Bohrer Relies on Virtual Forests to Elucidate Real Ones



bohrer copy.jpgWith the aid of time spent among simulated trees, Gil Bohrer, a graduate student in civil and environmental engineering from Israel, is getting a better handle on how wind flows through the forest. Inside his virtual world, trees can be moved around or made transparent and air currents of differing temperatures appear as brightly colored, undulating masses.



A member of professor Roni Avissar’s lab, Bohrer is one of the first at the Pratt School to capitalize on the Duke Immersive Virtual Environment (DiVE), a theater-like enclosure that surrounds users with computerized virtual reality images projected onto the walls, floor and ceiling. Specialized tracking sensors allow the computer to pinpoint the user’s location within the space, to adjust the perspective accordingly.

Bohrer’s imaginary forest starts with careful measurements of a real one. A computer program then translates that information into images that can be projected onscreen; a leap that makes what would otherwise be a complicated array of numbers into a visual pattern that can be understood more readily.

Bohrer’s goal is to incorporate higher-resolution information about ground cover and the structure of forests–— data gathered from biologists working in the field--into already computationally intensive climate models of the atmosphere.

He first grew interested in the DiVe as a presentation and communication tool, he said.

“Because I work at the interface of different disciplines, it’s easy and more attractive to take people there to show them the forest, air flow, the wind pattern,” Bohrer said. “It makes it much more intuitive.”

He soon realized other scientific benefits to loading his data into the DiVE.

“The classic way to handle a terabyte of numbers is to average, but in doing that you can lose the spatial patterns,” Bohrer said. “There’s no simple way to handle spatial information if you don’t know in advance what pattern you are looking for”.

“Yet our brains are very good at pattern recognition. Working in the dive you can begin to understand patterns and dynamics that you wouldn’t other wise notice. Every now and then, you get a cool new idea.”

So far, Bohrer has found that winds tend to blow more strongly upward over shorter trees than taller ones, a finding he can take back with him to the forest for further study. New understandings, such as this, can help to unravel which trees are most likely to get their progeny to clearings where they can grow and or suggest what buffer is required to prevent genetically engineered trees from intermixing with those in the wild, he said.

It might also have application to the dispersal of seeds or spiders, or even germ warfare, he added.

With his model nearly complete, Bohrer will soon travel to the rainforest of Panama. There he will meet up with collaborators studying the dispersal of seeds. The study will allow him to validate the utility and accuracy of his model, he said.

Avissar and Bohrer are co-authors of two funded grant proposals to continue this line of investigation: a three-year grant from the USDA entitled "Dispersal of viable GM pollen" and a two-year NSF grant entitled "Seed dispersal by wind and plant recruitment in tropical forests –— an interdisciplinary investigation across multiple scales.”

After completing his doctorate, which he anticipates within the year, he said he will pursue an academic position anywhere in the world.