Abschlussarbeiten
Investigations of Regional Tree Line Migration - Examples from the Altai and Tien Shan Mountains
Art der Abschlussarbeit
Master
Autoren
- Hartley, Catherine
Betreuer
- Dr.rer.nat. Nikolas Prechtel
- Dipl.-Ing. Tino Pieczonka
Abstract
Research Objective
The alpine treeline is a climate-dependent boundary between forest and alpine tundra. Treelines are rather model lines than directly observable, since tree growth does not stop abruptly at most locations. Several regional studies report cases of an upward treeline migration since the beginning of the 20th Century. This correlates with a global trend of increased air temperature and, in association, more favourable conditions for tree recruitment.
Study areas in the Central Altai Mountains and the Central Tien Shan are chosen to reflect the sensitive Inner Asian mountain environments. The regions are remote, uninhabited and have a low anthropogenic load, thereby enabling to focus on a potential climate-induced treeline migration.
The overall objective is to assess the potential migration of treelines in the Central Altai and Central Tien Shan in the past c. 40 years by using declassified Corona KH-4, Hexagon KH-9, and RapidEye imagery.
Preliminary Results
Preliminary results show that the treeline in the Altai and Tien Shan mountains has remained mostly stable from the 1970s to present.
Downward shifts could be identified in isolated areas and are characterised by likely local anthropogenic or environmental disturbances, e.g. influence of avalanches, rock falls or wildfires. The majority of migrating treelines, however, experienced a slight positive elevation shift. This advance was below 20 alt. metres on average and has most frequently been observed along diffuse treelines. The minor upward migration could mainly be attributed to a densification of shrubs rather than to true treeline propagation. It might, however, indicate the gradual development of a more favourable climate for vegetation growth at high altitudes.
The alpine treeline is a climate-dependent boundary between forest and alpine tundra. Treelines are rather model lines than directly observable, since tree growth does not stop abruptly at most locations. Several regional studies report cases of an upward treeline migration since the beginning of the 20th Century. This correlates with a global trend of increased air temperature and, in association, more favourable conditions for tree recruitment.
Study areas in the Central Altai Mountains and the Central Tien Shan are chosen to reflect the sensitive Inner Asian mountain environments. The regions are remote, uninhabited and have a low anthropogenic load, thereby enabling to focus on a potential climate-induced treeline migration.
The overall objective is to assess the potential migration of treelines in the Central Altai and Central Tien Shan in the past c. 40 years by using declassified Corona KH-4, Hexagon KH-9, and RapidEye imagery.
Preliminary Results
Preliminary results show that the treeline in the Altai and Tien Shan mountains has remained mostly stable from the 1970s to present.
Downward shifts could be identified in isolated areas and are characterised by likely local anthropogenic or environmental disturbances, e.g. influence of avalanches, rock falls or wildfires. The majority of migrating treelines, however, experienced a slight positive elevation shift. This advance was below 20 alt. metres on average and has most frequently been observed along diffuse treelines. The minor upward migration could mainly be attributed to a densification of shrubs rather than to true treeline propagation. It might, however, indicate the gradual development of a more favourable climate for vegetation growth at high altitudes.
Schlagwörter
Global Change Assessment, Climate Change, RapidEye, KH-9 Hexagon, KH-4 Corona, Tien Shan, Altai
Berichtsjahr
2014