Publication Date:
1996-12-01
Description:
Sitka spruce (Piceasitchensis (Bong.) Carrière) seedlings were cultured using two nursery methods of blackout (short photoperiod) application: static treatment (constant day length of 14.28 h) and dynamic treatment (day length varying over length of experiment, with a mean of 14.28 h). Both methods when compared with a control (natural day length) reduced seedling height by inducing terminal bud set, increased seedling root weight, and decreased shoot to root and sturdiness ratios. Both static and dynamic blackout treatment seedlings had 26 and 30% lammas flush, respectively. Compared with control, both methods accelerated cold hardiness acquisition. After winter storage at −2 °C, treated seedlings flushed sooner than did control stock under light:dark temperatures of 25:20 °C. Under a cooler regime, 15:5 °C, differences among treatments were not significant. After planting in a common garden trial, terminal bud phenology had a range of treatment responses. Control seedlings flushed later and set bud sooner. Dynamic treatment seedlings' bud set phenology was nearest to that of controls. At a common garden trial and a reforestation site, blackout-treated seedlings had greater first-season terminal height increment. Planting check was observed for all treatments in the field during the second and third growing seasons. After five field seasons there was no height difference among treatments, and survival averaged 87%. Groundline stem diameter was never different among treatments. Biologically, the dynamic treatment is intermediate between the static and control treatments, but the static treatment is recommended because it is easier to apply in the nursery, and differences between the dynamic and static treatments were minimal.
Print ISSN:
0045-5067
Electronic ISSN:
1208-6037
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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