Evaluation of forest resistance to drought using time series of hyperspectral and LiDAR data
Mediterranean and temperate forests are being affected by intense and frequent droughts that will become more frequent and severe under future climate change. Together with its economic and environmental effects, this fact makes the evaluation and the reduction of the drought impacts in forest ecosystems vital. This issue has widely accepted by both scientists, and forest managers. As such several forest management practices such as mechanical thinning or prescribed fire are hoped to increase forest resilience to drought. The main problem is the lack of information needed for forest managers in the decision making procedure. Remote sensing data can be used to evaluate forest evolution under different forest management practices. However, the potential of combining airborne hyperspectral time data and LiDAR data to examine forest resilience to drought still need further investigation.
This research aims to examine whether different forest management practices will affect forest resilience to drought. The study site is a mixed conifer forest within Sierra National Forest in central California, USA. The study will benefit from a long term experimental set of forest treatments (i.e. understory thinning; overstory thinning; prescribed fire; and the combination of each type of thinning with prescribed fire) at the Teakettle Experimental Forest site, where a 4-year time series imaging spectroscopy data and LiDAR imagery exist. The canopy structural and physiological changes over time will be evaluated using spectral and LiDAR features to examine how/whether forest drought resilience is affected. The student is expected to assess the temporal evolution of canopy conditions in terms of biomass and canopy water content in each treatment plot to examine whether their decline would be higher in the most stressed or less resilient plots.
North, Malcolm, Jim Innes, and Harold Zald "Comparison of thinning and prescribed fire restoration treatments to Sierran mixed-conifer historic conditions." Canadian Journal of Forest Research, vol. 37, no. 2, 2007, p. 331.
This MSc topic can be easily applied for M-SE students since the topic covers many aspect and can be focused in different ways. Understanding how drought resilient is the forest under different management practices will be helpful to define a management plan in this type of forest. There are different data sources available for the student to consider in the analysis (hyperspectal images, LiDAR, flux tower data, meteorological data, soil information, vegetation map, etc.). The student also may explore the main physical processes that control vegetation responses to drought. In conclusion: the topic is broad and there is enough data to adapt it to M-SE thesis.