|Analyses of Intrinsic Water-Use Efficiency Indicate Performance Differences of Ponderosa Pine and Douglas-fir in Response to CO2 Enrichment
||Aim: Increasing intrinsic water-use efficiency (iWUE) in trees is a global-scale response to increasing levels of atmospheric carbon dioxide (Ca). Our primary goal was to determine whether significant differences in either iWUE or radial growth exist...
|Does an August Singularity Exist in the Northern Rockies of the United States?
||Climatic singularities offer a degree of orderliness to notable meteorological events that are typically characterized by significant temporal variability. Significant deviations from normal daily maximum temperatures that occur following the passage...
|Drought-Busting Tropical Cyclones in the Southeastern Atlantic United States: 1950–2008
||Droughts and tropical cyclones (TCs) are climatologically common events in the southeastern United States, yet little research has examined the potential for TCs to ameliorate drought impacts. Here, we identify the frequency of TCs that abruptly end ...
|Human Agency, Environmental Drivers, and Western Juniper Establishment During the Late Holocene
||Western juniper (Juniperus occidentalis var. occidentalis) is undergoing rapid rates of expansion, and human activities (domestic livestock grazing, fire suppression) are typically presented as the primary agents of change. To determine the importanc...
|Impacts of an extreme early-season freeze event in the Interior Pacific Northwest (30 October-3 November 2002) on Western juniper woodlands
||In mid-autumn 2002, an exceptional 5-day cold spell affected much of the interior Pacific Northwest, with minimum temperatures averaging 13[degree]C below long-term means (1953-21)112). On 31 October, minimum temperature records occurred at 98 of the...
|Impacts of Human Disturbance on the Temporal Stability of Climate–Growth Relationships in a Red Spruce Forest, Southern Appalachian Mountains, USA
||We used dendrochronological techniques to develop a tree-ring chronology (AD 1874–2009) from live trees and investigated the temporal stability of regional climate signals in the heavily disturbed red spruce (Picea rubens Sarg.) and Fraser fir [Abies...
|Increasing Water-Use Efficiency and Age-Specific Growth Responses of Old-Growth Ponderosa Pine Trees
||We examined radial growth responses of ponderosa pine (Pinus ponderosa var. ponderosa) between 1905–1954 and 1955–2004 to determine if the effects of increased intrinsic water-use efficiencies (iWUE) caused by elevated atmospheric CO2 concentrations ...
|Mountain Pine Beetle Selectivity in Old-Growth Ponderosa Pine Forests, Montana, USA
||A historically unprecedented mountain pine beetle (MPB) outbreak affected western Montana during the past decade. We examined radial growth rates (AD 1860–2007/8) of co-occurring mature healthy and MPB-infected ponderosa pine trees collected at two s...
|Ocean–Atmosphere Influences on Low-Frequency Warm-Season Drought Variability in the Gulf Coast and Southeastern United States
||From the 344 state climate divisions in the conterminous United States, nine distinct regions of warm-season drought variability are identified using principal component analysis. The drought metric used is the Palmer hydrological drought index for t...
|Post-drought Growth Response of Western Juniper (Juniperus occidentalis var. occidentalis) in Central Oregon
||Increased atmospheric CO2 may affect the physiological response of natural trees to drought. We examined radial growth rates developed from five western juniper chronologies to determine if post-drought growth responses have changed. Using prior year...
|Radial Growth Rate Increases in Naturally Occurring Ponderosa Pine Trees: A Late-20th Century CO2 Fertilization Effect?
||The primary objective of this study was to determine if gradually increasing levels of atmospheric CO2, as opposed to ‘step’ increases commonly employed in controlled studies, have a positive impact on radial growth rates of ponderosa pine (Pinus pon...
|Radial Growth Rates of Two Co-Occurring Coniferous Trees in the Northern Rockies During the Past Century
||We examined radial growth rates of locally co-occurring Douglas-Fir (PSME e Pseudotsuga menziesii var. glauca) and ponderosa pine (PIPO e Pinus ponderosa var. ponderosa) trees growing within the Northern Rockies to determine if there are differential...
|Reconstructing Annual Area Burned in the Northern Rockies, USA: AD 1626–2008
||We used a tree-ring chronology as a proxy for annual area burned (AAB) in the northern Rockies, USA during AD 1626–2008. We correlated annual ring widths of alpine larch trees (Larex lyallii) sampled at a single high-elevation site in western Montana...
|Relationships Between Aerosols and Precipitation in the Southern Appalachian Mountains
||There are many uncertainties associated with aerosol-precipitation interactions, particularly in mountain regions where a variety of processes at different spatial scales influence precipitation patterns. Statistical relationships between aerosols an...
|Succession and Disturbance in an Endangered Red Spruce-Fraser Fir Forest in the Southern Appalachian Mountains, North Carolina, USA
||Red spruce-Fraser fir forests are geographically limited to high elevations in the Appalachian Mountains (USA) and are considered to be endangered in the USA. We investigated the successional status and radial growth patterns in the heavily disturbed...
|Topoedaphic and Morphological Complexity of Foliar Damage and Mortality Within Western Juniper (Juniperus Occidentalis Var. Occidentalis) Woodlands Following an Extreme Meteorological Event
||Aim An extreme early season freeze event in October 2002 resulted in significant foliar damage and/or mortality within western juniper woodlands. We identify the geographical patterns of tree damage based on morphological, topographical and edaphic p...
|Trends in mid-latitude cyclone frequency and occurrence during fire season in the Northern Rockies: 1900-2004.
||We examined changes in the timing and frequency of major midlatitude cyclones (MLCs) during August through October for eight climate stations in the Northern Rockies from 1900-2004. As MLCs can effectively diminish fire activity through both cooler t...
|Tropical Cyclones and Drought Amelioration in the Gulf and Southeastern Coastal United States
||Precipitation from land-falling tropical cyclones (TCs) has a significant hydroclimatic influence in the southeastern United States, particularly during drought years. The frequency with which TCs ended drought conditions was examined for southeaster...
|United States Drought of 2007: Historical Perspectives
||The impacts of the United States drought of 2007 to both society and ecosystems were substantive and included multi-billion dollar agricultural losses and the second worst wildfire season on record. The purpose of this paper is to place the 2007 drou...
|Use of Atmospheric CO2-Sensitive Trees May Influence Dendroclimatic Reconstructions
||We examined recent radial growth increases in western juniper trees using an 11-site chronology dating from AD 1000–2006. By various measures, radial growth during the late 20th/early 21st centuries was exceptional, with increases occurring absent of...