Spatial Aspects of Forest and Forest Soil Management

This thesis deals with spatial aspects of forests and forest soils at the regional scale and at the small scale within forest stands. Two approaches were taken to address this topic. At the regional level an investigation was made to determine the influence of soil mineralogy on the variations in site quality. Site quality generally benefits from easily weathered minerals, although the relationship between site quality and soil mineralogy is complex and depend on the overall geology. The potential to predict site quality from soil mineralogy is improved if it is made within geological regions. An intensive sampling was made in three forest stands of different ages to determine the amount of within-stand variation, the extent to which it is spatially structured, the scales at which spatial variation exists, and the effort needed to estimate it. The results indicate that there is substantial variation within forest stands in both tree and soil properties. For many properties the variation was found to be spatially correlated at distances from 10 m to 170 m, which corresponds to average patch size. Mean diameter and tree height had rather strong spatial correlation, whereas for basal area and stem density it was weak. Estimations by kriging gave poor results for most forest properties unless sampling intensity was high, which would require other data collection methods than traditional field sampling. Harvester based data collection is proposed as one approach to accomplish this. Data collected by the harvester in a thinning was used to estimate the forest properties of the stand.