Forest in four time layers “X 99”


On a mission by the county administrative board in Gävleborg, LMV has interpreted the change in forests within six economical maps in the county and in four time layers. The interpretation has been performed in photo material from the 1950’s, 60’s, 70’s and 90’s. Black and white aerial photos have been used where CIR-photos are absent. The study has been concentrated on areas close to streams and the key habitats where simple vegetation map layers and forest age map layers have been produced. Outside key habitats and stream zones only adult deciduous forests, young forests, clear cuts, non forests and forests with higher ecological values have been mapped. Zones close to streams have been found by buffering the lines of mono lined streams. Changes between the time layers in a number of questions from the costumer have been analyzed and are presented in an Excel-file called x99. It contains four simple vegetation maps and forest age maps in the different time layers, with emphasis on analysis of change in key habitats, in stream zones 5 m and 30 m, and in the change of adult deciduous forests. This kind of study has been performed within six economical maps in Gävleborg. I answered some questions from the County Administrative Board (Olle Kellner) in an Excel-file. For example “How has the area of adult deciduous changed over time?”, “What did the key habitats look like in the 1950’s?” and “How has the stream zones changed?”. I did the preparation work, controls and analysis automatically (more or less) by creating AML’s. The project is concentrated on the forestry business care close to streams, the history of key habitats and the change in deciduous forests.

Fig4: Analysis through the four time layers since
1950; red dashed are areas that have been young

or clear felled in any layer, green blue estimated to
be over 170 years , green over 140 years, brown is
over 30 years 1950 and not clear felled since then
and yellow is not forestland (mires and so on)

Fig 3
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