Productivity of Larch of Different Origin in the Voronezh Region

Abstract

Experimental verification of the influence of Larix genus seeds origin on the properties of trees grown from them has been started in the last century, while attempts to introduce larch to forest-steppe were first undertaken in the 1880s. However, there is still no general interrelated pattern of the factors determining the success of larch growth in forest-steppe conditions. The research aims to reveal the effect of seed origin on the stability and productivity of larch plantations in the Central forest-steppe of the Voronezh region. The object is the Larix collection and geographical plantations planted in 1955 in the 7th quarter of the Zhivotinovskoe forestry of the Voronezh State Forestry University. Systematic observations of the study object showed that not all of the presented larch forms can be recommended for C2 conditions of the Central forest-steppe of the Voronezh region. We noted that Siberian larch and Sukachev larch, as well as European larch, grow well in the C2 conditions on gray forest sandy soils, namely, they are characterized by high preservation and productivity. Sukachev larch of Arkhangelsk origin and Siberian larch of Irkutsk and Krasnoyarsk origins, as well as European larch from the Baltic states, have an increased resistance to natural and climatic factors in the Central forest-steppe of the Voronezh region. However, when introducing the above mentioned forms of larch into plantations, one should take into account the specificity of the climate of the Central foreststeppe of the Voronezh region, which is characterized by long periods of drought, leading to a moisture deficit for the entire plant community. In the C2 conditions, larch forms a surface root system, which in the dry period negatively affects the growth of stands and causes stress to trees, leading to weakening of the stand. This is especially significant for specimens aged 55–65 yrs. The weakened larch stand cannot resist phytophages, namely, the colonization of the black pine barbell (Monochamus galloprovincialis (Olivier)), which enhances the complete falling off of larch stand in the studied conditions. The research results give a related pattern of formation of larch plantations in the C2 conditions, allow us to select the forms of larch, the best for the creation of production plots of this species in the Voronezh region.