Figure 1.

Quantifying Electric Fields in Nature

(A) Atmospheric potential gradient (APG) measured for 30 min periods across 3 days using a field mill (Chillworth JCI131) at the University of Bristol School of Veterinary Sciences, Langford. Colors depict recordings from different days in June 2016.

(B) Scale bar for (C) and (D).

(C) Finite element analysis (FEA) model of electric field (e-field) enhancement around a geometrically domed oak tree in an APG strength of 4 kVm⁻¹.

(D) FEA model detailing the e-field around geometrically sharp tree branches in an APG strength of 4 kVm⁻¹.

(E) Two-dimensional plot of the e-field along cut lines (red; left inset) of (C) oak modeled as geometrically domed (solid) and (D) branches (dashed) in an APG of 4 kVm⁻¹ (red) and 1 kVm⁻¹ (black). Inset: detail of area indicated by the gray box.

See also Figure S1.