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- Creators: Arizona State University
Still, the NPS remains committed to the preservation of our natural and cultural heritage. Yet the practice of that promise is evolving, slowly and iteratively, but detectably. Through explorations of legal and scholarly literature, as well as interviews across the government, non-profit, and academic sectors, I’ve tracked the evolution of preservation in parks. How is preservation shifting to address socio-ecological change? How has preservation evolved before? How should the NPS preserve parks moving forward?
The practice of preservation has come to rely on science, including partnerships with academic researchers, as well as inventory and monitoring programs. That shift has in part been guided by goals that have also become more informed by science, like ecological integrity. While some interviewees see science as a solution to the NPS’s challenges, others wonder how applying science can get “gnarly,” due to uncertainty, lack of clear policies, and the diversity of parks and resources. “Gnarly” questions stem in part from the complexity of the NPS as a socio-ecological system, as well as from disputed, normative concepts that underpin the broader philosophy of preservation, including naturalness. What’s natural in the context of pervasive anthropogenic change? Further, I describe how parks hold deep, sometimes conflicting, cultural and symbolic significance for their local and historical communities and for our nation. Understanding and considering those values is part of the gnarly task park managers face in their mission to preserve parks. I explain why this type of conceptual and values-based uncertainty cannot be reduced through science.
Shade plays an important role in designing pedestrian-friendly outdoor spaces in hot desert cities. This study investigates the impact of photovoltaic canopy shade and tree shade on thermal comfort through meteorological observations and field surveys at a pedestrian mall on Arizona State University's Tempe campus. During the course of 1 year, on selected clear calm days representative of each season, we conducted hourly meteorological transects from 7:00 a.m. to 6:00 p.m. and surveyed 1284 people about their thermal perception, comfort, and preferences. Shade lowered thermal sensation votes by approximately 1 point on a semantic differential 9-point scale, increasing thermal comfort in all seasons except winter. Shade type (tree or solar canopy) did not significantly impact perceived comfort, suggesting that artificial and natural shades are equally efficient in hot dry climates. Globe temperature explained 51 % of the variance in thermal sensation votes and was the only statistically significant meteorological predictor. Important non-meteorological factors included adaptation, thermal comfort vote, thermal preference, gender, season, and time of day. A regression of subjective thermal sensation on physiological equivalent temperature yielded a neutral temperature of 28.6 °C. The acceptable comfort range was 19.1 °C-38.1 °C with a preferred temperature of 20.8 °C. Respondents exposed to above neutral temperature felt more comfortable if they had been in air-conditioning 5 min prior to the survey, indicating a lagged response to outdoor conditions. Our study highlights the importance of active solar access management in hot urban areas to reduce thermal stress.