Using infrared thermography to assess viability of Pinussylvestris and Piceaabies seedlings before planting

One-year-old Scots pine (Pinussylvestris L.) and 2-year-old Norway spruce (Piceaabies (L.) Karst.) seedlings were lifted and stored under an array of conditions to test infrared thermography as a means of determining seedling viability. After winter storage, temperature was measured on each seedling with an infrared thermovision scanner (3–5 μm) in an environment favoring transpiration (vapor pressure deficit of the ambient air 1.6–2.9 kPa, photosynthetic photon flux density 1500 μmol•m−2•s−1). Thereafter the seedlings were planted in the field. Visual signs of damage were assessed and annual height increments were measured after one and two growing seasons. Significant positive correlations were found between seedling temperature and degree of damage. The warmest seedlings had a lower survival rate as a group when compared with the remaining seedlings. There were significant negative correlations between seedling temperature and annual height increment in the first growing season.