Arctic Field Projects

Project Title: Canopy gas exchange and growth of white spruce near the Arctic treeline: confronting measurements with models along natural and experimental resource gradients (Award# 0909155)

PI: Sullivan, Patrick "Paddy" ( )
Phone: (907) 786.1270 
Institute/Department: U of Alaska, Anchorage, Department of Biological Sciences 
IPY Project? NO
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ANS
Program Manager: Dr. William Wiseman (
Discipline(s): | Biology | Meteorology and Climate |

Project Web Site(s):

Science Summary:
The position of the arctic treeline has important implications for surface energy budgets and carbon cycling in a changing climate. Modeling efforts suggest these effects are relevant on regional and global scales. The understanding of the controls on tree growth at the arctic treeline has been developed using tree ring studies, which are necessarily correlative and not mechanistic in nature. These tree ring studies have identified both positive and negative radial growth responses to warming in the latter half of the 20th century. Investigators have speculated that negative growth trends reflect an increasing importance of temperature-induced drought stress and that treeline advance may be expected in mesic and wet areas, but not in dry areas, with future climate warming. Recent work has revealed several important complexities that clearly show we have oversimplified the relationships between climate and tree growth at the arctic treeline. Detailed measurements of seasonal changes in tree physiology and growth in response to changes in resource availability are now required to take our understanding to the next level. This work will coordinate continuous measurements of white spruce canopy gas exchange with weekly measurements of branch gas exchange and leader, branch, radial and fine root growth in trees receiving factorial nutrient and water supplements along a gradient of parent material depth. Results of the study will, for the first time: resolve the seasonality of C uptake and water loss in treeline white spruce; compare the seasonality and magnitudes of growth in all major organs; articulate the consequences of changes in resource availability for white spruce gas exchange physiology and growth along a gradient where resource availability varies naturally; and identify a process-based model that accurately describes the relationships between climate and tree growth at the arctic treeline.

Logistics Summary:
The goal of this study is to develop a continuous record of tree canopy gas exchange, while monitoring carbon allocation and growth in all major organs (branch, leader, stem and fine roots). The field work, from 2009 to 2012, will be based at the same Agashashok River site as the PI’s prior post-doc fellowship (NSF grant 0528748 in this database). To access the field site, each year the team will travel commercially to Kotzebue, putting in from there to the Agashashok field site by snowmachine, or if conditions prevent that, by fixed-wing plane. In fall of 2009, a team will travel to the Agashashok site to establish the field experiment. In 2010 a team of two will visit the site in late March, via snowmachine, to transport/stage the equipment and to conduct snowpack sampling. PFS project manager, Christie Haupert, will assist the PI with the spring put-in. They will spend about 3 days at the Aggie in this effort before departing. Later, in mid-May, the PI will return with two students. He will spend about about two weeks training the students on experiment protocols and instrument maintenance before departing, leaving the two to continue the field work. Resupply and mid-season crew change-outs will be supported via fixed-wing air support. The PI will visit up to 2 times throughout the summer. The 2011 field season will be similar to 2010. The PI and his graduate student will visit the site in late March, via snowmachine, spending about three days in the field. Starting in mid-May to capture the start of sap flow, the PI will accompany two students into the field. The PI will depart 2 weeks later, while the students will continue the field work until the end of August. The students will fly to Kotzebue periodically for resupply. In mid to late Sep, the PI will return to the field and stay until early Oct depending on timing of the fall season. Resupply and mid-season crew change-outs will be supported via fixed-wing air support. In 2012, the PI will visit the site with a field assistant, spending about 10 days on 4 different occasions: in late March, May/early June, early July and mid-late August. The researchers will travel to/from the site in March via snowmachine. After the melt season, a subcontractor based in Kotzebue will support fixed-wing air travel for putting in/taking out of the camp, crew change-outs, PI visits, and resupply.

CPS will provide Kotzebue lodging, vehicles, and storage; air charters between Kotzebue and the field site; camping gear and freight. The PI will make and pay for all other logistics through the grant.
SeasonField SiteDate InDate Out#People
2009Alaska - Agashashok River3
2009Alaska - Kotzebue3
2010Alaska - Agashashok River03 / 30 / 2010 06 / 30 / 20104
2010Alaska - Kotzebue03 / 29 / 2010 06 / 30 / 20104
2011Alaska - Agashashok River04 / 04 / 2011 09 / 30 / 20114
2011Alaska - Kotzebue04 / 04 / 2011 09 / 30 / 20114
2012Alaska - Agashashok River03 / 25 / 2012 08 / 30 / 20123
2012Alaska - Kotzebue03 / 25 / 2012 08 / 30 / 20123

Generated from:
Parameters used to generate this report:, Grant# = "0909155", IPY = "ALL" 
     Number of projects returned based on your query parameters = 1