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  1. 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 …

  2. 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 …

  3. The majesty and mystery of Alaska yellow cedar | Geophysical Institute

    Jul 23, 2021 · A tree near one of our campsites had a crack at its base through which we could pass the folded saw. Yet the tree was still alive, with just one rope of cambium — the outer bark that …

  4. 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 …

  5. Burls - Geophysical Institute

    Nov 20, 2025 · Burls, spherical woody growths on the trunks of spruce, birch and other trees, are commonly found throughout wooded parts of Alaska.

  6. 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: …

  7. 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 …

  8. Burls and Human Cancer | Geophysical Institute

    Dec 4, 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 and into each …

  9. Orange trees in the Alaska Range | Geophysical Institute

    Sep 3, 2020 · It was a tree disease known as spruce needle rust, which infects only the current year’s needles of white, black and Sitka spruce trees. The orange powder is composed of millions of tiny …

  10. Formerly Frosty Footing Causes Drunken Forests

    Sep 21, 1995 · By the unique pattern of the tree rings, they determined the tree began its fight to right itself after a thermokarst developed 120 years ago. The same thing that makes trees tipsy causes …