Trends in Forest Soil Acidity: A GAM Based Approach with Application on Swedish Forest Soil Inventory Data
2018 (engelsk)Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hp
Oppgave
Abstract [en]
The acidification of soils has been a continuous process since at least the beginning of the 20th century. Therefore, an inquiry of how and when the soil pH levels have changed is relevant to gain better understanding of this process. The aim of this thesis is to study the average national soil pH level over time in Sweden and the local spatial differences within Sweden over time. With data from the Swedish National Forest Inventory, soil pH surfaces are estimated for each surveyed year together with the national average soil pH using a generalized additive modeling approach with one model for each pair of consecutive years. A decreasing trend in average national level soil pH was found together with some very weak evidence of year-to-year differences in the spatial structure of soil pH.
sted, utgiver, år, opplag, sider
2018.
Emneord [en]
soil pH, soap film smoothing, generalized additive models, spatial modeling
HSV kategori
Identifikatorer
URN: urn:nbn:se:uu:diva-352392OAI: oai:DiVA.org:uu-352392DiVA, id: diva2:1215453
Eksternt samarbeid
Sveriges Lantbruksuniversitet
Fag / kurs
Statistics
Utdanningsprogram
Master Programme in Statistics
Presentation
2018-05-30, B139, Ekonomikum, Kyrkogårdsgatan 10, Uppsala, 09:55 (engelsk)
Veileder
Examiner
2018-06-192018-06-082018-06-19bibliografisk kontrollert