The field performance of bare-root stock compared with container stock of western hemlock and western red cedar under Irish conditions.

Abstract

The first-year survival and height growth of container-grown seedlings were compared with those achieved by bare-root stock of western red cedar (Thuja plicata D. Don) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) planted in field trials in Ireland. In the first experiment using western hemlock planted in 1995/96 on a reforestation site, there was no consistent effect of stock type or date of planting (October, December, January and March) on field performance. Seedlings planted on part of the site that was mounded survived better and suffered less weevil damage than those planted on the part that was not mounded. In the second experiment carried out in 1997/98, seedlings of both species were stored in co-extruded polythene bags at ambient temperatures for up to four weeks after lifting in November, December, January and March, and then planted on a reforestation site. Containerised seedlings of both species survived well in the field regardless of date of planting or duration of storage. However, bare-root western red cedar stock had a lower survival than containerised seedlings. Survival was reduced further by extended storage for plants lifted on some dates. Western hemlock bare-root stock survived well except for seedlings stored after lifting in February. Seedlings planted in March had the lowest survival (bare-root western red cedar only) and height increment (both species). Despite the superior tolerance of container stock to handling stresses, better performance can be expected for such seedlings planted before the end of February. Well-conditioned, carefully handled bare-root western hemlock should perform well if planted from November to February.