DENDROCHRONOLOGY ACROSS BORDERS: DEVELOPING A NETWORK OF QUERCUS GARRYANA TREE-RING CHRONOLOGIES FOR THE PACIFIC NORTHWEST David A. Jordan1, Gabriel I. Yospin2, Bart R. Johnson3, and Doug McCutchen4 1 Department of Geography and Environment, Trinity Western University, Langley, BC 2 InsUtute on Ecosystems, Montana State University, Bozeman, MT 3 Department of Landscape Architecture, University of Oregon, Eugene, OR 4 San Juan County Land Bank, Friday Harbour, WA Cascadia Prairie Oak Partnership 2015 Conference, October 26-29, 2015, Tacoma, Washington CONSERVATION WITHOUT BORDERS: Working Across Boundaries to Restore Prairie and Oak CommuniMes Acknowledgements Co-authors: Dr. Bart Johnson, University of Oregon, Dr. Gabe Yospin, University of Oregon/ Montana State Univ Co-author: Doug McCutchen, Ruthie Dougherty, Steve Ulvi Jane KerMs, U.S. Forest Service, Staff at Finley Nature Refuge City of Victoria Parks staff: Thomas Munson, Dan MarZoco and Craig Pelton Research funding provided by Naonal Science Foundaon Outline 1. Background • The problem, why does it maer, goals and objecves 2. Methods • Dendrochronology (Tree-ring science) • Field and Laboratory • Study Areas 3. Results and Discussion 4. Summary Background:The fate of oak habitat? 44% Agriculture 30% Forest 14% Other natural vegetaUon 8% Built features 4% Unknown 2-10% remains, 90-95% on private land Hulse, Gregory and Baker. 2002. Willame[e River Basin planning atlas Background: Why does it maYer? Willame[e Valley oak savanna & woodland: • >95 nave vertebrate species associated w/ Willame[e Valley grasslands (Veseley and Rosenberg 2010) • >714 nave plant species of which more than 391 are found principally or exclusively in grassland habitats (Ed Alverson, TNC, unpublished data). • >1100 species of arthropods in upland prairies (Wilson et al. 1998), including 350-400 species of nave bees in oak savannas, many specialiZed to one plant species or genus. Today 80% are likely exMrpated or extremely rare (Andy Moldenke, OSU, unpublished data). • Six federally-listed plant and insect species (USFWS 2010). • High cultural value and significance – recreaonal, aestheMc, spiritual Background: Goals and ObjecUves Goal: ConMnue building a knowledge base for oak habitat conservaon and restoraon planning • Response of oak to present and past disturbance, both natural and anthropogenic, e.g. fire history, growth suppression and release • GIS mapping of oak habitats and trajectories of change, e.g. historic stand reconstrucMon (pre-se[lement) Current Objecve: • Create a network of site-specific Garry oak tree- ring chronologies for the Pacific Northwest Methods Dendrochronology dendron = tree chronos = Mme logos = word = the science of Principle of crossdang In the Field 5.15 mm increment cores OpportunisMc sampling of cross-secMons from dead trees In the Lab 2. 1. 1 mm 3. Study sites CNERA, Saltspring Island, BC; 48.7N, 123.4W 222 m Cady Mtn, San Juan Island, WA; 48.5N, 123.1W 250 m Beacon Hill, Victoria, BC; 48.4N, 123.3W 9 m Chip Ross, Corvallis, OR; Finely Nature Reserve, OR; 44.6N, 123.3W 263 m 44.4N, 123.3W 120 m Mt. Pisgah, Eugene, OR; 44.0N, 122.9W 270 m Jim’s Creek, Oakridge, OR; 43.5N, 122.4W 756 m Results and Discussion Episodic growth release from overtopping by Douglas-fir Results and Discussion Extending chronologies with non-living samples 1707 1715 1729 1709 1731 1744 1747 1788 1738 1805 1781 1809 1788 1796 Beacon Hill fire history 1707, 1709, 1715, 1729, 1731, 1738, 1822 1744, 1747, 1781, 1788, 1796, 1805, 1846 1809, 1822, 1846 Average = 9.2 yrs Results and Discussion Chip Ross Marker rings: 1680, 1705-06, 1722, (CR) 1741, 1762, 1864, 1934, 1938 Finley NR Marker rings: 1705-06, 1712, 1799-1800, (FNR) 1804, 1828, 1881, 1894, 1918, 1978 Jim’s Creek Marker rings: 1641, 1658, 1674, 1705-06, (JC) 1741, 1800, 1849, 1909, 1945, 1977-78 Mt. Pisgah Marker rings: 1706, 1712, 1739-40-41, (MP) 1763, 1777, 1829-30, 1847, 1896, 1918 Age structure (JC) Age Structure (CR) 12 12 10 10 8 8 6 6 4 Frequency 4 2 2 0 0 Year (AD) Year (AD) Age structure (FNR) Age structure (MP) 12 12 10 10 8 8 6 6 4 Frequency 4 2 2 0 0 Year (AD) Year (AD) Results and Discussion StandardiZed ring-width index and sample depth for FNR 2.5 30 25 2 sample depth 20 1.5 growth index 15 1 10 0.5 5 Sample depth (n) Ring-width index 0 0 Year (AD) Stand-wide growth suppression due to overtopping by Douglas-fir Results and Discussion Historical landscape level change at Finley Nature Reserve – oak prairie/savanna – douglas-fir woodland Results and Discussion Cady Mountain Preserve, San Juan Island, WA Marker rings: observed 560 km south at Jim’s Creek! 1741 1736 1800 1841 1871 Results and Discussion World Record: 465 years at coring height! 3.5 3 Sample ID: CML14809 2.5 2 1.5 Ring width (mm) 1 0.5 0 Year (AD) Results and Discussion Oldest living Quercus garryana tree in the world!? Species Age Quercus robur 930 RC Quercus petraea 866 RC Quercus garryana 465 XD, RC Quercus alba 407 XD Quercus gambelii 406 XD Quercus stellata 373 XD Quercus rubra 326 XD h[p://www.rmtrr.org/oldlist.htm Summary • Possible to crossdate Garry oak making it a valuable source of dendroecological data • Significant radial growth response (suppression/release) • Possible to create crossdated fire scar chronologies • Strong common radial-growth signal (some region-wide marker rings) • IdenMfy and mapping of legacy oak habitats QuesUons? [email protected] Study Areas Portland Chip Ross Park Salem Finley Nature Refuge (FNR) Corvallis Jim’s Creek Eugene Mount Pisgah .