Treesearch

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....

In 1913, the Fort Valley Experimental Forest initiated an unprecedented case-study experiment to determine the effects of harvesting methods on tree regeneration and growth on a ponderosa pine-Gambel oak forest at Coulter Ranch in northern Arizona. The harvesting methods examined were seed-tree, group selection, and light selection. In addition, the effects of livestock grazing (excluded or not) were examined. We revisited the Coulter Ranch Study Site to examine the effects of these treatments on historical (1913) and contemporary (2003-2006) stand density and tree size. The key finding...

Diameter increment is an important variable in modeling tree growth. Most facets of predicted tree development are dependent in part on diameter or diameter increment, the most commonly measured stand variable. The behavior of the Forest Vegetation Simulator (FVS) largely relies on the performance of the diameter increment model and the subsequent use of predicted dbh in forecasting tree attributes.Previous research has shown the efficacy of localized inventory data in calibrating model parameters when better predictions of individual and stand growth in focal geographic areas are sought....

The Forest Vegetation Simulator (FVS) is a suite of computer modeling tools for predicting the long-term effects of alternative forest management actions. FVS was developed in the early 1980s and is used throughout the United Sates and British Columbia. The Third FVS conference, held February 13-15, 2007, in Fort Collins Colorado, contains 20 papers. They describe the use of FVS on the stand and landscape scale, and to analyze fuels management in the presence of insects and fire. Several papers compare FVS predictions of the effects of insects and disease to field measurements. FVS is...

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...

Forest management will protect genetic integrity of tree species only if their genetic diversity is understood and considered in decision-making. Genetic knowledge is particularly important for species such as ponderosa pine (Pinus ponderosa Dougl. ex Laws.) that are distributed across wide geographic distances and types of climates. A ponderosa pine study initiated in 1910 at the Fort Valley Experimental Forest is among the earliest ponderosa pine genetic research efforts in the United States. This study contributed to the description of ponderosa pine’s varietal differences, genetic...

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...

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.