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  1. Northern Tree Habitats - Geophysical Institute

    Apr 13, 2026 · 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. Tree Rings and History | Geophysical Institute

    Feb 12, 2026 · 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 …

  3. More on Why Tree Trunks Spiral | Geophysical Institute

    Apr 13, 2026 · 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: …

  4. 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 implies, the feltleaf …

  5. The Pinhole: Nature's Lens | Geophysical Institute

    Jul 10, 1972 · Sunlight passing through minor apertures between tree leaves is focused like the rays in a pinhole camera (and, just as with a simple lens, the image is upside-down).

  6. 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 …

  7. Bark beetles take Connecticut-size bite out of Alaska | Geophysical ...

    Feb 26, 2004 · Knowing that, forest managers might be able to anticipate an outbreak and plan tree harvests ahead of the beetles or try preventative measures that might work on small outbreaks, such …

  8. 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 newborn red …

  9. Cottonwood and Balsam Poplar | Geophysical Institute

    4 days ago · 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 …

  10. Tamarack -- Not A Dead Spruce | Geophysical Institute

    Apr 13, 2026 · It is not possible to foretell if tamarack may some day become a commercial crop, but one thing is certain: the "spruce that dies" each fall has some unique qualities that make it a …