The overall goal of the project is to study, apply and evaluate the different technologies and methodologies used in assessing water status of forest tree species and ecosystems. In Greece, climate change is expected to alter water availability caused by, either the increase in frequency, intensity and duration of drought events or by flooding. The assessment of water status of forest species is therefore crucial for the (1) characterization of the water balance at tree and ecosystem levels, and (2) understanding of water availability-driven ecological processes, such as inter- and intra- specific competition, forest establishment and growth.

Various methods and techniques that measure water status at various scales ranging from leaf to ecosystem levels are applied such as:

• Gas exchange

• Soil and plant water status

• Sap flow rates and signatures of various heavy isotopes

These methods are used at the experimentally planted Pinus ponderosa trees at the Nebraska National Forest (NNF) USA and at the experimental site of a typical Mediterranean pine, Pinus halepensis, in Greece. The objectives are:

(1) the comparison of the water balance of the two pine species and ecosystems, each being representative of different climatic region (continental in Nebraska vs. Mediterranean arid conditions in Greece)

(2) testing the applicability of the methodology developed and tested in Nebraska under different water conditions in Greece.

The experimental site that has been established for the above purpose, is established in a natural Alepo pine forest of Stavronikita in Kassandra Chalkidiki, Greece. The site is comprised of:

• A fully equipped automatic meteorological station.

• A 22 m meteorological tower on which an open path CO₂ and H₂O analyzer, an air temperature and relative humidity sensor and a sonic anemometer are in operational mode.

• Sap flow measuring system on four trees.

Data obtained from this research will allow us to make landscape level estimates of evapotranspiration, validate ecosystem models and develop models that predict larger scale and longer-term impacts of climate change on ecosystem processes e.g. water availability, carbon sequestration, hydrological cycle and fire risk.

Composition of the research teams:

(1)   Greek side

Project leader:     Dr. Kalliopi Radoglou
Research team:    Mr. George Chalyvopoulos
                             Ms. Stavroula Stolaki
                             Dr. Mariangela Fotelli
                             Dr. Argyro Zerva

(2)   American side

Project leader:     Dr. Tala Awada
Research team:    Dr. David Wedin
                             Dr. Edwin Harvey
                             Dr. Xinhua Zhou