Searching for thresholds in climate–radial growth relationships of Engelmann spruce and subalpine fir, Jasper National Park, Alberta, Canada

2013 ◽  
Vol 31 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Sarah J. Hart ◽  
Colin P. Laroque
Author(s):  
A. Knapp ◽  
W. Smith

Prescribed burning in U.S. National Parks has been employed as a substitute for natural fires to achieve vegetation and/or wildlife management objectives (Habeck 1970). One specific management objective in Glacier National Park (GNP) is the restoration of plant community diversity to pre-fire-suppression levels.


1994 ◽  
Vol 24 (9) ◽  
pp. 1921-1932 ◽  
Author(s):  
David W. Peterson ◽  
David L. Peterson

Dendroecological techniques were used to study the influence of climate on the growth of subalpine fir (Abieslasiocarpa (Hook.) Nutt.), Engelmann spruce (Piceaengelmannii Parry), and subalpine larch (Larixlyallii Parl.) in the North Cascade Mountains of Washington state. Study sites were selected on different topographic features at three points along an elevation gradient (ridgetop, valley slope, and valley floor) to characterize site influences on growth response to climate. Mixed species stands were sampled to identify possible differences in species response to climate on a common site. Species differences account for most of the variability in radial growth patterns and response to climate. The greatest differences are between subalpine fir and subalpine larch, while the greatest similarities are between subalpine fir and Engelmann spruce. After species, aspect is the most significant factor affecting growth response to climate. Spring snowpack and summer temperature are the primary climatic factors influencing growth. Spring snowpack is negatively correlated with growth for all three species, but the relationship is strongest for subalpine fir and weakest for subalpine larch. Subalpine larch growth is positively correlated with June temperature. Subalpine fir growth is positively correlated with July–August temperature. Engelmann spruce growth is positively correlated with June–August temperature, but unusually warm July–August temperatures are associated with reduced growth the following year. The response of subalpine forests in the North Cascades to future climate change will depend on winter snowpack accumulations and spring snowmelt rates. Earlier meltouts and warmer summers would benefit growth on north aspect sites, but could also increase the frequency and severity of summer drought conditions on ridges and south-aspect sites, where summer soil moisture may already be limiting.


1990 ◽  
Vol 20 (6) ◽  
pp. 730-737 ◽  
Author(s):  
Mary A. Arthur ◽  
Timothy J. Fahey

We classified dead bole wood in an old-growth Engelmann spruce – subalpine fir (Piceaengelmannii Parry – Abieslasiocarpa (Hook.) Nutt.) forest in Rocky Mountain National Park, Colorado, into decay classes and measured dead bole surface area, volume, biomass, and nutrient content. Biomass of dead boles was 70 Mg/ha, about half as large as aboveground live biomass in these forests. Net accumulation of N, P, Ca, and Na occurred with increasing decay. The N:P ratio varied little with decay, approaching a value of 20 in the most decayed wood, typical of that found in other studies of dead boles. Loss of K during bole decay exceeded the rate of weight loss, whereas Mg loss followed weight loss. The total pools of nutrients in dead boles and in parentheses, the amount of nutrients stored in dead boles as a percentage of total above- and below-ground living, forest floor, and dead wood nutrients were 92.2 kg N/ha (7%), 4.89 kg P/ha (5%), 67.9 kg K/ha (16%), 156.6 kg Ca/ha (12%), 28.9 kg Mg/ha (17%), and 0.74 kg Na/ha (9%). Storage of relatively high amounts of Ca in dead wood of most natural forests indicates that management could have a significant effect on its availability in the long term.


2003 ◽  
Vol 33 (5) ◽  
pp. 847-853 ◽  
Author(s):  
Sylvia E Welke ◽  
Graeme D Hope ◽  
Gary A Hunt

The effect of timber harvesting on the biomass, nutrient standing crop, and decomposition of fine roots (<2 mm) was studied in a high elevation, Engelmann spruce (Picea engelmannii Parry ex Engelm.) – subalpine fir (Abies lasiocarpa (Hook.) Nutt.) forest. Root dynamics were compared in openings of different sizes. The sequential core method was used to collect fine root samples over 4 years. Differences in fine root biomass between opening sizes were most significant for the active fine root portion and were most pronounced in the fall compared with the spring. Active fine root biomass was significantly lower in the 10-ha clearcuts (164 kg/ha) compared with control plots (275 kg/ha). Furthermore, active fine root biomass was often lower in the 1.0-ha opening than in the 0.1-ha and control plots. A similar trend was established for inactive fine root biomass, although this was not consistent over sampling years. Nutrient concentrations of K, but no other elements, were higher in control plots. Nutrient standing crops, however, followed trends observed in fine root biomass. In the 10-ha clearcuts, the largest changes in fine root biomass occurred at the edge of the opening. The findings suggest that small (<10 ha) cutblocks may maintain greater fine root longevity.


2002 ◽  
Vol 32 (11) ◽  
pp. 2010-2021 ◽  
Author(s):  
Jeanine M Rhemtulla ◽  
Ronald J Hall ◽  
Eric S Higgs ◽  
S Ellen Macdonald

Repeat ground photographs (taken in 1915 and 1997) from a series of topographical survey stations and repeat aerial photographs (flown in 1949 and 1991) were analysed to assess changes in vegetation composition and distribution in the montane ecoregion of Jasper National Park, in the Rocky Mountains of Alberta, Canada. A quantitative approach for assessing relative vegetation change in repeat ground photographs was developed and tested. The results indicated a shift towards late-successional vegetation types and an increase in crown closure in coniferous stands. Grasslands, shrub, juvenile forest, and open forests decreased in extent, and closed-canopy forests became more prevalent. The majority of forest stands succeeded to dominance by coniferous species. Changes in vegetation patterns were likely largely attributable to shifts in the fire regime over the last century, although climatic conditions and human activity may also have been contributing factors. Implications of observed changes include decreased habitat diversity, increased possibility of insect outbreaks, and potential for future high-intensity fire events. Results of the study increase knowledge of historical reference conditions and may help to establish restoration goals for the montane ecoregion of the park.


1986 ◽  
Vol 23 (6) ◽  
pp. 804-812 ◽  
Author(s):  
A. B. Beaudoin ◽  
R. H. King

The magnetite composition from three sets of samples of Mazama, St. Helens set Y, and Bridge River tephras from Jasper and Banff national parks are used to test whether discriminant function analysis can unambiguously distinguish these tephras. The multivariate method is found to be very sensitive to the change in reference samples. St. Helens set Y tephra is clearly distinguished. However, discrimination between Mazama and Bridge River tephras is less distinct. A set of unknown tephras from the Sunwapta Pass area was used to test the classification schemes. Unknown tephras are assigned to different tephra types depending on which reference tephra set is used in the discriminant function analysis.


2018 ◽  
Vol 48 ◽  
pp. 10-19 ◽  
Author(s):  
Raphaël D. Chavardès ◽  
Lori D. Daniels ◽  
Ze’ev Gedalof ◽  
David W. Andison

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