STSM Scientific Report
The ecophysiological field equipment for forest ecosystems monitoring
STSM Information
COST Action: FP0903 "Research, monitoring and modelling in the study of climate change and air
pollution impacts on forest ecosystems"
COST STSM Reference Number: COST-STSM-FP0903-10925
Period: 2012-07-16 to 2012-08-05
STSM Applicant: Dr Vitas Marozas, Aleksandras Stulginskis University,Kaunas(LT) ,
vitas.marozas@asu.lt
Host: Rainer Matyssek,Technische Universität München,Freising(DE), matyssek@wzw.tum.de
Purpose of the STSM
The climate change and pollutants has consequences in the functioning of forest ecosystems. The
combination between climate change and pollution has an effect on gas exchange at different levels.
It is important to improve our knowledge of the responses of trees at the different levels and to be
able to explain the processes of trees response to climate change and pollutants. Different types of
measurements are used to address those responses: gas-exchange, sap-flow and others.
The purpose of the visit to Chair for Ecophysiology of Plants, Research Department Ecology and
Ecosystem Management, Center of Life and Food Sciences Weihenstephan, Technische Universität
München was to get familiar with experimental ecophysiological methodology (gas exchange,
xylem sapflow etc.), its theoretical background, to learn new techniques, to study literature for
further research; to get familiar with ongoing research projects in host institution and develop new
collaboration.
Description of the work carried out during the STSM
During the STSM the following ecophysiological methodology and equipment was studied:
The gas exchange system LICOR 6400. The LI-6400 is LI-COR’s third generation gas exchange
system. The LI-6400 is an open system. The measurements of photosynthesis and transpiration are
based on the differences in CO2 and H2O in an air stream that is flowing through the leaf cuvette
(LI-6400 Manual, 1998). The theoretical background of the gas exchange system was studied and
practical experience of measuring was gained.
Sap flow measurement methodology and equipment. During visit the installation of thermal
dissipation probe transpiration sensor in the forest was acquainted. The Thermal Dissipation Probe
(TDP) transpiration sensor measures sap velocity which is converted to volumetric flow rate. The
basic TDP probe has two thermocouple needles inserted in the sapwood, the upper one containing
an electric heater. The probe needles measure the temperature differences between the heated
needle and the sapwood ambient temperature below. The variable and the maximum temperature
difference at zero flow provide a direct conversion to sap velocity.
During the STSM it was opportunity to visit the group of Gerhard Wieser of The Research and
Training Centre for Forests, Natural Hazards and Landscape in Innsbruck. The sap flow measuring
system installed in alpine environment conditions was studied.
Other system used in the experiment in the growth chamber implemented by Dr. Karl-Heinz
Häberle was familiarized. The EMS 62 sap flow system includes the EMS 62 controlling module,
sap flow sensor SF 60, radiation shield, connecting cables and a datalogger. Measuring principle is
based on the stem heat balance method with external heating and internal temperature sensing
(Lindroth et al. 1995, Čermák et al. 2004). The sensor consists of two similar cylindrical parts. Each
part wraps the stem with insulation foam. One part contains linear heating elements which are
pressed to the stem by soft foam. A needle thermocouple is inserted to the stem in radial direction at
the level of upper edge of heating elements (in direction of water movement). Second cylinder has
no heaters and it just covers the reference needle thermocouple located with respect to the thermal
symmetry. The water passing along the sensor is warmed and the temperature increase is measured
with thermocouples as the water leaves the heated space. The feedback loop of EMS 62 module
maintains the temperature difference at preset level 2 K or 4 K. Then, the input power is directly
proportional to the amount of water passing the sensor in terms of kg/hr (EMS 62 sap flow system
instruction manual, 2010).
Stable isotope method. The use of stable isotopes in ecology has expanded tremendously in the last
decade. Natural abundance isotope can be used to find patterns and mechanisms at the organism
level, to trace food webs, follow whole ecosystem nutrient cycling in ecosystems. Isotopic analysis
has become almost a standard tool for physiologists, ecologists, and other scientists studying
element or material cycling in the environment. The access to isotope ratio mass spectrometers has
increased and prices for analysis have decreased. This is chance for ecologists from a broad range
of disciplines, not necessarily trained as isotope chemists, to use stable isotope analysis in their
research (Michener and Lajtha, 2007). During the visit it was opportunity to join to the advanced
ecophysiology course and get acquainted with all steps of use of stable isotope δ18O method
detecting different water sources used by trees.
Description of the main results obtained
The experience of use of Li-COR gas exchange system in the field surveys.
The experience of use of different kinds of sap flow measurement systems.
Introductional study of the use of the stable isotope method in forest ecosystems.
STSM visit resulted establishment new relations that lead forward collaborations in the field of use
of stable isotope in dendroecology and air pollution bioindication.
Description about how the results contribute to the Action aims
Visit of STSM will contribute to the scientific objectives of a COST Action FP0903. The main
objective of the Action is to increase understanding of state and potential of forest mitigation and
adaptation to climate change in a polluted environment, and to reconcile process oriented research,
long-term monitoring and applied modelling at comprehensive forest research sites. The other
objectives of the Action include add value to the current forest monitoring and improve data quality
for extrapolation to larger scales; increase the multidisciplinary knowledge of current state and
future potential of forest mitigation and adaptation to climate change in a polluted environment;
improve European research infrastructure and capacity building; enhance the role of European
forest research in the global community; improve transnational cooperation in the field of forest
protection.
The techniques and methodology learned during this STSM, developed ideas for future
collaboration will contribute to the aims of the COST action.
Confirmation by the host institution of the successful execution of the STSM
Copy of the confirmation is attached.
Authorization to post the report at the Action website
I authorize the posting of this report to the Action website.