Chapter 3: Trees Feed & Shelter Terrestrial Life

At a meta level, trees and other plants turn energy from the Sun into usable forms that fuel nearly all terrestrial life—including us humans. I want to start with humans because I’m fascinated by the depth to which we rely on plants.

We know that plants store and move fresh water, which is essential to all human life. Food—another basic need—also comes directly from plants or from something that consumes plants. For example, spinach is a plant that we eat, and grass feeds cows, which we also eat.

After food and water, our next basic need is shelter. We use wood, concrete, and steel to build our homes and office buildings. Wood comes from trees and both metal and concrete production rely heavily on fossil fuels, which also come from trees. Most fossil fuels are from the Carboniferous Period, when vast quantities of lush plant life died and over time formed deposits of coal, oil, and natural gas.

Speaking of which, as of 2022 nearly 82% of our global energy was powered by fossil fuels. We need energy to make electricity, power transportation, and operate industry. Energy production is at the center of our economy.

Production and consumption are also at the center of our economy. We use plant materials to make fabrics, textiles, art, clothing, tools, furniture, and so much more. Even plastic is derived from plants! After all, it is made from fossil fuels.

What about when we get sick? Roughly 25% of prescriptions dispensed in the United States are derived from plants, ranging from painkillers and weight-loss medications to treatments for Alzheimer’s, Parkinson’s, and cancer. Scientists believe that many more plant-based medicines have yet to be discovered.

Put this book down for a minute and look at all the objects around you. Think about how each object is made and where it comes from. Many—if not most—will trace back either directly or indirectly to trees and other plants. It’s incredible!

This is not unique to humans. Plants form the foundation for all terrestrial food. Their leaves, twigs, stems, and bark feed beetles, worms, caterpillars, ants, cicadas, and all sorts of other insects, which in turn feed birds, bats, lizards, fish, opossums, and a litany of other insectivores and omnivores. Their roots and decaying parts feed robust populations of life in the soil. These in turn feed other life and on and on this goes, forming complex food webs. Plants and soil also provide shelter for terrestrial life. Tree hollows, branches for nesting, fields for bedding, grass shelters, burrows, and tunnels are but a few examples.

But not all plants are equal. Some plants provide more food and shelter than others. The ones that provide the most food and shelter for the local life that need it are called native species. Native tree species are those that have lived in a given ecosystem alongside many other local insects, birds, and mammals for timespans best measured on the Cosmic Calendar. Only with such time can caterpillars and other insects develop the adaptations necessary to overcome the trees’ defenses and feed from their leaves. When this happens, insect populations increase and provide food for predatory birds and mammals. With time, highly specialized relationships and complex food webs develop. Here are three examples:

• Koalas only feed on leaves from eucalyptus trees in Australia.
• The Kirtland’s warbler only nests in young jack pines, which grow in Canada.
• Red disa only grows in the Western Cape of South Africa and is pollinated exclusively by the Table Mountain pride butterfly.

Similar examples are endless.

Trees help feed, house, and support all terrestrial life, including us humans. Those that are native do this best for the greatest diversity of life. While doing so, they pull CO₂ from the atmosphere and sequester it.