Reducing windthrow losses in Farm Forestry

Abstract

The study comprised a field and laboratory investigation on the stability of Sitka spruce trees planted on a surface water gley. The field-testing was conducted at Ballyfarnon Forest in County Sligo in the north west of Ireland. Nine destructive monotonic pulling tests were conducted on trees selected from three different site preparations, namely, mole drained, double mouldboard ploughed and an uncultivated control. Dynamic testing, using a mechanical rocking device, was performed on a tree selected from the uncultivated control. A simple shear apparatus was used to conduct monotonic and cyclic tests on reconstituted samples of the Ballyfarnon soil. This allowed a comparison of soil behaviour under monotonic and cyclic loading. A computer software package was used to model the behaviour of groundwater for soil mole drained at two drain spacings. Results from this mathematical modeling were compared to experimental data gathered during a previous study. Results indicate that the use of mole drainage as a site preparation technique produces more stable trees than either double mouldboard ploughing or no cultivation.