Kristina Blennow
Visiting research fellow
Spatial Variation in Near-Ground Radiation and Low Temperature - Interactions with Forest Vegetation
Author
Summary, in English
The methodologies include the development and use of a digital image analysis system for hemispherical photographs, the use of Geographic Information Systems (GIS) and statistical methods, field data acquisition of meteorological elements, plant structure, growth and photosynthetic performance.
Temperature and amounts of intercepted direct radiant energy for seedlings on clear days (IDRE) were related to chlorophyll a fluorescence and the dry weight of seedlings. The combination of increased IDRE with reduced minimum temperatures resulted in persistent and strong photoinhibition as the season progressed, with likely implications for the establishment of tree seedlings at forest edges, and within shelterwood. For models of spatial distribution of low air temperature, the sky view factor was used to parameterise the radiative cooling, whilst drainage, ponding and stagnation of cold air, and thermal properties of the ground were all considered.
The models hint at which scales and processes govern the development of spatial variations in low temperature for the construction of corresponding mechanistic models. The methodology is well suited for detecting areas that will be frost prone after clearing of forest and for comparing the magnitudes of impacts on low air temperature of forest management practices, such as shelterwood and soil preparation. The results can be used to formulate ground rules for use in practical forestry.
Department/s
- Dept of Physical Geography and Ecosystem Science
Publishing year
1997
Language
English
Document type
Dissertation
Publisher
Lund University Press
Topic
- Physical Geography
Keywords
- light interception
- hemispherical photograph
- growth
- forest fragmentation
- fluorescence
- cold-induced photoinhibition
- GIS
- view factor
- radiative cooling
- frost protection
- agro-climatic mapping
- forest clear-cut
- local climate
- Microclimate
- Physical geography
- geomorphology
- pedology
- cartography
- climatology
- Fysisk geografi
- geomorfologi
- marklära
- kartografi
- klimatologi
Status
Published
Supervisor
- [unknown] [unknown]
ISBN/ISSN/Other
- ISBN: 91-7966-443-1
- ISRN: LUNBDS/NBNG--96/1132--SE
Defence date
31 October 1997
Defence time
10:15
Defence place
Main Lecture Hall, Department of Physical Geography, Sölvegatan 13, Lund
Opponent
- Kurth Perttu (Professor)