Every once in awhile I stop to contemplate the amazing qualities of trees and all we owe them – these giant organisms who we live side by side with. While we may often appreciate specific trees or trees in specific situations, I want to acknowledge the breadth of importance that trees have to human culture and to sustaining human (and non-human) life.
Trees are amazing
Trees are among the largest and the oldest organisms on earth, and through the ages humans have assigned them special significance. Tree worship was the norm in pre-Christian Europe (http://www.dailykos.com/story/2010/11/17/921316/-), with vestiges of this practice surviving in popular superstitions today. Early Jews were likely tree worshippers as well (http://www.haaretz.com/jewish/features/.premium-1.640711), and through Africa, Asia, the Americas and more, ancient and contemporary cultures alike give special honor to trees. This instinct makes perfect sense when we consider how integral trees are to creating the conditions that make human life possible.
Trees are useful
Many cultures and civilizations have relied on trees for everyday material existence. First Nations from parts of the Pacific Northwest used the fibrous bark of the red cedar tree for clothes, house building material, basket making, and more. The olive tree is integral to middle eastern history and culture, and has provided sustenance to people there for at least 7000 years. In tropical regions the coconut palm is similarly interwoven with human culture, and it was distributed around the globe by ancient people who valued it for food, shelter, tools, and fuel. Today in the Pacific Northwest, our mighty Douglas fir tree is a premium building material used locally but also exported to markets in China and India.
Trees shape our environment
From an ecological perspective, the role that trees play is even more profound than simply supplying us with food and building materials. Trees are a huge contributor to making life on earth even possible. All green plants produce oxygen, but because trees are large they produce more of it. Other than the oceans (full of phytoplankton), trees are our top producers of oxygen.
Trees also modify their immediate climate and environment in surprising ways. In areas such as the Redwood belt of California, or Oregon’s old-growth fir forests, fog drip caused by atmospheric moisture condensing on needles is responsible for ⅓ to ½ of the total precipitation of the immediate area. In boggy areas trees draw up water and contribute to drying the soil. In very arid areas trees play a role in reversing the damages of desertification. In cities, street trees intercept water before it falls to the ground, reducing the need for stormwater infrastructure. A mature tree can store up to 100 gallons of water droplets on its leaves, and that water simply evaporates back to the atmosphere.
Well placed trees can also modify local climates to reduce energy consumption. In 1989 the citizens of Sacramento CA voted to close the local nuclear power plant, Rancho Seco. Rather than build a new power plant, the utility district launched an aggressive energy conservation strategy that included planting a half million new shade trees in residential lots. The strategy worked, and the trees proved a cost effective way to reduce summer cooling demands while also improving air quality and reducing the urban heat island effect.
Trees also provide key habitat for the birds and beasts that we share the world with. Cities and farms tend to be poor in trees, which drastically reduces the number of species that can find homes. Planting trees will bring more birds to your area, both because the trees provide food and shelter directly, and because they host insects that the birds can eat.
Trees are cut down for many reasons, including for building materials and to make room for houses and streets and agriculture. Trees are big, and messy, and block the sun – there are lots of reasons not to plant a tree. However, considering all the good that trees do, there are even more reasons to plant one, or two, or ten when you can. Even on a smallish city lot there is often opportunity to plant a few trees and still leave space for you. Place them on the edges, or where they will shade your house in the summer, or on the north side of your garden. Even when they drop leaves and block the sun, take a moment to appreciate and enjoy it.