The science of Dendrochronology (derived from the Greek words for “tree – dendron” and “knowing the time – chronology”) is a set of techniques by which the annual growth layers of trees can be assigned to a definite calendar year. The history of changes in the tree’s environment is reflected in various properties of the tree rings. These properties include ring width, cell size, wood density, trace element composition, and concentrations of stable isotopes and radioactive isotopes. External environmental variables affect the physiological processes that control tree growth and leave a permanent record in ring properties.
Tree-ring series can be used to reconstruct past variations in precipitation, temperature, soil moisture, river flows, frequency of droughts, forest fires, major forest pest outbreaks, and other phenomena important to the management of natural resources and the natural and human environment. What can be reconstructed depends on those factors that limit growth. The reconstructions typically cover several centuries, but can occasionally extend to millennia and, as a result, be a valuable tool for researchers and managers in their quest to understand the variability of systems on timescales beyond the reach of conventional instrumental records. Such understanding can be especially important in forested regions in the Northern Hemisphere where general circulation models project considerably increased temperature as a consequence of increasing greenhouse gases.
In this course, the participants will be introduced to techniques of dendrochronology and conduct practical training sessions in the techniques. The instrumental and proxy records (tree-ring chronologies) will be used to place the climatic conditions faced in the management of trees, water, livestock, indigenous herbivores, and people and their needs in a proper long-term perspective. By understanding climate variability through time, managers and planners will be able to reduce the risk of failure in attaining the anticipated outcomes because of the changing characteristics of the climate. The interactions of participants at the summer course will spur research activities that lead to the more sustainable development of natural resources in the Northern Hemisphere Forest regions, and will also introduce students to dendrochronological techniques that may apply to any type of climate reconstruction and environmental management. The training, in particular, will strengthen the participants’ capability to directly apply dendrochronology in natural resources, hydrology, climatology, anthropology, archeology, and other fields in which improved knowledge of environmental variability is important.
The interactions should also increase the likelihood of future collaboration of researchers in Europe, the Middle East/North Africa, the USA, China, and other Asian countries. Forests of the Northern Hemisphere are a key component of resource management. The collaboration will benefit society by helping reduce the likelihood of future international stress due to resource shortages. In this context, dendrochronology can be used as a tool for environmental research and management. The attending students will also benefit from learning how to use this tool in improving their scientific and professional profiles. The findings of the summer course will be distributed to a wider audience through a course website whose location will be distributed on appropriate internet user forums.
Topics to be Covered
Chronology Development: Sample preparation, cross-dating (skeleton plots), ring-width measurement, standardization, and assessment of chronology quality;
Dendroclimatic Reconstructions: Identification and reconstruction of the climatic signal in tree rings;
- Dendroarchaeology: Case studies from North America and Jordan;
- Dendrohydrology: Regional drought reconstructions for the USA, Eastern Mediterranean, North Africa, and Colorado River reconstruction of annual flow;
- Dendroecology: Fire history and climate patterns in conifer forests of USA, North Africa, and Eastern Mediterranean;
- Dendroclimatology: Precipitation and drought index reconstructions in the eastern and western Mediterranean, Eurasia, and the USA;
- Role of Dendrochronology in natural resource management: Collaborative planning for water sustainability in the Eastern Mediterranean and North Africa.