River Birch

(Betula occidentalis)

Characteristics:

Leaves: ovate, serrated

Tree: multi-stemmed, peeling bark

Height: approx 30'

Take a Deep Breath

On the underside of a leaf there are small openings, akin to pores in your skin, called stomates. Stomates allow for exchanges of oxygen and water that are necessary for photosynthesis, which is necessary for the plant to stay alive. In very basic terms, plants "breath" in carbon dioxide, and "breath out" water. If water is in good supply, the plant can grow quickly. This is a niche that riparian trees have capitalized on; by growing in and along streambeds their supply of water is fairly consistent and the tree is able to sustain considerably quick growth. The ability to grow quickly from the abundance of water offsets the disadvantage of possible damage a tree may sustain during flood events. Even if a large rock or log floats along and damages the bark, riparian trees are able to grow quickly enough to recover from the damage.

A Dead Leaf is a Good Leaf

Just as a car is fueled by decomposed organic matter (fossil fuels) so is the City Creek ecosystem. The dead leaf litter is what provides most of the energy in the creek. When the leaves fall from the trees they land in the stream where aquatic insects feed on them. When the leaves fall on dry land, detritivours and other insects decompose them.

See You Around

One of the mantras in Ecology is Energy flows and nutrients cycle. One important part of the nutrient cycle takes place in the riparian tree roots, which not only act as a flood control but also a filter for the watershed on City Creek. The roots of the riparian trees absorb large portions of the excess phosphorus and nitrogen that is comes into the watersheds from over-fertilizing and over-irrigating yards, lawns and agricultural areas.

 

Riparian Trees

 

Cottonwoods

 

Box Elder

 

Human Impact

 

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