Structural analysis of seasonal dynamics of daily growth of annual shoots of woolly-stemmed willow

Abstract

Given the complex characteristics of woolly–stemmed willow. The necessity of studying the regularities of seasonal dynamics of daily growth of annual shoots is substantiated. The study used material from the model inbred-clone population. Empirical data were processed using structural–harmonic analysis methods. It was found that the seasonal dynamics of the daily growth of shoots is cyclic quasi–periodic. Empirical series of dynamics at the highest level of significance are approximated by sums of elementary harmonics with a period of oscillation of 9.2 to 92.0 days. Revealed high-amplitude harmonic with the oscillation period of 23.0 to 92.0 day and low amplitude with a period of oscillation of 9.2 to 18.4 days. On all the studied shoots only the fourth harmonics coincide with the oscillation period of 23.0 days. The main contribution to the seasonal dynamics of shoot growth is made by three high-amplitude harmonics, which form two main signals with oscillation periods of 23 and 36 days. Other harmonics have a modulating effect on the seasonal dynamics of shoot growth. The first harmonics with a period of oscillation 92.0 days determine the nonlinearity of the seasonal trend of growth of shoots. Higher harmonics with a period of oscillation of 9.2 to 15.3 days form the resulting quasi–cyclic oscillation. Significant interclonal and intraclonal differences in the rhythm of daily growth of annual shoots were not revealed. On this basis, the proposed recommendations for agroforestry–technical events in the plantings of woolly–stemmed willow.