Comparative Temporal Infrared Thermography of Arboricultural Materials for Sun-Induced Trunk Injury Prevention in Broad-Leaved Woody Plants

Using an infrared (IR) thermal camera, we evaluated the efficacy of six arboricultural materials for preventing sunscald and frost crack. The trunks of adult Yoshino cherry (Prunus × yedoensis) and Japanese zelkova (Zelkova serrata) were treated with (i–iii) three paint types (white water paint [P–W], white latex paint [P–L], and quicklime [P–Q]), (iv and v) two band wrap types [brown tree wrap (B–B) and white tree wrap (B–W)], and (vi) a wound paste: thiophanate-methyl paste (TP) in the shape of a band 10 cm thick. Outdoor IR thermographs were captured four times a day at 3 h intervals (09:00 a.m., 12:00 p.m., 03:00 p.m. and 06:00 p.m.) over four consecutive days in late October 2019. Bark temperatures recorded for P–W, P–L, P–Q and B–W treatments were consistently lower than those for untreated trunks. The mean temperature difference between B–W and untreated bark (up to 4.57°C) remained pronounced between 09:00 a.m. and 06:00 p.m. for both tree species each day. Conversely, no significant differences in bark temperatures were observed under B–B and TP treatments compared with untreated bark (p = 0.01). Elevated bark temperature was observed on the south side compared with the other three cardinal directions; however, temperatures were similar in all directions at 06:00 p.m. These findings suggest that white tree wrapping may provide a viable approach to prevent sun-induced trunk injuries, leveraging the light reflectivity of the white colour and thermal insulation properties of the wrapping material.