Rosinedal

The research site is located on Rosinedalsheden, just east of the town of Vindeln. The forest consists of naturally regenerated 80-year-old pines, and the soil is a deep sedimentary deposit of fine and coarse moraine. The ground vegetation is dominated by bilberry and lingonberry shrubs. The experiment was established in the summer of 2005, and annual nitrogen fertilization (SkogCan) began in 2006.

The experiment covers three areas of 13-15 hectares each. The treatments, applied over the entire area, include an untreated control area and an annual addition of 20 and 50 kg (100 kg during the first few years) of nitrogen per hectare. In the center of each area, there is a climate station and a mast, where atmospheric carbon fluxes are measured using eddy flux technology.

Researchers use different approaches to study carbon fluxes and carbon storage in the stand. Using eddy flux technology, the exchange of carbon dioxide between the forest stand and the atmosphere is continuously recorded. This technique provides an integrated value of the stand's carbon balance. The experiment also measures the individual physiological processes related to tree growth and the stand's carbon storage: photosynthesis, transpiration, and respiration from the stems and needles, ground vegetation, and roots.

The research site at Rosinedal is nearly ideal for this type of study. Its uniform stand structure and relatively flat terrain simplify the use of eddy flux technology. The fact that the stand is even-aged and consists of a single tree species—pine—also simplifies the physiological measurements on the trees and other vegetation.

In addition to physiological measurements, there is also a sampling program for stand growth, crown development (photography with a fisheye lens), vegetation inventory, litterfall, nutrient content in needles, as well as soil moisture and soil water chemistry.

Nitrogen availability is a significant limiting factor for growth in most northern coniferous forests, and the response to nitrogen fertilization in Rosinedal has been strong—the production of stem wood has almost doubled since fertilization started in 2006. Research has also shown that fertilization with high nitrogen doses has drastically reduced the production of fruiting bodies of fungi, while the effect of the low nitrogen dose seems to be slightly positive regarding this production. In addition to the significant increase in stem wood growth, needle biomass has also increased substantially, while fine root biomass has decreased.

The studies are conducted by researchers at SLU's Faculty of Forest Sciences, as well as several domestic and international guest researchers.