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  1. Northern Tree Habitats - Geophysical Institute

    Dec 11, 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. Cottonwood and Balsam Poplar | Geophysical Institute

    Dec 11, 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 …

  3. Trees as Earthquake Fault Indicators | Geophysical Institute

    Dec 11, 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 …

  4. The majesty and mystery of Alaska yellow cedar | Geophysical …

    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 …

  5. Tree Rings and History | Geophysical Institute

    Dec 11, 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 …

  6. More on Why Tree Trunks Spiral | Geophysical Institute

    Dec 11, 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 …

  7. Witches' Broom | Geophysical Institute

    Dec 11, 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 …

  8. Boreal owls perform by daylight | Geophysical Institute

    Mar 20, 2024 · The late biologist Dave Klein attached the nest box to a black spruce tree north of the University of Alaska Fairbanks ski trails many years ago. In search of a mate, the owl sings …

  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 …

  10. Tropical Fossils in Alaska | Geophysical Institute

    Dec 11, 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 …