Evaluating the biophysical and social results of Keep Indianapolis Beautiful’s urban tree plantings as a social-ecological system

Background/Question/Methods

This presentation discusses the methods and results of a holistic evaluation of volunteer, neighborhood-initiated tree planting projects in Indianapolis, Indiana, that considers both how the biophysical environment and human-related factors such as community characteristics and institutional variables impact urban tree survival and growth. Our work is informed by a variety of fields including urban ecology, sustainable urban forest management, social-ecological systems, and collective action research. Trees planted in Indianapolis neighborhoods between 2006-2009 via neighborhood-initiated tree plantings organized by the nonprofit Keep Indianapolis Beautiful, Inc., were re-inventoried during the summers of 2011 and 2012 by high schoolers using a simple tree and site data collection protocol developed by the authors and informed by the Urban Forestry Data Collection Standards (http://www.unri.org/standards/) for use on young, recently-planted trees in order to assess the social-ecological variables that affect mortality and growth rates. The authors also conducted ethnographic semi-structured interviews and used Participatory Action Research methods to discover how involvement in neighborhood-initiated tree planting programs - as a form of collective action - might have social impacts at both the neighborhood and individual level. The rich, qualitative, case study-like data from interviews is used to inform neighborhood-level analyses of tree growth and condition and generate preliminary conclusions about the relationships between trees and people involved in neighborhood-initiated tree plantings.

Results/Conclusions

Preliminary results indicate that planting area dimensions, neighborhood watering strategy, and tree species influence tree survival and growth. For instance, neighborhoods that agreed to water trees collectively (as a group) for once a week from April-October during the first two years after tree planting have higher tree survival rates than neighborhoods that chose to water trees individually. Although high variability in our dataset and heterogeneity in the urban environment limits our ability to draw conclusions about causal mechanisms, we believe the results of our study can inform nonprofit-led urban tree planting efforts by increasing knowledge of tree growth and survival and social co-benefits of tree planting projects, and giving urban foresters and urban ecologists a greater understanding of the biophysical and social factors that may yield successful urban tree plantings. In the near future, we plan to expand these research methods to tree planting projects in multiple cities to assess the robustness of our results across different regions of the U.S.