How are trees helpful in the process of water cycle


How Forest Structure Influences the Water Cycle

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Posted inResearch Spotlights

New research looks at how changes in the arrangement of trees and canopy thickness influence the transport of water from the land surface to the atmosphere.

by Kate Wheeling

An instrument tower stands at the University of Michigan Biological Station, where researchers measured stable isotopic signals in water vapor amid two plots of forest to study how disturbances in forest structure influence water transport from the land to the atmosphere. Credit: Richard Fiorella

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Source: Journal of Geophysical Research: Biogeosciences

Forests are a critical cog in the global water cycle: Trees pull water from the ground and release it into the atmosphere as vapor through pores in their leaves in a process called transpiration, which can drive temperatures and rainfall across the globe. Forests are also dynamic ecosystems, with both natural events, such as pest infestations and droughts, and anthropogenic activities like logging potentially causing dramatic changes in forest structure. Despite the important roles forests play, the relationship between forest structure and the global water cycle is not well understood.

To help fill gaps in our understanding of this relationship, Aron et al. compared two forest sites in Michigan to find out how disturbances in forest structure can influence water transport from the land surface to the atmosphere.

The team selected two adjacent field sites at the University of Michigan Biological Station in Northern Lower Michigan: an undisturbed, control site dominated by bigtooth aspen and paper birch and a site where researchers in 2008 purposefully killed aspen and birches, giving this disturbed site a much more open canopy than the control. The arrangement of trees within a forest influences the amount of light and heat that reaches the ground, affecting not just transpiration but also other processes like evaporation and entrainment—the process by which air above the canopy is mixed into the canopy—which also contribute to the amount of water vapor that reaches the atmosphere.

Taking advantage of the fact that each of these processes results in distinct isotopic signals in water vapor, the researchers measured stable water isotopes at six heights in the two forest sites during the spring, summer, and fall of 2016.

The results revealed that the disturbed canopy was both drier and warmer than the undisturbed control site. The control site also exhibited a more stratified isotopic profile, suggesting less vertical mixing of the air in the forests, whereas the more open canopy appeared to encourage more mixing. The differences between the two sites were most prominent in the summer and spring.

The study demonstrates that forest canopy can regulate the rate at which moisture and energy are returned to the atmosphere at a local scale, which can in turn influence water retention and the makeup of forest ecosystems. The results provide important context for researchers interested in modeling how both forest ecology and water cycles will evolve as climate change progresses. (Journal of Geophysical Research: Biogeosciences, https://doi.org/10.1029/2019JG005118, 2019)

—Kate Wheeling, Freelance Writer

Citation:

Wheeling, K. (2019), How forest structure influences the water cycle, Eos, 100, https://doi.org/10.1029/2019EO134709. Published on 15 October 2019.

Text © 2019. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Tagged: Climate Change, forests, Journal of Geophysical Research: Biogeosciences, water cycle

Trees And The Water Cycle

The importance of the water cycle

The availability of water for all living organisms and for the regulation of local and global weather patterns is dependent on the water cycle. While just 3% of the water on earth is fresh water, two thirds of this is locked up in ice sheets, glaciers or the ground. The remainder is present in rivers, lakes and wetlands or takes the form of water vapour, as clouds or precipitation which recycle and restore fresh water sources. [1] Alterations to the water cycle can have negative effects for organisms that have adapted to a specific climate. For example, sustained drought can eliminate plant populations, while some salamander species can only survive in environments with a certain amount of soil saturation. [2]

Status in Kenya

Natural water resources in Kenya do not provide enough water in some areas and water basins are only able to reach so far; this leaves much of the population without fresh water. [15] Although clean water kiosks are situated in some parts of Kenya, most people cannot afford to purchase water, leaving many with no other choice but to walk miles to the closest water source. [3] Due to the overuse of land and rapid growth of community settlements in Kenya, and the fact that they are also used by wild animals, these sources are often polluted with water borne diseases, responsible for the death of over 5,000 children a year. [18]

Additionally, Kenya experiences persistent droughts that are becoming more frequent as a result of environmental degradation and climate change. Currently dry periods occur at least once a year, and the frequency of droughts has increased alarmingly. Longer time periods between droughts allowed farmland to recover and crops to be harvested before the next drought occurred; however this is no longer the case. During the end of 2009 and early 2010, ten million people were at risk of starvation after harvests failed as a result of drought. [6]

Deforestation maximises the ongoing water crisis in Kenya. For example, Lake Naivasha is a freshwater lake situated north west of the capital Nairobi. It once exhibited cycles of rising and falling water levels that now appear to have been disrupted. The lake is supplied by the Aberdare Mountain Range, formerly characterised by thick forests that regulated the temperature of the atmosphere, trapped moisture, promoted rainfall and supplied many other vital ecosystem services. However, there has been mass deforestation in the area and throughout Kenya over the last few decades, to make way for farmland and to supply the charcoal and timber production industries, amongst others. Decreased forest cover has led to a weakened ability of the ecosystem to trap moisture and promote cloud cover, resulting in less rainfall. Consequently, the streams and rivers that supply Lake Naivasha in addition to other lakes have shrunk or completely dried up, due to a drop in water levels. [7]

Image: The Word Forest Organisation

Trees provide water cycle management

75% of the world’s fresh water supply is generated by forests that guide water into rivers, lakes and the groundwater table, while promoting the formation of clouds. Trees extract groundwater via their roots and recycle it back into the atmosphere from the soil through a process called transpiration; this increases the capacity of the soil to store water. [4] The water vapour contains biological particles such as microorganisms, fungal spores and pollen, as well as other biological debris that provide a surface for atmospheric water to condense into rain droplets and cluster together to form clouds. The newly created clouds attract higher clouds that would have previously passed over the area, adding additional rain to the forest. This explains why deforestation results in increased frequencies of drought and flooding due to irregular rainfall. [12]

This lack of water can cause the landscape to shift into a barren desert environment with inhospitable living conditions. [8] Rivers and streams are kept cool by the shade trees offer. [9] This prevents the water from evaporating too rapidly, maximising the quantity of water and value of the river to both people and wildlife.

Trees are described as ‘natural sponges’ due to an ability to collect and filter rainwater, which is then released slowly into rivers and streams. Without them, the rain runs off into streams and rivers so fast that the top layer of the soil can become eroded due to the lack of roots anchoring it down. [10] This leaves the landscape vulnerable to flooding and landslides, as well as decreasing the fertility of the soil, reducing water infiltration and increasing the rate of runoff. [16]

The strong roots of trees not only protect against soil erosion but also absorb nutrients and sediment that would otherwise flow into streams and rivers, polluting the water. Communities in Kenya have to depend on expensive water filtration systems to provide clean water and this cost is maximised where erosion occurs, due to poorer water quality. [13] Therefore, healthy functioning forest ecosystems are able to act as natural infrastructure and reduce water management costs.

Water cycling benefits provided by trees

Water cycle management benefits for the local community

Today, citizens of developed countries often take having access to clean drinking water for granted. In contrast, most of Kenya’s citizens walk miles every day to obtain water that is often unsuitable for human consumption. Wildlife also depends on these same water sources. Reforesting Kenya’s landscape creates a wealth of benefits for the local community and is the most practical and affordable method of sustaining a higher quantity and quality supply of fresh water for both people and wildlife. [14]

However, it is important to consider that just planting trees does not always increase the water supply. This depends largely on selecting suitable sites and species of trees, as well as scale, forest structure, density and management methods put in place. [13]

Forest cover has been directly linked to reducing the costs of drinking water treatment. This is due to the ability of trees to remove excess agricultural fertiliser before the chemicals run off into rivers and streams, polluting the water. [16] Furthermore, more regular and predictable rainfall would increase agricultural yields, decrease irrigation cycles and improve food security in these areas. [11]

Impact on overall ecosystem health and other ecosystem services

Local deforestation in Kenya can affect the global water cycle. Greenpeace have stated that deforestation in Kenya causes decreased rainfall in the Midwest of the USA by 5-35%, negatively affecting agricultural production and other sectors. [5]

Changes in the water cycle as a result of deforestation directly affect the carbon cycle. Carbon sequestration is a co-benefit of the recycling of precipitation that simultaneously cools planetary surfaces. We know that removing trees allows more carbon to remain in the atmosphere. [17] The increasing incidence of drought can worsen fires in shrublands and grasslands, heighten the potential for forest fires, resulting in further loss of forest cover, and release even more carbon dioxide into the atmosphere. [9]

Image: PXHere

In summary, the importance of trees in the global regulation of water is often overlooked, but forests can make a major difference to the quality and quality of water available to us if planted and nurtured appropriately.

To find out more about the work of The Word Forest Organisation, have a look around our website and watch our film #TreesAreTheKey narrated by Kate Winslet.

References

1: https://gpm.nasa.gov/resources/faq/why-are-water-cycle-processes-important
2: https://socratic.org/questions/why-is-the-water-cycle-important-to-all-life-on-the-earth
3: https://www.bbc.co.uk/news/world-africa-50253189
4: https://eos.org/research-spotlights/how-forest-structure-influences-the-water-cycle
5: https://www. wri.org/blog/2017/03/3-surprising-ways-water-depends-healthy-forests
6: https://issafrica.org/iss-today/the-cycle-of-drought-in-kenya-a-looming-humanitarian-crisis
7: https://www.voanews.com/archive/kenya-experiencing-effects-deforestation-climate-change-0
8: http://sustainablefootprint.org/nederlands-trees-and-the-water-cycle/
9: http://coolgeography.co.uk/advanced/Human_Influences_Water_Cycle.php
10: https://blog.ecosia.org/trees-kenya-water-towers-photography-green-belt-movement-ecosia/
11: https://www.kiwash.org/planting_trees_to_protect_water_and_increase_climate_resilience
12: https://forestsnews.cifor.org/49010/linking-trees-and-water?fnl=
13: https://sdg.iisd.org/commentary/guest-articles/afforestation-increases-water-supply-but-only-with-these-consideLinking trees and waterrations/
14: https://www.thegiftedtree.com/how-to-improve-water-quality-by-planting-trees/
15: https://thewaterproject.org/water-crisis/water-in-crisis-kenya
16: https://onetreeplanted. org/blogs/stories/trees-clean-water
17: https://www.sciencedaily.com/releases/2017/03/170320110039.htm
18: https://www.unicef.org/media/media_19974.html

Alice O’Grady and the Team

Why forests are so important for our planet. What is the forest for

Author Historian Views 55 Published

By conserving or restoring forests, people improve the environment and have a positive impact on the climate. The green suits of the planet are "laboratories" for the production of oxygen, without which the existence of life on Earth is unthinkable.

Contents

  1. The impact of forests on nature and human life
  2. Fresh water is a merit of the forest
  3. The economic role of forests
  4. Forests help us breathe
  5. Over 2000 million people depend on forests for their lives
  6. Forests are more than just trees
  7. Forest layers
  8. Forest types
  9. Forest value
  10. Fight corrupt officials and illegal logging
  11. Avoid products containing palm oil
  12. Plant trees and participate in reforestation
  13. Consequences of human intervention in forest life
  14. The importance of forests in human life
  15. Forests help us breathe

The impact of forests on nature and human life

Forests are a source of energy produced by nature itself . Its importance cannot be overestimated. It protects the environment by cleaning it from all types of chemical and physical pollution. It shapes the culture and customs of entire peoples and is the source of many resources without which people cannot live. Visit the Good Forest website to see for yourself.

Forests are unfairly called "the green lungs of the Earth". Plants and trees produce oxygen, without which living beings cannot exist. Forests help remove dirt and dust from the air, which settles on the leaves and branches of coniferous trees and falls to the ground. Forests release a lot of moisture, keeping humidity levels high and protecting forests and other areas from drought.

Trees act like powerful pumps. Water that falls out of the atmosphere during rain is partly absorbed by the land, partly into the sea, and partly re-entered into the atmosphere. Only a small part remains to participate in important biological processes.

The forests are beautiful.

There is a natural water cycle: water falls to the ground in the form of precipitation. A drop of water absorbed by plants can evaporate several times and fall to the ground. Therefore, it rains much more than from the sea. And the reason for this is the work of forests.

Green Sea balances the temperature. Precious dew can be found in the forests on warm summer days, and at night they provide protection from cold winds. This can be explained by the fact that in open areas the soil and air heat up faster than in forests.

A canopy of trees evaporates more moisture, which lowers the temperature. At night, open areas quickly give off the heat accumulated during the day, while trees in the forest give off less heat. This evens out the temperature and promotes crop growth.

The most important function of forests is to fight against the wind. Strong air currents can destroy everything in its path. The inhabitants of the deserts of the South Caucasus know firsthand that hurricanes can dry out all living organisms.

However, the winds weaken when they encounter an obstacle in the way, which is the forest. Less dense plantings can be especially helpful in wind control. It does not rise above the trees, but loses its power as it passes between them.

Fresh water is the merit of the forest

Lack of drinking water is the most important environmental problem. Humanity cannot exist without water. Trees are part of the natural water cycle and help move water inland. Modern researchers believe that a land away from oceans, seas and forests would be uninhabitable.

Rivers flow through forests.

When the snow melts, trees stop the flow of water and prevent soil clods from breaking down. Deforestation can lead to the formation of swamps in the upper parts of the forest areas. A few trees can't fight the excess water for long, and as it rises higher and higher, they become more and more flooded, destroying the root system.

The economic role of forests

Forests are a huge source of wealth, without which a person cannot feel comfortable. Even in ancient times, people hunted wild animals, gathered berries and mushrooms and looked for ways to treat them.

The gift of the forest was a panacea for all diseases. To this day, folk remedies have many fans, and cosmetic companies use natural oils to manufacture their products. The main material use of forests is wood, which is used in the production of furniture, building materials, paper and various types of wood fuel.

Human impact on forests

Today, the popularity of wood products has declined significantly. Where previously wood was required to build a house, brick and aerated concrete are now preferred.

Batteries have replaced heat in the kitchen, and paper has replaced electronic media. However, the benefits of forests cannot be completely ruled out. They cannot completely replace what has been an important part of the economy for centuries.

Coniferous forests are found in the cold regions of North America and Eurasia. They consist of spruce, fir, pine and evergreen trees, the seeds of which ripen in cones.

Forests help us breathe

Air pollution kills seven million people a year.

Forests recycle the oxygen we need to live and absorb the carbon dioxide we exhale (or exhale). Mature deciduous trees are estimated to provide oxygen to 2-10 people per day. Phytoplankton in the oceans provide half of the Earth's oxygen and are therefore more productive, but forests are still the planet's main source of high quality air.

Over 2000 million people depend on forests for their lives

We don't realize it, but forests help us every day!

According to WWF, our forests provide us with shelter, livelihood, water, food and fuel. Almost all activities are directly or indirectly related to forests. Some of them are easy to list: timber extraction, paper production, etc. Others are less obvious, as many everyday products (drugs, cosmetics, detergents) contain ingredients from forest herbs and trees.

Forests are more than just trees

Deforestation has already threatened a million animal species

80% of the Earth's biodiversity lives in forests. Insects and earthworms provide nutrients to the soil, bees and birds carry pollen and seeds, wolves and big cats scare away hungry and herbivorous animals. Biodiversity is important for both ecosystems and humans. Among other things, trees provide important oases of shade through their branches and leaves. In cities, trees help keep buildings cool by reducing the need for fans and air conditioners, and large forests can regulate ambient temperatures.

What do you think is more important, saving forests or planting new trees? Discuss this question in the comments or with Telegram chat participants.

The gift of the forest was a panacea for all diseases. To this day, folk remedies have many fans, and cosmetic companies use natural oils to manufacture their products. The main material use of forests is wood, which is used in the production of furniture, building materials, paper and various types of wood fuel.

Forest layers

The forest consists of different layers. The first tier, or dome, is tall trees. The layer formed by shrubs and stunted trees is called low vegetation. This is followed by a layer of grass and moss. The densest layer is the forest floor. Millions of organisms live on 1 m2, from bacteria to mice. Below is another layer - the undergrowth.

Forest types

Biologists distinguish between different main forest types: coniferous, deciduous, mixed and tropical.

Coniferous forests are found in the cold regions of North America and Eurasia. They consist of spruce, fir, pine and evergreen trees, the seeds of which ripen in cones.

Temperate forests predominate, deciduous trees - birch, oak, flame and ash. Each fall, the leaves are shed to allow water to evaporate through the foliage, thus avoiding moisture loss.

Mixed forests are forests containing both deciduous and coniferous trees. They are found in central and western Europe, eastern Asia and North America.

Liquid rainforests are equatorial, subcutaneous, and tropical forests in humid climates. These forests are characterized by a wide variety of flora and fauna.

Forests occupy about 30% of the land area, more than 40 million hectares, and about half of the forests are tropical and subtropical.

The importance of forests

The role of forests is extremely important. They improve the climate, prevent floods and mountain storms, soil erosion and river formation, and dust storms. They also fix the sand that moves and helps to accumulate soil moisture in the fields. Through their leaves and needles, forests convert carbon dioxide into oxygen and are vital to life on our planet. They also contain many living organisms.

Near cities and industrial centers, forests act as powerful filters, preventing harmful impurities from entering the sky. Forests are the cleanest places for people to relax. There they grow mushrooms, berries, nuts and medicinal plants. Animals, birds and insects find shelter and food in the forests. Forests have aesthetic value. Their beauty and graphics inspire poets and artists.

Some forest insects reproduce in incredible numbers and can destroy entire forests, such as gypsum. Insects are eaten by birds, which regulate their numbers.

Fight corrupt officials and illegal logging

Reducing corruption is important to reduce deforestation, as officials at various levels are often bribed by illegal logging companies.

For example, 70% of Indonesia's wood exports come from illegal logging. In addition to significant damage to the rainforest, the country is losing about $3.7 billion in revenue each year. Therefore, illegal logging does more harm than good to the country.

According to the Ministry of Natural Resources and Ecology of the Russian Federation, illegal logging has increased by 70% over the past five years. Each year, the only bonus is up to 1.5 million cubic meters of illegally harvested timber. According to the estimates of international organizations IUFRO, UNEP, INTERPOL and public environmental organizations, the volume of illegal logging in Russia is 20-25% of the volume of legal logging. According to Rosleskhoz, the volume of illegal logging is growing, but the number of detected cases over the past nine years has been regularly decreasing: to 11,500 cases in 2016 compared to 2008.

One of the most common ways to combat illegal logging is through activities, disclosure and independent surveys on social media, and reporting information to the police and local forestry authorities.

Activists are also creating smartphone apps to monitor and share information about illegal logging. For example, in Romania there is an app, Inscepertorul Padurii, that allows users to enter a truck's registration number to see if it has an official logging license. If the number does not exist in the database, the download is illegal and the user must notify the police. Global Forest Watch has developed an application called Forest Watcher that monitors areas of intact protected forests, including in Russia. The app notifies users of nearby entries and allows you to upload live photos of those entries.

Avoid products containing palm oil

Palm oil production has become one of the main causes of rainforest destruction. Palm oil is found in many products sold in supermarkets. Most of the world's palm oil production comes from Indonesia and Malaysia. Here, tropical rainforests are shrinking at an alarming rate of 970,000 hectares per year, making room for new plantations.

It is difficult to avoid buying products containing palm oil, as it can be present in various forms in both cosmetics and food. One possible solution is to completely stop buying products from companies responsible for clearing tropical forests for palm oil production. If you're not ready to go to such extreme lengths, choose your favorite certified palm oil products. Ensure that at least 95% of the palm oil used was produced in accordance with environmental and ethical standards.

Plant trees and participate in reforestation

The simplest strategy to combat deforestation is to plant trees. Have you heard the story of Jadab Payen of Majuli in Hindustan? The Indian Forest Man planted an entire forest with his own hands as the former president of a country called Jadav - a tree a day for over 40 years.

However, Greenpeace Russia warns that forest cultivation, even by amateur foresters, can bring both harm and benefit to the environment. For example, huge damage can be caused by planting forests on the remaining steppe ecosystems. A huge risk is associated with planting exotic trees and shrubs. They can replace endemic species (the most typical example is ash or American maple). In addition, dangerous parasites or pathogens can be introduced into planting material from remote areas. Therefore, before you start growing wood, you need to talk to the hazards.

Until then, you can take advantage of easy-to-use services that allow you to plant trees from the comfort of your home, at any time.

Prepared by Anton Chugunov Plant A provided by forests, mineral deposits, FEMA, waldhilfe.de

Participate in the All-Russian flash mob "Add greenery"! Let's work together to make the environment beautiful, comfortable and bright!

There is a natural water cycle: water falls to the ground in the form of precipitation. A drop of water absorbed by plants can evaporate several times and fall to the ground. Therefore, it rains much more than from the sea. And the reason for this is the work of forests.

Consequences of human intervention in forest life

Any human activity related to agriculture affects its habitat. Sometimes people can only appreciate the extent of the environmental damage caused by their intervention over time.

For example, the importance of forests for nature and for humans became apparent when large areas of coniferous forests were cut down. All lands were immediately populated with less valuable tree species: birch, poplar. The swamp area has increased significantly, as the forest not only retained moisture, but also used it. Changes in the composition of the plant kingdom steadily led to the disappearance of some animal species and the appearance of other species of fauna on these lands.

The importance of the forest in human life

The forest has always played a huge role in human life. Today, the importance of forests has increased as their numbers have been greatly reduced. The role of the forest in human life can be divided into three components - ecological, economic and social.

The ecological role lies in the quality of the environment and the conservation of nature. Every living being needs conditions for life. It is trees that contribute to the fact that modern man breathes clean air, can engage in agriculture and benefit from it.

Forest plays an important economic role for modern man. Wood is grown in the forests, from which building materials, paper, furniture, fuel, food, materials and pharmaceuticals are produced.

Wood is the main material resource. But berries, mushrooms and medicinal plants that grow only in forests are also in demand. While people are looking for alternatives to forest resources, wood will always be in demand. The fossil fuel that replaces wood is running out, and it costs much more than wood. The replacement of paper bags with plastic ones has caused a lot of damage to the land cover due to the fact that plastic is not recycled. The timber industry often becomes an urban activity requiring a large number of workers and machinery. Therefore, the role of the forest will always be very important both for the environment and for the modern world.

The social role of the forest is the role of historical connection. The forest is an element in the development of peoples, their cultures and their relationship with nature. Since time immemorial, the forest has been a source of resources for survival, providing food, water and shelter. In folk songs, fairy tales and stories, the forest has always played an important role. Today, forests serve as a place where people can relax and get some fresh air.

Forests help us breathe

Forests produce oxygen through photosynthesis, which we need to breathe. They also absorb the carbon dioxide we exhale (or expel). It is estimated that a mature, leafy tree produces oxygen for 2-10 people daily. Phytoplankton are more productive, providing half of the Earth's oxygen, but forests are still a key source of quality air.

The water cycle in nature Water and wood

Since the time of studying physical geography at school, everyone knows about the water cycle in nature. Evaporation - clouds - rain - streams and rivers - oceans - evaporation. It's been that way for centuries.

But few people know that there is another water cycle. Here the main characters are plants.

I offer you the work of A.D. Tarabrin for information and reflection.

Eternal cycle. The water cycle: absorption and evaporation.

Each tree has its own age, which is measured in tens, hundreds, and sometimes thousands of years. Each tree with its roots goes deep into the soil and is firmly established in it, and its crown rushes all towards the sunlight. Hence, there are two types of nutrition: soil and air. From the soil in the greatest quantities it consumes water. So, one adult birch absorbs and evaporates 75 liters of water per day, and linden 200 liters of water. One hectare of a hundred-year-old oak forest evaporates at least 1200 tons of water during the spring-summer period, and 2070 tons of beech forest.

The water cycle: how a tree obtains water.

Roots absorb water from the soil. However, not the entire root system is involved in this process. The largest part of the roots is covered with a cork that does not allow water to pass through, and therefore only conducts the already absorbed water into the trunk, strengthens the tree in the soil. Only roots no more than half a millimeter thick absorb water.

Usually we have a very distorted idea of ​​the true dimensions of the root system, since we judge them by those miserable remains that we see in a dug out tree or herbaceous plant. If you grow plants in special wooden boxes so that you can then carefully wash the root system from the soil and take into account the total length of all roots, then even for one herbaceous plant (rye) it turns out to be 650 kilometers! A two-three-year-old apple tree already has 45,000 kilometers of roots.

What prevents trees from completing the water cycle?

All activity (absorption of water and mineral nutrient salts) and growth of roots are connected with their intense respiration. To do this, the roots need a constant supply of oxygen. Therefore, the most terrible enemy of all individual trees, groves, alleys, parks are unorganized and irresponsible visitors. Randomly walking, they trample down the soil around the trees so that it begins to approach the asphalt in density. Life-giving oxygen ceases to flow to the roots, and they begin to “suffocate”. The inflow of water into the trunk is sharply reduced, and it does not flow to the top at all. As a result, dryness, gradual drying, death.

What is involved in the water cycle?

Together with water, the tree absorbs mineral salts from the soil containing nitrogen, potassium, phosphorus and other nutrients. The soil nutrition of a tree in a forest and plants in a field is different. The annual harvest in the field carries away all the nutrients absorbed by the plant from the soil. In the forest, on the other hand, the full harvest (cutting of the forest) occurs once every 50-100 years.

At the same time, leaves, needles, small branches, fruits, remains of buds, flowers, and bark fall from trees every year. All this creates a special top layer of soil - the forest floor. It contains about 75 percent of all nutrients taken by the tree from the soil. Thus, in terms of soil nutrition, the forest tree feeds itself, returning in the form of litter most of what it takes from the soil. That is why forests can grow without fertilizers.

Of course, the forest floor must rot, rot, before the mineral nutrients contained in it become available again to the roots of the trees. The main role in the decomposition of the forest litter is played by fungi, densely penetrating it with thin white threads (hyphae). The forest loves just such soil, and the forest floor is often one of the decisive conditions for its normal growth.

In the water cycle, the tree is able to extract nutrients.

Almost half of every tree is carbon. Where does it come from? Until the 17th century, it was believed that all plants feed on the "juices of the earth" in much the same way that animals do, assimilating their food. The Dutch scientist Van Helmont was the first to doubt this. He took 80 kilograms of well-dried earth, poured it into a barrel and planted a 2.25 kilogram willow branch there. After five years, during which the plant was watered with rainwater, the branch dug out and cleared of soil weighed 66 kilograms. The soil mass loss was only 56 grams. It became clear that the plant could not increase its mass in such a way only due to the soil.

Plants can "fix" the air. Does this require water?

More than two hundred years ago, in 1753, the brilliant Russian scientist M. V. Lomonosov wrote: It is impossible for them to receive so much resinous matter into themselves from the endless sand.

In 1771, the English scientist D. Priestley makes his famous experiment with a mouse and a branch of a green plant. The mouse, planted under a glass cap, after a while suffocated and died. If, along with the mouse, a mint branch was placed under the cap, the mouse remained alive. D. Priestley concluded from this that green plants "correct" the air spoiled by the breath of animals. However, rebuttals of this discovery soon appeared, as other scientists turned out that green plants, like animals, make the air unfit for breathing and burning.

The emerging contradiction was resolved by Jan Ingenguz in 1774, who established that air purification by green plants really occurs, but only in the light, to which D. Priestley and other scientists who repeated his experience did not attach any importance.

The photosynthesis reaction is based on water. Here is the cycle!

Later it was found that green plants, purifying the air, absorb carbon dioxide (this is their air supply) and release oxygen. Further, it turned out that the volumes of carbon dioxide absorbed and oxygen released are equal, and that the plant also uses water along with carbon dioxide. This process was called photosynthesis (from the Greek words "photos" - light and "synthesis" - the formation of complex chemical compounds from simple ones). The total reaction of photosynthesis is as follows:

6C0 2 +6H 2 O + 674 big energy calories =

C 6 Hi 2 0 6 +602.

As you can see, from six molecules of carbon dioxide and six molecules of water, with the absorption of 674 large calories of solar energy in a green leaf of a plant, one molecule of glucose sugar is obtained and six molecules of free oxygen are released into the air. However, it should immediately be said that in the above formula only the beginning and end of the reaction are given. In fact, it is much more complicated, it has many intermediate stages, the study of which continues at the present time. Its significance is global, cosmic, since life itself on Earth is possible only thanks to photosynthesis.

What wouldn't be without water?

When each sugar molecule is created, 674 large calories of solar energy, intercepted by a green leaf, are preserved in it. On the whole, in the process of photosynthesis, only land plants annually form at least 400 billion tons of organic substances with an energy reserve that could be provided only by 200,000 hydroelectric power plants like the Kuibyshev one, that is, each with a capacity of 10 billion kilowatt-hours of energy per year.

All reserves on the Earth of coal, peat, oil, oil shale are conserved solar energy obtained in the process of photosynthesis of plants that lived on Earth many centuries ago. And food serves as a source of strength in our body precisely because, according to K. A. Timiryazev, it is canned sunlight.

And again water! In the circle!

Carbohydrates (sugars) formed during photosynthesis must move from the leaves to their places of consumption throughout the tree. The main consumers of carbohydrates are shoots and roots, which absorb water and mineral salts, constantly grow in the soil and therefore need a continuous supply of such nutrition. This means that sugars must pass through the entire tree, that is, overcome a distance of several tens of meters. The sugars move from the leaves down the bark of the trunk, not the wood. To prove this, a ring of bark is removed from the trunk or branch to the wood without damaging it. In this case, the water flow is not interrupted, as the water moves along the wood of the trunk. Sahara, having reached the annular notch, stop and their further movement stops. Roots deprived of an influx of organic matter die off, and the tree eventually dies.

Water-solvent. It is the essence of the cycle.

The sugars formed in the leaves are used very intensively by the tree itself. First, they are consumed, as already noted, by the growing tops of stems and roots to build new cells. Second, all living cells consume sugars through respiration, the process by which all plants, like animals, obtain energy. Finally, thirdly, carbohydrates and other organic substances are deposited by the tree in a reserve, usually in an insoluble form, until they are needed.

Already in the second half of summer, the tree begins to store part of the products of photosynthesis (sugar). (Organic substances formed in excess can be stored only in living cells. This is due to the fact that only a living cell is able to carry out the necessary transformations of substances: a reserve form of carbohydrates - starch, insoluble in water, into sugars that can move in the form of solutions throughout wood and therefore called the transport form of carbohydrates

In the eternal cycle of water life was born on our planet.

In the trunk of an adult tree, living cells contain only the outer growth rings of wood. The death of wood in different trees ends at different times, so the number of layers of wood in which living cells are preserved is not the same.


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