2011 International Year of Forests – a tree through a magnifying glass

This post is also available in: Dutch.

Flowers of the Oliba tree (Capparis odoratissima) on Curaçao, the fragrant creamy white flowers attract not only many bees and other insects, but birds and bats will also feast on the nectar and will thus provide for pollination.

Differences among trees

No forest without trees. That’s a given. Forests consist of trees, different species of trees in all shapes and sizes. They all have their own properties. One is almost 5000 years old and still lives on happily while the other has lived its life in less than 10 years. Some species grow to more than 115 meters high, the Coast Redwood in Redwood National Park in the U.S. is one example, and others are no bigger than a few centimeters.

Anatomy of a tree

Trees are extraordinary organisms that are built a lot more complex than we might think. The ease with which humans cut down trees would be much less if everyone realizes how much a tree has to go through to grow as big and broad as we can observe. Trees consist of several parts: the roots, trunk, branches, leaves, flowers and fruits. All have their own role within the life of the tree.

Roots

Roots ensure that the tree stays firmly anchored in the soil and are constantly in search of water and nutrients essential for the survival of the organism. The tree roots that clog septic tanks are often from trees that are not even located in the immediate surroundings.

The Mata Piska tree (Jacquinia armillaris), a tree that will stay small, with a clearly defined trunk and a crown with branches and leaves. Because of the shape of the tree optimum use is made of available sunlight.

Trunk

The trunk contains the transport vessels which transport water and nutrients upward from the roots to the leaves.  There, under the influence of sunlight, these essentials are converted into sugars and starches, which in turn are stored as a reserve for hard times. In addition, the trunk ensures the strength of the tree. Often forgotten is the fact that the trunk also serves to elevate the food factories in the leaves as high as possible towards the much needed sunlight. This is especially important in forest where there is fierce competition for sunlight. Not surprisingly, in tropical forests with their high density of plants and trees, most trees grow to impressive heights.

Branches

The branches have a similar function as the trunk, and ensure that the leaves will grow spread out so they don’t have to compete with each other for sunlight.

Leaves

The leaves are the true factory within the plant. As mentioned earlier, within the leaves a lot of work is done to produce food for the plant. Water and carbon dioxide are transformed into sugars and oxygen under the influence of sunlight. The sugars are stored in the leaves themselves but also in the trunk and roots. The oxygen is considered ‘waste’ and is excreted through the stomata, the little ‘mouths’ located at the underside of the leaves.  This process is happily utilized by humans and lots of other animals by breathing.

Flowers of the Wayaka (Lignum Vitae - Guaiacum officinale)

Flowers

Flowers are the propagation tools of the tree. Various fertilization tricks are applied, like luring animals with tasty nectar, and this way the tree makes sure the fertilized flower is transformed into a fruit that hides the precious seeds. Some tree species work together with birds like the hummingbird. If you observe hummingbirds well you’ll see an occasional individual with a powdery substance around its beak. This substance can vary in color but is usually white to yellow – pollen. While sucking the nectar from a flower the bird will accidentally touch the stamens with its bill and the base of the bill gets ‘dirty’. When the animal visits a flower of a similar tree a little of the pollen remains behind fertilizing the flower.  The trees regulate this process by all flowering at the same time. Besides birds like the hummingbird also insects, most important of which bees, play a role in the process, as well as  mammals such as mice, monkeys and reptiles such as lizards.

A seed coming out of a Wayaka fruit, nicely red to attract birds.

Seed distribution

Also for spreading the seeds several tricks developed over time. Some trees wrap their seeds in a juicy fruit that is attractive as food for larger animals. The fruit is eaten, the seeds end up in the gut and are defecated elsewhere in a convenient amount of manure. A good example of a local tree that applies this trick is the Shimaruku (West Indian cherry – Malpighia emarginata). Other trees will make sure the wind will carry their seeds as far as possible. An example of this is the Kapok tree (Ceiba pentandra). By packaging the seeds in cotton-like balls that are easily carried away by the wind, the seeds are spread out over large areas, insuring the survival of the species.

The economic benefits of a tree

Trees are essential to our society, although our destructive talent not always reflects that. Fruits and even flowers provide food and spices. Mangoes, apples, oranges and many other fruits are examples.  And then there is the clove, a spice that we often use. It’s nothing else than the dried flowers of the clove plant. Also leaves are used, for example as medicine and herbs. On Curacao the leaves of the Watakeli (Bourreria succulenta) in the past were soaked in rum because of its beneficial effect on the potency and against back pain. Another example is the famous bay leaf.
Especially in developing countries tree branches are used to make fires for warming and cooking. The branches of some trees, such as liquorice, are used to prepare confectionery (drop – a Dutch delicacy) and medicines. Campfires would not exist if there were no branches to be found. Furniture is made from the wood of the branches and trunks, houses are built, boats pieced together, paper produced and so on. Roots are less frequently used because they are difficult to extract from the ground, and often heavily branched so the wood can only be used for wood fires.

The ecological benefits of tree

Trees are indispensable for the ecology. The leaves serve as food for mammals, insects, reptiles and even birds. Flowers and fruits of course as well. The canopy provides shelter to various animals during rainfall, but also creates a micro-climate which is pleasant for animals and plants such as orchids, to live in. The bark of the trunk often is home to different small organisms. The roots stabilize the soil in which the tree grows, minimizing erosion, and they provide a home for all kinds of animals, plants and other living organisms such as fungi. Even intimate working relationships between trees and soil-dwelling fungi have been discovered.

Respect for trees

A world without trees would be unimaginable. They are awesome organisms, already inhabiting the earth long before man came along. They ensure that human beings can live the way they like so much, with plenty of oxygen in each gulp of air, a succulent fruit to sink the teeth into, and hardwoods to make teak furniture and wooden roof beams from. We should be a lot more respectful towards them!

Michelle da Costa Gomez

About Michelle da Costa Gomez