{'fraction_non_alphanumeric': 0.025611175785797437, 'fraction_numerical': 0.002328288707799767, 'mean_word_length': 5.099290780141844, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Hemlock: A Forest Giant on the Edge

Editor’s Note: Eastern hemlock (Tsuga canadensis) is an iconic tree species in northeastern forests and the Appalachian Mountains. It has faced peril in the past but is now faced with perhaps its most deadly threat—the invasive and devastating insect pest, hemlock woolly adelgid. In this new book, Harvard Forest director David Foster and several colleagues and scientific collaborators explore the history and ecology of and challenges to the majestic eastern hemlock. Presented here by permission of the publisher is an excerpt from Chapter Three: Prehistory to Present, written by Wyatt Oswald, David Foster, and Jonathan Thompson. In the previous part of the chapter the authors describe the process of extracting 3-inch-wide, 3-foot-long sediment cores from a pond for later paleoecological analyses of the material.