Tree-Ring Talk

Annually Resolved Forest Biomass Growth in Europe – Observed and Simulated Climate Sensitivity

In light of current and projected increases in global temperatures and atmospheric CO2 concentrations throughout the 21st century, it is crucial to understand the long-term effects of environmental changes and climatic variability on the terrestrial carbon cycle. To complement traditional methods of quantifying carbon cycle dynamics such as forest inventories, eddy-covariance measurements and remote sensing, we established a biomass-oriented tree-ring network along a large climate gradient across Europe.

Coupling radial growth and reproduction in Mediterranean and tropical forests

Negative interannual relationships between tree growth and reproduction may reflect allocation trade-offs or may simply result from dependence on different climatic conditions. Interspecific variation in how tree growth and reproduction respond to interannual climate variation provide insights into how tree species composition may be altered under future climate change. Long-term growth, reproduction and climatic records were used to investigate how climate, tree radial growth and reproduction patterns are related in in two different regions, Mediterranean and tropical.

‘Blue rings’ in multi-century bristlecone pine from near upper tree limit in California and Nevada

Our strongly replicated collections of dendrochronologically dated tree-ring material of bristlecone pine (Pinus longaeva) from multiple locations in the high mountains of the Great Basin and nearby regions constitute a unique environmental archive. Their tree-ring widths have yielded multi-millennial histories of moisture availability, tree growth, temperature and tree-line elevation as well as of the chronology and influence of climatically effective, explosive volcanic eruptions.

Reconstruction of Ob River, Russia, discharge from ring widths of floodplain trees

The Ob River is the third largest Eurasian river supplying heat and freshwater to the Arctic Ocean. These inputs influence water salinity, ice coverage, ocean temperatures, ocean circulation, and ultimately the global climate system. Variability of discharge of the Ob River on long time scales is poorly understood because gaged flow records are short.

Drought, heat and cold stress...and bugs: the Mediterranean joy of tree life

Mediterranean forests provide multiple challenges and opportunities to dendroecology. I will cover some of these questions by presenting three examples we have studied. These study cases include different stressors such as drought-induced dieback affecting silver fir forests, winter drought involving Scots pine stands, and defoliations caused by the pine processionary moth. Tree rings allow addressing these disturbance factors following a retrospective approach. However, I will emphasize that such observational studies must be complemented by other sources of information (e.g.

Co-varying influences on growth of eastern U.S. deciduous hardwood trees

The assumption that a single dominant climatic factor (e.g. water balance or temperature) in extreme sites and locations limits tree growth allows for annually resolved climate reconstruction.

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