Treesearch

Rainfall interception by a tree's crown is one of the most important hydrological processes in an ecosystem, yet the mechanisms of interception are not well understood. A process-based experiment was conducted under five simulated rainfall intensities (from 10 to 150 mm h−1) to directly quantify tree crown interception and examine the effect of rainfall traits and crown structure characteristics on interception for broadleaf (Platycladus orientalis, Pinus tabulaeformis) and needle tree species (Quercus variabilis, Acer truncatum). Results indicated that (1) the interception process was...

Climate model projections for tropical regions show clear perturbation of precipitation patterns leading to increased frequency and severity of drought in some regions. Previous work has shown declining soil moisture to be a strong driver of changes in microbial trait distribution, however, the feedback of any shift in functional potential on ecosystem properties related to carbon cycling are poorly understood. Here we show that drought-induced changes in microbial functional diversity and activity shape, and are in turn shaped by, the composition of dissolved and soil-associated carbon....

Thinning with removal of whole trees in a plantation or natural forest stand raises two main concerns – soil compaction from the ground-based machinery and nutrient depletion particularly with whole tree harvest as is often practiced for attendant fuels reduction. To address these concerns, two sets of experimental treatments were imposed in young ponderosa pine plantations. In the first set, we applied four treatments to test the effects of thinning with biomass removal using progressively more soil manipulations: (I) control, (II) thinning only with all biomass removed, (III) same as...

The National Wildfire Coordinating Group’s definition of extreme fire behavior indicates a level of fire behavior characteristics that ordinarily precludes methods of direct control action. One or more of the following is usually involved: high rate of spread, prolific crowning/ spotting, presence of fire whirls, and strong convection column. Predictability is difficult as such fires often influence their environment to some degree and behave erratically, sometimes dangerously. Alternate terms include “blow up” and “fire storm.” Fire managers examining fires over the last 100 years have...

This study examines perceptions of three stakeholder groups (African American Family Forest Landowner, Government Agency, and Nonprofit) regarding federal landowner assistance programs in the southern United States by combining a SWOT (strength, weakness, opportunity, and threat) analysis with the AHP (analytical hierarchy process). Factors with the highest priority values were professional advice, lack of staff members, forestland retention, and heirs’ property under the SWOT categories of strength, weakness, opportunity, and threat across stakeholder groups, respectively. The guidelines...

Amendment of soil nutrients through fertilization is used to increase wood production of forest stands. Subsequent allocation of growth to individual trees and the resulting increase in stand volume and value, however, depend on stand density at the time of treatment. Our primary research question was: To what extent can volume growth per acre in precommercially thinned or nonthinned portions of a poor-site, 30-year-old coast Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) plantation be increased by a single application of 200 or 400 lb nitrogen (N)/acre as urea? Each...

Metropolitan development in the USA has historically relied on systems of centralized infrastructure that assume a population density and level of economic activity that has not been consistently sustained in post-industrial urban landscapes. In many cities, this has resulted in dependence on systems that are environmentally, economically, and socially unsustainable. Reliance on this deteriorating social and physical infrastructure results in waste and decreased efficiencies. While numerous cities could exemplify this trend, the present work highlights two compelling cases: Detroit,...

Mode of inheritance of hatch traits in Lymantria dispar L. was determined by crossing populations nearly fixed for the phenotypic extremes. The nondiapausing phenotype was inherited via a single recessive gene and the phenotype with reduced low temperature exposure requirements before hatch was inherited via a single dominant gene. There was no evidence for sex-linkage or cytoplasmic effects with either gene. Eggs from 43 geographic populations were evaluated for hatch characteristics after being held for 60d at 5ºC followed by incubation at 25ºC. There was considerable variation both...

Microbial-mediated decomposition and nutrient mineralization are major drivers of forest productivity. As landscape-scale fuel reduction treatments are being implemented throughout the fire-prone western United States of America, it is important to evaluate operationally how these wildfire mitigation treatments alter belowground processes. We quantified these important belowground components before and after management-applied fuel treatments of thinning alone, thinning combined with prescribed fire, and prescribed fire in ponderosa pine (Pinus ponderosa) stands at the Southwest Plateau,...

In many forests of the world, the summer season (temporal element) brings drought conditions causing low soil moisture in the upper soil profile (spatial element) - a potentially large barrier to seedling establishment. We evaluated the relationship between initial seedling root depth, temporal and spatial changes in soil moisture during drought after outplanting, and subsequent seedling performance using seedlings of Pinus ponderosa Laws. var. ponderosa grown in three containers similar in dimension except for depth (i.e. three stocktypes). Soil moisture patterns were quantified and...