Girdling was tested alone and in combination with stem injections of gibberellin A4/7 (GA4/7) on 9-year-old rooted cuttings of Sitka spruce in the Lost Lake seed orchard near Victoria. As is characteristic for this orchard, the untreated trees produced few seed cones and no pollen cones. Girdling did not elicit a flowering response when applied alone, but in combination with GA4/7 the trees produced an abundance of both seed and pollen cones. For Sitka spruce, as for other conifers, GA4/7 stem injection is a practical and highly effective treatment for promoting flowering in seed orchards.
Download Research Note 107 (398 KB)
To view this document you need the current version of
Adobe Acrobat Reader, available free from the
Adobe Web Site.
Updated May 29, 2009