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  1. Cottonwood and Balsam Poplar | Geophysical Institute

    Jul 31, 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 …

  2. Northern Tree Habitats - Geophysical Institute

    Jul 31, 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 …

  3. The war within the aspen leaves | Geophysical Institute

    Jul 31, 2025 · They think the fierce, silent conflict has probably benefited both the insect population and a tree that’s been under siege in Interior Alaska for a long time. Leaf miners …

  4. More on Why Tree Trunks Spiral | Geophysical Institute

    Jul 31, 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 …

  5. Burls - Geophysical Institute

    Jul 31, 2025 · Burls, spherical woody growths on the trunks of spruce, birch and other trees, are commonly found throughout wooded parts of Alaska.

  6. Witches' Broom | Geophysical Institute

    Jul 31, 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 …

  7. 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 …

  8. Tree Rings and History | Geophysical Institute

    Jul 31, 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 …

  9. 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 …

  10. Tropical Fossils in Alaska | Geophysical Institute

    Jul 31, 2025 · 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 …

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