Water + Trees = Our Survival
As you lean against that sturdy trunk under the shade of a thriving tree, drinking a refreshing glass of water on a hot afternoon, you might want to raise your glass to your arboreal protector. That tree and its many cousins are key to the clean water you hold in your hand.
Like all natural systems, trees and water and humans need each other for balance and health. When we plant trees, we contribute to clean water because forests are one of nature’s best filtration systems.
HOW DO TREES FILTER WATER?
Secreted beneath the soil, tree roots with tiny hairs stretch far and wide, acting as ceaseless police capturing toxins from the water as it falls from clouds to leaves to ground to roots. The hairs hold those harmful substances, allowing the cleaned water to feed nearby plants or flow through the earth to replenish the water table by joining a stream, river, pond, or lake.
Shade under the trees helps preserve soil moisture. In turn, trees re-up some of the water from the soil and feed it back into the air during transpiration, the process of releasing oxygen and water into the air through the leaves. Transpiration is the reason the air in a forest feels moist and rich.
It’s a gorgeous natural cycle feeding everything involved:
– Rain from clouds falls through the air, collecting pollution on its way to the tree tops
– Leaves in the tree canopy hold some of that water, combining it with carbon dioxide and sunlight to make sugar that feeds the tree (photosynthesis)
– Oxygen is produced by photosynthesis and released into the air for us lucky humans and other oxygen-breathing creatures
– Down the bark flows the rain that wasn’t absorbed, and along the way some of the harmful particulates from polluted air are held by the myriad ridges and tunnels in the tree bark
– Unabsorbed rainwater passes into the ground where tiny hairs on the underground network of spreading roots help anchor the tree, hold the soil from eroding, and capture more toxins from the rainwater
– Beneath and near the tree, plants and soil alike absorb the water, keeping the area moist and nourishing a bounty of life forms
– Rainwater merges with minerals in the vibrant soil
– When the tree draws this mineral-rich water back up from the soil, it’s nourished from root to leaf, where it again releases oxygen and water into the air to feed the clouds that bring the rain that falls on the tree…and perpetuates the cycle of life
In one year, a single large tree can take about 100 gallons of water from the ground and put it back into the air. And when only 5% more trees are planted in a community, it can reduce storm-water runoff by about two percent.
In areas prone to flooding, these trees could make the difference between destruction and safety.
WHAT IS A WATERSHED AND WHY DO WE CARE?
Excess water running down a tree moves through the land to eventually merge into a nearby stream. Streams connect to each other until rivers are formed. Those rivers eventually empty into the sea.
All the land between the tree that originally captured the rain and the sea into which the river flows is the watershed.
If a watershed is healthy and well-managed, it helps prevent floods. Forests are vital to maintaining the watershed because they soak up some of the rainwater, help keep it in the soil, and anchor that soil from washing away.
A healthy watershed promotes abundant groundwater supplies that can exist hundreds of feet below the surface.
Groundwater provides cities and towns with the water essential for drinking, manufacturing, agriculture, etc. A well-maintained watershed helps lower costs associated with municipal water treatments.
According to Phyllis Bongard and Gary Wyatt, “A well-designed riparian forest buffer protects water quality, enhances aquatic and wildlife habitats and can provide income opportunities for landowners.”
Riparian forests are those that border fresh water — streams, ponds, lakes, canals, marshes, reservoirs, or rivers. Their aesthetic value is immeasurable, and multitudes of animals and plants thrive within them.
But their role in water preservation is essential.
As water runs off cropland or from industrial areas peppered with pesticides and toxins, that polluted water enters the watershed. Carefully constructed and maintained Riparian forest buffers (RFBs) protect the aquatic environment by filtering sediment, nutrients, and pesticides.
Sediment may be natural, but too much of it in a stream disrupts plant life, promotes bank erosion, increases flooding, and compromises the municipal water in towns and cities. Runoff from neighboring croplands brings with it both nutrients and pesticides. But pesticides frequently contain nitrate-nitrogen and phosphorus, which can deplete the amount of oxygen in the water, threatening animals and fish, and entering the watershed.
RFBs generally consist of three zones:
1. Unmanaged woody zone near a stream — left to its own design, this area teems with life in its natural balance and state. Each species plays its role in fertilizing the soil, purifying the water, or feeding other species.
2. Woody zone — lying near or next to the unmanaged zone, the woody zone can be cultivated and managed for income, adding to the local economy. When well managed, these woody zones continually produce valuable income-generating raw materials while providing animals, insects, and birds a natural habitat that sustains natural, cyclic vitality.
3. Grassy zone — lies next to the woody zone and is often composed of grasses that can include forbs for cultivation or grazing.
Riparian forests provide a buffer that promotes wildlife habitats and water health. Trees provide the shade that prevents streams and rivers from becoming too warm for cold-water species of fish. Debris from the trees collects in the water and promotes fish and reptile breeding habitats.
Thriving fish and reptile populations bring and sustain other species further up the food chain: raptors, herons, or ducks. Every species contributes to enhancing and sustaining the natural balance, which then promotes the local economy by providing raw materials, sport fishing and hunting, and outdoor recreation.
The union of humans and trees is a marriage that produces healthy offspring and sustains the common good: rich soil, stable watershed, abundant animals, birds, and fish, and pure water.
With dedicated thought and care, we can create Riparian forests which nurture vital watersheds that feed the earth, give babies a healthy area in which to grow strong, add to local economies, and sustain natural recreational areas for creativity and education.
How can your community increase its tree population by 5% this year?
What if we measured wealth by the number of trees we planted?
Increase your riches, plant a tree today!