Prairies and Savannas of Colorado - Part 1

Shortgrass prairie of eastern Colorado

Colorado is an interesting place to say the least.  There is a mystery about the native vegetation of the high plains and the front range, where the prairies of the central United States meet the dynamic and erratic landscape of the rocky mountains.  Living in Denver now, I am eager to learn more about this dry landscape and how it might of looked prior to the great changes that occured when it was settled by Europeans.

Denver lies within an area known as the flat to rolling high plains where the native shortgrass vegetation was blue grama grass, buffalo grass, assorted wildflowers and probably treeless.  This area predominated the northeastern and eastern side of the state and ran into western Nebraska and Kansas.  As you move closer to the foothills, you reach a narrow ecoregion known as the 'front range fans' where sedimentary deposits have eroded down out of the foothills trapping more moisture and allowing more tallgrass and mixed-grass species to grow.  Annual precipitation is higher here as well due to a proximity to the weather-making mountains.  This is where it gets interesting.  Because this narrow area of landscape is slightly wetter than the eastern high plains, isolated areas of tallgrass prairie with big bluestem, indiangrass and switchgrass can be found.  This type of prairie is common 500 miles to the east, but in Colorado it can be found here along the front range and in isolated basins within the rockies where precipitation is higher than average.

Ponderosa pine forests - south of Denver

As you move south out of Denver towards Colorado Springs, there is a rise in elevation and the landscape is more dissected and picturesque. This area, known as the 'southwestern tablelands' ecoregion, consists of mixed-grass prairies and ponderosa pine woodlands.  The area receives more rainfall annually and is a bit cooler due to the elevated hills and scattered mesas.  It reminds me a lot more of the dry areas of northern Michigan like Mio and Grayling (minus the mesas), where it is gently rolling and full of pine trees.  As opposed to northern Michigan, where red pine, jack pine and white pine are dominant among a variety of deciduous trees, the pine forests in this region are almost all ponderosa pine.  There are areas where gamble oak is common along with native shrubs, but ponderosa pine is almost always the dominant tree species.  An area called the "black forest" due to an abundance of ponderosa pine woodlands, is just north of Colorado Springs and is my next area of exploration.

Cottonwood Savanna

When Emily, John and Sophia came to town, we had a chance to venture into the high plains area east of Denver to pick pumpkins and get in the Halloween mood.  It was here that I noticed how sandy and dry it was.  As we rode the hay wagon out to the pumpkin patch, we passed through an old pasture area full of big cottonwood trees.  In true savanna fashion, they were widely-spaced apart and had big open crowns.  Was this characteristic of areas within the high plains?  Big cottonwood savannas?  Who knows, I was a little distracted by all the "goatheads" that I got in the bottom of my sandles (a few were in my feet too!).  Goatheads, as the locals call them, are invasive, viney plants with seedheads that are rock-hard and full of little burs.  Other common names are "puncturevine" and "devil's eyelash" - scientific name Tribulus terrestris.  They grow all over hell and will grow in absolutely hellish conditions, thus the high plains!!