Tree Diversity

By Marilyn Loser

How species diverse is the Alamosa Community Forest? Eighty percent of the trees listed in the 1995 Public Tree Inventory were Siberian Elms (25%), Colorado Blue Spruces (16%), Crab Apples, Willows, Russian Olives, and Cottonwoods (about 10% each). This is a better mixture than in some cities, but it could be a lot better. So who cares, they grow here don’t they?

In any forest ecosystem, diversity plays a major role in long-term stability. Overuse of a single type of tree greatly increases the vulnerability of the tree to insects and diseases that can devastate an entire species in a region. Two examples come to mind.

The first is not a result of human beings planting a single species, but it illustrates the point in our area. Driving from Alamosa to Espanola on Highway 285 through Tres Piedras and Ojo Caliente I am saddened as I observe the decimated pinon forest.  I’ve driven this highway for more than 40 years and always loved dropping off the high mesa through healthy, old pinons studding the red earth as I headed into Ojo. Now, if it weren’t for a few junipers, the landscape would be barren in places. The nearby town of Los Alamos, NM, lost more than 90% of its pinon trees over 10-feet. Pinon bark beetles, a constant and usually harmless part of the pinon-juniper ecosystem, gained the upper hand during extreme drought conditions in recent years.

The midwest lost entire populations of elms, the most popular urban tree at the time due to its wonderful shade and beautiful shape, in the mid 1930’s when Dutch elm disease exploded.

A greater diversity of trees also means a greater diversity of wildlife. Trees provide fruit, seeds, and shelter.  And don’t forget the aesthetical value of a wide variety of tree species:  short/tall, wide/skinny, green/purple/grey-leafed, and small/lobed/wide/needle-leafed. Some are fragrant and the variations of flowers and seeds are delightful.

OK, OK, reality check.  We live in Alamosa. I pore over glossy catalogues describing saplings that can shade your family picnic or entire backyard in under five years (maybe I exaggerate a bit). Given our high altitude, low annual precipitation, generally poor soil, high gusting winds, and temperature extremes (sometimes within a short time period) trees probably aren’t going to grow several feet a year.

Please! Don’t give up. There are a variety of trees that do well here – please consult the tree lists at the non-commercial website: or consult one of our local greenhouses.  If I’m not familiar with a tree I tend to look for trees that are rated Zone 2 or 3 and survive above 7,500 feet (altitude information is sometimes hard to find ) because I live on the western end of town and my yard is not as protected as is downtown Alamosa.  I consult local greenhouses; we are fortunate to have knowledgeable personnel and a wider variety of tree species for purchase than just a few years ago.

Current Happening One. The Alamosa Tree Board and volunteers are conducting the first phase of the Alamosa Public Tree Inventory.  So far they’ve logged GPS (global positioning system) coordinates for more than 800 trees and volunteers are starting to verify tree species and diameter and to log various tree conditions.  These data will be used with tree software to assess the Community Forest, in conjunction with Alamosa’s GPS system under the expertise of Jeanette Luttrell. Andrew Reis is already out there gathering data! We’ll be doing more data collection in August.  If you’re interested in volunteering -- Grab a Partner and Take a Walk -- please contact or .  We’d love your help!

Current Happening Two.  According to Heinz Bergann, Director of The Alamosa Department of Parks and Recreation, the department is in the process of planting new trees. Two Autumn Blaze Maples have been planted in Olympian Park, four Snow Spring Crabs in Zapata Park, and four Austrian Pines at the Cemetery. In addition, four good-sized trees will be planted along Main Street this summer.

“Acts of creation are ordinarily reserved for gods and poets. To plant a pine, one need only own a shovel.”  Aldo Leopold