Tree-Ring Talk

Blue Intensity in Pinus sylvestris: application, validation and climatic sensitivity of a new palaeoclimate proxy for tree ring research

Minimum blue intensity measurements of resin-extracted Pinus sylvestris samples, are shown to provide a robust and reliable surrogate for maximum latewood density. Blue intensity data from fifteen trees, are reported relative to a standard blue-scale in a manner similar to grey-scale calibration in X-ray densitometry. The resulting time series are highly correlated with X-ray densitometry data generated from the same samples and preserve a high level of signal strength.

Remotely Sensed Land Surface Phenology of The Madrean Sky Islands and Beyond

This research is exploring geospatio-temporal data to develop an assessment of changes in landscape scale phenology (Timing of biological events such as green-up and flowering) for vegetation along elevation gradients for mountain sky islands in the drylands of the Southwest US and Northern Mexico. The main goal is to better understand the variability in climate and vegetation green-up relationships as they vary seasonally and interannually and along the elevation and latitudinal gradients.

Tree-Rings, Documents, and Oral Histories in Cebolla Creek, New Mexico

The Cebolla Creek area of west-central New Mexico is an isolated area of lava flows, pinyon-juniper forests, and flat valley bottoms that is part of the El Malpais National Conservation Area. Completely depopulated today, in the early 20th century the area was home to Navajo, Hispanic, and Anglo populations who hunted, gathered, and farmed the canyon’s resources. Research over the past five years has illuminated aspects of interaction and land-use by these groups during a critical time in New Mexico’s history.

Forest carbon cycle responses to atmospheric and environmental change

Environmental scientists are challenged to understand the effects of a range of environmental perturbations to the Earth system from global phenomena like climatic or atmospheric change to land use transformations. Ecologists can also observe, collect, record and store more data, more frequently and more extensively than ever before. One approach to address these problems and opportunities is to fuse observations with mathematical models to infer responses to environmental change. The seminar will introduce some of the projects I've been working on in the last few years.

Extracting insight on forest carbon cycles through observations and modeling

I will describe some of the observational approaches we have deployed to measure the net rate of carbon dioxide exchange between a forest ecosystem and the atmosphere. The observed net exchange of CO₂ represents the sum of several components of gross CO₂ exchange, which in turn represent fundamental tree and soil metabolic processes. One challenge we have had is: how do we extract insight about how these component processes might be responding to environmental change at various scales from an observed time series?

Subscribe to Tree-Ring Talk