The June 2011Massachusetts tornado profoundly altered the landscape over a wide geographic area.

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1 SPRINGFIELD TORNADO IMPACTS ON TREE CANOPY, TEMPERATURE & HUMIDITY Fall 2011 USDA Forest Service Northern Research Station TREE CANOPY LOSS IN THE TORNADO IMPACT ZONE WAS EXTENSIVE, WITH MANY LARGE SHADE TREES DESTROYED. The June 2011Massachusetts tornado profoundly altered the landscape over a wide geographic area. On June 1, 2011 a series of tornadoes ripped through Western Massachusetts, and included the second strongest tornado ever recorded in Massachusetts, with wind speeds estimated at 136 to 165 mph, according to the National Weather Service. The most severe tornado was the EF-3, on the Enhanced Fujita Damage Classification Scale, that carved a half-mile-wide path for 39 miles from Westfield to Charlton, killing three people and injuring 200. In Springfield, the tornados impacted city s South End, Upper Hill, Metro Center, Six Corners, East Forest Park and Sixteen Acres neighborhoods. CANOPY LOSS TREE FAILURE STRUCTURE DAMAGE

2 Tornado Effects on Residential Springfield, MA Street Tree Canopy Cover, Temperature, and Humidity: Preliminary Assessment Introduction Recent modeling studies have reported on the impact of residential trees on urban microclimate and on energy use for heating and cooling (McPherson et al. 1997, Simpson and McPherson 1998, Maco and McPherson 2003, McPherson et al. 2005). There are few studies that empirically quantify the relationship of the presence, abundance, and type of residential trees to local microclimate (Heisler and Brazel 2010). In Sacramento, CA, tree cover density was negatively correlated with local wind speed and with cooling degree days (Sailor et al. 1992). In Baltimore, MD, increasing tree cover generally APPROXIMATELY 1.4 MILLION POUNDS OF SEQUESTERED CO2 HAS BEEN LOST resulted in cooler temperatures during the daylight hours (Heisler et al. 2007). On June 1, 2011, an EF3 tornado traveled a 39-mile track across southcentral Massachusetts ( jun01_2011_summary.php). The tornado s track crossed the city of Springfield, MA, affecting several neighborhoods, damaging over 480 buildings and 13,000 public trees, with an estimated cost of over $106 million. This event created an opportunity to empirically measure the effect of the loss of neighborhood trees on streetside microclimate (temperature, relative humidity). The results of an initial proof-ofconcept study are presented here, providing a preliminary estimate of the impact of the tornado on the localized mico-climate of the impact zone. CONTEXT TREE LOSS CANOPY DAMAGE Map 1. New England regional context IMPACT ZONE Map 2. Massachusetts map, with Springfield identified in red, and Hampden County noted in pink. CANOPY LOSS

3 Study Area and Methods: Establishing a Proof-of-Concept for Expanded Research and Modeling in the Tornado Impact Zone IN THE FIELD BUTTON MONITOR STUDY AREA Figure 1. Tornado affected (red box) and unaffected (yellow box) neighborhoods and forested Dan Baker Cove Park, East Forest Park, Springfield, MA PLACING MONITOR DATA COLLECTION CANOPY ASSESSMENT Study Area and Methods We measured air temperature and relative humidity in two adjacent residential neighborhoods in the East Forest Park area of Springfield (Fig.). Data loggers (ibutton Hydrochrons) were placed on two blocks of three streets in the tornado damaged area (two units were disturbed during the study). Matching data loggers were placed in two blocks of the same or paired streets in unaffected neighborhood just to the south of the tornado track (Fig. 1). A single data logger was placed the forested Dan Baker Cove Park, just north of the tornado damaged area. Data loggers were enclosed in window-screen envelopes and hung by wires from street signs. Temperature and relative humidity were recorded three times a day, night (0000 hrs), morning (0800 hrs), and afternoon (1600 hrs) for the duration of the preliminary study (30 Aug 26 Sep 2011). Tree canopy cover was measured at each data logger location using a spherical densiometer. Canopy cover was measured four times at each location in the cardinal directions. Information on the residential trees of the study area was obtained from the Springfield urban tree inventory. Regional weather statistics can be obtained from NOAA weather stations located at Barnes Airport, Westfield MA and Westover AFB, Chicopee, MA. Paired, daily mean temperature and relative humidity data were analyzed to assess the effects of the tornado damage to residential trees on streetside microclimate.

4 Results and Discussion of Tornado Effects on Residential Springfield, MA Street Tree Canopy Results The tornado nearly eliminated street-side tree canopy cover, from an average of 44% cover in the control, unaffected neighborhood to less than 1% in the tornado affected neighborhood (Table 1). Mean morning and afternoon temperatures increased between 1-2ºC in the tornado affected neighborhood compared to the unaffected neighborhood (Table 1). The paired differences in morning and afternoon temperatures, between the two neighborhoods, were highly significant (Table 2). Night-time temperatures were only slightly less in the tornado affected neighborhood than the unaffected one (Table 1), a non-significant effect. Daytime temperatures at the single forest site were cooler than either of the residential sites and nighttime temperatures were similar among all sites (Table 1). Mean daily humidity was similar in the tornado affected and unaffected neighborhoods, but typically greater in the urban forest site (Fig. 2). Mean percent relative humidity were slightly less in the tornado affected neighborhood than unaffected neighborhood in the morning and afternoon, and slightly greater in the nighttime (Table1). Discussion The results of this preliminary study indicate that there is a obvious difference in the canopy density and the mico-climate characteristics between the tornado impact zone and nearby areas that were not affected by the storm event. The noted difference in afternoon daily temperatures between the two areas provides preliminary quantifiable findings that supports the antidotal evidence from residents of the impacted area, related to increase use of air-conditioning units, personal comfort levels and an overall increase in energy costs in July and August Further study of this component is necessary to quantify any real relationship between energy costs in 2011, compared to pre-tornado summer periods. Urban Heat Islands Implementation of urban heat island (UHI) mitigation strategies such as increased vegetative cover can reduce the impacts of biophysical hazards in cities, including heat stress related to elevated temperatures, air pollution and associated public health effects. Such strategies also can lower the demand for airconditioning-related energy production. Solecki, et al Additionally, the noted change in canopy cover reported in the results of this study, again, seem to correlate with residents in the impact zone, who report that much of the neighborhood lacks any shade, seems hotter and is noisier than in the past. Also, noted is the seemingly limited variety of songbirds that are heard in the tornado impact zone. It appears that the tornado has greatly impacted much of the tree canopy, mico-climate, wildlife habitat and the overall appeal of tree-lined streets and large shade trees growing on personal property. The proposed planting of new trees, which are intended to produce significant benefits over time, provides a unique opportunity to develop a long-term monitoring study within the tornado impact zone. The establishment of a significant scientific study will provide information, data and findings on an urbanized landscape that is undergoing dramatic change, ranging from tree loss to increased canopy cover. The study of past costs and benefits, along with closer examination of micro-climate impacts, and finally, the monitoring of newly planted trees in the impact zone will provide relevant, scientifically-based information for urban foresters, planners and the scientific community to process.

5 IMPACTS Table 1. Mean street-side temperature (ºC) and percent relative humidity (RH) by time of day and mean percent tree canopy cover in tornado affected and unaffected residential neighborhoods and from a single urban forest site, East Forest Park, Springfield, MA, 30 Aug 26 Sep Figure 2. Daily street-side temperatures (ºC) by time of day, East Forest Park, Springfield, MA, 30 Aug 26 Sep 2011.

6 Literature cited Heisler, Gordon M. and Brazel, Anthony. J The urban physical environment: temperature and urban heat islands. Pgs In: Aitkenhead-Peterson, J. and Volder, A. (Eds.) Urban Ecosystem Ecology. American Society of Agronomy, Agronomy Monograph 55. Heisler, Gordon, Walton, Jeffrey, Yesilonis, Ian, Nowak, David, Pouyat, Richard, Grant, Richard, Grimmond, Sue, Hyde, Karla, and Bacon, Gregory Empirical modeling and mapping of below-canopy air temperatures in Baltimore, MD and vicinity. In: Proceedings of the 7th Urban Environment Symposium. American Meteorlogical Society, San Diego, CA. Maco, Scott E. and McPherson, E. Gregory A practical approach to assessing structure, function, and value of street tree populations in small communities. Journal of Arboriculture 29: McPherson, E. Gregory, Nowak, David, Heisler, Gordon, Grimmond, Sue, Souch, Catherine, Grant, Rich, and Rowntree, Rowan Quantifying urban forest structure, function, and value: the Chicago Urban Forest Climate Project. Urban Ecosystems 1: McPherson, Greg, Simpson, James R., Peper, Paula J., Maco, Scott E., and Xiao, Qingfu Municipal forest benefits and costs in five US cities. Journal of Forestry 103: Sailor, David J., Rainer, Leo, and Akabri, Hashem Measured impact of neighborhood tree cover on microclimate. Pgs In: Proceedings of the 1992 ACEEE Summer Study on Energy Efficiency in Buildings. Volume 9. American Council for an Energy-Efficient Economy. Washington, D.C. Simpson, J.R. and McPherson, E.G Simulation of tree shade impacts on residential energy use for space conditioning in Sacramento. Atmoshpheric Environment 32: William D. Solecki, Cynthia Rosenzweig, Lily Parshall, Greg Pope, Maria Clark, Jennifer Cox, Mary Wiencke Mitigation of the heat island effect in urban New Jersey. Global Environmental Change, Part B: Environmental Hazards. Volume 6, Issue 1, 2005, Pages Project Study Team Robert T. Brooks, Ph.D. Dr. Brooks studies the ecology of ephemeral or "vernal" pools of northeastern forests. His current research includes study of the effectiveness of Massachusetts forestry Best Management Practices and Conservation Management Practices for vernal pools and vernal pool fauna, and projected climate change effects on the hydrology and ecology of vernal pools. rbrooks@fs.fed.us David V. Bloniarz, Ph.D. Dr. Bloniarz is an Urban Forester with an extensive background in urban forest management and landscape design. Presently Dr. Bloniarz is project coordinator of the USDA Forest Service Northern Research Station s Urban Natural Resources Institute, located at the University of Massachusetts/Amherst. dbloniarz@fs.fed.us For more information, contact the UF Forest Service Northern Research Station