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Linder, S. 1998. NPP Boreal Forest: Flakaliden, Sweden, 1986-1996. Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A.
The 8.25 ha Flakaliden study site (64.12 N 19.45 E) is situated in northern Sweden, about 60 km west of the city of Umeå. The site has a harsh boreal climate with short cool summers of long days, and long, cold winters of short days. Monthly mean air temperature ranges from -8.7 C in February to 14.4 C in July. More than one-third of precipitation falls as snow.
The study site was planted with 4-year old seedlings in 1963 after clear-felling, prescribed burning, and scarification. The fertilisation experiment, consisting of four treatments with four replicates each (100 m x 50 m plots), commenced in 1987. Treatments comprised irrigation with sprinklers, solid fertilisation, irrigation with liquid fertiliser, and a control. The annual dose of nitrogen was initially 100 kg N/ha, the other nutrients (P, K, Ca, S, Mg) being supplied in fixed proportion to N, adjusted annually against needle samples, in an attempt to attain the optimal nutrient dose. The N dose was reduced 25% in 1990. Complete inventories were carried out in 1986, 1991 and 1996, determining height and diameter at breast height for every tree. In the intervening years, about 100 trees per treatment were sub-sampled.
After three years' treatment, height and diameter growth in both fertilised stands was double that of the control stand. After 10 years, volume growth of fertilised stands was almost four times that of the control. There was no effect of irrigation on growth. Data from this site were used to parameterise and test the BIOMASS process-based model: parameter values are available from the references below.
Total net primary production of a 36-year-old untreated stand in 1995 was estimated at 291 g/m2/year (above-ground = 198; below-ground = 93 g/m2/year), and increased more than three times in the irrigated and fertilised treatment to 902 g/m2/year, with more carbon allocated to shoot than root growth (above-ground = 678; below-ground = 224 g/m2/year).
A longer set of climate data is available from the Svartberget Experimental Station (25 km to Northeast; elevation 225 m).
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E-mail: sune.linder@spek.slu.se
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references and summaries for the Flakaliden site.