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During the second project phase (2001-2004) the following work packages are carried out:
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- The micrometeorological measurements at Kranzberger Forst are continued for providing basic data for B2 as well as the entire SFB.
- Quasi-continuous radiation measurements at 200 points initiated during the first phase are continued, with high time and spectral resolution (within PAR regime)aimed at investigating leaf metabolism, xylem flow, growth, space sequestriation and net C gain at intensively studied branches to be upscaled,in close cooperation with B4 and C3,for the entire stand.
- Quasi-continuous radiation measurements at 60 additional points within the ozone fumigation regime covering the entire UV-VIS-IR range, with high time and spectral resolution, aimed at validating the 3-D radiation model based on biomass distribution data provided by B1 and investigating relations between tree dimensions and biomass implemented by C3.
- Modelling of the PAR radiation field for the stand and its variations with time with possible applications for stand growth models (C3).
- Computation of vertical radiation gradients(extinction curves) for several spectral regions aimed at determining red/dark red ratios (phytochrome 660/730) and blue light fractions (cryptochrome) which vary with increasing depth in the stand.In cooperation with B4 and C3 their influence on photosynthesis and morphogenetic features, how related patterns of growth and architecture at these 60 points from the sun crown down to the shade crown regions change, are investigated.
- The continuous free-air ozone fumigation of 5 beech and 5 spruce crowns (2x ambient up to 150 ppb maximum) is continued during the entire vegetation periods 2001, 2002 and 2003.
- A micro-method for determining the real ozone deposition on plant surfaces is being developed in the laboratory and implemented in the experimental stand. The ozone diffusion from the thin stationary leaf boundary layer into the leaf via the stomata is modelled using conductivity data for the stomata provided by B4.
- The interactions of volatile hydrocarbons from natural and anthropogenic sources with ozone, under controlled ozone stress conditions, are to be investigated in a separate DFG project (RA 765/5-1), with emphasis on ethylene.
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