Tree-Ring Talk

Climate Change and Invasive Species as Agents of Evolution and the Use of a New Research Platform, The Southwest Experimental Garden Array, to Provide Genetics-Based Solutions to Assisted Migration and Other Global Challenges

Climate change, invasive species and other global challenges are agents of selection that are affecting the ecology and evolution of foundation plant species (cottonwood, pine, eucalypts).  These impacts cascade to affect whole communities of associated species and their ecosystem processes.  Using observational studies in the wild and common garden experiments we partition genetic and environmental variation and show how gene by environmental interactions are redefining communities composed of 1000s of species.  Using an array of common gardens where the same genotypes, populations and mul

Augmenting the Interior West Forest Inventory and Analysis Program with a Dense Network of Tree Ring Data

The Forest Inventory and Analysis (FIA) program of the USDA Forest Service has conducted state-by-state forest inventories for 80 years.  Because of an emphasis on individual states as inventory units, for most of the program history it was rare for contiguous areas larger than one or two states to be measured concurrently.  As a result, attempts to conduct details time-series analysis tended to be limited by confounding geographic bias.  When the FIA program converted to a new annual inventory system, starting in the late 1990s, issues with geographic and temporal bias were mostly eliminat

Adaptation to environmental variation in short-lived organisms: what can tree rings tell us?

Organismal survival can depend on response to environmental variation.  Several modes of response to environmental variation have been documented, including adaptive tracking, adaptive phenotypic plasticity and the evolution of so-called “bet hedging” traits.  I present empirical evidence that short-lived organisms, including the monocarpic herb, Lobelia inflata (Campanulaceae), adapt to environmental variation.  Genetic population differentiation among traits of five eastern North American populations of L.

The New Home of Tutankhamun: The Grand Egyptian Museum in Giza

The Grand Egyptian Museum (GEM) holds in trust for Egypt and the world a chronological statement for the ancient story of Egypt over the past 7000 years of history. Neighboring a timeless wonder, the Giza Pyramids, the new museum is to pay homage to eternal ancient Egyptian history, monuments, and treasures and hosting over 100,000 artifacts, around 5000 of which belong to the golden Pharaoh Tutankhamun. The project is conceived as an integration of a complex of museums and facilities capable of offering both educational and recreational opportunities.

Pinus nigra encroachment at high altitude in the Central Apennines (Italy)

In the central Apennines the treeline is usually composed by Fagus sylvatica L. forests located between 1500-1800 m a.s.l., whereas on some other sites it is replaced by extensive black pine plantations to reduce slope-erosion. On one hand the upward shift of beech forests is a very slow or blocked process, on the other black pine natural expansion has been documented well above its altitudinal range of 800 - 1500 m a.s.l.

LTRR seminar

Dendro & Egypt

The Egyptology Workgroup of the LTRR/Egyptian Expedition will present a series of brief illustrated lectures intended to update colleagues and interested members of the community on our current projects and research. Presentations have three related foci: graduate student thesis research (Egyptology), postdoctoral research (regarding artistic and linguistic trends with important chronological considerations), and collaborative research projects in progress and preparation (dendrochronology/dendroarchaeology).

Dendrochronological Sourcing of Timbers from the Great Houses of Chaco Canyon, New Mexico

The cultural history of Chaco Canyon is characterized by connections with distant landscapes. From utilitarian ceramics to prestige items, goods arrived in Chaco from all directions, and from great distances. Wood beams, necessary for the construction of the Great Houses, are no exception. Strontium isotopes have revealed that spruce and fir timbers were likely carried to Chaco from forested mountains ranges over 50 km away. Ponderosa pine is the predominant architectural timber species at Chaco, and presently grows at many upland areas and mountain ranges surrounding Chaco Canyon.

Quantitative reflectance of modern wildfire charcoals: Implications for the origin of sedimentary charcoal assemblages and inference of past wildfire regime shifts

To what degree are crown fires part of the meta-fire regime of Southwestern ponderosa pine forests over millennial timescales? Fire-scar records and calibrated fire-climate reconstructions suggest the role of crown fires may have been limited over the last 1500 years but high energy alluvial fan records may indicate elevated crown fire activity during severe droughts, peaking during the Mid-Holocene Altithermal and, perhaps, during the Medieval Climate Period.

Tree-ring δ13C tracks flux tower ecosystem productivity estimates in a NE temperate forest

We investigated relationships between tree-ring δ13C and growth, and flux tower estimates of gross primary productivity (GPP) at Harvard Forest from 1992 to 2010.  Seasonal variations of derived photosynthetic isotope discrimination (D13C) and leaf intercellular CO2 concentration (ci) showed significant increasing trends for the dominant deciduous and coniferous species.

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