In Finland there are two grades of roundwood timber for each tree species: logs and pulpwood, or small-diameter wood. Each of these has a three-letter abbreviation in Finnish, where the two first letters denote the species. Thus, pine log is abbreviated MÄT, pulpwood pine MÄK, spruce log KUT, pulpwood spruce KUK, birch log KOT, and pulpwood birch KOK. Pulpwood is derived from small-diameter trees and the crowns of large trees. Large-sized wood of poor quality is also used as pulpwood. Pulpwood is used to manufacture pulp. Saw-timber tree is a tree which yields at least one log, i.e., a straight four-metre stem whose minimum top diameter is 15 cm – or, in the case of small-diameter logs, even smaller. Less common grades of timber include spars, which are larger than pulpwood but smaller than logs; poles, which are longer than logs; split or firewood billets; veneer or peeler blocks, which are larger-than-usual spruce or birch logs used for plywood; and Egyptian balks. Egyptian balk means a balk with a minimum thickness of 75 mm and a cross-section which is approximately square in shape. Its length is 3 to 6.7 metres. Almost all of the production is exported to Egypt. Battens are planks produced in sawing, with a thickness of 38 to 175 mm. The most recent timber grade is forest energy timber, which is abbreviated as MEK.