University of Twente Student Theses


Use of process based models to assess the spatio-temporal variability of the effect of climate change on forest development.

Murungweni, Florence Mazwi (2010) Use of process based models to assess the spatio-temporal variability of the effect of climate change on forest development.

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Abstract:Advances in the study of climate change have seen much emphasis placed on the variability and non-static nature of climate. With the projected trends of likely impacts of climate change on forest ecosystems, it has become important to incorporate climate change consideration in forest development. However under these circumstances, forest managers require models that can function across spatial and temporal scales. The study aimed firstly to validate the responses of the physiological principles of predicting growth model (3PG) and the 3PG-Nitrogen (3PGN) in estimating above ground biomass and secondly to evaluate the effect of climate change on Stem biomass production of Sitka spruce across Scotland. The aboveground biomass production was simulated using the 3PG and the 3PGN models. Precipitation, temperature, soil, and solar radiation data were used to run the models. Permanent sample point data provided with observed biomass data that were compared graphically to model outputs. The 3PG model gave better results than 3PGN when observed above ground biomass (AGB) is low in the measured plots. The 3PGN model performance was better in cases where observed above ground biomass was higher. To evaluate the models performance Root Mean Square Error (RMSE) method was used. The 3PGN predictions gave a RMSE of 40.1tDM/ha while 3PG gave RMSE of 44.4tDM/ha. For climate change analysis 3PGN-spatial was used in running the simulations. Stem biomass production results showed that less productive areas are situated to the north and north-west parts of Scotland producing between 1-30 tDM/ha. Areas to the south and south-east show stem biomass of between 91-105tDM/ha. The model also predicts that baseline stem biomass (1961-1990) will increase mostly in the south and south-east Scotland until the 2050s (2040 – 2069) period. By the 2080s (2070 -2099) period, the prediction indicates both increase and decrease in stem biomass production in parts of south-east Scotland. Predicted temperature had more influence on stem biomass production when compared to predicted precipitation. The study demonstrates that 3PGN and 3PGN-Spatial process based models can provide more accurate and relevant forest productivity estimates at both stand and landscape level. Keywords: Climate, Forest, Biomass, Scotland, 3PG, 3PGN, 3PGN-Spatial
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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