Objectives

The main objectives of this research project are:

to characterize the ecophysiological mechanisms of BVOC emissions by means of both growth chamber and in situ measurements at different heights in the canopy;
more
to characterize BVOC emissions at stand level during different phenological periods in the growing season;
more
to propose improved emission algorithms based on these observations and on previously reported measurements for these tree species, and to incorporate these algorithms in a BVOC emission model to provide improved BVOC emission estimates.
more

More specifically, following steps are proposed in order to achieve these goals:

(1) design of an optimal strategy for growth chamber measurements of BVOC emissions based on GC-MS;
(2) intercomparison of different techniques (PTR-MS and GC-MS) to measure BVOC emissions in growth chamber conditions;
(3) characterization of BVOC emissions in growth chamber of beech ( Fagus sylvatica L.), Douglas fir ( Pseudotsuga menziesii ) and Norway spruce ( Picea abies ) during different phenological conditions relevant for the species (e.g. leaf development, fully leafed period, leaf senescence and leafless period);
(4) characterization of the relationship between BVOC emissions and CO₂and water vapour exchanges in growth chamber experiments;
(5) characterization of the relationship between BVOC emissions and environmental variables like air temperature, air relative humidity, and soil drought stress;
(6) characterization of BVOC emission at different heights in the canopy of a full grown beech in natural conditions during different phenological phases during the growing season;

More specifically, following steps are proposed in order to achieve these goals:

(1) design of an optimal strategy for BVOC emission measurements at stand level based on PTR-MS;
(2) BVOC emission measurements at stand level from deciduous (beech, Fagus sylvatica L.) and coniferous species (Douglas fir, Pseudotsuga menziesii and Norway spruce, Picea abies);
(3) analysis of the emission behaviour of these tree species during different phenological conditions relevant for the species (e.g. leaf development, fully leafed period, leaf senenescence and leafless period);
(4) characterization of the relationship between BVOC emissions, climatic variables and physiological fluxes (photosynthesis, respiration, transpiration);

More specifically, following steps are proposed in order to achieve these goals:

(1) critical analysis of BVOC dynamics observed at the different experimental levels (growth chamber, canopy, stand) in function of the measured variables, coupling with CO₂ and water vapour exchange and for the different phenological phases;
(2) scaling of the results obtained at the level of the growth chamber and canopy level to stand level based on an existing BVOC emission model; and
(3) development of improved emission algorithms for estimating annual BVOC emissions by forests in Belgium, based on results obtained under (1) and (2).