Analysing the whole set of resultant data one arrives at a generalized concept of Karelian birchtype development abnormalities in woody plants, which appears as a chain of interrelated statements and comprises the mechanisms of patterned wood formation and inheritance, and problems of Karelian birch genesis. According to this concept, Karelian birch is an ecological form of silver birch that appears in areas with a favourable climate under a specific combination of environmental factors including temperature, light, soil moisture and fertility, which united action causes a rise in sucrose content in the phloem exudate, which, in turn, induces a change in the programme of cell development in the cambial zone and leads to formation of structural abnormalities known as «Karelian birch figured wood». These structural abnormalities are within the normal range of response of silver birch genotype. From the viewpoint of the organism functional condition, Karelian birch is an example of metabolic disorder. Inheritance of metabolic disorders is quite a widespread natural phenomenon. The process may involve epigenetic inheritance. Such inheritance is unsteady: the tendency for abnormal development in Karelian birch progeny may either show quite late in the ontogeny (if at all), or may grow stronger or weaker (up to normalization of the structure) depending on changes in environmental conditions.