Brian W. Geils

Compromise programming in forest management.

ABSTRACT Multi-objective decision-making (MODM) is an appropriate approach for evaluating a forest management scenario involving multiple interests. Todays land managers must accommodate commercial as well as non-commercial objectives that may be expressed quantitatively and/or qualitatively, and respond to social, political, economic and cultural changes. The spatial and temporal characteristics of a forest ecosystem and the huge number of variables involved require the management of such a system in a spatiotemporal MODM framework. The particular MODM technique used in this paper is Compromise Programming. This technique is used to determine the most satisfactory management option, Compromise Programming uses a common management response indicator to solve a forest ecosystem management scenario in a fair and equitable manner.

Distribution of Ribes, an alternate host of white pine blister rust, in Colorado and Wyoming

Abstract Ribes (currants and gooseberries) are alternate hosts for Cronartium ribicola, the invasive fungus that causes blister rust of white pines (Pinus, subgenus Strobus) in the Rocky Mountain region of Colorado and Wyoming. The location, species, and density of Ribes can affect the spread and impact of this potentially serious forest disease. We assessed the distribution and density of Ribes growing near white pine stands for 15 study areas in Colorado and Wyoming with 1258 survey plots of two types, an intensive white pine/Ribes survey and an extensive Ribes survey. Species present, total numbers of stems and bushes, average number of stems per bush, and average stem length were recorded. Various Ribes species were present in all study areas across a range of elevations. The most frequent and common species were R. cereum, R. inerme, R. lacustre, and R. montigenum. Densities and probabilities of occurrence were related to site variables and varied by Ribes species. The most common predictive variables included type of dominant overstory, elevation, and general plot classification such as riparian area. The predictive information provided can be utilized by tree health specialists for risk rating of forests and in planning white pine blister rust mitigation projects. We expect that other areas in Colorado and Wyoming with similar site characteristics will have similar distributions and densities of Ribes and thus have similar risks to white pine blister rust.

Cycles of Research at Fort Valley, Arizona, Our First Forest Experiment Station

We present a history of the origin and development of long-term, place-based research at Fort Valley, Arizona, site of the first experiment station established by the USDA Forest Service. Initially named the Coconino Experiment Station, this field laboratory was founded to solve a crucial problem with ponderosa pine reforestation and to institute a federal research program in forest science. The laboratory was soon renamed the Fort Valley Experiment Station and later designated along with its forest tracts as the Fort Valley Experimental Forest (FVEF). The science program at Fort Valley has proceeded through three cycles of research, each consisting of problem recognition, investigation, resolution, and incorporation into subsequent work. Fundamental investigations in silvics began in the first research cycle and broadened in the second cycle to integrate practical knowledge in silviculture, ecology, and related fields for improving resource management. The principal research objective in the present third cycle is to provide the scientific basis of restoration and forest health projects for managing ecosystems at a landscape scale. A common theme across these cycles has been ponderosa pine and its ecological interactions with climate and disturbance. From cycle to cycle, however, the scope of that theme has expanded from regenerating trees, to interacting biotic communities, to functioning ecosystems. The next cycle of research at FVEF will need to develop adaptive and mitigation strategies for responding to new environmental and resource crises. This research will require better integration of ecological and evolutionary perspectives through such approaches as ecosystem genomics. FVEF could contribute to this research by conducting innovative, manipulative experiments, enhancing physical and management infrastructures, and compiling long-term records of climate, disturbance, and vegetation responses.

Linking Parasitic Plant-Induced Host Morphology to Tritrophic Interactions

Abstract We investigated the tritrophic interactions among southwestern dwarf mistletoe [Arceuthobium vaginatum (Willd.) Presl subsp. cryptopodum], mistletoe herbivores, and host pine (Pinus ponderosa Dougl. ex Laws. and C. Laws. variety scopulorum Engelm.)-associated predators. In an observational study, we characterized differences in pine-associated arthropods and pine branch morphology between branches either parasitized by mistletoe (brooms) or not visibly infected. Compared with noninfected branches, brooms had a more reticulate branching structure, collected 36 times more dead needles and supported 1.7 times more arthropod predators. In a manipulative field experiment, we investigated whether pine-associated predators fed upon lepidopteran herbivores of mistletoe and thereby reduced herbivore damage to the parasite. Over a 30-d trial, herbivores fed upon approximately two-thirds of available mistletoe shoots. Predator removal increased herbivore survival by 56% but had no detectable effect on the level of herbivory damage. We speculate that herbivores compete for mistletoe shoots and that increased per-capita feeding compensated for predator reduction of herbivore abundance. In summary, our results demonstrate that mistletoe parasitism altered the pine arthropod community, including an increase in the density of predators that likely feed upon mistletoe herbivores.