*2.1. Study Area*

We analyzed the wild blueberry fields in Maine, USA as a whole, and two specific fields with a good record of yield data (Figure 1). The wild blueberry fields in the major production region are located in the Washington and Hancock counties of Maine (referred to as "Maine WB Fields", Figure 1a,b). The two specific fields selected were the Airport wild blueberry field at Deblois, Maine (referred to as "Airport", Figure 1c), and the Baxter wild blueberry field at Deblois, Maine (referred to as "Baxter", Figure 1c). The soil of the wild blueberry fields in Maine is well-drained sandy loam acidic soil [25]. The studied region has a four-season climate with an average annual minimum temperature of −10.6 ◦C and a maximum temperature of 24.2 ◦C, and monthly average precipitation as low as 85.1 mm and as high as 136.4 mm [26].

**Figure 1.** Location of the study sites: (**a**) a map of the state of Maine (light blue color), USA showing the location of the major wild blueberry production region (Washington and Hancock County) in dark blue color; (**b**) a map of the major wild blueberry production region in Maine showing 89 wild blueberry fields in red polygons for this study with an area of 0.06 km<sup>2</sup> (250 m <sup>×</sup> 250 m) or larger; (**c**) Airport and Baxter wild blueberry fields of Wyman's in Deblois, Washington County, ME, USA.
