By Marilyn Loser
Alamosa Tree Workshops: Next week is Arbor Week in Alamosa. There are several free workshops.
Basic Tree Planting: May 3, 9:30 a.m. Ruthie Brown, Master Gardener, Green Spot, 589-6362.
Tree Care: Fertilizing & Spraying, Pests & Diseases: May 9, 9:30 a.m. Ruthie Brown, Master Gardener, Green Spot, 589-6362.
Trees: Selection and Care: May 16, 9-10 a.m. Jeff Burns, Colorado State Forester, will answer questions on tree selection, care, & pruning. North River Greenhouse, 589-5660.
The Right Tree in the Right Place: You may be thinking of planting a new tree this spring. A tree has a better chance of thriving if it is planted in a spot where it can grow to its mature size and shape. Also, maintenance costs will be lower.
But what does this mean for Alamosa’s unique environment? Minimum Temperature: Hardiness zones are important. Alamosa is mostly Zone 3 and Zone 4. If you live in town where there are lots of houses, streets, and trees for protection, you are mostly Zone 4. If your home is less protected from wind and has fewer surrounding dwellings and trees, you are more likely to be Zone 3. The last few years our temperatures haven't dipped down to -40 deg. F., but they did in the 1980's. Think long-term when considering a tree.
Elevation: Alamosa is about 7,500 ft. This is fine for many trees, but some don't thrive at this altitude. It can be hard to find elevation values for some trees and different sources differ in their recommendations.
Moisture: Alamosa is naturally very dry. Our typical annual rainfall is 6-8 inches. However, if your tree will be in a well-watered lawn, or near the river, it may get plenty of water. Most tree roots only grow between 12-18 inches below the surface. Most newly planted trees will need to be watered for at least several years. Many will need supplemental water their entire lives.
Light: Consider the lighting conditions where you want to plant your tree. Think both about seasonal and daily lighting. Alamosa is known as "The Land of Cool Sunshine"; most days are very sunny. Some trees, like pines, do best in full sun. Others, like maples, are tolerant of a wider range of light conditions.
Soil: Know your soil. Alamosa soil is typically alkaline, ranges from sandy to clay (even within one area), and does not have many nutrients. Further, soil compaction from vehicle traffic or construction or even foot traffic can hamper the tree's ability to send out roots and receive air, water, and nutrients.
Pests: In general, Alamosa has fewer pests than many places since it is high, cold, and dry. However, many cottonwood and willow species are loved by aphids. Some trees, such as Robinson crabapples, are virtually pest free.
Air Pollution: Unless you live on a busy street, the ability for your trees to tolerate air pollution is not a major problem in Alamosa. And, the more trees we have, the less the air pollution problem will be.
There are several factors you need to consider in addition to the environment. Purpose: Why are you going to plant a tree? And why in a particular place?
Size and Location: This may be the most overlooked consideration. Consider many of the large trees planted under power lines in Alamosa -- what were people thinking? Envision what the tree will look like 5, 15, 35, and 80 years from now. Hard to imagine, but really, really, try! We don't plant trees just for ourselves -- they are for future generations.
Shade: Alamosa has very sunny summers and many people want shade. Shade cools our homes and yards. Make sure to consider winter shade, which most of us don't want. Will the tree block sunny windows or solar collectors? Make sure to consider the angle of the sun both summer and winter. Higher, wide-crowned trees that drop their leaves in winter provide the most shade. Medium trees do well in Alamosa as most require less water and most homes are one-storey.
Aesthetics: Are you looking for a variety of shape and color? Do you have a large or small space? What other trees and shrubs do you have?
Windbreaks & Screens: Are you trying to screen an eyesore or create a windbreak? Dense, low branched evergreens may be the best option for screens. Mixtures of dense trees may provide the best windbreaks. Some species tolerate wind better than others.
Crown Form or Shape: Do you have a narrow space? Consider a columnar (tall, narrow) shape. Do you want a single tree to spread shade over a large circular area? Consider a round, oval, or V shape.
Community Factors: How does your tree fit into the Community Forest? Many of the beautiful, but aging, trees in Alamosa are cottonwoods or Siberian elms -- as much as 40% of the public trees in the Community Forest. A species diverse forest is usually a healthier forest.
Local garden centers and nurseries now stock a wide range of trees suitable to Alamosa. Consider selecting a tree from the Alamosa Tree Board Approved list at http://www.AlamosaTrees.net.
Some of the general information in this article was provided by Tree City USA. Next time, Alamosa Trees will look at Buying and Planting a Tree.
“Other holidays repose upon the past, Arbor Day proposes for the future.” J. Sterling Morton, Arbor Day Founder