Morphometric parameters of pine needles in Tolkuse bog in the dune field in Southwest Estonia

Needle characteristics of Scots pines (Pinus sylvestris L.) in Tolkuse bog (SW Estonia) their length, dry weight and area are discussed. Samples of needles and peat were collected from seven small forest stands in Tolkuse bog in summer 2004. The sampling sites were selected from transect across the bog margin towards its centre (site I - bog margin, site VII - bog centre). Sample branches (n = 30) were collected from the southern sides of the crowns of three trees at heights of 1.5 and 3.0 m. Soil analysis of the samples showed that the pH of peat in Tolkuse bog was in the range 3.3-4.2. The nutrient concentrations of Tolkuse bog peat (% of dry mass) varied as follows: total N 0.7-1.5, total P 0.07-0.14, total K 0.02-0.06, Ca 0.14-0.51 and Mg 0.06-0.22. As compared with other sampling sites a significantly higher concentration of nutrients was observed in the peat at site V. This may explain the best growth of the needles at this site. Site VII, located in the centre of the bog between hollows where bog water is closest to the surface, had the smallest measurements of needles. This indicates that this site has the least favourable conditions for pine growth. Needles growing in the crown at a height of 3 m from the ground had a considerably smaller needle area than those at a height of 1.5 m from the ground.