On the structure of tree crown on the example of biennial shoot systems of Ulmus glabra Huds

Using the example of crowns of Ulmus glabra Huds. individuals of the virginal age state, the structure of biennial shoots systems (BSS), the occurrence of different types of them in the crown as a whole and in its different parts are analyzed. Identified features of the structure of the maternal shoot for three functionally different types of BSS: Filling-up, Growth, Basic and Narrow-Outline and Super-growth. Comprehensive analysis of morphology of the maternal axis and lateral shoots revealed the characteristics and enabled us to construct a discriminant function significantly separating the three types of BSS. The predictive accuracy of its classification by sample values is 94 percent. Special zones are identified on the maternal shoots of Growth and Basic BSS, which determine their difference and similarity. The fact that such zonality of the maternal shoot is determined only in the second year of his life corresponds to the idea of BSS as a single module of space-time aggregation in tree crown.