Animal HousingBiodiversityDeforestationFood ForestsGlobal Warming/Climate ChangeLandPlant SystemsRegional Water CycleSoil ConservationSoil RehabilitationTrees

The Truth About Trees

by Julia Mitchell

When one thinks of trees and the benefit they have for us as humans, the obvious comes to mind: Trees help reduce the effects of global warming by reducing carbon dioxide concentration in the atmosphere. The photosynthetic process provides the trees with nutrients, and humans with the primary element required to sustain life — oxygen. Trees are often referred to as the “lungs of the world.”

All of the above is mainstream knowledge. It is the basic information we learn as children in grade school. But what if I told you it’s only the tip of the iceberg? Trees are more than just the “lungs of the world”. Their role on this earth is pervasive, yet so often taken for granted.

So, what is a tree?

A tree is a cooperative, a protector, a moderator, a creator, and a teacher.

The tree as a cooperative

A tree stands tall with its stem and crown. This is visible to you as you admire it. The common mental representation of a tree is made of up of just those ‘above ground’ parts.

The parts of the tree that we often do not think about are the humus and detritus collected at the soil surface boundary, and the root and root associates under our feet. These are equally, if not more, essential to the existence of the tree than the more visibly pronounced parts. In essence, a tree is perpetually standing in its own decomposition. Much of the tree, as it sheds its weight many times over to earth and air, eventually becomes grass, fungus, insect life, birds and mammals. It is the cooperation of these many ‘by-products’ that make a tree so rich – they exist because of the tree, belong with it and function as part of it. Birds nest, squirrels burrow and eat fungus, and insects prune and assist in decomposing the surplus leaves and activate essential soil bacteria. Animals are messengers to the tree and trees act as a garden for animals. This is a pure example of life depending on life. It is a total being that involves minerals, plants, animals, debris (detritus) and life. All of these elements make up the ‘tree cooperative’.

The tree as a protector

Trees protect us from many elements. Forest edges are the strongest collection of trees and should never be cut down. Trees adapt to withstand high winds by spreading their root mats to rely on their weight or anchoring their roots deep in rock crevices. They create special wood cells to bear the tension and compression from wind. With the wind come many particles of dust, ice, sand and other small particles. Within a few hundred meters, a forest of trees can remove fine dusts and industrial aerosols. Therefore, trees protect us from wind that could be damaging to our habitats and small air particles that could be damaging to our lungs.

The tree as a moderator

Trees moderate temperature due to two distinct processes – evaporation and condensation. Evaporation causes local heat loss during the day which cools the air in hot weather. Condensation causes local heat gain which warms the air at night. Additionally, leaves have twice the specific heat (the heat capacity per unit mass of a body) than soil, meaning plants can be up at 15 degrees warmer than their surrounding environment. In certain climates, trees even act as dehumidifiers by directly absorbing moisture in the air. If dry hot air enters a forest, it is shaded, cooled, and humidified. If cold humid air enters the forest, it is warmed, dehumidified and slow released through the leaves of the trees. As humans, we can strategically place trees and plants to moderate temperature. Reddish and white coloured leaves reflect light (up to 85%). This reflection can be used to cool down areas in warm summer months. Dark green leaves only reflect about 2% of light; the rest is absorbed and radiated as heat. This absorption and radiation of heat can be used to provide heat during cold winter months. The trees moderate extreme temperatures and humidity so it is tolerable enough to accommodate life.

Not only do trees moderate temperature, they moderate and conserve incoming energy. Every tree or plant species intercepts raindrops, decreasing the impact of the raindrops to prevent erosion. The leaves catch the rain, some of which is absorbed through them as required, and the remainder is left to return to the air through evaporation. Any rain that falls through the canopy (throughfall) has, on its way down, collected plant cells and nutrients and is much richer than regular rainwater. This throughfall is then directed in patters to peripheral roots, and serve all the needs of growth in that forest. Therefore trees use, collect, enrich and properly direct water so it can be optimized in the forest system naturally with no human intervention.

The tree as a creator

Trees play a key role in the creation of soil by producing root pressure and humic acid to breakdown the rock underground. Trees also contribute to the creation of the atmosphere through gaseous exchange (the production of oxygen) and the establishment and maintenance of the water vapour cycle.

Furthermore, trees create precipitation through compression, condensation, evapo-transpiration and melting:

Wind blowing at a forest edge will be compressed. This compression causes more water vapour which, in turn, cools the ascending air. This phenomenon, referred to as an “Ekman Spiral”, can produce rainfall in the right conditions. Therefore, lines of trees impact the air moving over them which can affect the climate and rainfall in the local area. This upward spiral of humid air coming up from the forest carries insects, pollen, and bacteria. These organic particles create the nuclei for rain. Materials given up by vegetation may be a critical factor for rainfall inland from forests.

Along coastlines, warmer land surface causes cool inland air flow. When this air is humid, it can fall on leaves as condensation (droplets of water). In this situation, condensation precipitation can be higher than rainfall precipitation. Examples can be found as rain forest along the coasts of Hawaii, Washington and Oregon as well as the redwood forests of California. A large tree can increase the available surface for condensation due to the large surface area given by leaves. Bigger trees intercept more moist air, thus creating more condensation. Fog also increases the precipitation through condensation over that of clear air.

Forests create clouds. Clouds are made through evaporation off the leaves by day and water transpiration as part of their life process. Trees can return up to 75% of their water to air – which can be enough to form new rain clouds. The 25% water that is not returned to the air from trees is sent down into the soil and eventually reaches the streams and rivers. Forested areas return ten times as much moisture as bare ground and twice as much as grasslands. It is highly likely that the deforestation of an area is directly related to downwind drought. It is important to note that the forest is continually recycling water to air and rain whilst producing 50% of its own rain.

Trees also slow the melting of snow and prevent the snow sublimation directly to air. The benefits of trees are not limited to coast lines, but can be seen on any high slope. Even a small belt of trees entraps large quantities of drifting snow, and the release of this snowmelt is a more gradual process.

The tree as a teacher

Trees indicate local wind direction and intensity and from these indicators we can place windbreaks to reduce heat loss in homes, avoid damage from catastrophic winds and to steer the winds to well-placed wind turbines. They are biologically equipped to protect us from strong winds that could be damaging to our habitats. Trees also teach us about nature – through observing the ‘tree cooperative’, we can identify key behaviours and patterns of animals, bacteria and fungi, insects, water, sun and shade.

In conclusion, trees are not just here to convert carbon dioxide to oxygen for us to breathe. Their purpose reaches much farther and cannot be ignored. Trees fight drought, prevent soil erosion, stabilize earth, shade us from sun, are key in the conservation of water, provide us with heat, control the effects of wind, provide shelter for animals and encourage biodiversity and nutrients for soil. So, the next time you see a beautiful tree, don’t just thank it for being beautiful; thank it for being on of the most valuable things on this planet.

8 Comments

  1. Whew! After reading that title I was afraid we were about to hear how trees are actually a government/corporatist plot to plunder more of our wealth, subjugate us, and ruin the planet. Most “truth” these days seems to go along those lines, unfortunately. ;)

  2. Fantastic article, enjoyable and informative

    I would add trees are a great way for kids to grow up and play, in a much healthier way than gaming consoles. I grew up climbing the big Brazilian pepper trees in the backyard with friends, we played tree chasy, would jump off the tree, and it was an endless source of fun and exercise. I read somewhere an article that many parents aren’t letting their kids play because of the ‘dangers’ -craziness.

    There is nothing like meditating under a large pine tree, in Russia research was done on the energy that pyramidal structures make, and it is quite significant and powerful

    They are a wonderful source of low-maintenance food too, just look at the tastes and yields a mulberry tree has to offer. Perhaps fruit trees can be used as a ‘gateway’ for novices to get into permaculture

    Building materials: In the pacific islands palm leaves are used for the roof, and woven into matts, used as the perfect natural carpet to give a layer between the beach sand and allow dust to settle below. Posts can be used as post shore reinforcement for underground housing as described from Mike Oehler’s underground house book

    Trees seem to be a strong anchor point for shelters, and with the popularity of tee pees and yurts, can be a great anchor point for various kinds of these shelters including trees houses. Yay for trees

    JBob, is isn’t it better to hear about how we are being subjugated and plundered than for it to actually continue under the cover of secrecy and ignorance? Most of the mainstream seems to distract us from these obvious points and maybe that is why it continues

  3. Great article. The CSIRO** that Bill Mollison once worked for
    as a forest biologist has reported that a mature Eucalyptus tree
    gives habitat like food, shelter, fun ‘n games, to 350 insect and animal species (C’wealth Scientific & Industrial Research Organisation, Australia)
    Also the Gould League of Victoria has available (or did have) a great educational poster, ideal for Permaculture educational events, with the heading “The Tree- Nature’s Boarding House” with pictures of Australian animals etc enjoying their house. I don’t know Gould L. contact details.

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