Event Title

Fine Root Dynamics of Trembling Aspen in Boreal Forest and Aspen Parkland in Central Canada

Event Website

http://www.nafew2009.org/

Start Date

23-6-2009 11:10 AM

End Date

23-6-2009 11:30 AM

Description

Fine roots constitute a relatively small component of ecosystem carbon pools but they are vitally important in carbon and nutrient cycles because of their role in water and nutrient uptake and high turnover rates. The objective of this study was to compare trembling aspen fine root (<2mm) dynamics, including standing crop, productivity, and turnover rates, between two forest regions. Sites were located in boreal forest near Prince Albert in central Saskatchewan and 500 km south in aspen parkland near Regina. The parkland site is a proxy for the expected future climate of the boreal site. Mini-rhizotrons were established in mature trembling aspen stands at both sites to a depth of 40 cm and were monitored throughout the 2004 growing season. The parkland site had significantly greater fine root biomass (23.2 vs 5.4 Mg/ha, p=0.018) and root length productivity (234.9 vs 29.8 m/m2 image/year, p=0.004) than the boreal site. Fine roots in the parkland site also made up a larger component of total tree biomass than in the boreal site and accounted for a larger percentage of the total net biomass production (50% vs 38%). Root size distribution differed between sites with the parkland site having significantly more standing crop and yearly production of the smallest root sizes (<0.2 mm). Fine root length turnover was similar between sites (41 vs 49 %/year, p=0.385). This study indicates that there are significant differences in trembling aspen fine root dynamics between these forest regions which raise questions about future C cycling and tree productivity in the boreal forest depending on how the fine roots respond to the future climate.

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Jun 23rd, 11:10 AM Jun 23rd, 11:30 AM

Fine Root Dynamics of Trembling Aspen in Boreal Forest and Aspen Parkland in Central Canada

Fine roots constitute a relatively small component of ecosystem carbon pools but they are vitally important in carbon and nutrient cycles because of their role in water and nutrient uptake and high turnover rates. The objective of this study was to compare trembling aspen fine root (<2mm) dynamics, including standing crop, productivity, and turnover rates, between two forest regions. Sites were located in boreal forest near Prince Albert in central Saskatchewan and 500 km south in aspen parkland near Regina. The parkland site is a proxy for the expected future climate of the boreal site. Mini-rhizotrons were established in mature trembling aspen stands at both sites to a depth of 40 cm and were monitored throughout the 2004 growing season. The parkland site had significantly greater fine root biomass (23.2 vs 5.4 Mg/ha, p=0.018) and root length productivity (234.9 vs 29.8 m/m2 image/year, p=0.004) than the boreal site. Fine roots in the parkland site also made up a larger component of total tree biomass than in the boreal site and accounted for a larger percentage of the total net biomass production (50% vs 38%). Root size distribution differed between sites with the parkland site having significantly more standing crop and yearly production of the smallest root sizes (<0.2 mm). Fine root length turnover was similar between sites (41 vs 49 %/year, p=0.385). This study indicates that there are significant differences in trembling aspen fine root dynamics between these forest regions which raise questions about future C cycling and tree productivity in the boreal forest depending on how the fine roots respond to the future climate.

http://digitalcommons.usu.edu/nafecology/sessions/aspen/5