Can the use of large, alternative nursery containers aid in field establishment of Juglans regia and Quercus robur seedlings?

Over the last 30 years in Italy, a high percentage of tree plantations have failed to achieve the objective of enhancing the quality of forest products, and also restoring/rehabilitating abandoned or degraded agricultural lands. In this study, we evaluated the effects of nursery cultivation in large, novel containers and duration of cultivation on early field establishment of 2-year-old seedlings of Quercus robur L. and Juglans regia L. Two sizes (9800 and 15,500 cm3) of a new container (Superoots Air-pot®) and one size (4900 cm3) of a traditional container (Plastecnic®) were tested and seedlings were sampled for shoot and root growth and biomass allocation. Prolonging the cultivation period to 2 years had a positive effect on both species, with a marked increase in above- and below-ground biomass, maintaining a desirable balance between shoot and root systems. Both sizes of Air-pots for Q. robur and the bigger Air-pot for J. regia produced seedlings that were taller than 1.5 m, with a low branch component combined with a high frequency of apical dominance. The quantity and size of first order lateral roots varied between years within containers, and increased in deeper substrate layers during the second year. Early field results did not show marked signs of transplanting stress, but with low height growth in all treatments. Seedlings grown in both Air-pots exhibited well-developed and well-structured root and shoot systems, thus showing promise in the establishment of high quality timber plantations of fine hardwoods; such attributes can be beneficial wherever proper seedling shoot and/or root sizes confer an advantage in reforestation and restoration scenarios.