the scientific discipline that studies the structure and properties of wood.

Xylology is concerned with all information on wood as a material available from research involving the use of biological, chemical, physical, mechanical, and other methods. The subject is included in the training of all forestry specialists in the higher educational institutions and technicums of the USSR. It consists of the following divisions: the structure of wood (macroscopic and microscopic); the chemical, physical, and mechanical properties of wood and the effect on them of a variety of factors; defects in wood; durability; and the particular characteristics of the wood of the main tree species of the USSR.

The efforts of A. E. Teploukhov, D. I. Zhuravskii, D. M. Kaigorodoy, N. M. Buryi, A. V. Gadolin, I. P. Borodin, N. A. Beleliubskii, N. A. Filippov, L. A. Ivanov, S. I. Vanin, L. M. Perelygin, A. Kh. Pevtsov, N. N. Chulitskii, and others have contributed greatly to the development of Soviet xylology.

Xylology as an independent educational discipline first took shape in the USSR in 1932. The first textbooks and manuals were written in the 1930’s, and the first steps were taken that year to standardize methods for the physical and mechanical testing of wood, the results of which were later used to define indexes for the properties of the wood of the most important commercial species of the USSR. A great deal of attention was focused on the structure of wood and its defects. Relationships were found between the properties of wood and silvicultural factors. The effects of moisture, temperature, acids, alkalis, and so forth on the properties of wood were determined. This research made possible the extensive use of wood in construction and in the airplane, ship, and railroad-car building industries.

Broad research has been conducted since the 1950’s on the fundamental properties of wood: microscopic and ultrafine structure, rheological properties, moisture deformations, internal stresses, anisotropy, thermophysical, dielectric, and piezoelectric properties, and nondestructive methods of testing strength. Methods of testing wood based on the use of infrared, luminous, and ultraviolet irradiation, X-rays, and nuclear radiation are being developed. Sonic and ultrasonic vibrations are also used in tests. Color and luster are investigated by objective methods. Research is under way on finding effective methods of detecting flaws in wood. The structure and properties of wood are being studied in order to improve the existing technological processes of drying, impregnating, mechanically treating, gluing, and finishing wood, as well as to develop new methods.