NPP Boreal Forest: Jädraås, Sweden, 1973-1980


[PHOTOGRAPH]
Photograph: Field work at Jädraås (click on the photo to view a series of images from this site).

Data Citation

Cite this data set as follows:

Linder, S., and G. I. Agren. 1998. NPP Boreal Forest: Jädraås, Sweden, 1973-1980. 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.

Description

Productivity of a boreal coniferous forest was determined at the Jädraås research site under the SWECON (Swedish Coniferous Forest Biome) Project which started in 1972. In this intensive study, the dynamics of above and below-ground biomass were monitored, together with energy and water budgets, and nutrient and soil processes, from 1973 to 1981. However, some experimental treatments and measurements have continued to the present day (1997).

The 1.5 x 2.5 km Jädraås study site (60.82 N 16.50 E) is situated at Ivantjärnsheden near Jädraås in central Sweden, at the southern limit of the "northern coniferous" region, about 30 km northwest of the town of Gävle. The site experiences cool summers with long days, and long, cold winters. Summer droughts occur because of the sandy soils with low water storage capacity. Land use history in the region includes forest grazing, burning for crops and grazing, charcoal burning, tar-burning, logging and felling for paper pulp. Charcoal and tar burning probably dominated recent land use at Jädraås, and the site was probably completely treeless around 1850-1860 due to charcoal consumption for smelting. Following regeneration, the forest stand at Jädraås was thinned around 1960.

The research plots at the site represent an age series of pine forest stands, ranging from those which were clear-felled in 1977 (plot "Ih 0") to those which were 125 years old in 1979 (i.e., established about 1854; plot "Ih V"). Studies of ecosystem productivity concentrated on plot "Ih II", which was harvested in 1957 and the seed trees thinned in 1962. The naturally-regenerated "Ih II" plot dates therefore from about 1960, and was about 14 years old when treatments started in 1974. Replicate 20 x 20 m plots were established for control, irrigated, irrigated and fertilised treatments. Fertilisation resulted in dramatic increases in productivity, persisting long after treatment was discontinued. Irrigation did not significantly increase productivity, with or without fertiliser.

Total net primary production of a 20-year-old untreated stand in 1979 was estimated at 860 g/m2/year (above-ground = 372 g/m2/year; below-ground = 488 g/m2/year), and was doubled in the irrigated and fertilised treatment to 1680 g/m2/year, with more carbon allocated to shoot than root growth (above-ground = 1222 g/m2/year; below-ground = 724 g/m2/year).

Contact Information

Contact: Dr. S. Linder
Dept. for Production Ecology
Swedish University of Agricultural Sciences
P.O. Box 7042
SE-75007 Uppsala
SWEDEN

Telephone +46 (18) 672440
Fax +46 (18) 673376
E-mail: sune.linder@spek.slu.se

Alternative Contact: Dr. G. I. Ågren
Dept. of Ecology and Environmental Research
Swedish University of Agricultural Sciences
P.O. Box 7072
SE-75007 Uppsala
SWEDEN

Telephone +46 (18) 672449
Fax +46 (18) 673430
E-mail: goran.agren@eom.slu.se

Click on the following linked phrase to view references and summaries for the Jädraås site.

Graphs Image
Click on the "Graphs" box to view climate data plots for this site.