## 3 Testbed Deployment  
Our WSN is deployed at the ASWP's Beechwood Farms Nature Reserve (BFNR), which is located in Fox Chapel in northern Allegheny County, Pennsylvania, USA, as shown in Figure 2. The BFNR is 134 acres of protected land, which is owned by the Western Pennsylvania Conservancy. The reserve facilitates power and Internet needs for the WSN gateway and has an accessible wooded area where nodes may be located. The hiking trails of the reserve are closed from dusk to dawn and attract mostly nature enthusiasts, such that the equipment is relatively well-protected from human interference. At the time the project started in 2010, the main competitors for WSN technology were Crossbow's MicaZ [9] and MoteIV's Tmote Sky [32] motes. This project invested in Crossbow's MicaZ MPR2400  
Figure 2: Location of the Audubon Society of Western Pennsylvania (ASWP) testbed (red dot) in Allegheny County (highlighted in cyan and enlarged), Pennsylvania, USA. radio and processor board for the network's base station and wireless motes. For environmental monitoring, the MDA300 data acquisition board [33] was selected because it provides onboard sensors and connections for up to seven external analog sensors. The onboard temperature and humidity sensors on the MDA300 allow for monitoring more health (e.g., electrical short circuits and water intrusion) and were therefore used on all the wireless motes in the network. In the spring of 2012, MEMSIC (previously Crossbow Inc.) IRIS motes [34] were added to the network. IRIS motes, while compatible with MicaZ networks, provide more memory and stronger transmission power compared to MicaZ motes. Both MicaZ and IRIS mote platforms are powered using rechargeable nickel-metal hydride (NiMH) AA batteries with charge capacity between 2450 and 2700 mAh. An initial analysis of the nodes lifetime at the ASWP testbed is presented in [35]. Based on the desired area for sensor measurements, the study region was divided into five sites. Site 1 corresponds to the area next to the BFNR Nature Center, where the WSN gateway and the base station are located. The purpose of this site is to relay the environmental sensor data from the nodes in other sites to the base station. Sites 2 through 5, which were designated as areas to conduct field sensor measurements, are located in the forested hill-sloped region of the reserve. The five sites, including the node locations, are presented in Figure 3.  
Figure 3: Map of the ASWP testbed (April 2014 configuration). Node 0 (_i.e._, base station) is located within the Beechwood Farms Nature Reserve (BFNR) Nature Center. Nodes are consecutively numbered based on their four-digit node identifier (given in the legend) and colored based on the deployment phase: phase 1 (April 2010, white), phase 2 (June 2010, blue), and phase 3 (July 2010, green). Orange and red colored nodes represent network additions that occurred after phase 3 (2012 and 2013 respectively). The wireless motes, data acquisition boards, batteries, and necessary environmental sensor circuitry were placed in waterproof polycarbonate enclosures. An antenna (omni-directional with 4.9 dBi gain) was mounted on the outside of the enclosure. To reduce the visibility of the network (for maintaining the aesthetics of the nature reserve), the enclosures were camouflaged and discretely located either hung from tree branches or mounted against tree trunks (see Figure 1). In addition, enclosures were mounted onto PVC-pipe stakes where vegetation was unavailable. The WSN deployment began in April 2010 via three initial phases. The first phase consisted of testing the connection between the base station, located inside the BFNR Nature Center, and the closest nodes in Site 1. The base station was connected to a gateway that was set on the inside ledge of an office window facing the field where the first nodes were located. Following the success of the first phase, the project moved into the second phase, which consisted of placing additional nodes in Site 1 and building the relays out to Sites 2 and 3.