Modeling Forest Biotic Dynamics

As the earth’s climate changes, scientists are concerned about the effects these changes will have on the earth’s ecosystems. Regents Professor Peter B. Reich (Forest Resources, Institute on the Environment) and post-doctoral researcher Emily Peters (Institute on the Environment) specialize in discovering the impacts of these changes. The Reich group’s main area of focus is the part of central North America that includes Minnesota. In this part of the continent, several types of ecosystems converge, including boreal forests (forest consisting mostly of coniferous trees), temperate hardwood forests, oak woodlands/savannas, and grasslands.

MSI has been working with Professor Reich and Dr. Peters to develop a distributed computing framework for the parallel photosynthesis and evapotranspiration model (PPnET). PPnET allows researchers to efficiently use PnET-CN (a widely used and well-tested ecosystem model) to simulate the effects of many simultaneously changing environmental factors on forests over large geographic areas. MSI is providing hardware, software, and consulting support to this project. Dr. Shuxia Zhang, in the HPC Operations group, developed an MPI-based program that allowed parallel jobs to start and restart flexibly. This made allowances for the availability of software licenses at any given time, as well as the availability of compute nodes on the supercomputers. Dr. Zhang also developed script tools that verified data integrity and the success of hundreds of thousands of inputs.

The Reich group used PPnET to simulate ecosystem responses to changes in climate and atmospheric CO2 concentrations in the Great Lakes region of North America. This simulation had 1 km spatial resolution, consisting of 200,000 forest grid cells. The computing time, which would take 25 days for serial runs – and would therefore be impractical – was reduced to six hours using 96 cores on a Linux cluster. This research has been published in the Canadian Journal of Forest Research (“Potential Climate Change Impacts on Temperature Forest Ecosystem Processes,” EB Peters, K Wythers, S Zhang, JB Bradford, PB Reich, Canadian Journal of Forest Research, DOI:10.1139/cjfr-2013-0013, published online July 17, 2013.)

Image Description:
Forest types with a 1-km grid resolution over the northern Great Lakes region of the United States, also known as the Laurentian Mixed Forest Province. This region includes six major forest types.
(Right) Map of changes in above-ground net primary production predicted from 1970 to 2100, under a high-emissions climate change scenario. 
©Canadian Journal of Forest Research, NRC Research Press (2013)

posted on October 9, 2013.

Update, October 28, 2013: The Minneapolis Star-Tribune published an article about climate change's effects on the north woods of Minnesota. Professor Reich and his project, B4WARMED, are discussed at the end of the article.

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