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  1. Northern Tree Habitats - Geophysical Institute

    Mar 12, 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

    Mar 12, 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. 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 invasion, …

  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. 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 …

  8. Pollen season arrives, blame the trees | Geophysical Institute

    May 7, 2008 · The airborne invaders are grains of tree pollen, specks so small that it would take eight of them to cover the period at the end of this sentence. The air is rich with pollen because spring is the …

  9. Trees as Earthquake Fault Indicators | Geophysical Institute

    3 days ago · 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 …

  10. Cottonwood and Balsam Poplar | Geophysical Institute

    Mar 12, 2026 · 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 …