Postglacial palaeoecology of the subalpine forest — grassland ecotone of southwestern Alberta: New insights on vegetation and climate change in the Canadian rocky mountains and adjacent foothills

1989 ◽  
Vol 73 (3-4) ◽  
pp. 155-173 ◽  
Author(s):  
G.M. Macdonald
Keyword(s):  
Climate Change ◽  
Rocky Mountains ◽  
Subalpine Forest ◽  
Canadian Rocky Mountains ◽  
Vegetation And Climate

scholarly journals Lodgepole pine and interior spruce radial growth response to climate and topography in the Canadian Rocky Mountains, Alberta

2021 ◽  
pp. 1-16
Author(s):  
Frances Ackerman ◽  
David Goldblum
Keyword(s):  
Climate Change ◽  
Rocky Mountains ◽  
Radial Growth ◽  
Growth Response ◽  
Lodgepole Pine ◽  
Slope Aspect ◽  
Climate Variables ◽  
Canadian Rocky Mountains ◽  
Growth Responses ◽  
Interior Spruce

Climate change may have spatially variable impacts on growth of trees in topographically diverse environments, making generalizing across broad spatial and temporal extents inappropriate. Therefore, topography must be considered when analyzing growth response to climate. We address these topo-climatic relationships in the Canadian Rocky Mountains, focusing on lodgepole pine (Pinus contorta Douglas ex Louden) and interior spruce (Picea glauca (Moench) Voss × Picea engelmannii hybrid Parry) growth response to climate, Palmer drought severity index (PDSI), aspect, and slope angle. Climate variables correlate with older lodgepole pine growth on south- and west-facing slopes, including previous August temperature, winter and spring precipitation, and previous late-summer and current spring PDSI, but younger lodgepole pine were generally less sensitive to climate. Climate variables correlate with interior spruce growth on all slope aspects, with winter temperature and PDSI important for young and old individuals. Numerous monthly growth–climate correlations are not temporally stable, with shifts over the past century, and response differs by slope aspect and angle. Both species are likely to be negatively affected by moisture stress in the future in some, but not all, topographic environments. Results suggest species-specific and site-specific spatiotemporally diverse climate–growth responses, indicating that climate change is likely to have spatially variable impacts on radial growth response in mountainous environments.

scholarly journals Influence of high-order mechanics on simulation of glacier response to climate change: insights from Haig Glacier, Canadian Rocky Mountains

2013 ◽  
Vol 7 (5) ◽  
pp. 1527-1541 ◽  
Author(s):  
S. Adhikari ◽  
S. J. Marshall
Keyword(s):  
Climate Change ◽  
Rocky Mountains ◽  
Numerical Models ◽  
Flow Speed ◽  
High Order ◽  
Canadian Rocky Mountains ◽  
Ice Dynamics ◽  
Flow Speeds ◽  
Glacier Advance

Abstract. Evolution of glaciers in response to climate change has mostly been simulated using simplified dynamical models. Because these models do not account for the influence of high-order physics, corresponding results may exhibit some biases. For Haig Glacier in the Canadian Rocky Mountains, we test this hypothesis by comparing simulation results obtained from 3-D numerical models that deal with different assumptions concerning physics, ranging from simple shear deformation to comprehensive Stokes flow. In glacier retreat scenarios, we find a minimal role of high-order mechanics in glacier evolution, as geometric effects at our site (the presence of an overdeepened bed) result in limited horizontal movement of ice (flow speed on the order of a few meters per year). Consequently, high-order and reduced models all predict that Haig Glacier ceases to exist by ca. 2080 under ongoing climate warming. The influence of high-order mechanics is evident, however, in glacier advance scenarios, where ice speeds are greater and ice dynamical effects become more important. Although similar studies on other glaciers are essential to generalize such findings, we advise that high-order mechanics are important and therefore should be considered while modeling the evolution of active glaciers. Reduced model predictions may be adequate for other glaciologic and topographic settings, particularly where flow speeds are low and where mass balance changes dominate over ice dynamics in determining glacier geometry.

scholarly journals Influence of high-order mechanics on simulation of glacier response to climate change: insights from Haig Glacier, Canadian Rocky Mountains

2013 ◽  
Vol 7 (2) ◽  
pp. 1707-1748 ◽  
Author(s):  
S. Adhikari ◽  
S. J. Marshall
Keyword(s):  
Climate Change ◽  
Rocky Mountains ◽  
Numerical Models ◽  
Flow Speed ◽  
High Order ◽  
Canadian Rocky Mountains ◽  
Ice Flow ◽  
Flow Speeds ◽  
Glacier Advance

Abstract. Evolution of glaciers in response to climate change has mostly been simulated using simplified dynamical models. Because these models do not account for the influence of high-order physics, corresponding results may exhibit some biases. For Haig Glacier in the Canadian Rocky Mountains, we test this hypothesis by comparing simulation results obtained from 3-D numerical models that deal with different assumptions concerning ice-flow physics, ranging from simple shear-deformation to comprehensive Stokes flow. In glacier retreat scenarios, we find a minimal role of high-order mechanics in glacier evolution, as geometric effects at our site (the presence of an overdeepened bed) result in limited horizontal movement of ice (flow speed on the order of a few meters per year). Consequently, high-order and reduced models all predict that Haig Glacier ceases to exist by ca. 2080 under ongoing climate warming. The influence of high-order mechanics is evident, however, in glacier advance scenarios, where ice speeds are greater and ice dynamical effects become more important. To generalize these findings for other glacier applications, we advise that high-order mechanics are important and therefore should be considered while modelling the evolution of active glaciers. Reduced model predictions may, however, be adequate for other glaciologic and topographic settings, particularly where flow speeds are low.

A 15,000 year record of vegetation and climate change from a treeline lake in the Rocky Mountains, Wyoming, USA

The Holocene ◽  
2011 ◽  
Vol 22 (7) ◽  
pp. 739-748 ◽  
Author(s):  
Scott Mensing ◽  
John Korfmacher ◽  
Thomas Minckley ◽  
Robert Musselman
Keyword(s):  
Climate Change ◽  
Rocky Mountains ◽  
Vegetation Change ◽  
Climatic Variability ◽  
High Elevation ◽  
Sagebrush Steppe ◽  
Climate Projections ◽  
Upward Movement ◽  
Regional Patterns ◽  
Vegetation And Climate

Future climate projections predict warming at high elevations that will impact treeline species, but complex topographic relief in mountains complicates ecologic response, and we have a limited number of long-term studies examining vegetation change related to climate. In this study, pollen and conifer stomata were analyzed from a 2.3 m sediment core extending to 15,330 cal. yr BP recovered from a treeline lake in the Rocky Mountains of Wyoming. Both pollen and stomata record a sequence of vegetation and climate change similar in most respects to other regional studies, with sagebrush steppe and lowered treeline during the Late Pleistocene, rapid upward movement of treeline beginning about 11,500 cal. yr BP, treeline above modern between ~9000 and 6000 cal. yr BP, and then moving downslope ~5000 cal. yr BP, reaching modern limits by ~3000 cal. yr BP. Between 6000 and 5000 cal. yr BP sediments become increasingly organic and sedimentation rates increase. We interpret this as evidence for lower lake levels during an extended dry period with warmer summer temperatures and treeline advance. The complex topography of the Rocky Mountains makes it challenging to identify regional patterns associated with short term climatic variability, but our results contribute to gaining a better understanding of past ecologic responses at high elevation sites.

Net precipitation in burned and unburned subalpine forest stands after wildfire in the northern Rocky Mountains

2019 ◽  
Vol 28 (10) ◽  
pp. 750 ◽  
Author(s):  
Chris H. S. Williams ◽  
Uldis Silins ◽  
Sheena A. Spencer ◽  
Michael J. Wagner ◽  
Micheal Stone ◽  
...  
Keyword(s):  
Rocky Mountains ◽  
Snow Water Equivalent ◽  
Snow Accumulation ◽  
Subalpine Forest ◽  
Canadian Rocky Mountains ◽  
Forest Stands ◽  
Canopy Interception ◽  
Northern Rocky Mountains ◽  
Annual Peak ◽  
Snow Water

Wildfire can exert considerable influence on many watershed processes, including the partitioning of precipitation by forest canopies. Despite general acknowledgement that canopy interception is reduced following wildfire, effects on net rainfall and snow accumulation have not been quantified. The objectives of this study were to document net rainfall and snow water equivalent (SWE) in burned and unburned (reference) forest stands over a 10-year period to characterise the effects of severe wildfire on net precipitation in the Canadian Rocky Mountains. Differences in summer (June–September) rainfall between burned and reference stands suggest that wildfire reduced rainfall interception by 65%, resulting in a 48% increase in net rainfall from 2006 to 2008. This represented an average annual increase in net rainfall of 122mm (36%) for 10 years after the fire. Similarly, a burned stand had 152mm (78%) higher mean annual peak SWE than a paired reference stand. Collectively, burned stands had 274mm (191–344mm; 51%) more mean annual net precipitation for the first decade after fire. These results suggest that increases in net precipitation are likely following wildfire in subalpine forests and that, owing to the slow growth of these forests, post-fire changes may alter precipitation–runoff relationships for many years.

Wildfires in the southern Canadian Rocky Mountains and their relationship to mid-tropospheric anomalies

1993 ◽  
Vol 23 (6) ◽  
pp. 1213-1222 ◽  
Author(s):  
E.A. Johnson ◽  
D.R. Wowchuk
Keyword(s):  
North America ◽  
Rocky Mountains ◽  
Large Scale ◽  
Fire Frequency ◽  
Fuel Moisture ◽  
Large Fire ◽  
Canadian Rocky Mountains ◽  
Area Burned ◽  
Upper Level ◽  
Moisture Conditions

In this paper we present evidence for a large-scale (synoptic-scale) meteorological mechanism controlling the fire frequency in the southern Canadian Rocky Mountains. This large-scale control may explain the similarity in average fire frequencies and timing of change in average fire frequencies for the southern Canadian Rocky Mountains. Over the last 86 years the size distribution of fires (annual area burned) in the southern Canadian Rockies was distinctly bimodal, with a separation between small- and large-fire years at approximately 10–25 ha annual area burned. During the last 35 years, large-fire years had significantly lower fuel moisture conditions and many mid-tropospheric surface-blocking events (high-pressure upper level ridges) during July and August (the period of greatest fire activity). Small-fire years in this period exhibited significantly higher fuel moisture conditions and fewer persistent mid-tropospheric surface-blocking events during July and August. Mid-tropospheric surface-blocking events during large-fire years were teleconnected (spatially and temporally correlated in 50 kPa heights) to upper level troughs in the North Pacific and eastern North America. This relationship takes the form of the positive mode of the Pacific North America pattern.

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