Tree-Ring Talk

White fir as an invasive species in the Pinaleño Mountains

Proliferation of shade-tolerant species during the period of fire exclusion has been put forth as a major driver of increased severity of fire and insect outbreak regimes in mixed-conifer forests of the interior West.  Both fire regimes and insect defoliator outbreak regimes are responsive to closed and multi-storied canopies.  Douglas-fir tussock moth (Orgyia pseudotsugae) and western spruce budworm (Choristoneura occidentalis), both major pests in interior West forests, are particularly responsive to the presence of white fir (Abies concolor).  However, quantitative studies chara

A Tree-Ring Smorgasbord

A traditional Swedish smörgåsbord contains many dishes, where you usually sample a little of each. In this talk, I will serve a tree-ring based smorgasbord, based on my career as a tree-ring scientist over the last twenty years or so. I will guide you through various environments and research projects across the world, with some special focus on the long-term research conducted in the central Scandinavian Mountains.

The Influence and Interactions of Humans, Climate, and Fire on Mixed Conifer Forest Dynamics in the Sierra Nevada, USA

Fire is recognized as keystone process in Sierra Nevada dry mixed conifer forests and it has been drastically reduced by decades of fire exclusion. Frequent fire is thought have created a fire-grained mosaic of multi-aged forests that developed as a result of self-organizing processes where burn patterns and forest structure interact to maintain a fine-grained mosaic over time.

Tree-Rings and the Coupled Carbon Cycle Climate System

Forest ecosystems are one of Earth’s primary biomes: they provide a diverse suite of ecosystems goods and services crucial for societal well-being and play a crucial role in our planet’s carbon cycle. However, great uncertainties exist regarding the quantification, dynamics, and driving processes of terrestrial carbon cycling, and thus also the fate of forested regions. Dendrochronological methods are remarkably well suited to investigate forest carbon cycling on long and temporally precise time-scales and at tree-level to continental spatial scales.

The Power of Paleo: How records of the past help us understand global warming, El Niño, and drought

The risks we face from a changing climate result from a combination of human-caused and natural variability. We can better prepare for future conditions if we fully understand natural patterns of climate variation and how those patterns have behaved in the recent past. Yet the instrumental record of climate variation is sparse and short – inadequate to characterize, for example, the multidecadal processes associated with megadroughts and fluctuations in global temperature, or the intrinsic variability in remote regions of the tropical Pacific critical to the El Niño system.

Global Change in the Great Lakes Region 14ka to 6ka: The Story from an Ancient Wood Project

The deglaciation of North America had profound affects on climate, hydrology, flora, humans, and megafauna. Pollen records have traditionally been the primary source of information about environmental change during deglaciation, but tree rings offer potential for insight into high-resolution variability of weather/climate during this period. Wood preserved in the Great Lakes area by various fortuitous circumstances has been systematically collected over the last decade to improve our environmental understanding of the period from ca. 14,000 to 6000 years ago.

Spatial and temporal dynamics of forest water-carbon exchange in Northeastern U.S.

Here, we use annually resolved δ13C tree rings measurements across a NE-USA forest network to derive intercellurar CO2 (ci) response caused by increasing atmospheric CO2 (ca) trends and climate change over the past two decades, concurrent with direct long-term measurements of ecosystem carbon and water exchange. We find a substantial increase in ci suggesting that for each one 1 ppm increase in ca, ci increased proportionally or at the same rate. This response corresponds to static or moderate increase in water use efficiency-the ratio of carbon gain to water loss, respectively.

The Dendroarchaeology of Pueblo III Kiva Construction on Mesa Verde, Colorado

For a century, dendrochronology has provided Southwestern archaeology with the most precise and accurate prehistoric chronological controls available in the world. Being accurate to the calendar year, lacking statistical uncertainty, and having seasonal resolution, tree-ring dating provides the backbone of Southwestern chronology, especially on the Colorado Plateau. In addition, comprehensive dendroarchaeological data illuminate important aspects of the behavior of the people who produced the structures with which the wood specimens are associated.

Meet the Artists of “Marking Time to a Changing Climate”

The artists of the current exhibit in the Bannister Building, Marking Time to a Changing Climate, will describe their work.

Please note that there is a public tour of the art exhibit in the half hour before the talks.

Tree rings go global: the use of large networks in environmental change research

A major goal of current environmental change research is to add more realism to projections of ecosystem functioning in a warming world. This requires a large-scale understanding of plant responses to climate variability and change. Forests in particular are a major player in the coupled biosphere-climate system and critically determine terrestrial carbon cycling. Studying tree growth on multiple spatiotemporal scales is thus a prerequisite to develop robust benchmarks e.g. for vegetation model simulations of forest productivity.

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