The life expectancy of trees primarily depends on the type and environmental conditions. Most of them live for about a century, but there are champions who are a thousand years old and more. Of course, we are talking about strong, healthy trees that are in favorable conditions and are not felled by humans.
How to know the age of a tree?
Before you know how many trees live, it is useful to understand how their age is calculated. The fact is that they grow in width unevenly. Trees receive energy for development from the sun through photosynthesis. Of course, during periods of solar activity, growth is more active, and during periods of decrease in the intensity of the sun, growth slows down.
The expansion of the trunk of a tree is due to the cambium, a special tissue that creates living cells inward( toward the center of the trunk) and outward from itself( toward the cortex).The cells that are inside the cambium become part of the wood - the supporting system, which carries nutrients from the roots to the leaves. Cells located outside the cambium( under the bark), deliver organic matter from the leaves to the roots, this fabric is called bast.
In the spring, the cambium creates wide cells with narrow walls. They are needed for more efficient and quick delivery of nutrients and trace elements. In the autumn, the cambium produces narrow, thick-walled cells that give the tree a special strength. Thus, for the year two types of fabrics are produced: one layer( spring) is lighter, the other layer( autumn) is much darker.
It is better to determine the number of bands with a microscope and special coloring matter, since they are quite narrow. According to the number of dark and light rings, it is possible to estimate not only the age of the tree, but also the climatic conditions in which it grew. Wider dark areas speak of unfavorable cold autumn and long winter.
To find out the age of a tree, you need to cut it. In some cases, this is impossible or undesirable.
In this situation, use the method of calculating the average statistical indicators. At the level of one and a half meters, the length of the trunk circumference( in centimeters) is calculated and divided by the constant π( ~ 3.14), the diameter of the tree is determined in this way.
This value is divided by the average annual increase for the studied plant species in this region. The result is a rough indicator of the longevity of the tree. Of course, this method gives only approximate figures. At the same time, the difference between them and the actual number of years can reach 20-30% or more.
Therefore, the most common way is to cut wood and count the number of rings.
What affects the lifespan?
Before finding out how many years trees live, consider what affects their age. Life expectancy is highly dependent on various environmental conditions. The most influential factors include:
- Genetic individual capabilities of the plant. At first glance, they are all the same, but in fact the trees vary in the shape and size of the leaves, the activity of the cambium, and other characteristics. All this has a strong influence on the adaptive capabilities of the plant to adverse conditions.
- Characteristics of the soil. Its composition, water saturation, saturation with microelements and nutrients. On impoverished agricultural lands, trees can grow poorly, while across the road, on rich, not yet cultivated soil, plants can live for centuries.
- Humidity and temperature have little impact, since the climate in each band is usually stable over a long period of time. The exception is global weather changes( ice ages).Of course, for short-lived plants, even a minor drought can have a fatal effect.
- The terrain characteristics( slope, mountains or large buildings) greatly change the level of illumination, strength, wind direction and other important parameters. And they, in turn, significantly reduce or increase the life of the tree.
- Forest Characteristics. With a high density of tall trees that grow nearby, the chances of a particular plant to achieve significant size are quite small. This is also influenced by the species diversity, for example, it is very difficult for a deciduous tree to grow in a dark coniferous forest.
- Diseases and pests. Pests include insects that bite the bark and leaves, as well as animals and arthropods that eat the roots. Diseases of trees are bacterial and fungal.
These are the most important natural conditions. But there are still artificial ones. A tree in a highly polluted urban environment lives less. Conversely, life expectancy increases significantly in large parks, where there is no dirt, but there is care for the plants and their protection from pests and diseases.
Interestingly, the life expectancy of wild trees is much higher than that of cultivated fruit plants. This is due to the fact that a person using the method of selection created cultures that in the shortest time gave maximum yields. Such high performance is directly related to the fact that the tree has little power and resources on itself, it gives all the fruit. As a result, lives much less.
The most common fruit trees in our breadth are apples and pears. They live up to half a century maximum, but wild species can grow 100-150 years. Other cultures - plum, sea buckthorn, apricot - live to 20-30 years. This is due to the fact that these cultures traditionally grow in southern latitudes. For example, a peach in our strip does not live at all longer than 15 years.
All wild deciduous trees grow much longer. Aspen and alder live up to 150 years, walnut trees live on average 2 centuries. Elm, ash and birch grow to 3 centuries, and beech lives up to 500 years. But the record is an oak tree - it lives on the average of one and a half millennia. Of course, we are talking about the possible life potential of these species of trees, since in real modern conditions no one will allow them to live for more than 100-200 years.
In coniferous trees
Coniferous plants live much longer than deciduous trees. This is due to lower metabolism, serious ability to adapt in harsh climatic conditions. The shape of the crown of a coniferous tree allows you to extract the maximum amount of energy that the sun can give.
Helps to survive and highly branched root system, as well as the fact that even in the winter period, the needles continue to produce nutrients, albeit in minimal quantities. The roots of this even from frozen ground can get minerals and water. In this case, the needles are covered with wax, which does not allow water to evaporate.
Fir - the most short-lived plant among conifers can exist up to 2 centuries. Spruce and pine common in our country live up to 600 years. European larch lives up to 500 years, and its Siberian counterpart - up to 900 years( a vivid example of the effect of low metabolism).Cedar pine lives to 1000 years, but the main long-lived tree is the sequoia, which has lived for an average of 5 thousand years.
For clarity, we reduce the life expectancy of trees to a table, the surrounding world of our country gives us the following figures:
It is impossible to list each tree name and life expectancy in one table, because there are too many varieties.