Treesearch

Fire has historically been a primary control on succession and vegetation dynamics in boreal systems, although modern changing climate is potentially increasing fire size and frequency. Large, often remote fires necessitate large-scale estimates of fire effects and consequences, often using Landsat satellite-derived dNBR (differenced Normalized Burn Ratio) to estimate burn severity. However, few studies have examined long-term field measures of ecosystem condition in relation to dNBR severity classes in boreal Alaska, USA. The goals of this study were: 1) assess changes in dominant...

Post-fire assessment is made after a wildfire incident to provide details about damage level and its distribution over burned areas. Such assessments inform restoration plans and future monitoring of ecosystem recovery. Due to the high cost and time to conduct fieldwork, remote sensing is an appealing alternative to assess post-fire condition over larger areas than can be surveyed practically in the field. The aim of this study is to use remote sensing data to characterize post-fire severity at tree level in a mixed conifer forest following the Cascade and East Zone megafires of 2007 in...

Aldo & Leonardo, a partnership between Colorado Art Ranch and the Aldo Leopold Wilderness Research Institute, was a project to celebrate the 50th anniversary of the Wilderness Act. The project was inspired by the scientific wisdom of Aldo Leopold and the artistic genius of Leonardo da Vinci. Our endeavor was an interdisciplinary collaboration of artists and scientists designed to celebrate the lands, resources and opportunities protected by the Wilderness Act. In 2013, we hosted one-month residencies in six diverse wilderness areas. Artists worked alongside wildland research scientists and...

Aldo & Leonardo, una asociación entre Colorado Art Ranch y el Aldo Leopold Wilderness Research Institute, fue un proyecto encargado de celebrar el 50 aniversario de la Ley sobre la Vida Silvestre. El proyecto se inspiró en la sabiduría científica de Aldo Leopold y el genio artístico de Leonardo da Vinci. Nuestro esfuerzo fue una colaboración interdisciplinaria de artistas y científicos diseñada para celebrar las tierras, los recursos y las oportunidades protegidos por la Ley de Vida Silvestre. En 2013, organizamos residencias de un mes en seis áreas silvestres diversas. Los artistas...

In fire-adapted conifer forests of the Western U.S., changing land use has led to increased forest densities and fuel conditions partly responsible for increasing the extent of high-severity wildfires in the region. In response, land managers often use mechanical thinning treatments to reduce fuels and increase overstory structural complexity, which can help improve stand resilience and restore complex spatial patterns that once characterized these stands. The outcomes of these treatments can vary greatly, resulting in a large gradient in aggregation of residual overstory trees. However,...

Fuel treatments are widely used to alter fuels in forested ecosystems to mitigate wildfire behavior and effects. However, few studies have examined long-term ecological effects of interacting fuel treatments (commercial harvests, pre-commercial thinnings, pile and burning, and prescribed fire) and wildfire. Using annually fitted Landsat satellite-derived Normalized Burn Ratio (NBR) curves and paired pre-fire treated and untreated field sites, we tested changes in the differenced NBR (dNBR) and years since treatment as predictors of biophysical attributes one and nine years after the 2007...

Our knowledge of the root system architecture of trees is still incomplete, especially concerning how biomass partitioning is regulated to achieve an optimal, but often unequal, distribution of resources. In addition, our comprehension of root system architecture development as a result of the adaptation process is limited because most studies lack a temporal approach. To add to our understanding, we excavated 32-year-old Pinus ponderosa trees from a steep, forested site in northern Idaho USA. The root systems were discretized by a low magnetic field digitizer and along with AMAPmod...

Biological soil crusts (BSCs) consist of a diverse and highly integrated community of organisms that effectively colonize and collectively stabilize soil surfaces. BSCs vary in terms of soil chemistry and texture as well as the environmental parameters that combine to support unique combinations of organisms - including cyanobacteria dominated, lichen-dominated, and bryophyte-dominated crusts. The list of organismal groups thatmake up BSC communities in various and unique combinations include - free living, lichenized, and mycorrhizal fungi, chemoheterotrophic bacteria, cyanobacteria,...

Our objective was to better understand how organic and inorganic nitrogen (N) forms supplied to a tree, Robinia pseudoacacia, and a perennial forb, Lupinus latifolius, affected plant growth and performance of their symbiotic, N-fixing rhizobia. In one experiment, we tested five sources of N [none; three inorganic forms (ammonium, nitrate, ammoniumnitrate); and an organic form (arginine)] in combination with or without rhizobia inoculation. We measured seedling morphology, allometry, nodule biomass, and N status. A second experiment explored combinations of supplied 15N and inoculation to...

First-year outplanting performance was measured in guindo santo (Eucryphia glutinosa (Poepp. & Endl.) Baill.), a Chilean endemic tree species in the Mediterranean climate zone, which is catalogued as a near-threatened species. The effects on survival of initial plant size, fertilization at establishment, and shade (with or without nurse trees) were evaluated during the first growth season. Planting guindo santo under nurse trees was the most important treatment to increase survival, compared with trees planted in full sun. We believe that the positive effects of nurse trees on survival are...