Forest Ecology

Ecology: (i-kol’ - je) n. The

relationship between organisms

and their environment

˘˘e —

The interaction between forests and their environment is inseparable from interactions between humans and forests.

Life ZonesTrees have various

tolerances for

environmental

conditions,

particularly water,

soil and temperature.

In Colorado, a tree’s

tolerance for these

variables influence

where the tend to grow

with respect to

altitude.

These are called life

zones.

General Forest Types in Colorado

Notice how the forest

types tend to follow

the life zones with

respect to altitude.

In the lower

montane life zone—

where we are—the

dominate forest type

is ponderosa pine.

But other species can be present within the ponderosa and over very short distances.

Forest

composition

(tree species,

and density)

can vary

widely

within short

distances,

and over

time.

Green

Mountain

Falls ca.

1899

Forests Change Over Time

Photo courtesy of the Ute Pass Historical Society

Green Mountain Falls 2008

Notice

how the

hillside

has

changed

in a

century.

• Forests always have been shaped and regenerated by disturbance.

Fires are the most common disturbance.

Wind: high winds associated with storms, tornados etc.

Insects and diseases.

People: both stupid and smart.

• Typical fire regimes vary in different life zones.

Sub-alpine: Infrequent, high intensity fires (stand replacement).

Montane: Mixed severity between high and low intensity fires.

Lower Montane: Frequent Low intensity.

•Keep in mind that any type of fire can happen

in in any life zone or forest type depending on the weather on any given day and because of long term drought.

Why the fires are getting bigger and

more destructive.

-or -

“The unnatural history of the Lower Montane.”

1.High grading by our “pioneer forefathers”.

2.Teddy Roosevelt and the conservationists.

3.The “big burn” of 1910.Egan, Timothy. 2009. The Big Burn: Teddy Roosevelt and the fire that saved America.MacLean, Norman. 1972. Young men and fire.

4.Suburbia on the range.

5.Keeping it “natural”.

The “Natural” Ponderosa pine forest of the lower montane.

• Grumpy (groupy/clumpy) trees.

--Note: Grumpy isn’t always the best

prescription in defensible spaces, small

suburban lots or in shaded fuel breaks.

• About 40 large trees per acre.

• Spaces in the forest canopy.

• Diversity of ages and species of trees.

• Clumps tended to be in lower, moister areas

• “Jail bars” on drier hillsides.

Summary

Cut the unhealthy trees.

Leave the healthy trees.

The rest will take care of itself.

Questions?

Dave Root,

Assistant District Forester,

113 South Boundary

Woodland Park, Co 80863

(719) 687-2921

david.root@colostate.edu