Trees are incredible plants: they are not only very useful (and necessary) in gardens, but they are also home to a wide variety of fauna and flora. They provide shade, fruits and, to top it all off, many species have leaves and / or flowers so pretty they look like something out of a children's story.
Do you want to know more about trees? Well, not only will you know what their characteristics are, but you will also know which ones can be in the shade, which ones in the sun, much, much more.
Table of Contents
- 1 Tree characteristics
- 2 Selection of trees for gardens
- 3 Curiosities about trees
- 3.1 Why are the leaves falling off?
- 3.2 Why do the leaves turn red, orange, or yellow in fall?
- 3.3 What are the records of the trees?
What is a tree?
The first thing we have to know is what a tree is. Although it is easy to recognize most of them, the truth is that sometimes we can have quite a few doubts. Well, to have them resolved we must know that a tree it is a plant that has a woody and raised trunk more or less thick (some authors establish a minimum diameter of 10cm) that branches to a height of about 5 meters or more forming the crown.
This crown becomes more and more dense as the years go by, since the tree produces secondary branches, and is composed of leaves that can be deciduous (they all fall at a certain season of the year, such as the Acer palmatum) or perennial (they can fall and be renewed throughout the year, or it may happen that they are renewed in a matter of a few weeks every X years, which is what the Brachychiton populneus).
What are its parts?
Trees are made up of four well-differentiated parts that are:
- Roots: they develop under the ground. Thanks to them, they can be well attached to the soil and feed on the nutrients they find in the soil.
- Trunk: is the part that holds the cup. The outer layer is called the crust, which can vary in thickness and color. If it is cut lengthwise, we will see the annual rings: the thickest show good years, with abundant water and a pleasant climate.
In the center of the trunk we have the heartwood or heart, which are dead woody cells, and towards the outside the sapwood, which are lighter rings. Between them is the cambium, which is divided into xylem (sapwood and heartwood) and phloem.
- Crown: it is made up of branches and leaves. It can be elongated and vertical, rounded, or flat.
- Branches: arise from five meters in height. In trees, a single dominant branch is usually easily distinguished, and the secondary ones.
- Leaves: they are the plants' food factories, since through them they can carry out photosynthesis. They are made up of the upper part (upper part) and the lower part (lower part). They can be of four types:
- Needles: needle-shaped, thin and fine.
- Squamiform: they have a scale shape.
- Pinnatifolias: the leaf blade is divided into leaflets, which are smaller leaves.
- Simple and undivided: each leaf is individually inserted into the branch by the petiole or stem.
- Flowers and fruits: in order to perpetuate the species, these plants have reproductive structures that, in most cases, are very showy as they have beautiful petals 🙂. Still, we cannot forget about conifers and Ginkgo, which are angiosperm plants and do not produce flowers. As for the fruits, they have a very variable shape and size, weighing from a few grams to more than 200g.
Where do trees live?
The trees live in practically the whole planet. But we will find a greater variety of species in temperate regions and, above all, in areas with a humid tropical climate, where mild temperatures and abundant rainfall allow these plants to grow continuously.
And it is that without water none of them could survive. Those who live in the savannas, such as the Adansonia (Baobab) have had to take a drastic measure to get ahead: dropping their leaves during the dry season in order to save water. During this period, it remains alive thanks to the water reserves inside its trunk, which is why it has thickened.
Depending on the degree of humidity and the conditions of the terrain, as well as the temperature and latitude, we will be able to know what type of forest will occur. As usual, in the lower parts, near the mountains, a forest of lush trees will grow, As the Fagus sylvatica (Beech), while conifers will grow in the highest parts which are more resistant to cold plants.
How many are there in the world?
It is estimated that there are more than three billion trees, which make up about 100.000 species, which is 25% of all living plant species that we find on the planet. All of them have a common origin, primitive trees that emerged about 380 million years ago, during the Devonian period.
Unfortunately, they are being cut down on a massive scale. From January to the end of July 2017, more than 2.941 hectares have been deforested, according to the portal world of meters.
How useful are they for humans?
Trees are very useful for humanity, as they serve to:
- Decorate: many species produce leaves and / or flowers with great ornamental value. In addition, there are some that can be worked as bonsai.
- Build: wood is used to build and make furniture, huts, tools.
- Shade: under its branches we can protect ourselves from the sun, something that comes in handy during the summer.
- Satisfy hunger: there are many trees that produce edible fruits, such as the orange tree or the mandarin.
- Breathe: when photosynthesizing, its leaves expel oxygen and absorb carbon dioxide. While they are not the most common type of plant, without trees the oxygen levels would not be high enough for us to breathe.
- Serve as inspiration: Writers, painters, even architects can be inspired by trees to create their works.
- Prevent erosion: by anchoring their roots in the ground, they prevent the wind and sun from eroding the ground.
Selection of trees for gardens
If you are looking for an evergreen tree for your garden, we recommend the following:
brachychiton is the name of the genus of a series of trees originating mainly from Australia. Some species are better known than others, such as the Brachychiton populneus or Brachychiton acerifolius, But all of them are ideal for low maintenance gardens, as they resist drought well once established.
As if this seems little to you, you should know that weak frosts of up to -4ºC they do not harm them.
Citrus fruits, such as lemon Tree, tangerine, Orange tree, the lime, etc. they are small trees ideal for gardens and orchards since they do not exceed 6m in height. Its fruits are edible (or can be used to sweeten dishes 😉), and they also have very pretty white flowers.
They can grow almost in any type of terrain, and also support an average temperature of -4ºC.
Delonix regia (Flamboyant)
El flamboyant It is a beautiful tree with a parasol crown native to Madagascar. Grows to a maximum height of 12m, and produces very striking red or orange flowers.
Live well in hot climates, without frost, in full sun and with a constant supply of water. The only drawback is that its roots are invasive, so to avoid problems it has to be planted at a minimum distance of 8 meters from pipes and so on.
La magnolia grandiflora is a tree native to the United States that reaches a height of 30 meters. Despite its size, it does not take up much space as it has a pyramidal shape. The flowers it has are large, pure white, very decorative.
You can have it in temperate climates with frosts of up to -6ºC and acid soils.
Maples are trees that grow in temperate regions of the world. They reach a height between 6 and 30 meters, and there is such a variety of species that it is very difficult to choose just one. Some of the best known are:
- Acer palmatum (japanese maple)
- Acer pseudoplatanus (fake banana maple)
- Acer (red maple)
- Acer monspessulanum
If you want to have one, you can have it as long as you live in an area with a temperate climate, with frosts of up to -15ºC.
El Horse Chestnut, known to botanists as Aesculus hippocastanum, is a large tree native to the Balkans. Reaches a height of 30 meters, with a 7-8m crown. It produces very showy flowers, white, so that apart from giving a good shade, in spring you can also enjoy them.
This tree withstands temperatures of up to -15ºC, but you need protection from the sun if they exceed 30ºC.
El japanese cherry, whose scientific name is Prunus serrulata, it is an amazing tree. Native to East Asia, reaches a height of 5-6 meters. During the spring, its branches are hidden behind the large number of flowers that sprout. It is so beautiful to see it bloom, that every year in Japan they have a festival called Hanami, which consists of enjoying its beauty with your loved ones.
It grows well in temperate climates, with a minimum temperature of up to -15ºC and maximum of 35ºC.
El beechthe Fagus sylvatica, is one of the most imposing trees that grows in the temperate regions of the Old Continent. Reaches a height of 30 meters, with a glass of 10m. The best thing is that there are two types: the normal variety, which has a green leaf, and the purple one, which is the one you can see in the image above.
To have it perfectly healthy you need, not only a lot of space, but also a slightly acidic soil and frequent waterings. Otherwise, it is well resistant to frosts of up to -15ºC, but from experience I can tell you that if it exceeds 30ºC the growth stops.
Curiosities about trees
Why are the leaves falling off?
During some seasons of the year (summer in tropical regions, and winter in temperate ones) many trees tend to be bare. When that happens, we might well think that they are not alive, although in reality we would be wrong.
To survive either the dry season or the cold season, they choose to stop feeding the leaves. Maintaining them would cost them extra energy at those times of the year; an expense that they cannot afford as their lives could be in danger.
Why do the leaves turn red, orange, or yellow in fall?
Deciduous trees often change color during autumn in temperate regions of the globe. Landscapes are stained in shades of yellow, red and orange before the trunks run out of their precious leaf blades. But why?
To find the answer we have to know what a little bit of botany: the leaves contain clorofila, which is a compound that is responsible for photosynthesis, but also absorbs the red and blue rays of sunlight, reflecting the green waves, which is why during the growing season the leaves are green. What happens is that as autumn approaches and the days get shorter and colder, it decomposes and gradually loses its green.
From green we go to yellow. The yellow of the carotenoids. These compounds are also necessary to do photonsynthesis, but absorb blue and green rays, reflecting yellow ones. When these also begin to disappear, the leaves turn reddish, coppery or brown.
Finally, we have at anthocyanins, which are compounds that absorb blue and green rays and reflect a range of colors such as scarlet or purple. This is why many maples look red during this wonderful time of year.
How do they photosynthesize?
Plants, and of course trees as well, photosynthesize in order to feed and grow. How do they do that? Chlorophyll absorb sunlight, which together with the carbon dioxide in the air, the plant can transform water and mineral salts that have been absorbed by the roots (raw sap) into processed sap.
But this is something that deciduous trees cannot do when they are leafless. What happens then? Nothing serious: they stay inviting thanks to the nutrients they have been storing throughout the year.
What are the records of the trees?
The Ginkgo, the most primitive
El Ginkgo biloba It is the only tree of the Gymnosperm family, and also the most primitive: its origin can be traced to 270 million years ago.
The Eucalyptus regnans, the tallest
Who else who least knows that eucalyptus trees are very fast growing trees that reach incredible heights, but the Eucalyptus regnans it is more amazing if possible. This species native to Australia reaches a height of up to 90 meters.
The Pinus longaeva, the oldest
It has a very slow growth, barely a couple of centimeters per year, but it is no wonder: the climate of its habitat is very cold throughout the year. Nevertheless, has a life expectancy of three thousand years, and a specimen was found that had 5000.
The Baobab, the surviving tree
The baobab is a tree that grows in the savannas. It grows very slowly, but in a place where rainfall is so low it cannot do much in a year. The normal thing is that it grows about 5-6cm per season, but still, little by little reaches a trunk with a diameter of up to 40 meters, inside which it has its water reserves.
The strangler fig, the meanest
Although it is not a tree as such, there comes a time in your life that does look like a tree. Its scientific name is ficus benghalensis, and it is a plant that no other plant would like to have as a companion. When a seed falls on a tree branch, it germinates and, over time, develops roots that when they touch the ground, will literally start to strangle it..
It often happens that it is not enough for him to have killed one, but that he goes for another, with which in the end it can occupy an area of 12 thousand square meters. Under its roots, festivals and events are held in India, where it is from.
The Giant Sequoya, the largest
If eucalyptus regnans is the highest, the Sequoiadendron giganteum it is the largest tree. It can reach a height of 80 meters, with a trunk so thick that it would take more than 20 people to hug it. And it may surprise us even more: specimens with an age of 3200 years have been found.
The bonsai, the smallest
Although it is not a tree that grows naturally, but is a work created by human beings, we could not stop including it in the article. Bonsai can be classified in many ways, one of them being according to its size, which can be:
- Shito or Kehitsubo: bonsai no taller than 5cm in height.
- Mame: from 5 to 15cm.
- shohin: from 15 to 21cm.
- Komono: from 21 to 40cm.
Thus, the Shito bonsai would undoubtedly be the smallest tree in the world, even if it is created by human hands 🙂.
And with this we are done. We hope that you have found it interesting and that you have learned a lot about these wonderful plants that are trees.