Potential use of papier mâché plugs for eucalypt seedling production in South Africa

Abstract

Rooting plugs were made by (1) mixing, pressurizing and gluing papier mâché (plugs), (2) cutting a sponge block, and (3) filling Hessian bags with standard growing medium. These treatments were also compared with three types of container used in commercial nurseries, giving three additional treatments: (4) Unigrow, (5) Sappi 49, and (6) Poly 98 deep. Eucalyptus dunnii and Eucalyptus grandis plants were raised from seed over 70 days. In each species and each treatment 60 plants were outplanted to determine survival and growth of the trees after 9 weeks. The nursery results showed that plugs yielded the tallest plants for E. grandis, and Sappi 49 resulted in the tallest E. dunnii. The sponge blocks produced significantly smaller trees in both species. After outplanting, the survival of trees was high for each treatment. There is a need to test performance attributes of the various types of planting stock under stressful site conditions to determine long-term benefits, if any, of producing planting stock in papier mâché plugs. If these studies are concluded successfully, papier mâché plugs could replace peat in commercial forest nurseries, preventing environmental degradation of peat-mined wetlands.