RT Journal Article
SR Electronic
T1 Origin of Frost Cracks in Stems of Trees
JF Arboriculture & Urban Forestry (AUF)
JO JOA
FD International Society of Arboriculture
SP 93
OP 97
DO 10.48044/jauf.1987.017
VO 13
IS 4
A1 Hans Kubler
YR 1987
UL http://auf.isa-arbor.com/content/13/4/93.abstract
AB Frost cracks in the stem of living trees are separations along the radial plane. They occur at temperatures below the freezing point of water and result mainly from “frost shrinkage” due to internal drying, that is, freeze-out of cell wall moisture into lumens of wood cells. Wood frost-shrinks more as temperatures are falling. The shrinkage leads to frost cracks mainly because wood tends to shrink more along the growth rings than in the direction of stem diameter. Other factors which contribute to frost cracks are ice layers which grow in the cooling wood, relatively rapid cooling of the stem surface, and expansion of freezing water in waterlogged zones of the stem. The reason why some trees frost-crack while others do not appears to be the notch effect of earlier injuries in the first place, as well as pockets of unusually wet wood in the stem.