The geologic origin of the Medusae Fossae Formation (MFF) has remained a mystery despite three decades of research. To better constrain its formation, an in-depth analysis of observations made in the literature was combined with a new survey of over 700 Mars Orbiter Camera narrow-angle images of the MFF to...
Canopy architectures of five structurally complex forest stands and three structurally simple forest stands in southwest Oregon and the Willamette Valley, Oregon, were evaluated and quantified through crown area profiles. Mixed conifer and mixed conifer-hardwood stands across a range of sites were sampled for crown widths and heights. Crown width...
Sclerotinia crown rot, caused by Sclerotinia minor and S. sclerotiorum,
is a disease of pyrethrum in Australia that may cause substantial decline
in plant density. The spatiotemporal characteristics of the disease
were quantified in 14 fields during three growing seasons. Fitting the
binary power law to disease incidence provided slope...
Crown profile equations were developed for stand-grown western hemlock (Tsuga heterophylla (Raf.) Sarg.) in northwest Oregon. The profile model uses a segmented approach, dividing the crown into an upper and lower portion at the point of the largest crown width (LCW). The model explains about 86% of the variation in...
Two nonspatial approaches for modeling tree crown recession (ΔHCB) were evaluated by using 5341 observations from Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). The first approach applies a static height-to-crown-base (HCB) equation at the start and end of the growth period and uses the difference in these predictions as an estimate of...
In the Pacific Northwestern United States, the hop powdery mildew fungus, Podosphaera macularis, survives overwintering periods in association with living host tissue because the ascigerious stage of the pathogen is not known to occur in this region. Field experiments were conducted over a 5-year period to describe the overwintering process...
Accurately monitoring tropical forest carbon stocks is a challenge that remains outstanding. Allometric models that consider tree diameter, height and wood density as predictors are currently used in most tropical forest carbon studies. In particular, a pantropical biomass model has been widely used for approximately a decade, and its most...
It would be valuable economically to know what are the biological triggers for formation of mature wood (currently of high value) and (or) what maintains production of juvenile wood (currently of low value), to develop silvicultural regimes that control the relative production of the two types of wood. Foresters commonly...
Fusarium crown rot (FCR) is one of the most widespread root and
crown diseases of wheat in the Pacific Northwest (PNW) of the United
States. Our objectives were to characterize crown rot severity and
distribution throughout the PNW by conducting a survey of 210 fields
covering the diverse dryland wheat-producing...
Establishing true depths of recovered sediments is critical to determining sedimentation rates for high-resolution paleoclimatic
studies. We have corrected the composite depth scale, which accounts for the entire continuous sedimentary sequence, so that sediment
depths are consistent with logging depths, or "true" depths. We accomplished this by taking advantage of...