Why does Colorado mountains grow so many trees yet no trees on the plains? (Denver: 2014, moving)

[Wendal]

Silly question. I know Colorado lacks an abundance of natural vegetation trees in areas like Denver due to the dry climate. But then why do higher elevation mountain towns like Estes Park, Breckenridge, Telluride and forested areas like RMNP have lots of trees? Is there more moisture in the higher elevations?

[bluescreen73]

Originally Posted by Wendal

Silly question. I know Colorado lacks an abundance of natural vegetation trees in areas like Denver due to the dry climate. But then why do higher elevation mountain towns like Estes Park, Breckenridge, Telluride and forested areas like RMNP have lots of trees? Is there more moisture in the higher elevations?

You actually answered your own question. The Eastern Plains are primarily a semi-arid steppe climate. Precipitation is low, the air is dry, and the evapotranspiration rate is high. There aren't many sources of running or standing water on the plains, either.

Estes Park only averages about 3" more precip than Denver, but it's in a Continental Subarctic Climate zone. Estes gets over 100" of snow per year and the year-round temps are lower so there's less evapotranspiration and the ground is wetter as a result.

[SUPbud]

In one word: Snow

[Loyoung]

Originally Posted by Wendal

Silly question. I know Colorado lacks an abundance of natural vegetation trees in areas like Denver due to the dry climate. But then why do higher elevation mountain towns like Estes Park, Breckenridge, Telluride and forested areas like RMNP have lots of trees? Is there more moisture in the higher elevations?

A lot of what was said above, evapotranspiration and sublimation are what keep those trees in place. Understanding why the grew there in the first place is a matter of understanding or past climate. Colorado used to be summer wet approximately 10000-2500 years ago. The higher precipitation levels allowed seeds to propagate in higher elevations. With the increase of wildfires and decrease of snow/precipitation, forest stands are no longer viable in many areas once a disturbance has occured.

[StealthRabbit]

Cooler regions with adequate snowpack to insulate and water seedlings... (There used to be a ski area in EP, / RMNP but not enough snow to really be viable after 1970s. + it was within RMNP, so commercial operation was discouraged)
Hidden Valley Ski Area (Ski Estes Park)
https://www.kunc.org/arts-life/2014-...ost-ski-resort

Having grown up in Estes Park (in the 50's and 60's), It is gonnas be a long time before reforestation recovers. It has not appreciably regenerated since the Pine Beetle infestations that began in the 1970's. It will take at least 40 yrs (likely 80), once the weather starts cooperating and providing the snow / moisture necessary for establishing a new forest.

Southern / central CO on western slope has some nice forests, but trees are really minature compared to regions of USA with more moisture. Forestry in Colorado is a very fine science. (climate / terrain / elevation)
https://www.fs.fed.us/rm/pubs_series...rmrs_rb023.pdf
https://csfs.colostate.edu/colorado-...database/logs/

On the otherhand.... having witnessed the devastation of Mt St Helens (1980 SWWA), 4 billion board feet of timber lost; and studied the regeneration of the landscape and timber.... weather / moisture makes a huge difference, as ~25-30 yrs can bring 100' tall trees in that climate.

[Phil P]

Precipitation is one of the reasons, but it's definitely not the only one. Transpiration is a factor as stated, so north slopes are more treed than south slopes because there's less sun to evaporate the moisture / snow. Snowpack is another, consistent water from melt > sporadic water from rain.

But another aspect that's not readily apparent is the soil / bedrock component and the slope of the mountain. On a mountain slope with granite bedrock a couple feet down, water from rain filters through the dirt till it hits the rock which it can't go through. So when you see a big rock chunk on a mountainside, the trees on top are shorter and more sparse as the water flows quickly down. On the bottom of the rock chunk, those trees capture a lot more moving groundwater.

On the plains, the water just filters down through the soil to the aquifer, it doesn't move down the slopeside for trees below to capture. There's a lot of above timberline area on many mountains for water to drain down to treed areas below, so mountainside trees are getting more water than ones on a level surface with no bedrock below would be. The slopes concentrate flowing groundwater. That's why in many parts across the west, the top of a plateau will be open, the bottom will be open, but the slopeside is treed.

[DurangoJoe]

Yes, the mountains receive a lot more moisture than the plains whether rain or snow.

[otowi]

I've heard some climatologists speculate that some of the trees lost in fires and recent beetle kill may not ever be replaced with the same forest in, say, the southwest portion of the state - because it appears the water situation may be permanently/long-term altered to the extent that such forests cannot come back, but rather a different biome will take its place....

[Wendal]

Thanks for the replies and enlightening info. I tried googling this question in the past but the only links that came up were reasons why trees do not grow above timberlines on mountains.



Speaking of forest fires, how long does it generally take for a forest to regenerate after a wildfire in Colorado? Can someone cite me some examples of before and after forest regeneration after a wildfire?


Given the warming climate, pine beetle epidemic and wildfires it seems Colorado's scenic forested landscape is pretty delicate.

[hikernut]

Originally Posted by Wendal

Speaking of forest fires, how long does it generally take for a forest to regenerate after a wildfire in Colorado? Can someone cite me some examples of before and after forest regeneration after a wildfire?

Try a web search on "Yellowstone fire recovery". About 1/3 of the park burned in 1988, so you'll find pictures showing the changes over that timeframe (33 years).