NO VEGETATION COMMUNITY IS AS CLOSELY LINKED TO COLORADO’S LANDSCAPE AESTHETICS AS ASPEN.
This is especially true during the autumn months. As the most widely distributed native tree species in North America, aspen (Populus tremuloides) forests are also some of the most biologically diverse ecosystems in the Intermountain West. Aspen stands also conserve water extremely well, and have often been referred to as asbestos forest types for their resistance to widfire.
Aspen is also a very unique species, propagating primarily via vegetative means (spreading through the roots) rather than by seed. Because of this vegetative growth, groves of aspen trees form clones, where adult trees (called rametes) are all genetically identical to each other and are connected by their root systems. As adult trees die off, new sprouts, called “suckers”, grow from the roots and the clone continues to survive. In some cases, individual clones may be tens of thousands of years old, and can grow very large. One particular clone in Utah, called Pando (Latin for “I Spread”), is estimated to cover over 100 acres, and may be one of the largest single living organisms on Earth.
Aspen are also host to a wide range of damaging insects, diseases and pathogens. Although there are many organisms that attack aspen, relatively few will kill or seriously injure trees except over long periods of time. Finally, browsing damage from ungulates such as deer or elk can suppress new shoots, while barking can also open a vector for disease.
MANAGEMENT OF ASPEN FORESTS ON BLUE VALLEY RANCH HAS FOCUSED ON SAVING AND REGENERATING EXISTING ASPEN CLONES.
There are three key elements to consider in aspen management:
- Hormonal stimulation
- Growth environment
- Protection from browsing by wildlife or livestock
Because of aspen’s clonal growth form, almost any kind of disturbance will stimulate new regrowth. Root ripping, burning, or cutting trees will remove the suppressing influence of the adult trees and prompt new shoots to sprout from the roots. The ranch’s other management programs, like prescribed fire, prescribed grazing and watershed management help create a healthy environment that keeps water and nutrients flowing thorough the ecosystem. And protecting new shoots from browsing through good livestock grazing management, managing wildlife distribution with hunting, and even wildlife fencing helps make sure that the new shoots have the best opportunity to grow into adult trees.
MONITORING DATA OVER THE LAST 20 YEARS HAS SHOWN LARGE INCREASES IN ASPEN REGENERATION.
In some cases, restoration efforts even managed to save some aspen clones that were only a few years away from dying off entirely. Hundreds of acres of hormonal stimulation, including root ripping, cutting and burning, has resulted in tens of thousands of new aspen shoots per acre. Aspen will thin itself out over time, so as long as the ranch’s management continues to provide a favorable growth environment, this will result in healthy adult aspen forests in less than a decade. In some places, where environmental conditions are not as favorable and browsing from wildlife is a danger, fencing has protected new aspen suckers and given them the opportunity to grow quickly into young saplings. In fact, some of the oldest enclosures on the ranch are doing so well that the fences are now being removed. Finally, a long-term hunting program has modified wildlife distribution patterns in such a way that new fencing is no longer required to protect new aspen shoots.