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  1. Northern Tree Habitats - Geophysical Institute

    Jun 12, 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. Tree Rings and History | Geophysical Institute

    May 1, 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 …

  4. Trees as Earthquake Fault Indicators | Geophysical Institute

    Jun 12, 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 …

  5. Witches' Broom | Geophysical Institute

    Jun 12, 2025 · In interior Alaska and some parts of Canada, witches' broom (an abnormal outgrowth of branches of the tree resembling the sweeping end of a broom), is commonly …

  6. Burls - Geophysical Institute

    May 22, 2025 · Burls, spherical woody growths on the trunks of spruce, birch and other trees, are commonly found throughout wooded parts of Alaska.

  7. 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. …

  8. Rock redwoods in Sutton, stone bird tracks in Denali

    Feb 10, 2011 · The twin stems of a 55-million year old fossil tree resting in the soil near Sutton, Alaska. Photo by Chris Williams. Tracks of a large, crane-like bird that walked in the Denali …

  9. 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 …

  10. Burls and Human Cancer | Geophysical Institute

    Jun 12, 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 …

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