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  1. Cottonwood and Balsam Poplar | Geophysical Institute

    Dec 4, 2025 · The Klukwan giant holds the national record for black cottonwood diameter. Its nearest rival, a tree near Salem, Oregon, does hold the national height record. The Klukwan giant belies the …

  2. Northern Tree Habitats - Geophysical Institute

    Dec 4, 2025 · Interior Alaskan forests have only six native tree species: white spruce, black spruce, quaking aspen, balsam poplar, larch (tamarack) and paper birch. Northern Canadian forests have all …

  3. Visit to an exotic tree plantation in Alaska | Geophysical Institute

    Jun 18, 2021 · The two-acre exotic tree plantation is part of a much-larger “boreal arboretum” on the UAF campus, which mostly consists of native spruce, birch, aspen, poplar and willow trees. Having …

  4. The Turkey and the Tambalacoque Tree - Geophysical Institute

    Nov 14, 1990 · The problem was the decline of the tambalacoque tree, a once common and useful source of timber for the island residents. Only thirteen of the trees remained, and they were sickly …

  5. More on Why Tree Trunks Spiral | Geophysical Institute

    Nov 20, 2025 · I eventually found a tree with a spiral lightning mark and it followed the spiral grain exactly. One tree, of course, proves nothing. "But why should the tree spiral? More speculation here: …

  6. Tropical Fossils in Alaska | Geophysical Institute

    2 days ago · A 20-inch fossil palm leaf that once waved over a tropical forest in Alaska 45-60 million years ago. The fossil was found in rocks near the Malaspina Glacier. Photo from the U.S. Geological …

  7. Witches' Broom | Geophysical Institute

    Dec 4, 2025 · Witches' broom on spruce trees is caused by a rust disease (a kind of fungus disease). The rust lives on the spruce tree throughout the year. Each spring, small yellow pustules appear on …

  8. Trees as Earthquake Fault Indicators | Geophysical Institute

    Dec 4, 2025 · Then using tree ring dating methods, it may be possible to date earthquakes occurring before historical records were kept. The ability to identify and date very large earthquakes occurring …

  9. Tree Rings and History | Geophysical Institute

    Dec 4, 2025 · A tree's age can be easily determined by counting its growth rings, as any Boy or Girl Scout knows. Annually, the tree adds new layers of wood which thicken during the growing season …

  10. Black Spruce | Geophysical Institute

    Dec 4, 2025 · Black spruce, unlike some other trees, tend to produce seed annually or nearly annually. They start bearing cones at about age 15. Once black spruce seed cones mature, they may remain …