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  1. Northern Tree Habitats - Geophysical Institute

    Jun 26, 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 …

  2. More on Why Tree Trunks Spiral | Geophysical Institute

    Jun 12, 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 …

  3. Trees as Earthquake Fault Indicators | Geophysical Institute

    Jun 26, 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 …

  4. The largest black spruce in Alaska | Geophysical Institute

    Aug 16, 2010 · The tree leans uphill, and its trunk is 45 inches around. When I hugged it, I could barely clasp my hands together. The largest black spruce in Alaska is a lucky tree, because its …

  5. Tree Rings and History | Geophysical Institute

    Jun 26, 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 …

  6. The secret life of red squirrels | Geophysical Institute

    Nov 27, 2024 · Stan Boutin has climbed more than 5,000 spruce trees in the last 30 years. He has often returned to the forest floor knowing if a ball of twigs and moss within the tree contained …

  7. Burls and Human Cancer | Geophysical Institute

    Jun 26, 2025 · Photograph of a section cut from a tree with 5 burls that simultaneously grew at the same level on the tree. Annual growth rings can be followed around the tree trunk at center …

  8. Feltleaf willows: Alaska’s most abundant tree | Geophysical Institute

    May 25, 2023 · The most plentiful moose food in the state — and probably Alaska’s most numerous tree — is the feltleaf willow, which was once called the Alaska willow. As its name …

  9. Tree line changes on the Kenai Peninsula - Geophysical Institute

    Feb 6, 2008 · The gradual change in tree line is one of many that people have noticed on the Kenai Peninsula in recent years. The most obvious is the 1980s-to-1990s Spruce bark beetle …

  10. Trees for a Cold Climate | Geophysical Institute

    Apr 1, 1993 · Back on the ground, I did a little research on why so few tree types grow naturally in the neighborhood. Winter's extreme cold easily eliminates some tree species hardy elsewhere. …