections, up to 12 stamens.
Pollination occurs in the usual ways: by wind or insects.
The fruit of the oak tree is an acorn, it ripens in the fall, and after wintering a new tree begins to grow . At the base there is always a hard, flattened cap, by which one can always determine whether it belongs to the oak family. The shape of the fruit is elongated or spherical, from golden to brown in color, depending on the type of plant and its place of growth.
The oak tree is propagated by cuttings, planting acorns; resumption of growth can occur from a living stump.
Botanical classification
Regardless of the variety, the scientific classification of the genus is as follows:
English oak occupies the conventional place of the end of the logical chain; in its place you can safely put the remaining types of wood.
How to grow an oak tree from an acorn
Natural growth of trees is a slow process. The acorn spreads with the help of birds and animals, vegetatively from roots and stumps, and self-seeding. The technique of growing oak is well known to forestry farms. Is it possible to grow an oak tree from an acorn at home? Any gardener can get a healthy tree from a seed if he knows the process algorithm.
Seed preparation
The first condition is to choose the right planting material. It is better to collect nuts from trees in the fall. Fallen fruits are also suitable, but there is a higher chance of damage to the kernel. Acorns are collected “on the fly,” since some of them are discarded. Suitability test: Place the fruit in a bowl of water for five minutes. Those that drown are suitable for sowing.
Stratification and germination
Oak seeds must go through a simulated wintering period. Take a container with a lid and holes for air, pour soil from the oak forest, and place the seeds in a cool place for three months. Then the acorns need to be germinated.
Growing seedlings
The seeds are transferred to moist sphagnum moss, covered with film, and kept at a temperature of 3-5 ° until roots appear. As the sprout grows, it is placed in a larger pot. Seedlings that have reached 10-15 cm with a strong root and 7-8 leaves can be transplanted into the ground.
Choosing a place and landing
A mature oak with powerful roots can damage surrounding communications - this is taken into account when replanting a seedling to a permanent place. The site must meet the following requirements:
- area more than 20 sq. m;
- good lighting;
- fertile soil.
The earth is dug up to saturate it with oxygen and cleared of weeds. Make a hole large enough to accommodate the root, fill it with soil, and water it. On compacted soil, an inclined drainage is made, since uniform moisture is necessary.
Care and protection
For the first 5 years, oak from an acorn grows slowly, barely reaching a height of 1 m. After planting, the seedling is watered abundantly for 5-7 days, and then as the soil dries. From the second year they are fed with mineral granules.
Young trees are afraid of cold weather. To prevent freezing, the roots are mulched with humus and dry leaves. The branches are bent down for the winter and burlap is put on. If there is a threat of fungal diseases or insect attacks, the seedling is sprayed with a solution of copper sulfate or insecticides.
The genus and its representatives
Olga Nikitina
The genus Oak (Quercus) is part of the beech family and has about 600 species, native to the temperate and tropical zones of the Northern Hemisphere, and some to northern South America.
This genus includes evergreen or deciduous trees, less often shrubs, with a tent-shaped crown formed by thick branches. A well-developed powerful trunk and large skeletal branches give most species monumentality and texture, for which landscape designers value this tree species.
The leaves are alternate, entire, serrated, or, as they are also called, lobed, carved. The flowers are arranged in earrings, and the pistillate ones are hardly noticeable. The fruits are acorns, sitting in cup-shaped pads, which small children call caps.
Oak grows slowly, especially in the first years of life. It is believed that the greatest increase in height occurs at the age of 20–80 years, and then thickening of the trunk is observed.
The deep taproot system contributes to the oak's extraordinary wind resistance. The wood is strong, hard and heavy.
Most species are forest-forming species, mainly light-loving and demanding soils. Although some species are less demanding, which allows them to be used in afforestation and green construction in dry areas, for example in the steppe zone on fairly highly saline soils.
Oak trees are propagated by sowing acorns, which sprout massively within a month in the spring. In the first year, seedlings form a tap root 40–60 cm long, and in the future it is almost impossible to replant young plants without damaging it. To form a fibrous root system in an oak tree, its seedlings that have reached a height of 8–10 cm have their roots trimmed with a sharp shovel. In the future, the procedure is repeated to obtain complete planting material.
Particularly valuable forms and varieties of oak are propagated by grafting onto local species.
The most famous and widespread species in our country is the petiolate (Q. robur), growing in the European part of Russia and Western Europe. This is a powerful, beautiful tree up to 40 m high. The trunk is covered with thick, roughly fissured bark. This species is the main forest-forming species in our country and lives up to 400–500 years.
The drought and salt tolerance of D. pedunculate served as a good recommendation for its use as the main species for all eight state protective forest belts. In the famous Stalinist plan for the transformation of nature, the petiolate was assigned one of the main roles. This mighty tree with a spreading tent-shaped crown can be found in ancient estates and parks.
English oak, its decorative forms and varieties are widely used in landscaping. Very interesting are grafted forms such as ' Pendula ' with weeping branches, ' Globosa ' with a rounded crown, ' Filicifolia ' with dissected leaf blades. But, perhaps, most often in landscape design, d. petiolate ' Fastigiata ' with a dense, columnar crown, since the branches grow at an acute upward angle.
The replacement species in the North Caucasus, Crimea and Western Ukraine is the rocky one (Q. petraea). This tree, up to 30 m high, differs from the previous species in having long petiolate leaves and acorns sitting on very short stalks. It looks very impressive in bouquet plantings and as a tapeworm in open areas.
In Mediterranean countries, evergreen oaks grow, which in Russia can only be grown in the southern regions. The legendary cork tree (Q. suber) is widespread in Southern Spain, Portugal and Italy, where it is mainly used for harvesting cork.
Holm oak (Q. ilex) is an evergreen tree up to 25 m high, with a very wide and spreading crown when standing freely. Very common in many Mediterranean countries. This species has beautiful dark green shiny leaves with gray felt pubescence underneath. The wood is hard and durable, as evidenced by the species name. Stonewood makes excellent living walls, as it lends itself well to pruning and has densely leafy shoots.
In the forests of the Far East, Japan and China you can also find interesting species, for example Q. mongolica. A tree up to 10–20 m high, with very large, up to 20 cm long, broadly obovate leaves with shallow lobes. In autumn, the foliage turns purple-red, which, combined with its size, looks quite impressive. The trunk is covered with smooth gray bark. It does well in cultivation in central Russia, so it is a pity that domestic nurseries do not grow this species, which would be widely used in landscape design.
Unlike the previous species, Q. glauca is quite thermophilic and is a tree up to 15 m high, growing in Japan, Korea and Southern China. This type of oak is especially decorative in the spring, when red, silvery-pubescent young leaves unfold. In Japan, the local population eats its acorns fried.
North America is home to a huge number of ornamental oak species, many of which thrive in our climate. The most famous and often found in the landscaping of Russian cities is the red one (Q. rubra), up to 35 m high, with a dome-shaped crown. The tree trunk is quite massive, covered with light gray, almost smooth bark. Unlike other representatives of this genus, D. red fruits ripen in the second year. In the first year, on the shoots you can only see a slightly overgrown plus with a small spherical acorn. In the conditions of central Russia, the tree feels very good, grows quickly and bears fruit abundantly. It is unusually beautiful in autumn, when its sharp-lobed leaves turn bright red, hence its specific name.
Scarlet oak (Q. coccinea) and swamp oak (Q. palustris) are very similar in appearance to the previous species, since they all belong to the same section Rubrae , but are more thermophilic. Distinctive features of the latter are deeply dissected, openwork leaves and branches hanging at the ends.
The Kaliningrad Botanical Garden can be proud of its valuable collection of oak trees. It has 18 types and decorative forms, from which an entire alley is created. In addition, the garden's arboretum is famous for the rare decorative forms of many other tree and shrub species.
| English oak | English oak, flowering | Cork oak, bark |
| Cork oak, fruits | Mongolian oak | Sessile oak, flowering |
| Red oak | DKB red, first year fruits | Swamp oak |
Beneficial features
Not only oak bark has beneficial properties. For example, acorns are used to treat intestinal disorders, hernias and skin diseases.
Oak foliage smells pleasant and is an obstacle to the development of rot. Fragrant bath brooms are made from tree branches. The leaves are used to line tubs intended for pickles. The preparations do not sour and become especially tasty.
You can also make children's crafts from acorns. Acorns look very beautiful: they have a round shape and a pleasant glossy shine.
Autumn oak is an amazing sight. A mighty crown of yellow foliage pleases the human eye. When the leaves of the buzzards dry out, they remain on the branches, attracting attention with a quiet and mysterious winter rustle.
- Author: Maria Sukhorukikh
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What are galls?
Sometimes at the end of summer, not very pleasant-looking spherical growths appear on oak leaves. These externally unsightly formations appear due to insects (gallworms) and are called galls. How does this happen? These insects lay eggs inside the leaf tissue itself, where their larvae subsequently develop. As a result, the pathologically overgrown tissue turns into a gall (“nut”).
The oak leaf (photo below) usually has green, round galls, usually attached to the bottom of the leaf.
Oddly enough, they (leaves with galls) are collected for brewing and drunk instead of tea with sugar or honey. Their decoction is also used in the form of lotions (1 glass of raw material is brewed with 1 liter of boiling water, then boiled for 5 minutes, infused and filtered).
The most useful are fresh green and unripe galls.
