Treesearch

The United States Geological Survey (USGS) Paleomagnetics Laboratory was established in 1970, when Dr. Donald P. Elston of USGS negotiated with officials of the U.S. Forest Service in Flagstaff for the use of several buildings at the Fort Valley Experimental Forest (FVEF). The Fort Valley location was ideal for use as a laboratory, because its distance from Flagstaff mitigated the possibility of outside magnetic disturbance, which could affect any results obtained. It should also be noted that the necessary space was potentially available, in that most of the buildings were in states of...

Information on the growth of forest plantations is necessary for planning of ecosystem-based management of the plantations. This information is also useful in validating or refining computer simulators that estimate plantation growth into the future. Such growth information has been obtained from a 45-year-old ponderosa pine (Pinus ponderosa) plantation in the Hart Prairie area north of the Fort Valley Experimental Forest headquarters. Average annual growth in terms of number of trees, basal area, and volume was obtained. Growth information such as that obtained on this plantation is...

Dendroctonus adjunctus is an aggressive bark beetle species that attacks several species of pine throughout its range from southern Utah and Colorado south to Guatemala. A current outbreak of D. adjunctus provided a unique opportunity to study the relationship between this beetle and pine resin chemistry in northern Arizona. We compared the resin composition of trees that had been attacked by D. adjunctus compared with unattacked trees and found significant differences in the composition of the monoterpenes α-pinene, ß-pinene, myrcene and limonene between attacked and unattacked trees....

Meteorological observations at Fort Valley Experimental Forest began with its establishment as early silvicultural research made heavy use of meteorological data. The Fort Valley weather data represent the longest climatological record for northern Arizona with records dating back to 1909. Importance of long-term meteorological records and access to the weather record are described.

Plant population models are valuable tools for assessing ecological tradeoffs between forest management approaches. In addition, these models can provide insight on plant life history patterns and processes important for persistence and recovery of populations in changing environments. In this study, we evaluated a set of ecological restoration alternatives for their long-term effects on buckbrush (Ceanothus fendleri Gray), a shrub common in understories of ponderosa pine (Pinus ponderosa Laws. var. scopulorum Engelm.) forests of the southwestern United States. The field data were collected...

In the last century, ponderosa pine forests in the Southwest have changed from more open park-like stands of older trees to denser stands of younger, small-diameter trees. Considerable information exists regarding ponderosa pine forest fire history and recent shifts in stand structure and composition, yet quantitative studies investigating understory reference conditions are lacking. We developed and applied an approach using phytoliths to understand forest-grassland vegetation dynamics and historical conditions. Phytoliths are particles of hydrated silica that form in the cells of living...

We summarize the key findings of tree ecophysiology studies performed at Taylor Woods, Fort Valley Experimental Forest, Arizona between 1994 and 2003 that provide unique insight on impacts of long-term stand density management in ponderosa pine forests on tree water relations, leaf gas exchange, radial growth, leaf area-to-sapwood-area ratio, growth efficiency, leaf area index, resin defenses, and stand-level above-ground carbon sequestration.

In 1927, the Fort Valley Experimental Forest initiated a range-timber reproduction study. The study was one of the first attempts to experimentally isolate the agents responsible for injury to ponderosa pine regeneration, and at the same time assess the impacts of livestock grazing on herbaceous vegetation. The study was conducted on the USFS range allotments northwest of Flagstaff, Arizona, known as Wild Bill and Willaha, and covered ~12,000 ha (~30,000 acres). Fifty-five permanently marked ponderosa pine "reproduction plots" were established to follow the fate of ponderosa pine seedlings,...

In 1992 an experiment was initiated at the G. A. Pearson Natural Area on the Fort Valley Experimental Forest to evaluate long-term ecosystem responses to two restoration treatments: thinning only and thinning with prescribed burning. Fifteen years of key findings about tree physiology, herbaceous, and ecosystem responses are presented.

Prescribed fire was introduced to high density ponderosa pine stands at Fort Valley and Long Valley Experimental Forests in 1976. This paper reports on mineral soil total carbon (C) and nitrogen (N) at Long Valley. Total soil C and N levels were highly variable and exhibited an increasing, but inconsistent, concentration trend related to burn interval. Total N ranged from 0.1 to 0.45%. Randomly collected soil sample C ranged from 2.2 to 5.7%, but stratified sampling indicated a greater total C range from 1.7 to 11.5%. Random sampling allows scaling up to stand and landscape level but...