Swedish National Forest Inventory: Tree ring data

Data from analyses of tree ring bore cores collected in the Swedish National Forest Inventory, containing annual ring data from around twenty tree species, 144 000 individual trees and 6.1 million measurements.

Extraction of cores for analysis of annual rings was included from the start of the Swedish National Forest Inventory in 1923. The width of the annual rings is measured for each sampled core. The width of the annual rings depends on the growth in a specific year and is affected by temperature and other climatic factors.

Swedish National Forest Inventory’s tree ring data is mainly used to calculate diameter growth, a measure of how much the stems grow, which forms the basis for calculating basal area growth (a measure of forest density) and volume growth. Tree ring data are also used to calculate the tree ring index (an index that describes growth in a calendar year relative to a normal year) and other growth analyses.

This dataset contains data on tree rings back to 1935, from samples taken annually since 1995. Samples are still taken every year and the dataset is updated annually.

Data are presented both by year (ring season) and in order of measurement to facilitate different types of analyses.

Data can be downloaded from website of the Swedish National Forest Inventory: Tree ring data.