The establishment and early growth of trees planted on drained peatlands in Newfoundland, Canada
One part of the afforestation programme consisted of the establishment of an afforestation trial on a bog and fen site in central Newfoundland to determine growth and nutrient response of newly-planted black spruce (Picea mariana (Mill.) B.S.P.) and eastern larch (Larix laricina ((Du Roi) K.Koch). The experimental design was a split-split-plot consisting of surface treatments (untilled, tilled) as main-plot treatments, fertilization (unfertilized, PK) as split-plot treatments and four ditch spacings ( 3 m, 5 m, 7 m, and 15 m) as split-split-plot treatments. A total of 3,960 25-week old container seedlings of each species were planted on each site at spacings of 0.50 m in rows of nine trees, each row being situated at a distance of 1.0 m apart. Surfaces were tilled at 0-200 mm depth using a farm rotovater attached to the back of a tractor. Ditches were made at depths of 0.50-0.75 m with a Dondi ditcher attached to the back of a tractor, and fertilizers were broadcast at the rate of 60 kg/ha P and 50 kg/ha K. The second part of the afforestation programme was a refertilization trial of 1) Japanese larch (Larix leptolepis Seib and Zucc.) and black spruce trees planted on Stephenville bog in western Newfoundland in 1968; and 2) black spruce, white spruce (Picea glauca (Moench) Voss) and lodgepole pine (Pinus contorta Dougl.) planted on Millertown fen in central Newfoundland in 1973. Both sites had been ploughed with a Parkgate-Tyne plough at 1.8 m spacings 1-2 years prior to planting. Following planting of the Stephenville site in 1968, the black spruce and Japanese larch were spot-fertilized (around each tree) with a top-dressing of 57 g of ground mineral rock phosphate. This procedure was repeated in 1970 with 128 g of a mixture of phosphate and potassium (20% P2O2, 20% K2O). On the Millertown site, all trees were spot-fertilized in 1973 with a mixture of 71 g urea, 99 g rock phosphate and 41 g potassium sulfate.