90 Rooney et al.: Reliability of Windshield Survey to Locate Hazards contractors in New England often charge approximately $5 per tree to inspect for hazards. In addition, many munici- palities lack the skilled labor needed to undertake a thor- ough inspection in-house. Conducting a windshield survey of certain areas presents another option for the municipality to save time and money. The main problem with choosing the windshield survey option is that no one has examined the method’s reliability at identifying roadside hazardous tree conditions. Many professionals in the tree care industry have questioned the validity of this hazard tree inspection method. The U.S. Park Service’s Hazard Tree Guidelines note that “… the obvious limitations of the effectiveness of this method may not allow it to be very persuasive in a court of law, and only a thor- ough documentation of findings will lend any credence to this method” (National Park Service 1991). Many urban foresters and arborists feel that in certain situations a windshield survey will not work effectively. For instance, it may not work well in congested urban areas where the arborist’s visibility may be poor or where the surrounding traffic conditions are difficult, causing some hazardous conditions to be missed. Other professionals feel that in any type of roadside situation, this method is unacceptable for a thorough hazard tree survey. This is due to the inability to effectively examine the tree from every angle and the inability to get close to the tree. “Subtle defects such as narrow cracks or girdling roots, even if they occur on the side facing the road, may go undetected simply because they cannot be readily seen from the road” (Pokorny 2003, p. 28). METHODOLOGY The community chosen for this case study was South Kingstown, Rhode Island, U.S. Located on the Atlantic coast in the southern part of the state, the town has vegetation types ranging from seaside scrublands in the southeast to mixed oak forest in the northwest. The town’s population is approximately 28,000 people, and the town has approximately 217 km (135 mi) of maintained roads. The town employs a part-time tree warden, and the total population of municipally maintained trees in the town is estimated to be 15,000 to 20,000. At the time of this case study, winter 2002–2003, the town had not yet implemented an annual hazard tree inspection program. South Kingstown was ideal for testing the windshield survey method because it contains a variety of roadside environments. The town has a wide range of street and neighborhood settings, ranging from rural to urban. The variety of street and neighborhood layouts creates a similar variety of planting locations. Additionally, South Kingstown’s tree population varies greatly. Trees managed by the town exhibit diverse conditions, species, and sizes, and some trees are extremely hazardous. The variety of neighborhoods and tree species, sizes, and conditions helped to test the effec- tiveness of a windshield survey over the range of variables. ©2005 International Society of Arboriculture Windshield Survey The windshield survey of 100% of town roads was intended to accomplish several things. First, it provided the data set for comparison with the traditional walking inspection. Once the sample areas within the town were determined, the windshield survey dataset was broken down to the specific randomly selected areas and then comparisons would be made. Second, the windshield survey was used to collect hazard tree data that would be given to the town’s tree warden and the local electric company once the project was completed. Those data would be used to remediate hazard trees. The windshield survey was also used to identify land use and road type. Roads, or road segments as necessary, were classified as, “developed,” “undeveloped,” or “no town trees present.” Each classification had distinct characteristics. A developed road or road segment had town trees growing in front of homes or businesses with lawns, in utility planting strips between the road and sidewalk, or in planting pits in a sidewalk. An undeveloped road or road segment had no sidewalk or maintained lawn and had a woodland setting or an old stone wall delineating the setback distance. A road or road segment with no town trees present, or if the existing town trees were not worth resurveying due to their small size, would be classified as “no town trees.” Such areas included new developments and older neighborhoods where the only trees were set back on private property. These areas were eliminated from the study. Each of the road types was used to create a stratified category to help determine sampling areas. Prior to commencing the windshield survey, the follow- ing protocols were established: 1. Because the major objective of this windshield survey was the identification of hazardous conditions, it was conducted after leaf drop. 2. A pick-up truck or SUV was used to drive the inspector during the windshield survey. 3. The person who conducted the survey is an ISA Certified Arborist and a Rhode Island licensed arborist who sat in the front passenger seat during the surveys; prior to surveying, he had received training in locating and identifying tree defects. 4. Aside from a clean driver’s license, the driver did not need any special qualifications, although familiarity with town roads was helpful. A personal digital assistant (PDA) was used to record all of the survey data, and Pendragon Forms® software was used to create a data collection form. The PDA was chosen because of its ability to synchronize with a desktop com- puter for quick data importation. A PDA also has the ability to store lists. This saves time by allowing the surveyor to pick a particular item from a list, instead of repeatedly typing each item.
March 2005
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