TAS-2: Athrotaxis history and dynamics

Title: Athrotaxis tree-ring fire history and dynamics

Investigators: Veblen, Holz, Bowman, Wood

Students:  Nacify (CU PhD)

Project Description

Objectives:  This research will combine landscape ecology (geospatial analysis of aerial photography), forest dynamics (stand structure analysis), and tree-ring fire history analyses to understand fire-climate-human linkages in Athrotaxis ecosystems in Tasmania. As stated in the ARC proposal we will:

  • Use sequences of historical aerial photography dating from the 1950s to map the extent and shape of historically recent fire events known to have killed stands of Athrotaxis and identify environmental correlates of burnt and unburnt stands (hereafter the landscape ecology study;
  • Reconstruct landscape-scale fire activity at an annual resolution in western Tasmania over the last 1,000 years by using dendrochronological techniques (hereafter the tree-ring fire history study;
  • Determine the relative influences of regional atmospheric patterns on fire occurrence at inter-annual and multidecadal scales (e.g. ENSO, AAO) in Tasmania with the use of instrumental and dendrochronologically reconstructed climate records (hereafter the fire-climate driver study;

Work Plan

  • Landscape ecology study:

Wood will take the lead on developing landscape ecology study.  This will involve the development of maps of past fires from historical aerial photography.  These maps will be the primary fire database for producing a biophysical model of landscape susceptibility to fire.  

  • Tree-ring fire history study:

Holz will take the lead on developing the tree-ring fire history study.  Data collection will include stand structure attributes, primarily ages and fire-scar samples from dead trees, and where permitted a limited sample of ages from living trees.  Wood is responsible for securing permits for collecting tree-ring samples. 

  • Fire-climate driver study: 

Holz will take the lead on developing the fire-climate driver study. This will be based both on existing documentary records of fires as well as new fire history data developed in the landscape ecology study and in the tree-ring fire history study.

Expected Outcomes and Related Activities

The results will be published with Wood as lead author on the landscape ecology study and Holz as lead author on the tree-ring fire history and fire-climate driver studies.

The tree-ring fire history data will be available for comparison with charcoals records developed by other participants in the PIRE/ARC studies.

Timeline

 Holz needs to be hired by ARC as soon as possible and begin his 2-year residence in Hobart approximately Jan. 1, 2012.   He and Wood (working 20% time on ARC) will conduct data acquisition, sample processing, and analyses during the first two years of the project.  They will advance as much as possible with manuscript writing during the first two years, but PIRE will employ Holz during year 3 and ARC will employ Wood during year 3 to allow continued data analyses and writing, as needed. 

Planning of the research will benefit from Wood’s short visit to Boulder in August 2011.

Opportunities for additional collaborations

One CU graduate student will participate in fieldwork and data analyses for 6 weeks in 2013, and if appropriate be included as a co-author on one or more of the resulting manuscripts.

Constraints

Research permits: Coring of trees for age determination must be obtained by the Tasmanian partners. Cutting of partial cross sections from live trees for dating fire scars is unlikely to be allowed.

Field safety: The Tasmanian partners must provide a field assistant for Holz so that there is always a team of at least two people when conducting fieldwork.

Year 2 Update

This project seeks to understand the fire history and ecology of Athrotaxis, a conifer with a distribution that extends across western and central Tasmania.  The research leverages support from the Australian Research Council grant to Bowman, Veblen, and Whitlock.  The ARC grant supports the participation of Holz, as a postdoc at University of Tasmania on PIRE-related activities for the next two years.  The dendroecological research has been slowed by the difficulty of obtaining permission to sample live and dead Athrotaxis.  Current permits allow sampling of only dead trees at two study sites (Abrotanella Rise and the Central Plateau). During year 2, Holz conducted field reconnaissance in ca. 10 sites across Tasmania, and led sample collection of tree-ring cores and fire-scar partial cross-sections (exclusively from dead trees) in two of them.  He assisted with collection of lake and peat-hollow sediment records in two sites, working with Fletcher, Wood, and Naficy.   Veblen met with Holz to visit sites already sampled as well as sites to be sampled next year when permission is granted.  During Veblen’s visit, the team also conducted reconnaissance of the Athrotaxis area, discussed and planned research, and drafted a summary of tree-ring research being developed for the Athrotaxis area under PIRE and ARC.  He met with Bowman and Brodribb to discuss future research plans.