The Needles and Shoots Structure Variability of Polish Populations of Scots Pine (Pinus sylvestris L.) at a 50-Years-Old Provenance Experiment in Central Poland

Abstract

The analysis of population variability usually concerns the adaptability of trees to changing climatic conditions and their timber production possibilities. It is already known that several phenotypic and genotypic features determine the adaptation possibilities of a population and every population of a given species may have different adaptability to climatic conditions. The assimilation apparatus is an important phenotypic feature that has a large impact on the functioning of tree organisms and their adaptability. Scots pine, which covers vast areas of Europe, is a very important species in the context of ecosystems’ sustainability preservation, especially in the era of global warming. Therefore, in our research, the inter-population and individual variability of morpho-anatomical features of shoots and needles were analyzed. Nine national origins of Scots pine (three populations each from northern, western, and central Poland), which are a part of a 50-year provenance experiment, were compared. Fragments of one-year-old shoots (5 cm long) with needles were collected from the top parts of tree crowns. An extensive analysis of the morphological parameters of the needles (length and width, density, dry mass) and the anatomical features of the shoots (thickness, the share of bark, wood, and pith) was performed. Our surveys showed that the differences between populations are much greater than between regions. The western pine populations, which have shown the highest volume of wood per ha, had the thickest shoots but the lowest dry mass. The northern populations, highly valued for the very good technical quality of wood, had thin shoots. Pine trees from central Poland had the highest density and dry mass of needles and the highest share of wood in shoots.