Kan markfuktighetskartor användas för att hitta skogsmark med hög bonitet?

• Main Author: Henriksson, Anders
• Format: Text
• Language: Swedish; English
• Published: 2015
• Subjects: Forestry - General aspects; Soil science and management; Northern Sweden
• Online Access: https://stud.epsilon.slu.se/7671/7/henriksson_a_150302.pdf

The depth-to-water-index (DTW-index) is derived from digital elevation models (DEM) to map soil wetness, in terms of distance from soil surface to the ground water table. The aim of this GIS based study was to investigate the existence of a relationship between DTW-index and forest site productivity (SP). The belief of such an assumed relationship was based on knowledge that the ground water level is related to site properties that can either promote or impede tree growth. Data primarily comprised rasters of the Krycklan catchment in northern Sweden and depicted DTW-index and a laser scanned vegetation height. The 100th height percentile of each pixel in the vegetation raster was assumed to mirror the top-height, letting it act as a relative measure of SP within a delineated area of equal stand age. Areas of equal age were delineated by recognition of fresh clear-cuts in a digitized ortophoto from 1963. Influence from disturbing factors was reduced by selecting areas on till soil where Scots Pine (Pinus Sylvestris L.) dominated. The result suggests a weak and likely non-significant relationship between the variables. The lack of compelling evidence for such a relationship is attributed to the methods used and we suggest a repeated study with a more developed study design. DTW-index härleds ur digitala höjdmodeller (DEM) vilket resulterar i kartläggning av markfuktighet, mätt som avståndet från markyta till grundvattennivå. Syftet med denna GIS-baserade studie var att undersöka förekomsten av ett samband mellan DTW-index och skoglig produktionsförmåga (bonitet). Ett sådant förmodat samband grundar sig på kunskap som pekar ut grundvattennivå som en faktor som kan gynna eller hämma träds tillväxt. Data omfattade raster över Krycklans avrinningsområde för DTW-index respektive laserskannad vegetationshöjd. Den högsta percentilen i varje pixel av vegetationsrastret antogs motsvara övre höjd, vilket tillät användning av denna variabel som ett relativt mått på bonitet inom ett avfattat område av lika beståndsålder. ...