A field day
Dr Kari T. Korhonen has been in charge of the 10th Finnish NFI since it was launched in 2004. He says the sampling design is based on the idea that a field crew can measure the plots of one cluster within a day. In Finnish conditions field work is possible only during the summer months when forest roads and tracks are passable. The field season starts in May with training of the crews. The Finnish NFI is carried out on very thin human resources, with most of the field workers engaged on temporary contracts. The work is carried out by 22 field crews of two or three members each. The leaders of the crews are forest professionals.
Satellite positioning has made it easier to ascertain that measurements are carried out exactly where they should be according to the sampling design. On each plot every 7th tree of those above 1.3 metres in height is chosen as a sample tree. The physical dimensions of the sample trees are measured.
The crew records the species of the sample trees, the dominant species in the plot and measures or estimates a very large number of other features constitutive of the forest and the forest environment, such as the volume of standing and fallen dead wood and presence of key biotopes as defined in the Forest Act.
Owing to an increased demand for updated information, during the current 10th NFI, the field crews cover the entire country in each of the five years of field measurements. Kari Korhonen says it is a bigger logistic challenge than the earlier method of covering the country progressively from south to north during the 8-10-year inventory period.
RISTO PITKÄNEN
PHOTO METLA
