Large-size timber
Wood with the diameter at the thinner end of at least 14 cm (measured without bark) measured in single logs.

Medium-size timber
Wood with the diameter at the thinner end (measured without bark) of at least 5 cm, and at thicker end of up to 24 cm, measured in single logs, in group of logs and stacks.

Merchantable timber
Volume of wood with the diameter at the thinner end of at least 7 cm measured with bark (gross merchantable timber) and 5 cm without bark (net merchantable timber).

Thinning
Tending cuts in forest stands over the sapling age, which remove the trees economically useless. Thinning positively affect the growth and quality of remaining trees, improve natural resistance of stands, forest sanitary condition and health.

Early thinning
Tending cuts made in stands at the age of about 20 - 50 years, with the objective to protect the most valuable stand elements and to give support to crop trees and to remove harmful weed trees. Early thinning improves the quality of produced timber, increases stand resistance to abiotic factors (e.g. snow- and wind-broken trees), improves the sanitary condition of the forest and prompts stand maturation.

Late thinning
Tending cuts made in stands aged 40-90 years, which aim is to shorten the period of cutting maturation by intensifying the increment through overexposure to light (providing more ligh), and preparing stand to renewal.

Timber harvesting
Production process associated with forest or fast-growing trees in plantations clear-cutting, logging and transporting wood graded assortments, and the preparatory and finishing works. The amount of crop is the size (volume) of prospective wood harvest resulting from the economic and financial plans (Forest Act, Art. 6, paragraph 1, item 10).

Timber volume
The volume of wood contained in the aboveground part of the tree, expressed in m3.