Influence of Moisture Loss During Storage on New Growth of Conifer Seedlings

The relationship between moisture loss from bare-root 2-year-old seedlings of Colorado spruce (Picea pungens glauca Engelm.) and percent survival and performance after extended storage at 0°C (32°F) was investigated. Moisture loss was examined by percent weight loss and moisture content (g H2O/g FW) during postharvest handling and storage. To generate different levels of moisture loss, seedlings were stored in various packages that differed in water permeability with a 0 and 1 day delay at 20°C (68°F) prior to 5 or 7 months of storage at 0°C (32°F). Depending on treatment, percent weight loss of seedlings varied from 0 to 60% and seedling survival ranged from 0 to 100%. When percent weight loss was below 25% all bare-root seedlings survived 5 and 7 months storage. Seedlings expressed a great degree of tolerance to desiccation stress, as demonstrated by those few which survived nearly 60% weight loss. Between 20 and 40% weight loss there was no direct relationship between moisture loss and percent survival. Bare-root Colorado Spruce seedlings grew with 100% survival following 5 and 7 months storage at 0°C (32°F) if packaged in either unsealed perforated or nonperforated polyethylene film.