News

National Climate Assessment released today

National Climate Assessment released today

Clark contributed to the Forests chapter: Earth’s climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities. The impacts of global climate change are already being felt in the United States and are projected to intensify in the future—but the severity of future impacts will depend largely on actions taken to reduce greenhouse gas emissions and to adapt to the changes that will occur… [read the report]  

Ecology: Tree water balance drives temperate forest responses to drought

Ecology: Tree water balance drives temperate forest responses to drought

The amount of water available to a tree determines its susceptibility to drought.  It has been one of the big unknowns in predicting responses to climate change. Here we show that it can be measured:  We apply this model to multiple seasonal droughts with tree transpiration measurements to demonstrate how species and size differences modulate moisture availability across landscapes. The depletion of individual moisture reservoirs can be tracked over the course of droughts and linked to biomass growth and reproductive…

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Ecosystem interactions control spring green-up, published in Remote Sensing of Environment

Ecosystem interactions control spring green-up, published in Remote Sensing of Environment

A warming climate is changing the pace of spring green-up.  Using remote sensing and a new approach that quantifies the rate of green-up, Seyednasrollah et al show that green-up is fast in the mountains and relatively insensitive to temperature anomalies, while slow development in warm, coastal forests can respond to temperature swings.  Confirming experimental evidence, this study shows that spring is compressed in cold climates, delayed in onset but then rapidly progressing to full leaf expansion. Conversely, mountainous forest green-up is more…

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Mycorrhizal fungi and seedlings change with tree successional status

Mycorrhizal fungi and seedlings change with tree successional status

Now out in Ecology: Arbuscular mycorrhizal (AM) fungi in the soil may influence tropical tree dynamics and forest succession. The mechanisms are poorly understood, because the functional characteristics and abundances of tree species and AM fungi are likely to be codependent. We used generalized joint attribute modeling to evaluate if AM fungi are associated with three forest community metrics for a sub-tropical montane forest in Puerto Rico.  (read more …)

National drought assessment honored

National drought assessment honored

On Thursday, December 8, Jim Vose, project leader of the U.S. Forest Service Integrated Forest Science accepted the Chief’s Award – one of the highest honors in the Forest Service — in the category of “Sustaining Forests and Grasslands.” Vose accepted as leader of a team that the award honored for “understanding the impacts of drought on the nation’s forests and grasslands: providing a scientific foundation for effective management responses.” read more… The National Assessment was led by Jim Vose, Jim Clark, Charlie…

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GJAM in Ecological Monographs

GJAM in Ecological Monographs

Probabilistic forecasts of species’ distributions, abundances, and traits require models that accommodate the joint distribution of species and attributes based on combinations of continuous and discrete observations, mostly zeros…  early view here, pdf here clarkms, appendixs1

ISBA announces best poster award

ISBA announces best poster award

The EnviBayes section of ISBA this year has granted two best posters awards at the ISBA World Conference in Forte Village (June 13th – 17th, Cagliari, Italy).  Joint Species distribution modeling: dimension reduction using Dirichlet processes by Daniel Taylor-Rodriguez, postdoc at the Department of Statistical Science Duke University, with Kimberly Kaufield from North Carolina State University, Erin Schliep of University of Missouri, James Clark and Alan Gelfand of Duke University. The paper is accepted at Bayesian Analysis, bayesanaly2016.

It works: predicting multiple traits from environment

It works: predicting multiple traits from environment

early view in Ecology Trait analysis aims to understand relationships between traits, species diversity, and the environment. Current methods could benefit from a model-based probabilistic framework that accommodates covariance between traits and quantifies contributions from inherent trait syndromes, species interactions, and responses to the environment… read more

Berdanier in Tree Physiol: Predictive models for sap flux

Berdanier in Tree Physiol: Predictive models for sap flux

Predicting whole-tree water use requires models that accommodate the variation in sap flux between wood types and by depth into the tree. We develop a method for scaling-up flux observations. As an illustrative example, we predict sap flux for a forest in North Carolina, quantifying changes in water use with tree species and size. We include computer software for generating whole-tree flow estimates with other observations in Excel® and the R programming language. treePhys_berdanier2016 treePhys_berdanier2016Suppl

National Drought Assessment released

National Drought Assessment released

full report … provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA). Produced every 4 years, the NCA evaluates the effects of global climate change on forests, agriculture, rangelands, land and water resources, human health and welfare, and biological diversity, and it projects major trends.  press release  

Drought and slow tree death published in Ecological Applications

Drought and slow tree death published in Ecological Applications

A new article published in Ecological Applications by Berdanier and Clark about forests and drought in the Southeast US. It is featured by the Nicholas School of the Environment and ClimateWire. The article can be found here: Aaron Baird Berdanier and James S. Clark In press. Multi-year drought-induced morbidity preceding tree death in Southeastern US forests. Ecological Applications. http://dx.doi.org/10.1890/15-0274.1 http://www.esajournals.org/doi/10.1890/15-0274.1