Project Title: Fire and Forest Histories of Central Oregon from Tree Rings

Progress Report

May 2010

Project Title: Fire and forest histories of central Oregon from tree rings

Principle Investigators: Emily K. Heyerdahl - Forest Service - Rocky Mtn Research Station

Donald A. Falk - University of Arizona

Cooperators:COFMS Fire History Advisory Board:

Geoff Babb - Bureau of Land Management

Lauren Miller - Deschutes National Forest

Jinny Pitman - Deschutes National Forest

Gregg Riegel - Deschutes National Forest

Amy Waltz - The Nature Conservancy

Duration of project:29 months over 3 fiscal years (May 2009 through September 2011)

Our six primary objectives are listed here, followed by progress as of May 2010.

1. Reconstruct annually accurate multi-century fire and forest histories from tree rings sampled systematically at 6 sites (approximately 1200-ac (500-ha) each): 4 sites that each span a range of forest types but are centered on mixed-conifer forests (2 sites on the east-slope of the Cascades and 2 sites in the Ochocos); 1 site dominated by western juniper; and 1 site dominated by lodgepole pine.

We finished sampling at one gridded site dominated by lodgepole pine in 2009 (POT, figure 1, table 1). We sampled 28 or 30 plots at one mixed-conifer site on the east slope of the Cascades (SHR) and 22 of 30 plots at a mixed-conifer site in the Ochocos (LYT).

We have selected one gridded site for sampling in 2010: the western juniper site at HSE. After consulting with Jeff Bell, Dave Owen, and Brian Sholz at the Ochoco National Forest, we mapped two potential sampling grids in the Ochocos (BBE and KAY) and will select one of these sites during field reconnaissance in June 2010 and sampled it in July 2010. We met with Brian Tandy of the Deschutes National Forest in April 2010 to identify potential sampling sites on the Sisters District and will meet with him again in early June to finalize a site to sample in 2010.

All field data collected in 2009 has been entered. Of the wood samples collected from 2,015trees in 2009, 1,341 (66%) have been crossdated.

Figure 1. Sampling sites. Black dots are gridded sites sampled in 2009. Yellow crosses are frequent-fire sites sampled in 2009. Red dots are gridded sites that will be sampled in 2010 (HSE and either KAY or BBE).

Table 1. Sites sampled in 2009.

1. Estimate modern fuel loading.

We estimated modern fuel loading for each of the plots we sampled in summer 2009 and will continue to do so for plots we sample in 2010. We have not yet assigned a fuel model to our plots and would appreciate help from COFMS in doing so.

1. Assess the confidence with which our fire histories could be extrapolated to unsampled areas by inferring the drivers of spatial variation within and among our sampling sites.

We have begun identifying new approaches to assessing synchrony in fire among our sites.

1. Identify the climate drivers of past regional-fire years in central Oregon from our tree-ring data and for modern regional-fire years from written archival records of fire; project future fire regimes using existing regional climate projections.

We collected fire-scarred sections from 3 sites in summer 2009 (DUN, SLO, and OSA, figure 1, table 1), which required one day of sampling per site. So far, we have crossdated sections from DUN. We obtained 20 fire-scarred sections that were collected by Peter Brown and colleagues near the Metolius River during the Dendroecology Field Week in 1994. We made a request to Karen Aarabas and Keith Hadley that they publicly archive their fire-scar and tree-ring width chronologies from Newberry Crater and received a positive response.

We have been able to local archival records of fire from the Ochoco National Forest but only for the past 30 years. We would appreciate any further information or assistance from COFMS in obtainingearlier records.

1. Link with landscape fire, vegetation, and climate change simulation model research that will simulate historical fire and vegetation dynamics in central Oregon.

We continue to work closely with Rachel Loehman (Research Ecologist, Rocky Mountain Research Station) to ensure that we collect the data she needs to parameterize FireBGCv2. Falk and Heyerdahl attended a FireBGCv2 user's workshop in November 2010.

1. Communicate our findings to COFMS and other potential users of the data in central Oregon via written reports, oral presentations, and a website.

Heyerdahl made three oral presentations about this research to the following groups:

1. Central Oregon Fire Management Service (October 6, 2009), Prineville, OR
2. Bend-Fort Rock District, Ochoco National Forest (Nov. 16, 2009), Bend, OR
3. Fire Science Symposium (April 28, 2010), Bend OR

We posted a web page about the project on January 7, 2010:

At the request of COFMS, we prepared a short paper about inferences regarding fire regime properties (Heyerdahl, E.K., D.A. Falk, and C.S. Wright. Composite fire intervals can accurately estimate mean fire intervals. February 25, 2010).

Overall, we're pleased with the progress we made in meeting our objectives for this year. This was despite a 4-month delay by the Albuquerque Service Center in hiring our primary field assistant, who could not began work until mid-September 2009, after the majority of the field season had passed. Because we were forced to sample with too few crew members for most of the field season, we were unable to complete all the sampling scheduled for summer 2009 and worked into October in an attempt to catch up. This in turn reduced our time during the fall to prepare and crossdate wood samples. Ultimately, we anticipate that these delays may delay final completion of the project by several months, until December 2011.

Deliverables and Technology Transfer

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