# How to determine age of tree by diameter

## Tree Age Calculator - How Old Is a Tree?

Created by Mehjabin Abdurrazaque

Reviewed by Wojciech Sas, PhD candidate and Rijk de Wet

Last updated: Sep 28, 2022

Table of contents:
• How to calculate the age of a tree?
• How to use tree age calculator?
• Tree growth factor chart — the smaller, the faster!
• FAQ

The tree age calculator guides you on how to calculate the age of a tree to understand its ecological and economical benefits, as you can learn at the tree value calculator. Our tool also tells you how much a tree grows in diameter or circumference in the given time so that you can design your yard suitably.

We also try to answer some interesting questions like:

• Do trees die of old age?
• How to tell how old a tree is by counting its rings?

And, don't forget to check our tree growth factor chart to find the fast-growing trees in your neighborhood!

### How to calculate the age of a tree?

The formula for calculating a tree's age is

age=gf⋅dbh\text{age} = \text{gf}\cdot \text{dbh}age=gf⋅dbh

Where:

• age\text{age}age — The tree's age in years;
• gf\text{gf}gf — The tree growth factor; and
• dbh\text{dbh}dbh — The diameter at breast height in inches.

Follow these steps to find your tree's age using this formula:

1. Measure the circumference at breast height (cbh) of the tree trunk using a measuring tape at 4.5 feet (1.3 meters) above the ground.
2. Divide the circumference cbh by pi (≈3.14) to obtain its diameter at breast height (dbh\text{dbh}dbh).
3. Convert dbh\text{dbh}dbh to inches.
4. Multiply the diameter in inches with the tree species' growth factor.

Growth factor of a tree
To determine a tree species' growth factor, scientists first estimate the actual age of trees of that species by counting their growth rings. Then, they divide the trees' diameters at breast height (we met this quantity at our tree diameter calculator) with their actual ages to obtain the tree species' growth factor.

### How to use tree age calculator?

It's very simple: select the type of tree and input the tree's circumference or diameter. 😎✨

Suppose you want to know the age of your red maple with a circumference of 6 feet and 3 inches (= 2 feet in diameter). To determine your tree's age using our tool, you'd follow these steps:

1. Scroll down the tree species' drop-down list and select Red maple.
2. To calculate your tree's age from its circumference:
• Choose the unit for circumference at breast height (cbh\text{cbh}cbh) from the drop-down list beside its input box. For your red maple, the unit is feet/inches. Then enter the circumference of 6 feet and 3 inches (if you are not familiar with this way to express length, visit the feet and inches calculator).
• Enter the tree's circumference in the input box — 666 in the box to the left of ft\text{ft}ft and 333 in the box to the left of in\text{in}in.

Ta-da! The calculator shows your tree's diameter at breast height (dbh\text{dbh}dbh) is 61 cm61\ \text{cm}61 cm (you can convert the length to obtain the diameter in feet or feet and inches) and its age 107 years107\ \text{years}107 years! It's a centenarian!

If you want to tell the tree's age from its diameter:

• Choose the unit for diameter at breast height from the drop-down list beside its input box — feet ($$\text{ft}$$).
• Enter your tree's diameter in the input box — 222.

🙋 If you can't find your tree in the list, enter your tree's growth factor in the input box for Growth factor. Most tree species have growth factors of 3, 4, or 5.

Did you know that you can roughly estimate your tree's birthday using our date calculator! Just enter your tree's age in days and today's date in our tool, and you can obtain a date close to your tree's actual birthday.

### Tree growth factor chart — the smaller, the faster!

You can use our tree growth factor not only to calculate your tree's age but also to learn which trees grow faster than your tree. The rule is: The smaller the tree growth factor, the faster the tree grows.

While you are here, check out our tree spacing calculator. It will help you determine the correct distance for planting different types of trees.

The tree growth factor chart for many different species of tree.

Tree species

Growth factor

American beech

6

American elm

4

American sycamore

4

Austrian pine

4.5

Basswood

3

Black cherry

5

Black maple

5

Black walnut

4.5

Black willow

2

Box elder

3

Bradford pear

3

Common horse chestnut

8

Colorado blue spruce

4.5

Cottonwood

2

Dogwood

7

Douglas fir

5

European beech

4

European white birch

5

Green ash

4

Honey locust

3

Ironwood

7

Kentucky coffee tree

3

Littleleaf linden

3

Northern red oak

4

Norway maple

4. 5

Norway spruce

5

Pin oak

3

Quaking aspen

2

Redbud

7

Red maple

4.5

Red pine (Norway pine)

5.5

River birch

3.5

Scarlet oak

4

Scotch pine

3.5

Shagbark hickory

7.5

Shingle oak

6

Shumard oak

3

Silver maple

3

Sugar maple

5.5

Sweetgum

4

Tulip tree

3

White ash

5

White fir

7. 5

White oak

5

White pine

5

Yellow buckeye

5

### FAQ

#### Do trees die of old age?

As a tree ages, its respiring tissue increases, but the photosynthetic area (leaf surface area) remains somewhat constant. Consequently, an older tree allocates more carbohydrates for life-sustaining respiration and less carbohydrate for root and stem elongation and repair, which initiates its senescence (physiological deterioration) phase. The tree becomes more vulnerable to diseases and other natural enemies and eventually becomes a snag.

#### How can I identify the fast-growing trees near me?

It's easier to find out which trees grow faster than others using the tree growth factor chart. The smaller the growth factor, the faster the tree grows!

#### How do I calculate an oak tree's age by diameter?

To determine an oak tree's age by diameter:

• Convert the diameter to inches.
• Multiply the diameter with the tree species' growth factor.
• The product is the tree's age in years!

For example, the age of your pin oak tree with a diameter of 3 ft at breast height (dbh) is 3 (the growth factor) times 39 (dbh in inches) = 117 years!

#### How do I count tree rings to estimate its age?

Each dark ring of the tree trunk represents a cycle of seasons, or one year. So, the total number of dark rings tells us the age of the tree in years. Count from the innermost dark ring to the outermost.

Mehjabin Abdurrazaque

Tree species

Growth factor

Circumference at breast height

Diameter at breast height

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## 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.

EXAMPLE:

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 determine the age of a tree

1. Based on documents or surveys.
Try to find information about pickup times. This is the most reliable way to determine the age, other methods give only approximate results. You can research this issue if possible. Ask old-timers or look for old photographs to find out information about the landing date.

2. By branches.
The age of a coniferous tree can be found by counting the number of whorls (tiers of annular arrangement of branches) on the trunk. Only one whorl forms on the trunk annually. After counting their number, add 3 (pine), 4 (spruce), 5 (fir) or 10 (cedar) to it. The thing is that the first whorl does not appear in the first year, but at different ages, depending on the type of tree. The resulting amount will indicate the age of the tree. But remember: the whorls are clearly visible until the age of 30-40, after which the lower branches begin to fall off, their bases become overgrown with wood and their traces are very difficult to detect!

Determining the age of a coniferous tree.

In a deciduous tree, age is determined by annual rings - but not the trunk, but the outer rings of the branch. The fact is that every year its growth begins with the apical bud. In this place, a transverse scar in the form of a thickening-ring remains on the branches. The first ring is formed at the point of departure from the trunk.

Determination of tree age by branch rings

3. Determining the age of a tree trunk
The diameter of the trunk is measured at a height of 1.3 m (at the level of the chest of an adult). It is believed that at this height the trunk of most tree species already has a rounded shape. Some authors recommend measuring the trunk diameter at a height of 30 cm.

Determining the location of the trunk measurement

3.1. The easiest way to determine the age of a tree.

Use the formula B=1.6 x D + 44 for this, where B is the age of the tree, years; D - its diameter at a height of 1.3 m from the ground (at the height of the chest of an average person) in cm; 44 - coefficient. It must be remembered that this method of determining is very approximate, the error can be from 5 to 15% in the direction of increasing age. At the same time, for a tree with a diameter of 20-44 cm, this error is about 5%, over 44 years - from 6 to 10%: the older the tree, the more often it falls into unfavorable conditions and the stronger the fluctuations in the width of the annual ring.

3.2. By annual increase
For this, it is not necessary to cut down a tree or use a special drill. As the tree grows, the thickness of its trunk increases every year. Knowing the average annual growth of a tree of this species in your area, you can divide the diameter of the trunk by it to determine the approximate age of the tree. The average annual increase depends on the type of tree and local conditions. For example, trees grow faster in a forest than in a city, so this method gives very approximate results. Divide the trunk diameter by the average annual increase in diameter.
We have already said that as a tree grows, the thickness of its trunk increases every year due to the formation of a new annual ring.
In fast-growing species (for example, poplar, willow, birch, eucalyptus, acacia, maple), the width of such a ring is 1-2 cm, in medium-growing species (common spruce, larch, Scots pine, plane tree, mulberry, common ash, elm) - mm , in slow-growing (Caucasian and Siberian fir, pedunculate oak, elm, linden, hornbeam, yew) - 1-4 mm (see tables 1 and 2).

The width of the annual layers varies greatly depending on many factors: species, age, growing conditions, position in the trunk. The narrowest annual rings (up to 1 mm) are formed in slow-growing species (boxwood), and the widest (1 cm or more) are characteristic of rapidly growing species (poplar, willow). In the trunk of a tree, the annual layers are wider than in the branches. At a young age and under favorable growth conditions, wider annual layers are formed.
The average annual increase depends on the type of tree and local conditions. For example, trees grow faster in a forest than in a city, so this method gives very approximate results.

#### How to measure the diameter of the barrel?

To measure the circumference of the trunk, it is convenient to use an ordinary tailor's tape (if the diameter of the trunk is less than 150 cm) or a tape measure 3-5 m long (if the diameter of the trunk is more than 1.5 m). Measurements with the help are usually made by two people: one takes the end of the tape measure and applies it to the trunk, the second takes the measurement. To measure the diameter of the trunk, a forest measuring fork is used. The simplest of them consists of a thick ruler up to 1 m long with divisions and legs - movable and fixed.

Stem gauge

#### What if there are no measuring tools?

But measuring tools may not always be at hand. What to do in this case? It must be remembered that a person is a measuring instrument in itself. For example, in an adult, the distance from the face to the fingertips of the outstretched hand is about 60 cm, the arm span (girth) is about 180 cm, the distance between the freely spread thumb and forefinger is 17-18 cm, between the thumb and little finger is 20 cm; middle finger length - 8-9cm, and the width is 2 cm, the length of the phalanx of the finger is about 2.4-2.5 cm (about 1 inch).

Some ancient measures of length compatible with the size of the human body.

#### Interesting facts from the life of centenarians.

Every day, leaving the house, we meet trees. They greet us with the rustle of leaves, cover us with these branches and leaves from the summer heat or rain. We know about the important role of trees in maintaining the earth's atmosphere: it is they who, with the help of chlorophyll, take oxygen from carbon dioxide and return it to the atmosphere, enabling people and animals to breathe and live. Many people know that some tree species purify the air from dust and harmful substances (for example, poplar), inhibit the development of pathogenic bacteria (for example, eucalyptus). But few of us think that these motionless giants are the longest-lived living creatures on Earth!

#### Who are centenarians?

There is a scientific definition - who is considered a long-liver. A long-liver is any member of wildlife whose life span is significantly longer than the average life expectancy of other members of its species.

#### Long-lived people.

Usually, speaking of centenarians, they mean only people. The Bible, for example, tells, for example, about long-lived patriarchs Seth (lived 912 years), Jared (lived 960 years), Methuselah (lived 969 years old). Whether this is so is unknown, since no documents have been preserved confirming the data of the Bible. According to the UN, a long-liver is a person who has lived 90 tons more years. It is reliably known about people whose age has exceeded this period: Frenchwoman Jeanne-Louise Calment (122 years old), Sarhat Ibragimovna Rashidova - a long-lived Azerbaijani (132 years old), Mohammed-Khoja Duridi - the oldest inhabitant of the planet (born in 1887). In Karachay-Cherkessia there is even a club of centenarians who are over 100 years old!

#### Centenarians of the animal world.

Long-lived animals are also known. For example, turtles (live up to 250 years), some types of mollusks (the oceanic venus mollusk is over 400 years old!), carps, sea urchins and sea bass (some individuals are up to 200 years old or more). The average life expectancy of elephants and whales is about the same as that of humans, but they can live up to 100 years or more. But sponges live the longest - up to 1500 years! It seemed like a very long time! But many types of plants live much longer!

#### Centenarians of the plant world.

Unlike humans and animals, trees grow throughout their lives. Therefore, it is natural to assume that the higher the tree, the older it is.

Conifers are one of the most ancient plants. They appeared on Earth tens of millions of years before the appearance of deciduous ones. As a result of longer natural selection, conifers turned out to have much more long-lived species. For example, larches - species that grow only in Russia and have much more rights than birch to be called "Russian trees" - live 500-600 years (5-6 times longer than long-livers of people!). Siberian fir lives up to 700 years, cedar pine (which is incorrectly called Siberian cedar) - up to 100 years. Everyone knows sequoias - coniferous trees from the Yellowstone Valley in the USA. They have a trunk up to 120 m high and up to 8 m thick. These giants live up to 5000 years!

(True, the fate of these giants was unenviable: in the pursuit of profit, most of the sequoias were cut down back in the 19th century and now no more than 50 trees of this species have survived, aged from 2500 to 3500 years. However, their seed children have spread throughout the world There are sequoias in Sochi, for example, on the square near the former Moskva Hotel, they are about 60 years old).

Sequoias: high and wide

But the oldest oldest American tree is not considered a sequoia, but a much less tall bristlecone pine from California (it is now 4845 years old!). Cypress trees, well-known to Sochi residents, do not lag behind American sequoias and pines: a specimen that has been growing in Iran for 4000 years has been observing human history. The pond cypress that grew up to 2012 in Florida was 3500 years old, and its neighbor began to grow 2000 years ago.

But they still live and live to the age of European firs. So, in Sweden, spruce grows, the age of which is neither more nor less than 9500 years! It was established not by counting annual rings, but by the radiocarbon method used by archaeologists.

In the Namib Desert in southern Africa, amazing velvichia grows - one of the oldest plant species. Unlike giant sequoias, velvichia rises barely half a meter above the ground, but it lives for more than 5000 years. That is, she was already half a thousand years old when the ancient Egyptians began to build their pyramids!

Welwitschia amazing

Another ancient coniferous plant - yew berry - is distributed throughout Europe from England to the Caucasus. In Great Britain there are specimens of yew that remember not only Robin Hood (XI century), but also King Arthur (VI century)!

#### Deciduous species

In general, deciduous trees are noticeably inferior to conifers in longevity, although surprisingly old specimens are also found among them. First of all, this applies to oaks. The number of veterans among them is especially large. At the gates of one of the colleges of Oxford University (England) in 1788 they cut down a giant oak tree, which was 9 years old.00 years. There is information that an oak grows in Lorraine (France), whose age is determined to be 1200 years old. Finally, the "Royal Oak" in Nordskoven (Denmark) is said to have lived in the world for almost 2000 years.

Buyukder plane tree in Turkey, according to local residents, is living its fourth millennium. The age of the famous edible chestnut on the slope of Etna in Sicily is estimated at almost 2000 years.

Oriental sycamore

Among fruit trees, habitual and familiar to us, apple and pear trees are durable. Wild, own-rooted, live up to 200 or more years, garden forms - up to 100-150. In central Russia, they live up to 150-200 years. Apricots live up to 300 years, mountain ash - up to 200 years or more.

Examples of tree longevity could be continued. The people honored and protected rare old trees, they were a kind of sights of the district. Scientists constantly identify, describe, take special account of such trees. In many countries, the patriarchs of forests fell into the category of natural monuments subject to, so to speak, personal protection.

#### What affects the age of plants?

Plants, unlike animals, grow throughout their lives. True, many trees, upon reaching a certain age, almost do not grow in height (for example, in oaks, growth in height stops at the age of 400-500 years). But the diameter of the trunk continues to increase throughout life. American researcher N. Stevenson believes that if people grew at the same rate as trees. Then by the age of 35-40, their weight would reach 500 kg, and they would retire with a weight of more than a ton.

The long life of trees is possible for several reasons.

Firstly, , it is facilitated by the fact that these plants extract nutrients, as a rule, from the atmosphere. From the soil, they take only ten percent of the substances necessary for life, everything else - from the air.

Another secret of longevity is the disunity and autonomy (independence) of wood vessels, which provide the tree with nutrients and water from its crown and soil. This allows the tree to continue to live even if one of its parts has died.

Another secret of is the plant's self-defense against adverse conditions. During cold weather or drought, the plant seems to freeze, almost stops its vital processes (microorganisms and some fish sometimes do the same), and, if necessary, sheds foliage and, as it were, falls asleep.

We all know about medicinal plants that allow a person to fight diseases. But many of the plants, including long-lived plants, are capable of producing protective compounds designed to fight deadly parasites and microorganisms (bacteria or fungal infection)

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### How to determine the age?

It is not determined out of curiosity. Often this is a necessary procedure in cases where a decision is made to cut or carry out vaccination procedures.

There are various methods:

• whorls (fan-shaped processes on the trunk) are counted in coniferous trees. Years are added to the obtained value: for spruce 7mdash; 3, for fir - 5, for cedar - 10;
• Knowing the average annual growth of a certain type of green spaces in your area, you need to measure the circumference of the trunk at a level of 1.3 meters from the ground, calculate the diameter and divide it by the growth factor.

A more accurate way is to count the annual rings inside the trunk.

### Steps

#### Estimation of age by stem radius

1. Measure the circumference of the trunk at chest height.

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In forestry, the average chest height is considered to be 1.4 meters from ground level. Wrap a measuring tape around the barrel at this height and record the circumference measured.

• If the tree is on a slope, measure 1.4 meters from the uphill side and mark the trunk, then do the same for the downhill side. The average chest height will be in the middle between these marks.
• If the trunk branches below a height of 1.4 meters, measure the circumference directly below the branch.

2. Find
diameter
and barrel radius. To determine the diameter, divide the measured circumference by pi, which is approximately 3.14. After that, find the radius: to do this, simply divide the resulting diameter by 2.
• Suppose the girth (circumference) of the trunk was 390 centimeters, then its diameter is about 124 centimeters, and the radius is about 62 centimeters.
3. Subtract 0.6-2.5 centimeters to account for bark thickness.

For thick-barked wood such as oak, subtract 2.5 centimeters from the radius. If the tree has a thin bark (for example, a birch), it is enough to subtract 0. 6 centimeters. If you're unsure and want a rough estimate, subtract 1.3 centimeters from the radius.

• If you leave out the bark, you'll have extra thickness, which will overestimate the age of the tree.
4. Look around for stumps or felled trees of the same species. If you can see the growth rings on them, measure the radius of the fallen trunk and count the number of growth rings. Then divide the barrel radius by the number of rings to get the average width of one ring.
5. If necessary, look up the average growth rate of a particular species.

If you can't find stumps or fallen trunks nearby, search the Internet for the average growth rate of the corresponding tree species. For more accurate results, enter your location when searching.

6. Divide the radius by the average width of the growth rings.

If you manage to find a stump or a fallen trunk nearby, divide the radius of the living tree by the average width of the rings.

• Let's say after removing the bark, you get a radius of 60 centimeters, and from a nearby stump you determine that the average width of the growth ring is 0.5 centimeters.
• Divide 60 by 0.5 to get 120 years.

7. Divide the girth of the trunk (its circumference) by the average annual growth rate.

If you have found the growth rate expressed in annual increase in trunk circumference, divide the measured circumference by this value.

• Let's assume that the circumference of the trunk is 390 centimeters, and the annual growth rate lies in the range of 1.9–2.5 centimeters. Divide 390 by 1.9, then divide 390 by 2.5. As a result, you will get an age of 156-205 years.

### Tree rings

In places where there is a periodic change in climate, circles appear in the trunk of trees. The process occurs due to the cambium located under the bark. These are living cells that provide growth through their division.

Plant dormant in winter. Life processes in it are inactive. Violent activity is activated in the spring and continues all summer. At this time, the cambium forms many new cells, and the color of summer is significantly different from the color of spring. As a result, a thin light and a wider dark stripe appears inside the trunk.

Dark circles are growth rings. In some tree species, they stand out more clearly, in others they are barely visible. Their thickness depends on the conditions in which the plant was located.

### Fruit tree seedlings

Seedling maturity recognition should be discussed separately.

A plant that sprouted in summer usually reaches a height of 70-100 cm in a year, the diameter of the trunk at a distance of 10 cm from the roots does not exceed 1-1.3 cm. A one-year-old seedling has not yet given lateral branches. Accordingly, there will be no traces of their removal. The roots are no longer than 35 cm, but usually not shorter than a quarter meter.

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Particular attention should be paid to seedlings from subtropical zones. They are able to begin branching in the first year under favorable conditions. Unscrupulous sellers may pass them off as a more mature plant, but, in the end, the southern seedling will not survive the winter of the middle zone.

 Seedling age Height Barrel diameter Number of branches Root length 2 years 1.5 m 2 cm 1-3 30-40 cm 3-4 years 1.5 m and above 3 cm 4-6 from 30-40 cm, developed skeletal

### Determine the age of the growth rings

Determine how old a tree can be by the circles on the cut at the base of its trunk or on the stump remaining from it. Ideally, plants form one ring per year. However, natural negative factors can contribute to the appearance of several rings or their absence in one year. If they are not clearly expressed, it is necessary to apply an aniline solution, blue or diluted ink to the cut.

A less radical way to do without a saw cut is to use a Pressler drill.

Its length should approximately correspond to the diameter of the tree. The process does not require cutting:

• hold the tool at chest level;
• screw it into the barrel to the core;
• we take out the sample and count the number of dark bands on it.

After the experiment, the tree needs a small healing procedure to cover up the drilled hole.

### Pressler incremental borer (age)

Our ancestors took care of how to determine the age of a tree by the trunk without causing any significant damage to it back in the 19th century. If it is not necessary or impossible to cut the plant, a special tool should be used, taking a sample of wood with it.

The drill consists of a conical, hollow cylinder with a thread at one end. The other edge has four edges. It is on this side that the handle is fixed, which simultaneously performs the function of a case. The tool also includes a plate with grooves.

A piece of wood taken for sampling is called a core. To extract such a fragment from a tree, the drill is placed at a right angle to the trunk, then screwed into it.

As the tool plunges into the wood, the latter fills the cavity of the tube. After the drill has been inserted to the required depth, a grooved plate is inserted into the tool through the hole on the handle. By turning the drill in the opposite direction, it is removed from the trunk.

The number of annual layers can be easily counted on the core. However, one should always consider how far from the roots the sample was taken. You can determine the age of a tree more accurately only by adding to the figure obtained by counting the rings, the number of years required to reach the height at which the core was taken. It depends on the breed of the plant and the conditions of its development.

The age borer allows extracting a core up to 35 cm long, which means that in this way it is possible to determine the age of a tree by a trunk diameter not exceeding 70 cm. layers are thin and hard to see. In such cases, an optical taxation device (OOT) is used.

This instrument is supplied with an eyepiece and a lens. A core is placed in it and, focusing, the wood structure enlarged by optics is examined.

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There are also several ways to determine the age of trees without using any tools.

### The age of a tree can be determined in several ways, all of them are conditionally divided into two groups.

Methods for determining the age of a tree:

1. Non-destructive - these are those that allow you to determine the age of a tree without damaging it or destroying it. Here we include the count of whorls, the measurement of the diameter of the trunk.
2. Destructive - suggest that in order to determine it, you need to cut down a tree or violate the integrity of the trunk, thereby injuring the plant. So you can determine the age of the tree by the rings, as well as determine the age of the tree by the diameter of the trunk.

### Sawn or felled

Many people have probably heard how trees with rings called annuals. It is enough to count their number, usually quite clearly visible at the site of the cut of the trunk.

For a more precise definition, it is better to make a cut twice, as close as possible to the roots, then sand. View through a magnifying glass or microscope. Sometimes the rings are not pronounced enough, then you can use a chemical "developer". An alcohol solution of aniline, liquid from ferrous chloride, blue, even ordinary ink diluted with water, potassium permanganate, will do.

There are some subtleties for different breeds. In this case, how to determine the age of a tree by annual rings depends on whether the plant belongs to deciduous or coniferous species. If the tree is a broad-leaved species, it is best to cut diagonally, this will increase the width of the usually thin and hard to see rings.

### Memory by the tree

Many trees live much longer than people, keeping the secrets of the experiences of entire generations. But the most important thing is that they keep a "memory map" of nature, which can be seen by making a cut in a tree trunk. After all, the easiest way to find out about age is to count the growth rings of trees. To date, through the efforts and labors of scientists, the most popular method for studying the age and growth conditions is taking a small sample from the trunk of a tree, called a core. At the same time, the woody plant does not suffer, but continues to develop. Between the wood and the bark is a cellular tissue called cambium. The growth rings are made up of cambium cells. They are unevenly divided, depending on the climate and weather conditions, enveloping the wood in a very thin ring, at least one millimeter in size. When dividing, these cells form a conductive tissue. Juices and nutrients move along it. This happens in the spring, when frosts recede, the soil thaws and the plant needs nutrition for further growth and development.