PEEC Amateur Naturalist

In 1942 the Manhattan Project laboratory was located at Los Alamos on the Pajarito Plateau; there it would be desirably situated on top of a set of mesas separated by canyons. The steep canyon walls and isolated location enhanced the possibilities for secrecy and security.

The geographic isolation of Los Alamos has meant that its people live in a spectacular natural setting unspoiled by extensive commercial and residential development. The population has remained stable at approximately 18,000 since the 1980 census. About 1,500 homes are situated close to the mesa rims with views down into the canyons. All homes are within short distances of the 60 miles of hiking trails that wind through the canyons and mesas, lead up into the Jemez Mountains, or drop down into White Rock Canyon and the Rio Grande. Vistas of the Jemez Mountains are seen from west-facing windows of houses and Mesa Public Library. Vistas of the Sangre de Cristo Mountains dominate views to the east.

What problems are faced in trying to preserve Los Alamos’s open space and vistas? First, they are threatened by fire and drought. The ponderosa tree, growing in the canyons and foothills around Los Alamos, is symbolic of this issue.  It has faced a tough life for the past 20 years. Drought, bark beetle infestation and fire have all taken a toll on these magnificent giants, home to Abert’s squirrels, Steller’s jays and other species.

Piñon and juniper trees also show the impact of fire and drought. Piñons were once a dominant feature of the lower areas of Los Alamos but now are dominated by junipers interspersed with grasses and shrubs. Look for the surviving junipers and dead piñons along the White Rock Rim Trail. Higher up in the Rendija and Guaje Canyon areas, the junipers are also dying out.

Another problem stemming from drought, fire and rain is evident in our canyons.  Separating the mesa tops are canyons, whose sides and bottoms have been ravaged by torrential summer rains. These rains now race down from fire-damaged forests, unstopped by the natural vegetation that formerly slowed and absorbed them.

The Los Alamos Reservoir shows the impact of rain in a canyon. It was filled with sediment after the Cerro Grande Fire in 2000. It has remained so, despite efforts to clear the sediment. Throughout the Jemez Mountains we find other examples of increased erosion after post-fire summer rains become floods. A dramatic example can be seen near Redondo Peak in the Valles Caldera: a hillside of rocks and boulders invades the forest of ponderosas, burying their bases 3 or 4 feet deep. 

A flow of boulders through a forested hillside. Photo by Robert Dryja

Rain leads to erosion also on mesa tops. Rather than being absorbed slowly, rain concentrates in channels and disappears over the mesa edges. Drought-affected plants now have even less water to support them.

Three specific areas of open space have their own needs for care. First is the Santa Fe National Forest on the west side of Los Alamos, which has had two large forest fires burn through it. What had been a forest of large ponderosa trees is now largely barren ground with grasses and shrubs of various kinds. Young ponderosa saplings are found here, all planted after the Cerro Grande Fire.

Second is lower Rendija/Guaje Canyon.  Sections of this area are now in the process of being transferred to Los Alamos County from the Department of Energy and the Department of Agriculture. It has sections of mature ponderosa forest that have not been heavily affected by drought, fire, and damaging rains. Here a person can sense what the Jemez Mountains were like when covered by a mature forest.

A mature ponderosa stand in Rendija Canyon. Photo by Robert Dryja

A third large open area is White Rock Canyon.  A major issue here is monitoring and protecting the petroglyphs throughout the canyon. In addition, intensive use of the White Rock Canyon Rim Trail has led to the proliferation of “social” trails.  Drought here has killed many of the piñon trees and other vegetation, leaving it susceptible to erosion.

White Rock petroglyphs. Courtesy/Craig Martin

The county government is reviewing an open space management plan. The plan proposes the systematic monitoring, planting, and thinning of trees, grasses and shrubs. It considers steps for erosion control, fire management and trail maintenance. 

Finally, it presents the opportunity to assure that the Rendija/Guaje Canyon area continues to maintain its wilderness character while becoming more accessible.

White Rock open space and trails shown in green and red. Courtesy/Los Alamos County

The scale and locations of Los Alamos open spaces can be seen in the following maps. Approximately one-third of the area of Los Alamos and of White Rock is open space. These spaces are shown in green and the hiking trails in red. Courtesy Los Alamos County.

To look at the Open Space Management Plan, click here.