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  1. Cottonwood and Balsam Poplar | Geophysical Institute

    Jul 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 …

  2. Northern Tree Habitats - Geophysical Institute

    Jul 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 …

  3. Witches' Broom | Geophysical Institute

    Jul 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 …

  4. Tree Rings and History | Geophysical Institute

    Jul 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 …

  5. Trees as Earthquake Fault Indicators | Geophysical Institute

    Jul 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 …

  6. Trees for a Cold Climate | Geophysical Institute

    Apr 1, 1993 · Back on the ground, I did a little research on why so few tree types grow naturally in the neighborhood. Winter's extreme cold easily eliminates some tree species hardy elsewhere. …

  7. The largest black spruce in Alaska | Geophysical Institute

    Aug 16, 2010 · The tree leans uphill, and its trunk is 45 inches around. When I hugged it, I could barely clasp my hands together. The largest black spruce in Alaska is a lucky tree, because its …

  8. Burls - Geophysical Institute

    Jul 2, 2025 · Burls, spherical woody growths on the trunks of spruce, birch and other trees, are commonly found throughout wooded parts of Alaska.

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

    Jul 11, 2025 · 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 …

  10. 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 …

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