Planting trees on agricultural land either as farm woodlands or agroforestry (trees integrated with farming) is one option for reducing the level of atmospheric carbon dioxide. Trees store carbon as biomass, and may increase carbon storage in the ground. A review of the literature outlined uncertainty relating to changes in carbon storage after planting trees on agricultural land. The aim of this thesis is to deter¬mine the impact of tree planting on arable and pasture land in terms of above and belowground carbon storage and thereby address these uncertainties, and assess the implications for the Woodland Carbon Code: a voluntary standard for carbon storage in UK woodlands. Measurements of soil organic carbon to a depth of 1.5 m were taken at two field sites in Bedfordshire in the UK: a 19 year old silvoarable trial, and a 14 year old silvopasture and farm woodland. On average 60% and 40% of the soil carbon (rel¬ative to 1.5 m) was found beneath 0.2 and 0.4 m in depth respectively. Whilst tree planting in the arable system showed gains in soil organic carbon (12.4 t C ha−1 at 0–40 cm), tree planting in the pasture was associated with losses of soil organic carbon (6.1–13.4 t C ha−1 at 0–10 cm). Evidence from a nearby mature grazed woodland indicate that these losses may be recovered. No differences associated with tree planting were found to the full 1.5 m, though this may be due to a lack of statistical power. Measurements of above and belowground biomass, and the root distribution of 19 year old poplar (Populus spp.) trees (at the silvoarable trial) and ash (Fraxinus excelsior) trees ranging from 7 to 21 years (at several field sites across Bedfordshire) were made, involving the destructive harvest of 48 trees. These measurements suggest that Forestry Commission yield tables overestimate yield for poplar trees grown in a silvoarable system. An allometric relationship for determining ash tree biomass from diameter measurements was established. The biophysical model Yield-SAFE was updated to take into account root growth, and was parameterised using field measurements. It was successfully used to describe existing tree growth at two sites, and was then used to predict future biomass carbon storage at the silvoarable trial. Measurements indicate that losses in soil carbon at relatively shallow depths can offset a large proportion of the carbon stored in tree biomass, but assessing changes on a site by site basis may be prohibitively expensive for schemes such as the Woodland Carbon Code.

No description available.

Durch das Ansteigen der Weltbevölkerung und das wirtschaftliche Aufstreben insbesondere der Entwicklungs- und Schwellenländer wird die Nachfrage nach dem Rohstoff Holz beträchtlich wachsen. Gleichzeitig ist die Entwicklung der weltweiten Waldfläche rückläufig. Eine wesentliche Frage für die nationalen Volkswirtschaften wird in der Zukunft sein, den bereits jetzt knapp werdenden Rohstoff Holz in ausreichendem Maße zur Verfügung zu stellen. Vor diesem Hintergrund beschäftigt sich die vorliegende Arbeit mit ertragskundlicher Analyse von Gehölzsystemen und den Möglichkeiten der Ertragssteigerung am Beispiel des Bundeslandes Sachsen. Im Zentrum stehen vor allem Kurzumtriebsplantagen im Vergleich mit Schlagweisen Hochwäldern. / The rise in the global population and in the economic ambitions of the developing and newly industrialising nations in particular will prompt a significant increase in the demand for wood. While these developments are taking place, however, the area of forest cover globally is in decline. An issue of central importance for national economies in the years to come will concern their ability to secure an adequate supply of the already limited raw material wood. Against this background, the study presented herein focuses on analyses of the yields provided by certain wood production systems and on the options to increase this yield. The study addresses the issue on the basis of the example of the German federal state Sachsen. A focal point of the study is short rotation coppice plantations, contrasted against age-class high forest stands.

Durch das Ansteigen der Weltbevölkerung und das wirtschaftliche Aufstreben insbesondere der Entwicklungs- und Schwellenländer wird die Nachfrage nach dem Rohstoff Holz beträchtlich wachsen. Gleichzeitig ist die Entwicklung der weltweiten Waldfläche rückläufig. Eine wesentliche Frage für die nationalen Volkswirtschaften wird in der Zukunft sein, den bereits jetzt knapp werdenden Rohstoff Holz in ausreichendem Maße zur Verfügung zu stellen. Vor diesem Hintergrund beschäftigt sich die vorliegende Arbeit mit ertragskundlicher Analyse von Gehölzsystemen und den Möglichkeiten der Ertragssteigerung am Beispiel des Bundeslandes Sachsen. Im Zentrum stehen vor allem Kurzumtriebsplantagen im Vergleich mit Schlagweisen Hochwäldern. / The rise in the global population and in the economic ambitions of the developing and newly industrialising nations in particular will prompt a significant increase in the demand for wood. While these developments are taking place, however, the area of forest cover globally is in decline. An issue of central importance for national economies in the years to come will concern their ability to secure an adequate supply of the already limited raw material wood. Against this background, the study presented herein focuses on analyses of the yields provided by certain wood production systems and on the options to increase this yield. The study addresses the issue on the basis of the example of the German federal state Sachsen. A focal point of the study is short rotation coppice plantations, contrasted against age-class high forest stands.

No description available.