Water use in trees

Project keywords: Evapotranspiration, climate warming, growth-climate relationships, water availability

Name of project lead: Jennifer Baltzer

Project team/partners: For each collaborator please specify: Team member name, role, organization and contact information
J. Baltzer (WLU), W. Quinton (WLU), O. Sonnentag (UdeM)

Status: In progress

Location: Scotty Creek (61°18’N, 121°18’W) and Havikpak Creek (68° 37′ N, 133° 76′ W)

Year and month project started: May 2012

Anticipated completion year of project? 2015

Executive year of project (example, year 1 or 2 or 3…) 2

Brief project description:

Background: A large proportion of permafrost regions are overlain by boreal forest and these forests contribute in important ways to local processes (e.g., vegetation – soil moisture – permafrost feedbacks) and in land-surface-atmosphere interactions (e.g., transpirational processes from forest canopy). However, we know little about the responses of common boreal tree species to changing conditions they are facing with climate warming and permafrost thaw.

Objective: Quantify intra- and inter-annual variation in sap flux in boreal species that will provide a comprehensive physiological understanding of responses of boreal forests to variation in ground and soil water availability, permafrost depth, timing of thaw and vapour pressure deficit.

Methodology: In 2012 and 2013, heat ratio method sap flow sensors (Baltzer CFI-funded equipment) will be fixed to large individuals of black spruce on plateau edges and interiors at Scotty Creek to quantify physiological responses to changing permafrost plateau conditions as permafrost thaws and soils become wetter. In 2014 and 2015 the sensors will be redeployed at Havikpak Creek to examine the responses of trees on continuous permafrost through the growing season where warming may be leading to greater water stress. In both cases, seasonal variation in sap flow will be measured corresponding with ongoing hydrometeorological measurements at these sites. Tree cores will be taken from the same trees to relate longer-term patterns of growth to individual-variation in sap flow. These sap flux sensors will also be used to quantify the contribution of evapotranspiration from trees to whole forest gas-flux being measured using Partnership-purchased eddy covariance systems at both Havikpak and Scotty Creeks.

Significance of the results (rationale): / project linkages

What are the key contributions to science/our knowledge base of northern environments

This research will provide mechanisms for documented changes in forest dynamics in response to climate change alone. This type of information is key when attempting to predict/understand cumulative impacts of direct and indirect human impacts. This is a first step in our integration of hydrological and ecological measurements; understanding the linkages between ecology and hydrology and the contribution of forests to ecosystem water fluxes is critical in developing more integrative predictive capacity for ecosystems.

What are the key contributions to cumulative effects monitoring in the NWT?

What is the relevance to decision-makers?

This work will provide important insights into a potentially key mechanism driving change in forests near in response to continued climate warming. From the perspective of predictive tool development, understanding the contribution of forests to ecosystem water fluxes and how this is changing with warming is critical in developing more integrative predictive capacity for ecosystems.

Which decision-makers will likely be impacted by / interested in results?

ENR managers

What is the relevance to communities?

What are the project milestones? (including beginning date and anticipated end-date)

May 2012, 2013 – Deploy sensors at Scotty Creek, NWT
May 2014, 2015 – Deploy sensors at Havikpak, NWT
Summer 2013 – Presentation and publication of 2012 results (similar outputs will be ongoing through the study period)
August 2015 – data collection complete
On-going dissemination of findings to the NWT and scientific community.

Key deliverables and reporting: Link to needs of NWT

1. The proposed work will result in multiple peer reviewed publication and presentations at international conferences

2. The proposed research will be reported to the Science Committee and appropriate GNWT agencies in the form of a manuscript/report

3. Results will be presented in a community format to inform interested local parties. This will include a demonstration of the methodology and information on how trees factor into water cycling in these forests.

Engagement, training and capacity building

This particular project contributes to the goal of improved predictive capacity in regards to water resources as the focus of the work is improved eco-hydrological predictive tools for long-term study sites in the NWT, thus the research is in response to Water Stewardship Strategy priorities that represent a range of stakeholders.

At the Scotty Creek site, we have a good working relationship with a number of communities, meeting regularly with them and keeping them informed and engaged in work at the site.

Links to WSIPlan and NWT Science Agenda

Water stewardship strategy keys to success
1.1H Collaboratively develop and implement an approach that provides for effective use of traditional, local and western scientific knowledge in water stewardship decision-making processes. 1 – With collaborative input from traditional, local and western scientific knowledge holders, develop an effective approach to inform water stewardship decisions. 2 – design effective tools to improve decision-making.

Develop and implement collaborative ecosystem-based research and monitoring programs. 2- develop collaborative partnerships that can enhance ecosystem-based water stewardship in the NWT.

Develop and implement collaborative research and monitoring programs for environmental stressors that can contribute to cumulative effects on NWT watersheds. 3- implement cumulative effects research and monitoring programs.

Key project tasks for next year (work plan pieces – research)

Complete 2013 sap flow measurements

Tree coring for all sampled sap flow trees

Present research at international meeting

Completion of 2 additional manuscripts in progress on the topic and submission 
to/publication in peer reviewed journals

Key project tasks for next year (work plan pieces – engagement, training and capacity building)

Plain language presentations at community meetings in Fort Simpson, Jean Marie, Trout Lake

Published Papers

Baltzer, J, Patankar, R, Downey, A, and Quinton, W (2013) Impacts of seasonal thaw and permafrost degradation on Picea mariana root function in a subarctic boreal peatland. Proceedings of the 9th International Sap Flow Workshop. Acta Horticulturae, accepted.