Localized low temperatures of the stem induced narrow diameters and obvious thickening of secondary cell walls of tracheids, which were identified as latewood tracheids. In addition, artificial cooling of stems induced cessation of cambial activity.
Begum et al. consider that cambium and its derivatives can respond directly to changes in temperature and a decrease in the temperature of the stem is a critical factor in the control of cambial activity and xylem differentiation in trees.
Shahanara Begum, Kayo Kudo, Yugo Matsuoka, Satoshi Nakaba, Yusuke Yamagishi, Eri Nabeshima, Md Hasnat Rahman, Widyanto Dwi Nugroho, Yuichiro Oribe, Hyun-O Jin, Ryo Funada, 2015, 'Localized cooling of stems induces latewood formation and cambial dormancy during seasons of active cambium in conifers', Annals of Botany, vol. 117, no. 3, pp. 465-477 http://dx.doi.org/10.1093/aob/mcv181