Winter injury on 4-year saplings of the high-performing Cryptomeria japonica variety “Takaoka#1” in central Shikoku

Abstract

Severe withering was observed on cedar-cutting varieties from Kyushu in a 4-year planting site in central Shikoku. Overall, 66 saplings out of 112 of the high-performing variety “Takaoka#1” showed dead foliage and stem, including individual deaths on a north-facing slope at 900 m above sea level. The proportion of saplings with dead parts was higher compared to the conventional variety “Tanoaka,” which showed five damaged saplings out of 109. The deadly damage to Takaoka#1 was suspected to be mainly caused by late and early frosts, as sudden air temperature drops were recorded in early spring and winter in 2023. Cold injury was not found on the stems, and the damage did not worsen in the mid-winter. Takaoka#1 might be more sensitive to cold temperatures than Tanoaka, thus requiring careful selection of planting sites.