Show simple item record

dc.contributor.authorMalcolm, Douglas C.en
dc.date.accessioned2019-02-15T14:34:56Z
dc.date.available2019-02-15T14:34:56Z
dc.date.issued1970en
dc.identifier.urihttp://hdl.handle.net/1842/35126
dc.description.abstracten
dc.description.abstractThe main objective of this investigation was to examine the relationships between various site factors and the productivity of Sitka spruce (Picea sitchensis Bong., Carr) plantations. The natural distribution of the species is notable for its great latitudinal range, although it is confined to a narrow belt along the Pacific coast of North America. The climatic conditions found in this region, whilst not precisely matched, are sufficiently similar to those found in North West Europe to have encouraged its use as an exotic species on a large scale. Much of the planting has been successful, but little was known of the relations between productivity and site factors for stands that were growing normally and could confidently be expected to reach utilisable sizes. The study was therefore confined to healthy stands over 30 years of age. The distribution of the productivity classes in Scottish forests appeared to show no very marked influence of gross climatic factors so four forest areas were selected for detailed examination. Each of these forests showed a wide range of productivity classes within a small area. Because of the constraints placed on the choice of stands to be sampled the sampling had to be systematic and involved visiting almost every stand in each area. Productivity was measured on a height:age basis to avoid treatment effects, although other productivity parameters such as basal area and volume were recorded in the 95 plots sampled. Variation in some site factors was examined initially before settling on sampling procedures. For each plot a series of physiographic and soil parameters were measured. All results were expressed so to describe the site potential for tree growth in the most meaningful way possible. The relation of the site factors to productivity of Sitka spruce was examined both by single factor and multivariate analyses. The results obtained by using different techniques of analysis were similar. The factors which emerged as having the strongest relationships to growth were also similar for the areas studied although any individual factor might not have the same importance in each. To aid in the elucidation of the relationships a cross -stratification on a physiographic basis was made. For the statistical analysis the total number of plots from which data had been collected was reduced to 77 because of doubts about the age of the remainder as recorded. The data showed that local climatic effects expressed as 'elevation' or relative elevation were the dominating factors affecting productivity at each of the forests. Within this effect the phosphorus status of the site proved the next most important individual variable. Multivariate analysis indicated a physico-chemical 'factor' which combined phosphorus status and soil structure, consistently important to productivity in each forest. Base status of the site was the best means of separating the sites but did not itself directly contribute much to productivity except at one forest. Neither the soil type nor ground vegetation were suitable for classifying potential productivity but prediction equations that accounted for over 70% of the variation in productivity were devised. The usefulness of these to management was thought less than their value for directing attention to the factors that limit production. Component analysis was considered more potent as a means of detecting combinations of factors that might be investigated further. The limitations to economically useful site improvements for this species were thought to be defined by the effect of elevation. This effect and the phosphorus nutrition of the tree should be the main directions for immediate further research.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2019 Block 22en
dc.relation.isreferencedbyen
dc.titleSite factors and the growth of Sitka spruceen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


Files in this item

This item appears in the following Collection(s)

Show simple item record