The pattern of ΦPSII measured at 150 µmol photons m-2 s-1 over the recovery period was similar to that of Fv/Fm. There was no statistical difference in ΦPSII between UV-filtered samples and UV-transmitted samples at T0.5 nor between ΦPSII values of site reference plants and UV-transmitted plants (Table 3, Fig. S2B). After 24 hours in recovery, ΦPSII of all samples had increased. ΦPSII of samples from UV-transmitting windows were significantly higher than those from UV-filtering windows. Site reference mean ΦPSII was 0.425 (σ = 0.044), and there was no significant difference between site reference and UV-transmitted samples. At T192, neither UV-filtering and UV-transmitting, nor UV-transmitting and site reference ΦPSII values were significantly different from one another (site reference mean = 0.630, σ = 0.039).