Treesearch

The Taylor Woods "Levels-of-Growing-Stock" study was established in 1962 to create a replicated ponderosa pine density experiment for the Southwest, making a valuable addition to research in the Fort Valley Experimental Forest. Basal area treatments ranged from 5-20 m2/ha (19-80 ft2/ac) when installed, designed as growing stock levels 30/40, 60, 80, 100, 120 and 150. Residual trees averaged only 12 cm DBH despite being 42 years old. These 0.3- to 0.5-ha (0.75- to 1.24-ac) plots, with three of each growing stock level, were revisited for maintenance on a decadal basis including a recent...

We describe an individual-tree model that uses contemporary measurements to "grow trees backward" and reconstruct past tree diameters and stand structure in ponderosa pine dominated stands of the Southwest. Model inputs are contemporary structural measurements of all snags, logs, stumps, and living trees, and radial growth measurements, if available. Key steps include the application of inverse decay functions to estimate snag and log death dates, and the estimation of tree size in the reconstruction year via radial growth data or accrued basal area increment. The model is provided as a...

One legacy of the Fort Valley Experimental Forest is the number and quality of long-term studies associated with it. One such study is the "Hill plots," which began in 1912 and is still being actively studied. Livestock exclosures were built at five sites to examine vegetation recovery when protected from livestock grazing. Sites span a range of soil types and elevations. Materials associated with the Hill plots include historical data, plant specimens, and photographs. In this paper, we summarize the research that has occurred on the Hill plots, historical personnel who worked on them,...

One of the main elements of dendrochronological standardization is the removal of the biological trend, i.e., the progressive decline of ring width along a cross-sectional radius that is mostly caused by the corresponding increase in stem diameter over time. A very common option for removing this biological trend is to fit a modified negative exponential curve to the ring-width measurements. Because this method has numerical and conceptual drawbacks, we propose an alternative way based on a simple assumption, namely that a constant basal area increment is distributed over a growing...

In dense ponderosa pine (Pinus ponderosa Laws.) forests of northern Arizona, forage limitations may lead to severe herbivory by large ungulates on certain plant species. In 1999, we fenced 76 buckbrush (Ceanothus fendleri Gray) shrubs to protect them from herbivores and study growth and reproduction in response to forest restoration treatments implemented on the Fort Valley Experimental Forest. After seven years, we removed fences from around half the plants and examined herbivore impacts on vegetative characteristics. In spring, and again in fall, we measured stem heights and took...

Five weather station sites were established in 1916 by Fort Valley personnel along an elevational gradient from the Experimental Station to near the top of the San Francisco Peaks to investigate the factors that controlled and limited forest types. The stations were located in the ponderosa pine, Douglas-fir, limber pine, Engelmann spruce, and Engelmann spruce/ bristlecone pine ("timberline") forest types. Climatological and phenological data were collected at one or more of these sites weekly from 1916 through 1920. Soil samples were taken monthly during the growing season at all sites in...

Between 1925 and 1936, the Fort Valley Experimental Forest (FVEF) scientists initiated a study to examine a series of forest thinning experiments in second growth ponderosa pine stands in Arizona and New Mexico. These early thinning plots furnished much of the early background for the development of methods used in forest management in the Southwest. The plots ranged from 0.1 ac to 5 ac (0.04 ha to 2.02 ha) in size and many of the thinning plots and control plots were remeasured at 2- to 10-year intervals until the 1940s. The first thinning plots in the Southwest, called the White Spar...

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...

We examined forest structure, tree recruitment, and spatial pattern over a 130-year period on cinder soils in northern Arizona. Data were collected from a 3.24 ha permanent, stem-mapped plot established in 1909. This site is unique in that it represents ponderosa pine (Pinus ponderosa Laws. var. scopulorum Engelm.) growing on black cinder soils, which are of limited extent in the Southwest. Tree diameter, tree density and spatial data reconstructed from 1874 and actual measurements from 1909 and 2004 were compared, and the current stand age-structure of living trees was examined. Unlike...

Pine regeneration following wildland fire continues to be a serious problem across the western and southeastern U.S. Frequency of large wildfires has increased over the last several decades and restoration of these burned areas is a major problem confronting land managers. Prescribed fires are used primarily to reduce heavy fuel loads and secondarily to reduce competition or prepare sites for natural or planted pine regeneration. In 1983, an experiment was initiated near the Fort Valley Experimental Forest to evaluate the growth of ponderosa pine (Pinus ponderosa) seedlings planted after a...