For Polly Hill Arboretum director Tim Boland, the swift demise of his oak forest that spans the arboretum property has been literally startling. “I’d be outside in the collections this winter and I would just hear wha-BAM!” The trees, ravaged by a plague of caterpillar infestation that lasted just over three years from 2005 to 2008, are now hollowed and rotting, teetering toward collapse. “I used to think these trees would stand for the next 10 years or so. They won’t. Within the next three to four years they’ll all be down,” Mr.

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