What causes our beautiful fall landscape?


By Roberta Tolan

PREVIEW Columnist

There’s nothing like it!

Every autumn we revel in the beauty of the mountainsides draped in swaths of gold and orange.  We plan road trips and hiking excursions around this anticipated beauty and invite houseguests to visit Pagosa when the color is peak. But the timing and intensity of the color is often unpredictable.

Why do our deciduous trees and shrubs turn color in the fall and what factors affect this annual event?

• Chlorophyllbreaks down.

The mixture of orange, yellow, red and purple is the result of chemical processes that take place in the tree as the seasons change from summer to winter. During the spring and summer the leaves have served as factories where most of the foods necessary for the tree’s growth are manufactured.  This food-making process takes place in the leaves’ cells which contain chlorophyll, the compound which gives the leaf its green color. Along with these green pigments are other pigments that range in color from yellow to orange, carotenes and xanthophyll pigments which, for example, give the orange color to a carrot.  Most of the year, these colors are masked by great amounts of green coloring.

But, in the fall, because of changes in the length of daylight and temperatures, the leaves stop their food-making process.  The chlorophyll breaks down, the green color disappears and the yellow to orange colors become visible and give the leaves their fall splendor. Many of our native trees, and trees introduced to Colorado, turn yellow in the fall. Aspen in the high country can turn entire mountainsides golden-yellow.

Each aspen tree is connected underground to other aspen trees through a system of roots.  These connected trees form a grove and are actually one large plant with many individual stems or trees and explains why entire hillsides will change color at the same time while an adjacent hillside is still green or turns a different shade of gold or orange.

Moisture during the fall keeps leaves bright and colorful for a longer period of time.  When conditions are dry, leaf color fades to brown and leaves drop quickly. Cooler temperatures also support a longer period of color, which is why fall color usually lasts longer in the mountains than along the Front Range.  The normal season for autumn color is September and October and on average, the best color occurs in late September and early October.  But with Colorado’s changing weather, fall color can occur earlier or later as seen this season.  Don’t miss the experience of driving, hiking, biking or riding through the magnificent aspen groves as the gold color falls around you. Get out and enjoy!

• Other changes take place in fall.

As the fall colors appear, other changes are taking place.  At the point where the stem of the leaf is attached to the tree, a special layer of cells develops and gradually severs the tissues that support the leaf. At the same time, the tree seals the cut so that when the leaf is finally blown off by the wind or falls from its own weight, it leaves behind a leaf scar on the stem. Most of our deciduous trees shed their leaves in the fall.  However, the dead brown leaves of the oaks and a few other species may stay on the tree until growth starts again in the spring.

• Only some trees lose leaves.

Most of the conifers — pines, spruces and firs, are evergreen and remain green year round.  Many species of pines such as Ponderosa pines, lose their oldest needles, the innermost needles in the fall. This is a natural process and is not caused by any insect or disease.

Master Gardener Program

Calling all gardening enthusiasts: applications are now available for the 2014 Colorado Master Gardener Program.

The Colorado Master Gardener Program is a volunteer based program that teaches in-depth, science based gardening information to individuals who then pass along their knowledge to others through volunteer service. This eleven week course trains volunteers in the latest horticulture information so they can then teach Archuleta County residents how to be successful gardeners in Colorado.  Training is provided in all elements of gardening and includes over 60 hours of hands-on training. A passion for gardening and a willingness to share your knowledge is required but no previous, formal horticulture experience is needed.

To become a Certified Colorado Master Gardener you must complete the Colorado Master Gardener training attending a minimum of 80 percent of the classes and provide a minimum of 50 hours of volunteer service before Oct. 31, 2014. The cost of the program which includes a four-color, 600-plus page manual is $275 and must be paid prior to the start of training.  Married couples who register together and receive only one copy of the training materials may participate at a reduced price of $445 per couple.  Partial scholarships are available through the Archuleta County Extension office and can be requested on the application form.  Those participants who do not wish to complete 50 hours of volunteer service may attend the trainings for the full registration cost of $625.

Classes will be offered beginning Thursday, Jan. 23, from 9 a.m.–4 p.m. and continue each Thursday through April 3.  Most classes will take place at the CSU Extension office at the Archuleta County Fairgrounds, but a few classes will be taught in Durango to take advantage of local expertise. A complete training schedule follows:

Jan. 23: Program Overview and the Science and Art of Plant Diagnostics.

Jan. 30: Soils, Fertilizers and Soil Amendments.

Feb. 6: How Plants Grow.

Feb. 13: Vegetables and Small Fruits.

Feb. 20: The Science of Planting Trees and Lawn Care.

Feb. 27: Entomology.

March 6: Mountain Gardening and Herbaceous Plants.

March 13: Water Wise Landscape Design.

March 20: Plant Pathology.

March 27: Weed Management.

April 3: Pruning Trees and Local Program Orientation.

The Colorado Master Gardener Program is a volunteer program and provides local opportunities for trained volunteers to give back to the community. Volunteer opportunities are always expanding but examples include creating and maintaining demonstration gardens, working at the Archuleta County Fair, helping educate children about gardening, answering gardening questions at the Farmers’ Market and designing new gardening programs for the County.

For more information about the Colorado Master Gardener Program in Archuleta County, or to reserve your space in the 2014 program, call the CSU Extension Program at 264-5931 and complete the application form. Registration begins Oct. 3 and continues through Dec. 20.

CPR/First Aid classes 

CPR and First Aid certification classes are now being offered monthly by the CSU Extension office on the second Monday and Wednesday of each month from 6-10 p.m. Anyone needing to receive or renew certification can register by calling the Extension office at 264-5931.

We will also attempt to schedule classes on additional dates with five or more registrations.  Cost for the classes is $80 for combined CPR/First Aid and $55 for CPR, First Aid or recertification. The type of information provided will vary with the needs of participants.


Oct. 10 — Mountain View Homemakers meeting, noon.

Oct. 11 — 4-H Pagosa Peaks Club meeting, 2 p.m.

Oct. 14 — Livestock Committee meeting, 5:30 p.m.

Oct. 14 — CPR training, 6 p.m.

Oct. 16 — 4-H Leaders meeting, 5:30 p.m.

Oct. 16 — First Aid training, 6 p.m.

Oct. 16 — Western Heritage Committee meeting, 6 p.m.

Oct. 16 — Mountain High Garden Club meeting, 10 a.m.

Oct. 18 — 4-H Wolf Creek Wonders Club meeting, 2 p.m.

Colorado State University Extension provides science based information on youth development (4-H), agriculture and natural resources, horticulture, family and consumer sciences and community development. Extension programs are available to all without discrimination.