PhD defence: Florian Reiner

Florian Reiner defends his thesis, 

Assessing trees in global drylands, continental scale mapping of tree cover at individual tree level.

Supervisors:
Associate professor Martin Brandt, IGN
Professor Rasmus Fensholt, IGN

Assessment Committee:
Associate professor Shaun Levick, CSIRO, Australia
Associate professor Martin Karlson, TEMA, Linköping University, Sweden
Associate professor Laura Vang Rasmussen (chair), IGN

Summary (shortened):
Global drylands cover 41% of the world and support more than 2 billion people. Due to low annual rainfall, drylands are characterised by sparse vegetation, with trees and shrubs Scattered across the landscape. These Trees Outside Forest play a key ecological role and provide vital ecosystem services to local communities. However, their extent, distribution and dynamics areot well understood at a global scale, as their scattered nature impedes their detection in current medium-resolution tree cover maps. There is an urgent need for an improved assessment of non-forest trees, with wide applications for conservation ecology, sustainable land management, agroforestry, and tree-based climate change mitigation. This thesis aims to develop new methods to assess dryland tree cover at single tree level and continental scale. The thesis is based on three first-authored articles. Common to all papers is an underlying approach applying state-of-the-art deep learning techniques to a new data source: 3 m resolution PlanetScope imagery. PlanetScope is a constellation of approximately 130 nanosatellites that provide daily 4-band optical imagery of the global land area, including a near-infrared band suitable for detecting vegetation.

A digital version of the PhD thesis can be obtained from the PhD secretary at phd@ign.ku.dk