How to know the age of tree

How Old Is My Tree?

If you know when the tree was planted and the age of the tree at the time of planting, obviously, you can easily and accurately determine its age. Most trees are between 5 – 10 years when they come out of the nursery.  The second most accurate way to estimate tree age is to count the annual rings of wood growth. However, we don’t want to injure or cut the tree down just to figure out its birthday.

Annual rings can be counted using two different methods. You can extract a core from the live tree using an increment borer, which can leave wounds in the tree.  Or, dead trees and trees which have been removed enable ring counting on the stump. Although counting rings provides an accurate estimate of age, most people do not have access to an increment borer for live trees or the tree must be cut down.

By following these easy steps, you can get a rough estimate of a live, standing trees age, without knowing when the tree was planted and without injuring or cutting the tree down.

STEP 1. Measure the circumference (c) of the tree trunk using a measuring tape that measures in feet and inches. This should be done at 4.5 feet above the ground or slightly below shoulder height.  This is known to arborist as the DBH or Diameter at Breast Height.


Our white oak tree measures 5 feet, 10 inches in circumference.

c = 5 feet, 10 inches or, 70 inches

STEP 2. Calculate the diameter (d). Divide the circumference by 3.14, a constant known as “pi”.  Formula:   c / 3.14 = d.  For the white oak if the diameter is 70 inches/3.14 = 22 inches DBH.

STEP 3. Multiply the diameter of the tree by the growth factor as determined by species.

Figure 1. Measure trunk circumference at 4.5 feet above the ground
Figure 2. Use a tape measure to determine circumference or diameter.

This is where we have so many variables that affect the accuracy of our answer.   Growth factor tables assume a consistent or linear relationship of diameter increment to years of growth. This assumes little variation in the many problems which can affect tree growth.

Woodland trees and urban trees grow quite differently. Trees in our neighborhoods, along streets and in the parks, are often under more stress and grow more slowly. Natural woodland trees are on undisturbed sites with less pressure.  Tree growth rates are affected tremendously by conditions such as water availability, climate, soil conditions, root stress, competition for light, and overall plant vigor. Further, the growth rates of species within genera can vary significantly. A white oak growing in a moist, well drained site will grow faster and be younger than a similar white oak in a dry, stressed tree lawn. So, only use this formula as a very rough estimate of a tree’s age.

Also, trees growing in a woodland environment typically have a restricted crown and therefore increase in circumference at about half of the rate of full, open-grown tree found in a park or residential landscape.   History tells us there are very few trees much older than about 250 years in the Midwest due to the early settlers clearing our forests for farm fields.

Back to our white oak tree.  We determined that the tree has a 22” DBH, so you would then multiply it by the growth factor of 5.0 (refer to table below), and our answer is 110 years old!  This oak tree is considered as a youngster for white oaks. Under perfect conditions, a white oak tree can live to be 300 or more years old. However, under urban conditions, most white oak trees may only live to be around 150 years old. So, this may be a more accurate number if the tree were in perfect, natural growing conditions. However, if our tree is in a park or residential area where the tree may be more stressed or crowded, it is likely the calculation of age is a little high. Often, I will apply my “urban forest factor” of deducting 25% from the age calculation. This is an anecdotal deduction based on experience with aging trees in different environmental situations. If we apply this factor, the tree is aged at about 83 years old.  So somewhere in that range would be a good guess.  Again, it’s all a fun estimation.

Formula for Aging Trees:
Diameter = Circumference divided by 3.14

Formula: DBH X Growth Factor

How to Tell How Old a Tree Is (Trick Works Every Time on All Tree Types)

Many people know the basic steps of how to tell how old a tree is using a simple trick… just count its rings.1

It works every time. You can check the cross-section of the tree’s branch and start with the first dark circle. Count outward from this dark circle till you reach the outermost dark ring. The total dark rings give you the age of the tree. Please note that the bark doesn’t count as a ring.

But, this can be tricky unless you have a cross-section of the trunk, and that would require it being cut.

Fortunately, there’s a much better way to tell how old a tree is.

Use a tree age calculator that works using the tree species’ growth factor. You can do it yourself, or use this convenient tool!

What Is the Trick to Tell the Age of All Trees?

The rings in a tree’s trunk are formed when cells divide and grow in layers during its life. The widths of these bands vary depending on the species and climate. By counting how many dark rings are visible on a tree trunk, you can calculate how old it is.7

However, if you use the calculator above, you can get a very close estimate to a tree’s age, without needing a cross section.

Here are some tips for using it:

  • When measuring the circumference of the truck, a fabric tape measure works well, but if you don’t have one, you can use any length of string. Just mark the string, lay it out flat, and then measure it using a regular tape measure or yard stick.
  • When making the circumference measurement, make sure to place the string around the trunk at about 4’6″ from the ground… this is about the height of a standard counter top, plus about a foot.

Keep reading to learn more about the age of any tree.

In general, if you see more than seven (or eight) annual growth rings per centimeter, your tree is quite old; if you see fewer than five or six per centimeter, it’s probably younger than that; and if there are none at all, then you have an ancient specimen whose age may be impossible to determine with confidence.

How To Tell Age of Tree Without Cutting it Down?

Knowing a tree’s age is an essential aspect of tree management. It determines how fast a tree grows, how long it will stay alive, and whether or not it needs to be cut down. There are many methods to determine the age of a tree without cutting into it, but they all have their drawbacks. Some of these methods include:

  • Stem diameter2 (the larger the diameter, the older the tree)
  • Bark thickness (the thicker the bark, the older the tree)
  • Millimeter-scale growth rings in the trunk (the more rings present in a section of the trunk, the older that section is)

How To Count Tree Rings for Age?

Tree rings are natural markings on the tree trunk that indicate how old it is. A tree’s age can be determined by counting the number of rings, which is how scientists date trees. The number of rings on a tree varies by species and location, so it’s important to know what kind of trees you’re working with when estimating their age.

The amount of information found in these rings depends on many factors, including climate and soil conditions. For example, the temperature will affect how fast your tree grows if you live in a cold climate. This means your tree will have fewer rings if it lives in a cold climate than if it lives in a warm one.

Related Reading: How many trees does it take to build a house?

Counting tree rings can be tricky because there are so many variables involved! If you don’t have experience counting tree rings, it’s best to find someone who does this regularly or hire an expert to help you!

How To Use Mitchell’s Rule Tree Age Calculator

Mitchell’s rule helps calculate a tree’s age by assuming that a tree’s girth expands by about 2. 5 cm each year.

This means you can measure the girth of a tree and divide it by 2.5 to get the age. But, it’s not always the most accurate method.

Related Reading: How many Christmas trees per acre can you plant?

Instead, by using a tree’s specific growth factor, you can approximate its age and still enjoy the stunning beauty of the living tree.

Tree Diameter Age Estimation Chart

One of the most dependable ways to estimate the age of a tree is by multiplying its diameter by its growth factor. Below are the growth factors for some common tree species.

Tree SpeciesGrowth Factor
Red Maple4.5
Silver Maple3.0
Sugar Maple5.5
River Birch3.5
White Birch5.0
Shagbark Hickory7.5
Green Ash4.0
Black Walnut4.5
Black Cherry5. 0
White Oak5.0
Red Oak4.0
Pin Oak3.0
American Elm4.0
White Ash5.0
Aspen spp2.0
American Beech6.0
European Beech4.0
European White Birch5.0
River Birch3.5
Paper Birch (aka White)5.0
Yellow Buckeye5.0
Kentucky Coffeetree3.0
Douglas Fir5.0
White Fir7.5
Common Horsechestnut8.0
Littleleaf Linden3.0
Black Maple5. 0
Norway Maple4.5
Northern Red Oak4.0
Scarlet Oak4.0
Shingle Oak6.0
Shumard Oak3.0
Bradford Pear3.0
Austrian Pine4.5
Red Pine5.5
Scotch Pine3.5
White Pine5.0
Tulip Poplar (Tulip Tree)3.0
Colorado Blue Spruce4.5
Norway Spruce5.0
American Sycamore4.0

How Old Is a Tree With 3.0 Rings?

If you want to know how old a tree is, and have a number like 3.0, it’s the growth factor. A growth factor is a rate at which a tree grows.

Pin oak, Silver maple, and linden have a 3.0 growth factor. You should find the diameter of a tree and then multiply it by the growth factor (3. 0). For example, if the diameter of a silver maple is 16 inches, its age is 48 years.

Related Reading: How many pieces of paper in a tree?

How To Find the Maximum Age of Tree

There is no correct answer to this. The maximum age depends on various things such as the weather, soil, and other factors that may affect its age. If you are looking for the maximum age of a tree, you can use an online calculator, which will give you a range of ages for your tree.

The best way to find out how old a tree is is to look at it yourself. You can use a ruler or tape measure and see if there are any evident signs that your tree has reached its maximum age. You should also remember that trees grow at different rates depending on their species, climate, soil type, and other factors, so it is impossible to say how old your tree will grow without researching first!

How To Figure Pine Tree Age by Diameter

Pine trees are often used for landscaping purposes, and their age can be determined3 by measuring their diameter and multiplying it by the growth factor.

Start by taking hold of the tree’s trunk and measuring the circumference. For example, if the circumference is 20 inches, the diameter will be 20 divided by 3.14. This will give you 6.36.

Related Reading: How many trees are planted each year?

The growth factor of a pine tree is 5.0. So the pine tree’s age in this example would be approximately 31.8 years.

International Society of Arboriculture Tree Growth Factor

The International Society of Arboriculture uses the diameter of a tree to figure out its age, which is then used to determine whether or not a tree is healthy.

The diameter is measured by figuring out the circumference of a tree first. Use a tape measure to measure the tree’s circumference and divide the number by 3.14. Once you have the diameter, multiply it with the growth factor to get the tree’s age.

How To Tell How Old a Tree is by Rings

A tree’s lifespan is determined by how often it produces and sheds its leaves and how much water it receives. A tree’s age can be determined based on its size, the number of rings in its trunk and branches, and whether or not the tree is still alive and growing.

The number of rings that your favorite tree has can be used to determine its exact age. Your local park department may also have an arborist who can tell you how old your favorite tree is based on its appearance and size.

Related Reading: How many trees are in the world?

There are several types of trees with varying methods for determining their ages. The deciduous (or “leaf”) tree is the most common type of tree; these include maples, elms, oaks, and birches. Other types include conifers (including pine trees) and evergreens (spruce trees, cypresses, and cedars).

Some trees have unique characteristics that allow for easy determination of their ages; for example, maples have visible rings which can be counted as part of determining their age.

How To Tell How Old a Pine Tree Is

It’s easy to determine the age of a pine tree. You first need to find the diameter of the tree. You can do this by measuring the circumference and dividing it by 3.14. Once you have the diameter, you multiply it by the growth rate.

The growth rate for a pine tree is 5.0. This calculation helps you determine the age of any pine tree.

How To Tell How Old a Palm Tree Is

Usually, the best way to tell the age of a tree4 is by looking at the trunk’s rings. However, palm trees do not have very thick trunks, so this method would be complicated.

You can check a palm tree’s age by checking if it survived radiocarbon dating. This is a method that checks the chemicals and assesses the age of the tree. Since this method is scientific, you would need an expert to help determine this.

This method, however, does not account for ailments and habitat. These factors do hinder growth.

How To Tell How Old a Redwood Tree Is?

To determine how old your tree is, simply use the ring method. The more the number of rings, the older the tree is. Most redwood trees live long, so this method may be time-consuming and frustrating.

Redwoods also have scars from diseases that affect their growth rate, but these scars do not always appear on the outside of their trunks.

If you see a dark patch on a redwood’s outer bark or trunk, this means there was a large-scale infestation of fungal root rot that caused damage to some parts of the tree’s root system. This is also a factor you should consider when calculating its age.

What Do Tree Rings Mean?

Tree rings are a form of tree growth that can indicate the age of a tree. It is essential to know when an individual tree was planted and how old it is. This can be used to determine whether or not a species is growing at the rate it should be.

To understand what tree ring samples mean, you need to understand what they are and why they’re essential. Tree rings are made up of a series of layers that form around a tree trunk after it has been cut down or pruned, which makes them easy to identify.

The different layers form in different parts of the tree depending on what caused them to grow in that area. For example, if an insect attacked the bark during growth, that part of the ring will show up as more brittle than other parts due to lackluster growth during that period.

Are Thick Tree Rings the Same as Smaller Rings?

The answer is yes, but not in the way you might think. Thick tree rings are a marker of a tree that grew in more favorable conditions. The thicker the ring, the more years and growth cycles it took for the tree to reach its full height.

This means that it could bloom and produce fruits earlier than other trees of its species.

Related Reading: How much carbon does a tree capture?

Smaller rings mean a tree did not reach its full height because it lived during a period when weather conditions were less favorable for growth. In other words, some trees do not grow larger than others because they couldn’t thrive under ideal conditions.

How Are Black Tree Rings Formed?

Black tree rings are formed when a tree grows during late summer and fall. This is because the leaves on a tree are still alive at this time and produce sugars. The sugars are then transported to the leaves through photosynthesis, which converts them into starch.

When the leaves wither back in the spring and summer, it’s only then that the sugars begin to be depleted. The trees begin to store energy by building up their wood matter, especially if there is not enough food available for them during their winter months.

They also begin to lose their leaves early in the spring because they do not have enough energy from photosynthesis to maintain them throughout the warmer season.

The trees’ reserves of energy are depleted as they cannot produce enough starch during these months while they build up more wood structures in preparation for winter.

How To Care for Older Trees?

Trees are an essential part of the ecosystem and can be a great addition to the landscape. However, there comes a time when you need to learn how to care for your trees and keep them healthy and happy. If you have older trees in your yard, you will want to know how to care for them so they can live a long healthy life.

The first thing you should do is make sure that you are watering your trees properly. If they are not getting enough water, they might not be able to grow to their full potential. You should also ensure that the soil around your tree is good and has plenty of nutrients so the roots can get what they need from there.

You should also ensure that all dead branches on your tree are cut off before winter comes because this will help protect them from freezing during cold weather. While it may seem easy at first glance, it requires some work upfront so that you can enjoy these beautiful trees for years to come!

Trees provide the planet with a much needed, and abundant source of carbon capture technology. Older trees especially need to be protected using carbon offset tree planting strategies and many of the best carbon offset programs do just that. These older forests work to reduce the overall eco footprint of the planet, and can be strengthened with new growth while protecting the old growth.

Are Older Trees More Susceptible to Diseases?

Trees over 30 years old are more susceptible to diseases5 because they have already had many years to develop their immune systems. If you have an older tree, it’s essential to ensure that you take care of it properly to prevent disease.

This means regularly watering the tree, keeping the soil moist, and not allowing the roots to dry. Ensure your tree gets enough sunlight by placing it where it gets plenty of natural light throughout the day. If you have a large tree, consider planting it near a fence or other structure so that it can get shade during hot summer days.

Can You Tell the Age of a Tree by Looking at its Leaves?

If you are looking for information about trees and how they grow, then yes, you can! Trees have leaves because they need them to photosynthesize. This means that they need sunlight to survive. When a tree is young, its leaves will be green and healthy. As it grows older, the leaves will begin to change color and become more mature.

If you want to find out how old a tree is, use the ring counting method. This will give you an idea of how long it has been since it was planted.

You can also use this method when you’re trying to determine if your tree is healthy or not. If there are cracks in the bark or pieces missing, this could mean that the tree needs some TLC before it can live another day!

It’s essential to know a tree’s age so you can care for it adequately. It’s also important to know the specific kind of tree you have and what its health needs are.

For example, if your tree has brown spots on its leaves and looks unhealthy, you might suspect a fungal infection. If you suspect this, it is recommended that you call a professional to come out and assess your tree.

The best way to care for your tree is by keeping it healthy, which means being able to monitor the health of its roots and trunk and applying natural pest fighters and fungal treatments when required.

As you know, a tree’s lifespan is directly linked to how well it’s cared for. A tree expert will be able to recognize a variety of indicators that provide clues to its age. So, if you want to maximize your enjoyment of the beautiful trees around you, it’s worth investigating if you could do anything better for them. Knowing how to tell how old a tree is can help you inspire others with a love and respect for these vital parts of nature.

Determining the age of trees in different ways

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We would like to start our research work with the fact that on one of the warm September days we went with our class on an autumn tour of the village of Pilna and looked into the Pilna park, located on the banks of the Pyana River. Our attention was drawn to the fact that the same-looking tree has a different height and thickness of the trunk. We noticed that the park has many different types of trees in good condition. But in the park there are sawn, broken and withered trees, there are overgrowths - and sometimes it’s hard to understand where the alleys are.

While examining the trees in the village and the park, we had a question: how long is the age of a tree? How to determine the age of a tree? The teacher told us that trees, like people, have their age. One tree can grow for several decades, another for several centuries. Throughout life, it is constantly growing, but only slowly.

We live in the countryside. Thousands of cubic meters of wood are burned in the furnaces of saunas and houses. Few of the residents think about what trees were sawn for fireboxes and cut down for household needs and construction. Some residents of the village of Pilna have an idea of ​​the park's trees as a property that does not belong to anyone. It is today that the nature that surrounds us is experiencing the growing influence of man


Interest in the study of trees growing in the park and the village of Pilna, and the acquisition of skills and abilities to determine the age of trees in various ways - purpose of our research work.


To achieve this goal, it is necessary to solve the following tasks:

Familiarize yourself with various methods of determining the age of trees.

Learn to work with different sources of information:

a) specialized literature on the topic

b) Internet

Select material (saw cuts) for research.

Analyze the collected material for research and make the necessary calculations, formalize the data of your research.

Observe, generalize, draw conclusions that will confirm the hypothesis.

Draw the attention of people or the population to the importance of green trees.


We assume that the age of a tree can be determined by certain signs.

Research period: from September 20, 2020 to February 20, 2021

Research methods: observation, survey, analysis, photography

Object of research: tree age

90 in the park and in the village of Pilna, tree cuts

Research work on the topic: "Determining the age of trees in different ways" consists of two parts: theoretical and practical.

Chapter 1. Theoretical part.

Research methods. Methods for determining the age of trees.

Eyewitnesses survey

for mutations



according to the characteristics of the bark

in the thickness of the barrel

for annual rings

1.1. Interviewing eyewitnesses

Obtaining information about the date of planting a tree is the most correct source. This can be a survey of old-timers or viewing old photos from eyewitnesses of tree planting, by whom it was planted and when.

1. 2. Determining the age of a tree by the features of the bark

The age of a tree can be determined by the features of the bark. If you look closely, you can see that the bark of young trees is thin, smooth and clean. And with age, the bark of trees changes, becomes dark, becomes covered with cracks, not only the color changes, but also the bark. It becomes thick with old trees and begins to crack.

1. 3. Determining the age of trees by trunk thickness

To do this, measure the circumference of the tree trunk at 1.5 m above the ground. From the scientific literature, we learned that each tree, on average, is 2 cm-2.5 cm thick per year. And if the forest is frequent, then this figure is 1 cm-1 cm. 5 mm. This method of determining the age of trees does not disturb the growth of trees.

1. 4. Determination of age by tree rings

Tree rings - a layer of wood growth for 1 year. An accurate way to determine the age of trees is to count the growth rings on the log cabin of the trunk. How many rings - so many years for a tree. It should be noted that trees always form one annual ring per year. Weather conditions and other reasons lead to the formation of several rings or, conversely, the absence of rings in a year. From the log cabin of the trunk, you can find out in which year the conditions for growth were favorable.

Studying the literature on this topic, we learned that growth rings are counted at a height of no more than one and a half meters (50 cm). You need to count from the center. Rings can be of different sizes depending on weather conditions. On the saw cut, you can see dark and light rings, they alternate. We count only light rings or dark ones. In some trees, the core begins to rot with age. Annual rings that are inside the trunk are destroyed, forming a hollow. It is impossible to determine the age of such a tree.

1. 5. Determining the age of trees using the Pressler age drill.

The drill is screwed into the trunk to its very core, then the drill is removed. When screwing in, wood gets inside the drill, which shows the number of growth rings. How many rings - so many years for a tree. From the Internet, we learned that a drill is required for measurement, the length of which is not less than seventy-five percent of the diameter of the trunk. When determining the age of a tree with a drill, a small hole is formed in the tree, not through. But the trees themselves heal the wounds inflicted on them, since they secrete sap, resin in the place of the wound and fill the wound-hole with it, which prevents insects from penetrating inside the tree - this does not harm the tree.

1. 6. Determining the age of trees by whorls.

Whorls are used to determine the age of coniferous trees (spruce, fir, pine). Whorls are a group of branches that diverge in a peculiar way on a tree trunk. Every year, the trees grow several branches at the same level. If we count the number of whorls and add 3 years for pine, 4 years for spruce, because such branches do not form in the first years. By counting the whorls, we got the approximate age of the tree.

Whorl is a group of leaves, branches or flowers located on the stem at the same height in conifers.

Chapter 2. Practical part

Research results.

Conducting a survey.

Trees always attract attention and amaze with their size. We became very interested in what our classmates and students of other classes know about the age of trees and by what signs. We compiled a small questionnaire, which reflected the following questions: How many years do you think trees live? Name what trees? What do you think, what external signs indicate the age of trees? Do you think it is possible to determine the age of trees without cutting them down? Should old trees be preserved? We interviewed the guys 16 guys from their 2nd "G" class and 14 people from the 5th grade. A total of 30 people were interviewed (Appendix 1). The data obtained during the survey, we analyzed and entered into the table.

Analysis of the results of a survey of students in our school (30 students).



Answer options

Number of students



How many years do you think trees live? Name what trees?

1000 (Oak)


3. 33%

500 (spruce)



150 (birch)



100 (aspen)



50 (apple)




What external signs do you think tell about the age of trees?

Number of branches


Bark type

Girth of the trunk

Crown sizes


16. 67%










Do you think it is possible to determine the age of trees without cutting them down?



63. 33%





Should old trees be preserved?







As a result of the analysis of the answers, we found that many students approximately know how many years trees live, from 50 to 1000 years.

Many students wrote that the age of trees can be determined by the height of the tree. 63.33% of children believe that it is possible to determine the age of trees without cutting them down, while 11 people believe that they cannot. Almost all students believe that old trees should be preserved, because by preserving trees, we save nature. They are not only monuments of wildlife, but also witnesses of extraordinary events that took place in the history of the Pilna land.

We examined the age of trees in several ways.

2.1.1. The first method is a survey of other people. We investigated when birch trees were planted in our Pilnin park. After interviewing the oldest resident of the village of Pilna, Ekaterina Grigorievna Galkina, we learned about the history of the Pilna park.

In the 50s the last street of the village was Rechnaya street. Follow her to the river. Piana was a huge wasteland with thorny vegetation. In 1956, on the eve of the 40th anniversary of October, the authorities thought about this territory.

GV Voronin was the surveyor at that time. He was instructed to measure the wasteland and draw a plan for the proposed park, which, in honor of the approaching date, they decided to call 40 years of October.

One autumn day in 1957, an activist gathered in the Leninsky garden to discuss everything related to the planting of a new park. Voronin's plan was approved, and it was decided to plant birches. The seedlings were taken in the Zhdanovsky and B-Andosovsky forests. The inhabitants of our village lovingly nursed their birch trees and watered them. After 5-8 years, a young birch round dance began to be visible in the wasteland.

According to eyewitness accounts, the birch trees in the Pilna park are 64 years old (2021-1957=64 years). And they interviewed the supply manager of our school Kazachkov E.G. We were interested to find out how old the birches that grow near the school are. The birch trees were planted in 1998 and were looked after by the students of the school in the first years. We calculated 2021-1998=23 years (Appendix No. 2).

2.1.2. The basis of the second research method lies in the analysis of the features of the cortex. Examining the birch bark near the old school, we noticed that the bark in the lower part of the trunk up to a height of 2.5 meters is completely black. It is covered with cracks and grooves, uneven and hard. There are a lot of lichens on the birch. This indicates that the tree is old. And on young birch trees, we saw a white, smooth and thin bark (Appendix No. 3).

2.1.3. We determined the age of the trees near one of the houses in the village and in the park by the thickness of the trunk. Together with the teacher, we measured the thickness of the trunk with a tape measure at a height of 1.5 m above the ground. The thickness of the willow trunk turned out to be 210 cm. It is believed that, on average, a tree grows in thickness by 2-2.5 cm per year. The teacher helped us calculate the age of the willow 210:2.5=84 years (Appendix 4, 5).

2.1.4. The next method of studying age is the study of saw cut. The study of saw cut is based on the method of ring analysis. From the sources, we found out that trees have the property of growing every year for a one-year ring.

We tried to determine the tree's age and growing conditions from the rings.

For the study, we took a cross cut of a linden tree. First, we carefully examined the saw cut with a magnifying glass, tried to make out the rings on the log cabin of the tree. We counted 5 annual rings. In the center they saw a loose core. The age of the tree is approximately 4-5 years. The width of the annual rings on different sides of the tree turned out to be approximately the same. The tree, apparently, grew on moist soil, fed enough. The condition of the wood was helped to determine the biology teacher of our school (Appendix 6).

We have noticed that some trees seem to start to rot at the core with age. Annual rings that are inside the trunk begin to collapse, forming a hollow. It is impossible to determine the age of such a tree. We were not able to count the number of growth rings in the old tree, because the wood in the center rotted, a hole formed (Appendix 6).

2.1.5. We learned from the Internet that it is possible to determine the age of a tree without damaging it with a device called a drill.

Use it to remove a pencil-thick piece from the trunk and count annual rings from it. Trees do not suffer from this. But we, unfortunately, could not find such a device in the Pilnin forestry.

2.1.6. Whorl age determination. To determine the age of the coniferous tree near the administration, we used whorls. This method is applicable only for coniferous trees that are no more than 30 - 40 years old. Whorls are a group of branches located on the stem at the same height. From the scientific literature, we learned that every year a tree grows several branches at the same level. We counted the number of whorls, it turned out to be 40, and 4 were added to the result, because branches are not formed in the first years. By counting the whorls and adding 4, we got the approximate age of the spruce: 40 + 4 = 44 years. So, they ate near the administration for about 44 years (Appendix 7).

As you can see, there are several methods for determining the age of trees. Some of them are quite correct, while others are not very accurate. These methods require damaging or cutting down the tree, while others require determining the age by calculating or collecting information about the tree's planting date. We believe that it is better to use methods that allow you to know the age of a tree without destroying it.

So, our hypothesis was confirmed: the age of trees can be determined by certain features.

In the course of our research work, we studied the age of trees in the Pilna park and in the village of Pilna and found out that the oldest tree is a willow that grows on one of the streets of the village. She is 84 years old, according to the stories of old-timers, she was planted by one of the residents of the village (Appendix 5).

During the search and study of the age of trees:

learned to determine the age of trees in different ways

learned what types of trees grow in the park and on the territory of the village of Pilna

learned a lot of new and interesting things while researching the history of tree planting


In the course of doing research, we learned that trees are the lungs of our planet, and thanks to them we breathe. But most importantly, we realized that by preserving our trees and nature, we are not only protecting it, but also preserving history.

We presented our research first in front of the class, and then at the school scientific and practical conference. Then they conducted a survey in the class. We asked our classmates why it is necessary to protect green spaces-trees? Most of the guys answered that without a reason it is impossible to cut down trees, as they grow very slowly. Each person should take care of the trees and take care of those trees that grow nearby and have their own history. They are of great benefit. And we came up with a proposal to hold community work days in the Pilninsk park every spring to clean up the park area and participate in the Feed the Birds in Winter campaign - after all, birds are orderlies of forests and parks (Appendix 8, 9).


Anuchin N. A. Forest Encyclopedia: In 2 vols. V.1 / Ed. G.I. Vorobyov, N. A. Anuchin, V. G. Atrokhin, V. N. Vinogradov and others - M .: Sov. Encyclopedia, 1985.

Bedouer K. Trees//Mini-encyclopedia in pictures. – M.: Makhaon, 2001.

Vohrintseva S.V. Trees and Leaves//The World Around: Fantasyland, 2003.

Golovkin B.N., Mazurenko M.T. I cognize the world//Encyclopedic edition - M.: LLC Astrel Publishing House, 2002.

Trees [Electronic resource]: Wikipedia. Free encyclopedia. – URL: http :// ru . Trees. - M.: Ast-Press, 1996.

Kozlova T. A., Sivoglazov V. I. Plants of the forest -. In 2 hours - M. "Enlightenment", 2014.

Tikhonov A.V., Rysakova I.V. Nature of Russia- Definition. - V. Rosman, 2009.

Appendix 1


Appendix 2


9000 9000 9055 90AL

We interviewed the supply manager of our Pilninskaya secondary school No. 2 named after. A.S. Pushkina Kazachkova E.G.

Birches were planted in 1998 by schoolchildren. We calculated: 2021-1998 = 23 years old birch near the school.

Appendix 3

Determining the age of trees by the features of the bark

Judging by the features of the bark, this tree is old, it has formed a hollow, ants have made their dwelling there.

Young birches have thin, smooth and clean bark. These are young birches.

Annex 4

Determining the age of trees by stem thickness

The birch in the park is about 40 years old.

The age of the birch near our school is approximately 23 years 58 cm:2.5 =23 years

Determining the age of trees by trunk girth

Appendix 5

The oldest trees in the village

The oldest tree in the village of Pilna is the willow, it is 84 years old.

This is a poplar, he is 82 years old.

Appendix 6

Determining the age of trees by annual rings

A saw cut of a fallen linden tree. The tree is about 5 years old.


barrel samples

Studying tree rings

Some trees begin to rot with age. In this case, the inner annual rings are destroyed, forming a hollow. It is impossible to determine the age of such a tree.

Appendix 7

Determining the age of coniferous trees by whorls

We counted 40, 45 whorls near the fir trees near the administration of our village, 40 + 4 = 44 years. Eliam is about 44-45 years old.

Appendix 8

Research work and community work in the park

We came up with a proposal to hold community work days in the park every year to clean up the park.

Trees are the lungs of our planet

The oldest birch in the park

We found out what trees grow in the park

Appendix 9

Feed the Birds in Winter Campaign

Participate in the school Feed the Birds in Winter campaign.

How scientists determine the age of things

Method one: dendrochronology

Tree growth rings are a pattern created by climate change. This pattern remains on old buildings and other wooden things and betrays their age.

How it works

Any schoolchild knows that the age of a tree can be determined by the number of growth rings on the cut. They appear due to the fact that in summer the tree grows quickly, and in winter cold growth slows down. Therefore, on the cut one can see the alternation of wide light rings of the warm season and narrow dark ones of the cold season.

Tree stump rings tell more than just the age of the felled tree. They judge climate changes: one year could be dry - and the tree grew more slowly, and the second, on the contrary, turned out to be rainy, and the tree grew great. Therefore, trees growing in the same region at the same time develop a similar pattern of growth rings. Scientists make archives of these patterns, then compare them with the pattern of wooden archaeological finds and determine the age of the finds. Wood clocks cover a period of more than 8000 years, and their accuracy reaches 1 year: after all, a tree adds only one ring per year.

Application example

In Veliky Novgorod, dendrochronology was used to date ancient pavements. A long time ago, Novgorod streets were narrow, three to four meters wide, but they were paved with glory: three pillars of logs with a diameter of 18-20 cm were laid along the street, and thicker logs with a diameter of 25-30 cm were laid on top. Approximately once every 20 Over the years, this impressive wooden structure has been renovated, and new logs were laid on top of the old logs. Such are the puff pies of wooden pavements: in some places, as many as 28 tiers have been preserved! Dendrochronologists had a place to roam.


Dinosaur bones also have growth rings (as well as amphibians, reptiles and some mammals). Light rings are wide and looser layers of bone tissue, which are laid down during periods of active growth: in spring and summer. And in winter, thin and dense layers formed. By peering into the rings of a dinosaur, scientists can understand how it grew and developed over its lifetime.

Second method: geochronological record

Different fossil animals and plants are characteristic of different geological periods. Almost like in the Chinese calendar: only instead of the year era - trilobites, unicellular fossils, etc. If an archaeologist or geologist has found such a characteristic fossil, then you can determine the approximate age of the reservoir.

How it works

Here lies a layer of rocks in front of the archaeologist. In this bed, he found some kind of fossil and is trying to figure out how old the fossil is. Guiding fossils will help him establish the geological era - plants and animals characteristic of a certain geological period, but not found either earlier or later.

To qualify as a leading fossil, a fossil must meet several difficult requirements: it must be easily recognizable, occur frequently in sediments, have a wide geographic distribution, and have a narrow time frame. If an archaeologist or geologist saw acritarchs * in the excavated layer, then he was in the Upper Precambrian. And if you stumble upon the shell of extinct arthropod trilobites, then the geochronological clock has struck the Cambrian**.

*Acritarchs are microscopic fossils of unicellular or seemingly unicellular organisms.

**Cambrian is a geological period that began 540 million years ago. We know little about the inhabitants of the Precambrian, and the Cambrian is characterized by the appearance of a mass of diverse multicellular creatures - the Cambrian explosion.

Application example

In 2014, members of the Pavlodar Geographical Society decided to go on a small expedition to the Shiderty River. It would seem that an ordinary river in the middle of the steppe, on the bank of limestone, some pebbles. But it was worth taking a closer look at the pebbles: some of them turned out to be fossils of ancient brachiopod molluscs. Yes, yes, in the steppe, far from the sea and the ocean, scientists have found the remains of marine animals. These fossils seem to whisper to researchers that hundreds of millions of years ago, in the far, far Devonian, the ancient Tethys ocean raged here.

Third method: radioisotope dating

Time passes - radioactive isotopes decay. If you know what fraction of the isotope has decayed, you know how much time has passed.

How it works

The guide fossils described in the previous chapter are a way to measure the approximate age of a find. To determine it more precisely, scientists use radioisotope dating. If an object contains a radioactive isotope*, then, based on its half-life and how much of the isotope has decayed, you can calculate the age of the object.

*Isotopes are varieties of the same chemical element with different numbers of neutrons in the nucleus. There are stable isotopes, and there are decaying over time - radioactive.

The most famous variation of this method is radiocarbon dating. Living organisms, along with food, absorb both ordinary carbon 12C and radioactive 14C. But when a plant or animal dies, it stops exchanging radioactive carbon with the environment. Remaining in the body, it gradually disintegrates, and its residual proportion becomes an indicator of age.

The limit of radiocarbon dating is 55,000-60,000 years. But there are other isotopes that allow you to look much further into the past. They are also used to measure age. For example, a very convenient mineral is zircon, it is used for uranium-lead dating of rocks. Zircon contains uranium isotopes, which then decay into lead isotopes. The starting point - analogous to the moment of death of an animal for the radiocarbon method - is the crystallization of zircon during lava cooling. There are other methods: potassium-argon, argon-argon, lead-lead.

Application example

In 1988, a report on radiocarbon dating of the famous Christian shrine - the Shroud of Turin, made a lot of noise. The traditional version says that this canvas contains traces of the blood of the crucified Christ, that is, it refers to the 1st century AD. But radiocarbon analysis conducted in three laboratories (Oxford University, Arizona State University and the Swiss Institute of Technology) showed that the shroud is much younger - about 1200-1300 years old. Around the same time, in 1353, the first mention of the shrine was recorded.

Fourth method: spectral analysis and gyrochronology

How to understand how old a star is? After all, it is impossible to reach out to it and take a piece for analysis and dating. So you have to watch how it glows and spins.

How it works

Stars age very unevenly: they do not change for 90% of their lives, and then they suddenly begin to transform dramatically. You can imagine it this way: a person reached the age of 3-4 years, then did not change for 80 years, and then turned gray in a year, hunched over and died. Astronomers are in a difficult position: it is very difficult to determine how old a star is.

Fortunately, much can be seen by looking closely at her light. If you expand the spectrum of the Sun, you get a rainbow with thin, thin black lines. These are absorption lines that correspond to different chemical elements. From the spectral absorption lines, one can judge the composition of the star. What does age have to do with it, you ask? The fact is that in the process of a thermonuclear reaction * the hydrogen in the star burns out, and the helium content grows. This means that the older the star, the more helium and less hydrogen in it, and you can see this from the absorption lines in the spectrum.

*We remind you that a star is a giant thermonuclear reactor in which helium nuclei are synthesized from hydrogen nuclei (that is, from protons).

In addition, the age of a star reveals its rotation period*. A young star spins at a certain speed, which steadily decreases as it grows older. One problem - it is difficult to see this rotation, very sensitive telescopes are needed. Astronomers use sunspots as a guide. But working with old stars is problematic because they have fewer and fewer spots. The method of determining the age of stars by rotation is called gyrochronology.

*Stars, like planets, rotate around their own axis. The sun, for example, makes one revolution in 30 days.

Application example

The Kepler space telescope helps scientists observe the rotation of stars - the same one that has already found thousands of exoplanets. To calibrate the gyrochronology method, in 2011, scientists at the Harvard-Smithsonian Center for Astrophysics tracked the 1-billion-year-old star cluster NGC 6811. It turned out that the stars of this cluster rotate around their axis about once every 10 days, as predicted by the method. Scientists decided to track the stars of the older cluster - NGC 6819, they are about 2.5 billion years old. And again, the speed of their rotation coincided with theoretical calculations - the method worked. But the arrows of gyrochronology still have to be tweaked, making adjustments for different groups of stars. Sometimes they don't spin the way the calculations predict. As soon as the magnetic field weakens, the star begins to "younger" - to spin faster.

Method Five: Paleomagnetism

Ceramics and other ferrous materials are a broken compass: they show the Earth's magnetic field of the past. Therefore, the magnetization of antiquities can indicate their age.

How it works

Archaeologists often come across ceramics: earthenware pots broken a thousand years ago, fragments of ancient wine jugs, plates that were once gathering dust in our ancestors’ cupboards, bricks... It turns out that science is capable of to tell when the excavated brick was burned in a furnace or when porridge was last cooked in an ancient pot. The point is paleomagnetism: at high temperatures, iron-containing materials like clay become magnetized, and when they cool down, they seem to “remember” the direction and intensity of the Earth’s magnetic field at a given moment (they are constantly changing, after all). The information that the pot or kiln retained at the time of firing can be analyzed and correlated with the chronological scales of the change in the magnetic field. So scientists find out the age of ancient ceramics with an error of only 10 years.

Application example

In the Trans-Baikal Territory there is a hill strewn with fragments of stones and pieces of tiles; some of them show green icing. In some places, the bases of columns peep out of the grass. This is the Kondui settlement. 600 years ago, here, in the valley of the Kondui and Barun rivers, stood the palace of the Genghisides, the heirs of the great Mongol Khan. Gold-plated discs of dragons glittered on the roof of bright green tiles, and monsters scowled from the walls. During the excavations of the Kondui Palace, archaeologists came across an abundance of building ceramics: several types of bricks, floor slabs, and tiles. So, somewhere nearby there should have been large kilns for firing. Paleomagnetism helped archaeologists find these furnaces. Ancient structures that were once heated to high temperatures remembered the Earth's magnetic field of the past and fonils, creating magnetic anomalies. Scientists identified them using a quantum magnetometer, found furnaces and divided them according to their functions: here they made bricks, and here they made tiles. So we learned a little more about the medieval palace, from which only tiles and a legend remained*.

*Once upon a time rich and powerful Tumur Khan lived in Mongolia. He had a son, Contoy. Traveling around the country, Contoy fell in love with the beautiful Baljit and married her without the permission of his father. Fearing his father's wrath, Kontoy settled near the river Kondui, became a khan and built a palace. But the father did not forgive his son and sent troops against him. The beautiful Baljit was killed, Kontoy was captured, and the palace was destroyed.

Sixth method: epigenetic clock

Cells are traitors worse than wrinkles. In their DNA (and not only in DNA) they store age markers that cannot be hidden.

How it works

Scientists use DNA to determine cell age. The fact is that as the cell determines its profession - whether it will be a neuron or a vessel cell - it winds the genes it does not need into balls and fixes them with something like molecular adhesive tape - methylation. The sections of DNA, on which the methyl group has been hung, become sticky and stick together with each other. Generally, the older a cell is, the more coiled DNA it has.

Knowing that the methylation profile changes with age, Steve Horvath, professor of human genetics and biostatistics at UCLA, analyzed human DNA methylation data for four years. And in 2013, he received an epigenetic clock that makes it possible to determine a person’s age by the methylation pattern of 353 DNA regions with a very small error. This indicator is many times more accurate than many other signs of aging, for example, the length of the DNA end section - telomere.

You can also see how the cage cleans up internal debris. One of the "cleaners" used by the cell is the digestive enzyme beta-galactosidase. It gets bigger with age.

The cell is gradually, division by division shortened. After about 50 divisions, telomeres end, the cell loses the ability to divide and becomes decrepit.

Application example

The Horvat epigenetic clock was first used a few years ago by European forensic scientists. The fact is that when a refugee without documents arrives in the country, his age is estimated by eye or from his own words. It is beneficial for a refugee to reduce his age, because minors have more rights and privileges. For example, they may summon adult relatives to the country or receive a lighter sentence for a crime. For example, in 2018, a young Afghan refugee filed a lawsuit against the police in the German city of Hildesheim demanding to recognize that, as a minor, he can count on concessions. The police responded by turning to age-determining methods based on methylation patterns. The actions of the authorities were then criticized because of the immaturity of the technology. But will the "Horvat's watch" ever mature?

Stress instantly made her an old woman!

Unlike a person, a cell can become decrepit at any moment - no matter how old it really is. To age, a cell only needs to be exposed to severe stress, such as exposure to toxic substances. After such a shock, she refuses to work normally and benefit the body. Scientifically decrepit cells are called senescent.

Seventh method: measuring the temperature of a corpse

We saved a gloomy example for the brave in spirit for the finale. It's not really about age - it's more about the fact that the medical examiner must carefully examine, sniff, feel the corpse and take its temperature in order to determine the approximate time of death.

How it works

There is a common plot in TV series about forensic science: a medical examiner moves his hands over the body, drops something into a test tube, looks through a microscope and names the exact time of death. In reality, everything is not so sterile-contactless. Rough and approximate indicators of the time of death are rigor mortis and cadaveric spots. Rigor occurs because muscle cells need energy to relax, and a dead body does not have it. Stopped blood circulation is to blame for the spots: the heart and vascular tone no longer drive the blood, therefore, under the influence of gravity, it moves and accumulates on the underside of the body.

The medical examiner can examine muscle irritability in a variety of ways. But most often he uses a simple and accurate method - temperature measurement. While the body has not yet cooled down to the ambient temperature, cooling occurs according to a certain schedule. The medical examiner measures the temperature, enters correction factors into the formula depending on body weight and cooling conditions (ambient temperature, clothing, humidity, and so on) and, taking into account other signs, sets the approximate time of death. Only the temperature must be measured very accurately: the usual method of "thermometer under the arm" is not suitable, nor is an infrared thermometer. The temperature has to be measured rectally.

Application example

Researchers in the Netherlands have recently suggested determining the time of death by skin temperature rather than rectal temperature. This method allows you to set the moment of death with an accuracy of 38 minutes, and not with an error of several hours, like earlier methods. Scientists came up with a mathematical model of cooling: they took the shape of the head as an ellipsoid, the limbs as cones, and the torso and neck as cylinders. Cooling time was then modeled for each item, taking into account body weight, thermal conductivity of fat, lean tissue, and cotton garments. They also examined the bodies of donors who bequeathed themselves to science. The method worked: the predictions that the model gave out coincided with the temperature that was observed in reality.

Prehistory of the scientific measurement of time

6000 BC e. - Sumerians in Mesopotamia use the concepts of "year", "month" and "zodiac".

At this time, the Sumerian zodiac is 36 constellations in which the Moon appears, and not the Sun, because the first calendar is lunar. Later, the Sumerians will come up with a "week".

5000 BC e. - the first annual calendar circles known to science.

Even then, on the territory of modern Germany, the beginning of the new year, like here, fell on the winter solstice.

3300 BC e. - the first sundial.

Discovered in 2013 in the Valley of the Kings in Egypt.

3000 BC e. The ancient Egyptians use the solar calendar.

A year consists of 365 days and is divided into 12 months of 30 days. The remaining five days are added at the end of the year.

2500-1300 BC e. - Water clocks are used in Persia, Mesopotamia, Egypt and China.

Water clock is a device for measuring time intervals in the form of a cylindrical vessel with a jet of water flowing out.

45 BC e. - Julius Caesar introduces the calendar developed by Alexandrian astronomers, named after him Julian.

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