AW Mountain Ecology Lesson

From WildWiki

Educational Goals

Return to Mountain Curriculum

• Students understand the main characteristics of a Montaine forest

• Students gain appreciation for the influence of elevation and climate on plant distribution

• Students learn how to identify/recognize major plant and animal species in the area

• Students gain a better sense of place and a deeper appreciation of the wilderness through careful observation

Key Points

The Uinta's are considered a Montaine forest which covers the better part of the western mountain states in the United States and Canada. The montaine forest is dominated by the conifers (cone bearing evergreen trees). Conifers cover a huge amount of area in the US and Canada. Why?

The soils suck in montaine forests and the climate is harsh. Cool summers and long, cold winters. Really low biodiversity at the same elevation. You have a 90 day growing season. Therefore, decomposition is slow and soils are nutrient poor. Lots of "duff" which is the accumulation of pine needles. Creates extreme acidity which in turn creates alot of leaching as the acid pulls out the minerals and nutrients.

Why dominated by evergreens?

Advantages with short growing season- there is a heavy price to pay for losing all your leaves in winter (nutrient loss). But there is also a price to pay for keeping leaves (winter drought). You get a lot of water loss in the winter through evaporation. But, look at the needles- they are set up for this. Very dry structure (not a lot of wasted area). Less surface area to lose water. Also an adaptation to heavy snow loading- sloughs off snow more easily. In essence, the conifers have adapted the best to this climate and soil- and thus, they are the most widespread.

There are three main types of conifers:

1. Pines (pines come in packets of leaves) 2. Furs (furs are flat leaved) 3. Spruce (spruce trees are square and more prickly than the above two)

Fun, conifer song to help remember (sung to the tune of New Years song...)

Furs are flat and friendly and pines they come in packets

And if you fall in to a spruce I doubt that you can hacket

Pines, spruce, and furs my friends

Pines, spruce, and furs

Lets all join in and give a shout to the dear old conifer!

Common Conifers:

• White Pine (5 needles- 5 letters in WHITE)

These are common in the Uinta's and include the Ponderosa Pine (found at lower elevation) and Lodgepole Pine (found at higher elevation).

• Yellow Pine (2-3 needles)

These are less common but you will see the Ponderosa Pine in UT and you can often identify it by its bark- which smells like butterscotch!

• Douglas Fir

• Englemann's Spruce

• Juniper

Other Trees

• Quaking Aspen- this is a very cool tree! It is found in both the montaine forests and the boreal forests (where Water wilderness is). Why?

Highly adaptive to the constraints of both biomes. It is not evergreen but it makes up for it. Its leaves have a flat stem (petiole) which allows it to flip over easily. This helps it slough off snow and also explains why it looks like it is shimmering or "quaking" in the wind. It also has photosynthetic bark (if you cut into the bark, you'll see that it is green). This allows it to continue to photosythesize even when its leaves have dropped.

Elevational Distribution

An important part of understanding mountain ecology is understanding the influence of elevation and slope on species distribution. South facing slopes get more sun and therefore have longer growing periods at higher elevations. North facing slopes get less sun and have shorter growing periods at the same elevation. North slopes also tend to be cooler and more moist at higher elevations. South slopes tend to be warmer and drier. You will see this is the differences between the species distribution on the 2 slopes. Where are the moose? On the north slope where it is more moist and forested lower down.

Dominant tree species by elevation:

8,000 ft Pine Savanna (Ponderosa Pine and Juniper)

10,000 ft Douglas Fir, Lodgepole Pine, Englemann Spruce

11,000 ft Some spruce but increasingly krumholtz- stunted alpine growth. Tree line.

11,000+ ft Alpine zone.