Using Urban Forests to Predict the Success of Western Red Cedar during Global Change Anna O’Brien University of Washington

Global Change

Ecosystems are changing in their basic characteristics, to which organisms are often finely adapted Temperatures, CO 2, & nitrogen deposition (nutrients) Global Change Melting sea ice & Animals Plants

How will our local conifers respond to global change? Pacific Northwest forests are almost entirely made up of conifer trees, they provide the ecosystem structure on which countless other organisms depend, and are economically important Conifers will respond to global change variables 1, and predicting this response is critical to conservation and management efforts I focus on Thuja plicata, Western Red Cedar Research Question 1. Handa, Korner, Hattenschwiler 2006; Yin, Liu, Lai 2008

Modeling Global Change TemperatureNitrogen deposition CO 2 levels Future vs Current Urban vs Rural Areas Urban areas resemble global change effects 2 Can therefore use the effects of urban areas on species and ecosystems to predict the effects of global change 2.Carreiro and Tripler 2005

Hypotheses Thuja plicata recent germinant. 1.Edges of forest with urban influence will have higher temperatures and soil nitrogen levels than urban forest centers and rural areas 2.Reproduction of trees will be reduced at urban forest edges compared to urban forest centers and rural areas. 3.Growth of trees will be increased at urban forest edges compared to urban forest centers and rural areas.

Seattle has forested parks in urban neighborhoods. Rural area sites included to account for edge effects unrelated to the urban influence. Study Site IButton R R R U U U U U

Growth: Take core with increment borer Environment: Measure temperature with iButton, and take soil sample from two locations Reproduction: Count seedlings Measurements

Environment-N Urban nitrogen levels > Rural nitrogen levels (P=.005) Urban park edge nitrogen levels may not be significantly greater than park center levels mg NO 3 /kg dry soil Soil Nitrogen (NO 3 ) Levels

Environment-Temperature Preliminary Temperature Data Edge Temperatures > Center Temperatures Temperature (°C) Feb 2009 Jun 2009 CENTER EDGE Schmitz Park – Temperatures

Reproduction Low germination totals Urban Center > Urban Edge Rural Edge > Rural Center Total germinants per number of plots

Growth 1.Obtain yearly growth data from tree cores 2.Obtain yearly temperature data for region & modify to local sites 3.Compare temperatures by year to tree growth

Directions Why so low germination? –Lack of viability –Herbivory –Fungi 3 3.Weber, Karst, Gilbert & Kimmins, 2005 Thuja plicata seed, USDA plants, 2009

Conclusions 1.Environment – Urban edges show influence consistent with global change 2.Reproduction – Urban edges have a significant negative effect; low germination totals concerning 3.Growth – Hypothesize that growth will be increased at edges compared to other areas What is the likely future success of Thuja plicata? What does this mean for conservation and management?

Acknowledgements Howard Hughes Medical Institute Janneke Hille Ris Lambers Brian Buchwitz Ailene Kane Irene Weber and Melissa Winstanley Seattle Parks, Cedar River Watershed, King County Parks, & Washington State Parks Questions?