A5087232228- Climate change and permafrost
- Cryospheric studies and observations
- Fire effects on ecosystems
- Geology and Paleoclimatology Research
- Landslides and related hazards
- Forest ecology and management
- Tree-ring climate responses
- Plant Water Relations and Carbon Dynamics
- Arctic and Antarctic ice dynamics
- Ecology and Vegetation Dynamics Studies
- Insect-Plant Interactions and Control
- Geological Studies and Exploration
- Insect Utilization and Effects
- Agricultural and Food Sciences
- Engineering and Material Science Research
- Agronomic Practices and Intercropping Systems
- Food Quality and Safety Studies
- Radioactive contamination and transfer
- Soil and Unsaturated Flow
- Business Strategies and Innovation
- Demographic Trends and Gender Preferences
- Forest Biomass Utilization and Management
- RNA modifications and cancer
- Nutrition, Health and Food Behavior
- Genomic variations and chromosomal abnormalities
Bureau of Land Management
2015-2025
University of Guelph
2024-2025
New York City Fire Department
2012
University of Washington
1998
Abstract Fire-induced permafrost degradation is well documented in boreal forests, but the role of fires initiating thermokarst development Arctic tundra less understood. Here we show that may induce widespread thaw subsidence terrain first seven years following disturbance. Quantitative analysis airborne LiDAR data acquired two and post-fire, detected across 34% burned area studied, compared to than 1% similar undisturbed, ice-rich units. The variability appears be influenced by interaction...
Abstract. Within the last century there has been widespread establishment of trees in mountain meadows Pacific Northwest. We reconstructed patterns tree invasion at 17 meadow sites central Cascade Range Oregon, USA ‐sites representing diverse physical environments and vegetation types experiencing different histories recent anthropogenic disturbance (sheep grazing). Spatial distributions age structures invasive populations were analysed with respect to climatic records grazing history....
Abstract In 2007, the Anaktuvuk River fire burned more than 1000 km 2 of arctic tundra in northern Alaska, ~ 50% which occurred an area with ice-rich syngenetic permafrost (Yedoma). By 2014, widespread degradation ice wedges was apparent Yedoma region. a 50 area, thaw subsidence detected across 15% land repeat airborne LiDAR data acquired 2009 and 2014. Updating observations 2021 dataset show that additional < 1% study indicating stabilization thaw-affected terrain. Ground temperature...
We used tree-ring records to reconstruct the stand initiation of an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in western Cascade Range southern Washington. All samples were prepared and crossdated. Following a stand-replacing fire, period lasted from 1500 1540, with gradual filling-in growing space over this period. sampled initial colonizers, establishing (at stump-height) 15001521 under open conditions. A small number hemlock (Tsuga heterophylla (Raf.) Sarg.) also...
Abstract Climate change is expected to induce shifts in the composition, structure and functioning of Arctic tundra ecosystems. Increases frequency severity fires have potential catalyse vegetation transitions with far‐reaching local, regional global consequences. We propose that post‐fire recovery, coupled climate change, may not necessarily lead pre‐fire conditions. Our hypothesis, based on surveys literature, suggests two climate–fire driven trajectories. One trajectory results increased...
Abstract Palmer amaranth, a competitive weed in cotton and soybeans, poses challenges due to its rapid growth, high fertility, herbicide resistance. Effective management strategies targeting sex ratios could reduce seed production by female plants. Protoporphyrinogen oxidase (PPO-) inhibiting herbicides play role the evolving resistance of Amaranthus spp. Midwestern US. These may also affect male-to-female ratio amaranth. A two-year field experiment (2015 2016) was conducted soybean...
Few fires are known to have burned the tundra of Arctic Slope north Brooks Range in Alaska, USA. A total 90 between 1969 and 2022 known. Because fire has been rare, old burns can be detected by traces thermokarst distinct vegetation they leave otherwise uniform tundra, which visible aerial photograph archives. Several prehistoric found this way. Detection sparsely populated remote area historically inconsistent opportunistic, relying on reports aircraft pilots. Fire logged into an...
Abstract. Studies in recent decades have shown strong evidence of physical and biological changes the Arctic tundra, largely response to rapid rates warming. Given important implications these for ecosystem services, hydrology, surface energy balance, carbon budgets, climate feedbacks, research on trends patterns is becoming increasingly can help better constrain estimates local, regional, global impacts as well inform mitigation adaptation strategies. Despite this great need, scientific...
The history of canopy disturbances over the lifetime an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand in western Cascade Range southern Washington was reconstructed using tree-ring records cross-dated samples from a 3.3-ha mapped plot. reconstruction detected pulses which many hemlock (Tsuga heterophylla (Raf.) Sarg.) synchronously experienced abrupt and sustained increases ringwidth, i.e., "growth-increases", focused on medium-sized or larger ([Formula: see text]0.8...
Mechanical (e.g., shearblading) and manual thinning) fuel treatments have become the preferred strategy of many fire managers agencies for reducing hazard in boreal forests. This study attempts to characterize effectiveness four through direct measurement intensity forest floor consumption during a single prescribed burn. The included (1) thinning trees removing debris (THIN-REMOVE-1 -2), (2) burning onsite, (3) shearblading leaving place (SHEAR), (4) piling windrows (SHEAR-ROW). Fire burned...
Our understanding of tundra fire effects in Northern Alaska is limited because fires have been relatively rare. We sampled a 70+ year-old burn visible 1948 aerial photograph for vegetation composition and structure, soil attributes, terrain rugosity, thermokarst pit density. Between 2017 the initially became wetter as ice wedges melted but then drained dried troughs hydrologically connected. The reference has become over last few decades appears to be lagging through similar sequence....
The Drought Code (DC) was developed as part of the Canadian Forest Fire Weather Index System in early 1970s to represent a deep column soil that dries relatively slowly. Unlike most other fire danger indices or codes operate on gravimetric moisture content and use logarithmic drying equation diffusion, DC is based model balances daily precipitation evaporation. This conceptually simple water balance ultimately implemented using “shortcut” facilitated ledgering by hand but also mixed with...
Sorption models were developed to predict the moisture content in fuelbeds of standing dead grass from ambient weather measurements. Intuition suggests that response time diurnal changes is negligible and tracks equilibrium under most field conditions. This assumption could be modelled by empirically fitting coefficients equations using Here, six commonly used wildland fire management other industries fit 293 measurements Alaska, U.S.A. Predictors air temperature either relative humidity or...
We used full-polarimetric L-band and P-band synthetic aperture radar (SAR) data collected from the recent NASA Arctic Boreal Vulnerability Experiment (ABoVE) airborne campaign Sentinel-1 C-band dual-polarization to understand sensitivity of backscatter intensity phase fire-induced changes in surface subsurface soil processes tundra underlain by permafrost. The 2007 Anaktuvuk River fire on Alaska North Slope was as a case study. At ~10-year postfire, we observed strong increase (>~3–4 dB)...
We used Malaise traps to sample arthropod community composition at biweekly intervals across an agroecosystem landscape in southern Ontario, Canada, evaluate the relative impact of site spacing, seasonal timing, weather conditions, local plant attributes, and agricultural extent on spatial temporal variation composition. The 15 field sites sampled spanned a wide gradient that isolation had strong DNA metabarcoding samples identified >10 000 different biodiversity index numbers. Local...
The Drought Code (DC) is a moisture code of the Canadian Forest Fire Weather Index System underlain by hydrological water balance model in which drying occurs negative exponential pattern with relatively long timelag. derives from measurements an evaporimeter and no soil parameters are specified, leaving its physical nature uncertain. One way to approximate attributes “DC equivalent soil” compare timelag known soils. In situ were made over course fire season black spruce-feathermoss forest...