Abstract: This paper gives a detailed description of microscopic and ultrastructure and their effects on the permeability of the woods of Picea jezoensis var. komarovii and Abies nephrolepis. The abundent amorphous substances are depo-sited in the bordered pit membrances and the different layers of cell wall andaround the microfibrils of tracheids, that may be a main factor of the lowpermeability in heartwood of the two woods.

Key words: Refractory wood, Microscopic and uitrastructure, Permeability