Living conditions of plants. Forest as a plant community. Adaptability of various plants to living together. Change in plant communities What are the living conditions in the upper layer of the forest?

Not only tiered placement allows different plants to coexist freely with each other.

By carefully observing the life of plants in a plant community, it is possible to identify other features of their adaptability to living together.

One of these devices is development at different times.

IN middle lane, for example, hazel grows - hazel. It blooms when tall trees have not yet covered with leaves and the wind freely transfers pollen from staminate flowers to pistillate flowers. Early flowering hazel - adaptation to life in the forest with other plants.

Trees whose crowns are located above all other plants in the forest are most often pollinated by the wind. They bloom before the leaves bloom. And most shrubs are pollinated by insects, since under the forest canopy (Forest canopy is a set of crowns of closed trees located in one or several tiers. Wikipedia) There is almost no wind. The green canopy of the forest does not allow the wind to penetrate to the plants in the tiers. Therefore, the fruits ripened on the bushes are not distributed by the wind, like most trees of the first tier, but by birds living in the forest. Berries and others juicy fruits, for example honeysuckle, raspberry, buckthorn, rosehip, euonymus, become tasty food for many birds in the fall.

Interesting adaptability herbaceous plants to life in the plant community of the broadleaf forest is the familiar early flowering of certain herbaceous plants called snowdrops.

Snowdrops are light-loving plants. They bloom in the spring, when the leafless branches of trees and shrubs of the forest freely transmit the rays of the sun. Early flowering of snowdrops is possible primarily because the soil of a broad-leaved forest freezes less in winter than in open places. Deep, loose snow cover and forest litter made of fallen leaves, dead parts of herbaceous plants, rotting dry branches and bark protect the soil from freezing. Under the snow in such a forest, the soil temperature is often around 0°C, never falling below minus 1-2°C. Due to stored nutrients snowdrops develop under the snow.

Adaptation to life under trees with a lack of light is the color of the petals of flowers of herbaceous plants. Thus, in herbaceous plants of coniferous, dark forests, the white color of the corollas of flowers predominates, which are clearly visible to pollinating insects.

Only plants that bloom before the leaves of trees and shrubs bloom or grow in forest clearings and edges have flowers with brightly colored petals, like those of the swimsuit, lungwort, corydalis, buttercups and others.

Studying the life of plants, one can notice that some plant communities are gradually replaced by others. For example, in a forest, living conditions are favorable for shade-tolerant grasses, ferns and other plants growing under the canopy of trees.

If you cut down the trees that make up the upper layers of the forest, then many shade-loving plants the lower tiers (oxalis, lily of the valley, lily of the valley, wintergreen and others) will die, their place will be taken by other, more light-loving plants and a different plant community will gradually emerge. A change in the sun exposure of plants is one of the reasons for the change in the forest plant community.

The plant community of a forest can also change when a sphagnum moss cover develops in the forest, which will lead to waterlogging and cause the death of plants. The forest is gradually being replaced by swamp vegetation. One plant community will be replaced by another.

Change plant communities may be caused by various reasons. Often these are fluctuations in climate, weather, soil changes, changes caused by plant life processes in the communities themselves.

In the existing plant community, due to these reasons, other species may appear, previously living ones may die off and die.

Thus, in aging birch forests, one can observe the displacement of light-loving birch by spruce, as a result of which, in a few years, instead of a light birch forest, a plant community of shady spruce forest appears.

The replacement of one plant community by another has a significant influence economic activity person.

Man cuts down forests and replaces them with arable land; drains swamps, plows up steppes; fixes the moving sands in the desert, turns the desert into blooming gardens.

Along with this, timely human intervention can extend the life of the plant community.

So, for example, an old, mossy meadow with compacted soil can be rejuvenated and turned into a meadow that again grows mainly cereals. To rejuvenate such meadows, special measures have been developed and applied: harrowing the meadow, sowing cereals and legumes, etc.

From a geography course, you know that in a forest, plants of different sizes are located on top of each other, forming tiers. This can be seen even on a small site.

The first tier includes the tallest trees: oak, ash, maple, birch, elm, poplar, beech.

Write down the characteristics of the tree layers. In it, indicate: name of tree species, height, diameter, age.

The height of a tree can be determined using an eclimeter - an instrument for measuring vertical angles on the ground.

Make an eclimeter in advance. Cut a rectangular board measuring 20X15 cm and nail a student protractor to it. Hang the protractor on the center of the semicircle strong thread small weight.

It is best to measure the height of a tree with two people. Stand at some distance from the tree and sight along the upper edge of the eclimeter towards the top of the tree. Then move back or forward until the plumb line reaches the 45 degree mark. From here, use a tape measure to measure the distance to the tree and add the amount of your height to your eyes. This will be the height of the tree.

The diameter of the tree can be determined as follows. Using a tape measure, measure the circumference of the tree at a height of approximately 140 cm and divide the resulting figure by 3.14.

It remains to determine the age of the tree of the first tier. You already know that the age coniferous trees can be determined by whorls of branches. TO deciduous trees this method is not applicable. Therefore, age is best determined by the growth rings on a fresh stump.

The second tier consists of trees slightly inferior in height to the main species. This is the undergrowth from shade-tolerant trees- rowan, bird cherry, wild apple and pear.

Describe the trees of the second tier in the same form as you described the first tier. To determine height and thickness, select the tallest tree of each species.

In addition to trees, various shrubs grow in the forest. They belong to the third tier. The shrub layer in a forest is also called the understory.

In terms of rock composition, it is the most diverse. These include hawthorn, buckthorn, hazel, elderberry, euonymus, honeysuckle, viburnum, and rose hips.

You may have noticed that in some places the bushes form such dense thickets that it is difficult to get through them.

Describe the shrubs that grow in the sample plot. Make records of the shrub layer in the following form: name of the shrub species, how many shrubs grow in the sample plot, average height, state.

See if there are any heavily oppressed trees in the third tier. Some trees, falling into favorable conditions, during their long life they cannot rise above the bush.

Try to determine the cause of the depressed state of the tree.

Place all herbs in the fourth tier. These are plants that have winter period Aboveground stems die off, only the roots and rhizomes of perennial plants remain alive.

In botany lessons you taught that herbs have their own biological features very diverse. Most cereals, sedges, etc. are perennial; to two-year-olds - umbelliferous, many cruciferous. There are also annuals.

Using reference literature, identify all types of grasses found on the sample site and write in the column: “Name of species.” In the second column, write down which plant species is quantitatively dominant and which species are rare.

In the third column, mark the phenological phase. The phases for flowering plants are as follows: vegetative - the plant has not yet bloomed, flowering, fruiting, seeding - the plants are seeded or have already been seeded, dying - above-ground shoots have dried up and died.

Pay attention to how the plants are arranged species composition regarding light, moisture and other conditions.

When studying the woody and herbaceous vegetation on the test site, you will certainly notice small trees - undergrowth. Determine: where are the shoots from seeds, and where are the shoots from old roots and stumps. Observe the struggle that young seedlings of trees with grass cover endure. Note in the log whether there are any cases of seedling death.

Determine which origin of the undergrowth develops better: seedlings or shoots. Explain the reasons for their unequal growth.

And to which tier do mushrooms belong? These plants, as well as microscopic algae and bacteria, belong to the fifth tier.

When studying the vegetation of the fifth tier, describe only the mushrooms. If you have literature with pictures and descriptions of mushrooms, try to determine their names.

From observations you know that each type of plant develops in certain conditions. Obviously, plants of different tiers also make different demands on living conditions - light, heat, soil.

Don't forget to collect plants for your botanical collection - herbarium. For large plants - trees and shrubs - take two copies of each species, for small ones - several.

A herbaceous plant, if it fits in a herbarium folder, dig it up by the roots. Shake off the soil from the roots, and if it doesn’t come off well, wash it off.

Place each type of plant in a herbarium folder with a label. In it write the serial number, date, location, name of the plant and number of the tier.

After finishing work on the test site, continue the specified route. When you come across other plant species, stop and explore the new plant community.

When studying a plant community, it is important not only to determine the type of plant and describe its characteristics, but to study the patterns of plant development.

Lesson on the topic: “Life conditions of plants. Forest as a plant community"

Goal: to continue acquaintance with plant communities, highlight distinctive features forests as a plant community

educational - to continue the formation of a caring attitude towards nature;

educational - repeat material on life forms of plants, plant communities,

become familiar with the concepts: layering, light-loving, shady, shade-tolerant, cold-resistant, heat-loving, xerophytic, mesophytic, hydrophytic plants,

learn to distinguish tiers in the forest and distribute plants into groups in relation to water, light, temperature;

developing - continue to get acquainted with the plants of your region.

Forms of work: teacher's story, discussion, heuristic conversation.

Equipment: table “Oakwood”, “Tiering”.

Lesson terms: layering, environmental factors, light-loving, shade-loving, shade-tolerant, heat-loving, cold-resistant, xerophytes, mesophytes, hydrophytes, life forms, plant community.

During the classes.

I. Organizational moment.

II. Test on the topic of lichens.

III. Learning new material

IV. Consolidation of material: working with terms at the end of § 62

V. Homework: § 62, be able to answer questions at the end of the paragraph, write down plants of coniferous and deciduous forests in a notebook.

Tree trunks are often inhabited by insects: longhorned beetles, borers, horntails, bark beetles, sapwood, pine beetles and others, which can not only accelerate the death of trees, but also damage the wood.

Some species (dormouse, weasel, squirrel, marten, chipmunk and others) descend from trees to the ground. Others, on the contrary, spend most of their time on the ground, but can climb trees and move around them (grouse grouse, forest cat, ermine, lynx, sable and others).

It is difficult to imagine a forest without the animals that live in the lower tier of the forest. In dense thickets of undergrowth closer to the soil and on the soil, where there is significantly less light due to the fact that

The tree crowns absorb it, and there is more moisture in the air and there is no wind, it nests a large number of birds. In the gloomy thickets, egg laying and chicks are safer. Elk - this forest giant, feeds only on plant foods: branches, shoots, tree bark, moss, lichen and mushrooms. He also likes berries. Moose likes to gnaw on the bark of aspen trees, and sometimes even spruce trees. The marks of his teeth are clearly visible on the trunks; they are located quite high above the ground.

Mammals - predators - live in the lower tier of the forest.

The brown bear is an example of an omnivore. He loves to eat large quantities of unripe spikelets of cereals, eats berries, roots, fruits, eggs and meat, and loves honey.

When hunting a large animal and killing the animal, the bear leaves the carcass to decompose for several days, then returns and eats the prey. Hedgehogs settle under tree roots, in dense bushes, under stones, and dig holes. They are predominantly omnivorous, but prefer animal food: invertebrates, amphibians, reptiles (hedgehogs are famous for their resistance to snake venom), carrion.

Vipers feed mainly on mouse-like rodents, amphibians and lizards, and destroy bird nests located on the ground.

There are animals whose life passes both above the ground and in the soil, for example, the red wood ant, the shrew, and mouse-like rodents.

Ants play a big role in spreading forest plants, as they serve as carriers of their seeds.

Mouse-like rodents feed on seeds and roots of forest plants, but they themselves are food for larger animals. Some animals live only in the soil.

Life in the soil is associated with the lack of light, difficulties of movement, high humidity or lack of water, a large number of dying plant roots and plant debris on its surface.

These are, first of all, earthworms. Total weight of earthworms

Earthworms By processing dead organic residues, they increase soil fertility, loosen and “ventilate” it, which creates favorable conditions for plants, microorganisms and other animals living in the soil.

Mole crickets can feed on both dead organic matter and living plant roots, causing damage to seedlings in nurseries and forest crops.

The mole, constantly loosening the soil, helps to increase its fertility. It destroys insects “harmful” to the forest, such as May beetle larvae.

Initially, they were noticed and arose from the definitions of data by the people, and the practical, scientifically developed division of forests into types was the founder of the doctrine of forests G. F. Morozov and other forest scientists. The division of forests into varieties was scientifically developed by the founder of the study of forests G.F. Morozov and other forest scientists.

Forest division

• Bor - pine forest on sandy, usually elevated or hilly terrain;
• ramen - predominantly spruce forest on clay or loamy soils;
• sogra - damp pine forest with an admixture of and other trees.

• The best drill (kondovaya) with durable, slightly reddish wood grows in a berry forest, that is, in a pine forest where there is a lot of berry bushes, especially blueberries.
• In Sogr, the pine has a tapering trunk, that is, quickly thinning towards the top, and therefore unsuitable for buildings. This pine is large-layered, with insufficiently strong wood.
• The most resinous pine grows in a white moss forest, where under the trees there is a lot of deer lichen, which has a light gray color.

Types of forests

• boron-white moss (or lichen boron),
• pine lingonberry (pine with lingonberries at the bottom),
• boron-blueberry (pine with blueberries),
• spruce forest (spruce with oxalis grass),
• maple oak forest (oak with an admixture of maple in the undergrowth, and at the bottom - a herbaceous plant from the Umbelliferae family - oak tree)

Classification of forests by tiers

• the upper one, consisting of tall trees,
• medium - from low trees and shrubs growing under the cover of large trees,
• the lower one is made of living forest litter: grasses, small, low growing bushes(lingonberries, raspberries), as well as mosses and lichens.

Living conditions of individual forest layers

flow in time