We determined whether in vitro plant growth regulator production by mycorrhizal fungi is correlated with conifer seedling growth and root IAA concentrations. Container-grown seedlings of interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), lodgepole pine (Pinus contorta Dougl.) and ponderosa pine (Pinus ponderosa Dougl.) were inoculated at seeding with ectomycorrhizal fungi having a hig...

[1] Tropospheric ozone (O3) effectively deposits to forested ecosystems but the fate of O3 within the forest canopy is unresolved. We partitioned total measured ecosystem daytime O3 deposition to a ponderosa pine (Pinus ponderosa) forest into its major loss pathways; stomatal uptake, non-stomatal surface deposition, and gas-phase chemistry. Total O3 flux was dominated by gas-phase chemistry dur...

We examined effects of prescribed fire on 3 wintering, bark-foraging birds, hairy woodpeckers (Picoides villosus), pygmy nuthatches (Sitta pygmaea), and white-breasted nuthatches (S. carolinensis), in ponderosa pine (Pinus ponderosa) forests of northern Arizona, USA. During winters of 2004–2006, we compared bird density, foraging behavior, and bark beetle activity among burned treatment and unb...

Low-elevation ponderosa pine (Pinus ponderosa Dougl. ex. Laws.) forests of the northern Rocky Mountains historically experienced frequent low-intensity fires that maintained open uneven-aged stands. A century of fire exclusion has contributed to denser ponderosa pine forests with greater competition for resources, higher tree stress and greater risk of insect attack and stand-destroying fire. A...

Currently, oak woodlands of Northern California and their associated mycorrhizal fungi are receiving more attention. In order to address the impact mycorrhizal fungal associations have on survival of various tree species in oak woodlands, we investigated the extramatrical fungal hyphae associated with several mature oak woodland tree species. Specifically our objective was to quantify the funga...

Snags provide an important resource for a rich assemblage of cavity-nesting birds in the southwestern United States. To expand our knowledge of snag use by cavity-nesting birds in this region, we documented characteristics of snags with and without excavated cavities in mixed-conifer and ponderosa pine (Pinus ponderosa Dougl. ex Laws) forest in north-central Arizona. Snags were sampled in 113 s...

The stable oxygen isotope ratio (6 0) of treering cellulose is jointly determined by the 6 0 of xylem water, the 8' 8 0 of atmospheric water vapor, the humidity of the atmosphere and perhaps by species-specific differences in leaf structure and function. Atmospheric humidity and the 6 0 of water vapor vary seasonally and annually, but if the canopy atmosphere is well mixed, atmospheric characte...

Analysis of seedling growth characteristics between two greenhouse cover types, old fiberglass and new polycarbonate, shows significant differences in height and sturdiness coefficients in ponderosa pine (Pinus ponderosa) seedlings. Three rates of nitrogen (N) application (20, 40, and 60 mg) indicate that seedling growth will increase under both cover types, but may cause a reduction in seedlin...

Conventional throughfall collection methods are labor intensive and analytically expensive to implement at broad scales. This study was conducted to test an alternative approach requiring infrequent sample collection and a greatly reduced number of chemical analyses. The major objective of the study was to determine the feasibility of using ion exchange resin (IER) to measure N deposition in th...