Eight-year-old plantations (11) of silver birch were studied on abandoned agricultural land in Estonia. Trees were planted on uncovered soil and on polyethylene. After eight growing seasons, the height and diameter at breast height of the trees grown on polyethylene were significantly (P < 0.001) larger than corresponding parameters of the trees grown on uncovered soil. The annual height increment of the birches grown on the polyethylene was significantly (P < 0.05) larger during six growing seasons after planting compared to that of the trees grown on uncovered soil. However, annual height increments were not significantly different in the 7th and the 8th growing seasons. The use of polyethylene mulching had a statistically significant effect (P < 0.001) on the height of the beginning of the live crown in 8-year-old plantations. The differences between the values of live crown ratio of the trees grown on polyethylene and the values of live crown ratio of the trees grown on uncovered soil decreased during six growing seasons. However, by the 7th and 8th growing seasons, there was no significant difference (P > 0.05) between the values of the live crown ratio. The height growth of silver birch grown without mulching as well as with mulching was found to be more intensive on Glossic Podzoluvisol, Calcaric Cambisol, Calcaric Luvisol and Dystric Gleysol; however, the height growth was more intensive on mulched soil. The height growth of the birches was modelled on the single-tree and stand levels for five soil types.
238 (Baumanlagen, die eine besondere Behandlung erfordern (z.B. Pappelpflanzungen, Wurzelholz von Erica arborea usw.). Biomasse. [Einschl. plantagenmässiger Anbau und Schnellwuchsbetrieb sowie Angaben über dafür geeignete Baumarten. (Nur für allgemeine Darstellungen über diesen Sachverhalt. Einzelmassnahmen sind jedoch in erster Linie mit den ihnen entsprechenden Nummern zu klassifizieren, z.B. bei Astung mit 245.1)].) 913 (Beziehungen zwischen Wald und landwirtschaftlich genutzten Flächen (Acker, Wiese, Weide usw.). Waldrodungen; Aufforstungen von landwirtschaftlichen Flächen; Wechselwirtschaft, wandernde Waldfeldwirtschaft. (Politik); Landnutzung [Siehe auch UDC 332.3 Landnutzung und Unterteilung für Querverweise und auch UDC 711.4 Landnutzung; UDC 712.2 Landschaftsplanung im allgemeinen]) 237.3 (Aufhöhen (Rabattieren u.ä.) und Bodenbedeckung meist mit organischem Material, gegen Feuchtigkeitsverlust usw., Mulchen) 561.1 (Höhenzuwachs) 176.1 (Dicotyledoneae [Siehe Anhang D])
