Preserving quaking leaves in the Valley

The health and ecological study of aspen communities is important to the North Platte River Valley for several reasons, and Paul Rogers PhD, director of the Western Aspen Alliance explained why at the Platte Valley Community Center Thursday night. According to Dr. Rogers, aspen systems are economically important because they support water conservation, forage for wildlife, can be used as fire breaks, create wildlife habitat, are important to recreation (think ski areas and leaf tours in the fall), are harvested for timber and are hot spots for hunting and wildlife viewing. Members of the public, and representatives from the Platte Valley Habitat Partnership, US Forest Service (USFS), Bureau of Land Management (BLM), Division of Wildlife (DOW), Wyoming Game and Fish (WGAF) and Wyoming Wildlife Foundation attended Platte Valley Aspen Days. The two-day event included a lecture entitled "Lessons from the Aspen Bush: Diversity Breeds Hope" on Thursday by Dr. Rogers and a field trip on Friday to aspen stands on both private and federal lands.

There is only one species of aspen in North America (Populus tremuloides), and it is the most widespread species on the continent, Rogers said.

In the Platte Valley, the slopes of the Sierra Madres and Medicine Bow mountains, there are large and small stands of aspen which cover the gamut from healthy to dying or dead. One of the main goals of the Platte Valley Habitat Partnership, which contributed support to Aspen Days, is to manage aspen resources in order to support wildlife habitat.

Aspen dependent wildlife include elk, mule deer, moose, beaver, a variety of rodents, raptors, owls, songbirds, insects and arachnids, Rogers said. The canopy created by aspen support grasses, flowers and shrubs, which in turn provide food and shelter for many of the animals already listed.

Some of the proposed methods for treating unhealthy stands of aspen include prescribed burns, mechanical thinning of conifers, dispersal of thinned and fallen trees to make natural barriers and fencing, according to Rogers. After the initial treatment of aspen stands, monitoring of the relative health of the forest will be conducted.

Most aspen trees in North America are 100 to 120 years old, although the stands, or clones, can be much older. Aspen stands are often a single living organism where new trees form from suckers on the root system of the entire colony. Dr. Rogers expressed disdain with reports that date clones with any specificity, such as claims that some aspen clones are as much as 80,000 years old. While he said that age range is possible, there is no valid way to date the age of a clone.

Historically, aspens have been shown to regenerate more easily during periods of increased moisture and especially after fire. In general, 20th century climates have been characterized as warmer, wetter and with reduced fire because of human management which has resulted in an increase in conifers and decreased aspen. Another significant impact to aspen systems has been the introduction of sheep; which browse on the young saplings and seedlings, wiping out the next generation of trees. In a healthy aspen forest there are a variety of different aged trees ranging from young saplings, to recruits (those trees which have survived long enough to grow taller than the browsing height of local ungulates), and mature trees. In a severely over-grazed forest there are no saplings or recruits, and the bare trunks of the mature trees are visible.

One promising line of research involves the natural diversity of aspen and genetic lines that are not as appealing to herbivores because of their taste. The chemical compounds found in some stands, or clones, are unpalatable to elk, deer and sheep. Some research in Arizona has shown success in planting "bad tasting" trees, which have not been decimated by local ungulates. It is important to note that the research is still ongoing and Dr. Rogers' preferred model invokes monitoring, experimentation, documentation of the experiment's results, and more monitoring. There is no global solution to insure the success of aspen systems, treatment of unhealthy stands will vary by regional and site specific localities, Rogers said.

During the field trip, participants were asked to remember that forests move in succession and all change is not bad. Natural processes need to be preserved, young saplings and recruit-age aspen need to be protected. Katie Cheesbrough, Terrestrial Habitat Biologist with the Wyoming Game and Fish Department, explained that the proposed treatment areas are intended to be classroom-like settings where appropriate management strategies for the Platte River Valley can be determined. The hope is to begin working on private lands where intensive review processes, such as National Environmental Policy Act compliance which is required on federal lands, are not necessary.

Throughout the tour it was emphasized that cooperation between private citizens and agencies will be critical to a timely management plan for aspen systems in the valley. Hope for this was evident as agency experts in fire and wildlife biology contributed to discussion of treatment plans for aspen stands on the privately owned Big Creek Ranch.