Canadian Forest Service Publications
Nutrient changes in peaty gley soils after clearfelling of Sitka spruce stands. 1991. Titus, B.D.; Malcolm, D.C. Forestry 64(3): 251-270.
Issued by: Pacific Forestry Centre
Catalog ID: 25412
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The roots of second-rotation Sitka spruce (Picea sitchensis (Bong.) Carr.) planted on peaty gley sites are restricted to the old litter (LFH) layer and are dependent on its decomposition for availability of nutrients. A series of these sites of increasing age from felling were sampled to estimate changes in the nutrient capital of the LFH horizon over time at Kielder Forest, Northumberland. Previous stand histories were reconstructed from stump data. Geographical, climatic, soil and mensurational data suggested that the use of a time series was justified. Nutrient capital in the LFH horizon generally declined over a 5 year period after clearfelling from approximately 999,51 and 83 kg ha -1 of N, P and K, respectively. However, N concentration increased over a 5 year period from 11 mg g -1 to 14 mg g -1, P concentration remained constant at about 0.6 mg g -1, and K concentration decreased from 1.0 mg g -1 to 0.7 mg g -1. Nutrient concentrations and contents of the LFH horizon were higher under the brash (slash) swathes that resulted from the use of organized felling techniques than under clear strips devoid of brash. The patterned input of nutrient capital in brash as a result of organized felling was also determined. Brash containing 219, 20 and 71 kg ha -1 of N, P and K, respectively, was systematically distributed at a rate of 49 t ha -1 over 66 per cent of the site after harvesting. The needles and small branch fractions contained 71 per cent of the N and 80 per cent of the P and K present in the brash.