Growth Resumption and Performance of Nonchilled Abies Seedlings after their First Winter

1988

S. 1486-1489

2 Abb., 1 Tab., 27 Lit. Ang.

Unselbständiges Werk

200038778

Survival, phenology, and growth of containerized noble fir (Abies procera Rehd.) and Shasta red fir (Abies magnifica A. Murr. var. shastensis Lemm.) seedlings were measured in response to dormancy induction, chilling, and postplanting irrigation treatments. Temperature, photoperiod, and moisture were varied to induce dormancy. Seedlings were not chilled during the first winter, but received natural chilling during the second winter. In the first growing season (no winter chilling), terminal buds did not flush, but remained alive and inactive. Buds on lateral branches flushed and extended normally. In the second season (natural winter chilling), all terminal buds and lateral buds flushed. Dormancy induction treatment did not significantly affect budbreak, survival, or growth. However, postplanting drought simulation significantly reduced height, diameter, and aboveground biomass. The results demonstrate that the terminal buds of planted, nonchilled seedlings of these true fir species can remain inactive through an entire season and then resume growth once their chilling requirements are fulfilled.