Submitted By: Allison Strauss, Annual Adventure Maven

Professor Marc Snyder left his one non-EV majors class for the last academic block of the year. By April, it was a pleasure to take general-requirement kids out to the woods every day and show them stuff.

In 2011, I was one of those general-requirement kids. The class was called Forest Ecology of the Colorado Front Range. That’s a colloquial term for the eastern edge of the Rockies where the state’s major cities are, including my school’s home of Colorado Springs. (Yes, Planned Parenthood-attack Colorado Springs. But sometimes known for Pikes Peak and the U.S. Olympic Training Center.)

Each morning, we piled into a van, and Marc would drive to a spot that exemplified whatever type of forest or ecological phenomenon he wanted to talk about that day. I’d jot down his commentary and sketch things in a small notebook that would inevitably get wet and crumpled.

In the evening, I’d convert my chicken-scratch to long form in a journal, then take notes on the night’s assigned reading, primarily from The Naturalist’s Guide to the Southern Rockies by Audrey Delella Benedict.

By the end of the course, my journal had become something of a guide book of its own, a layperson’s introduction to Forest Ecology of the Colorado Front Range. Now, with some editing and personal photographs, I’m sharing that guide here. Welcome to the first installment!

April 25, 2011

Forests by Altitude & Direction

The Southern Rockies Life Zone (where there are complete ecosystems) falls between the upper and lower Tree Lines. Trees only grow so far down a mountain because of draught, and so far up a mountain (approximately 11,500 feet) because of cold and wind. Different kinds of trees have their elevation preferences within the life zone, so the type of forest changes as one moves up a mountain. These forests distinguish different ecosystems.

North-facing slopes get less sun, meaning they’re cooler and hold snow longer. Higher elevation species, like spruce and fir, are more prominent on North-facing slopes, because the all-over climate is more like that normally just at high elevation. By the same token, South-facing slopes are the most temperate.

Ecosystem Participation

When a glacier melts, or a forest burns, or a quarry is a abandoned, the site becomes available for a new ecosystem. The order in which species appear there is called Succession.

First come the Colonizers. “Good colonizers exhibit rapid growth and a high tolerance for the sorts of environmental extremes associated with disturbed or newly exposed sites” (Benedict). Aspen and Lodgepole Pine are common colonizers.

Aspen at Crater Lake, with view of the Maroon Bells, Colorado

Most species are Generalists. They can adapt to and are therefore found in a broad range of ecosystems. Probably the Southern Rockies’ most successful generalists are the coyote and deer mouse.

Opposite of the Generalists are the Specialists. These species only live in specific conditions, like pika in high elevation talus, and Abert’s squirrel (Professor Marc Snyder’s specialty—I suspect he is one) in ponderosa forests.

Pika and Abert’s squirrel

Because of their sensitivity, specialist presence indicates the health of a given ecosystem. So specialists are also known as Indicator Species.

***

Much of this seemed obvious, things I had a sense of just by spending time in the environments described. Of course ecosystems change with altitude, for instance. But I hadn’t recognized that they do so in a consistent way from mountain to mountain. I’d imagined more of a patchwork where there were distinct horizontal bands. Having such realities parsed out and learning the vocabulary to sum them up gave form to my free-flowing observations from the trail. The overarching lesson for me was that very little in nature is arbitrary. The natural systems at work became all the more impressive.