Effects of Land Use, Habitat Fragmentation and Climate Warming on Stem Increment, Regeneration, and Hydraulic Architecture of Larix sibirica in the Mongolian Forest-Steppe

by Elmira Khansaritoreh
Doctoral thesis
Date of Examination:2017-08-31
Date of issue:2018-05-16
Advisor:Prof. Dr. Markus Hauck
Referee:Prof. Dr. Markus Hauck
Referee:Prof. Dr. Christoph Leuschner
Referee:Prof. Dr. Erwin Bergmeier
Referee:Prof. Dr. Dirk Hölscher
Referee:Prof. Dr. Hermann Behling
Referee:Prof. Dr. Holger Kreft
Persistent Address: http://dx.doi.org/10.53846/goediss-6833

 

 

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Abstract

English

Effects of land use intensity, forest fragmentation and climate warming on stem increment and hydraulic architecture of Larix sibirica growing at the southern fringe of the Eurosiberian boreal forest in the Mongolian forest-steppe were studied. Apparent climate-sensitivity of the trees in the heavily logged forests and small forest stands reveal that anthropogenic disturbance and forest fragmentation exacerbates the detrimental impact of climate warming on forests which are exposed to temperature increases far above the global average in Inner Asia (IPCC 2013). Although forest fragmentation resulted from logging, fire, and forest grazing, clearly affects annual stem increment, forest regeneration and microclimate, its effect on hydraulic architecture did not show a linear correlation with decreasing forest stand size. However, anatomic parameters (e.g. tracheid diameter, tracheid density and …) like tree-ring width, significantly correlated with climate, in particular with late summer precipitation of the prior year. Therefore, albeit summer drought has a negative effect on stemwood formation and tree growth, reduction of tracheid diameter size can protect L.sibirica trees against hydraulic failure and mortality. Vulnerability of larch tree growth and regeneration, even though adaptation mechanisms, increases necessity of conservation of moisture-limited Inner Asian forest against anthropogenic factors to minimize the unavoidable influence of harsh climatic condition.
Keywords: land use, forest fragmentation, climate warming, stem increment, hydraulic architecture, Larix sibirica, Mongolian forest-steppe, tree-ring width
 
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