About 77 results
Open links in new tab
  1. Northern Tree Habitats - Geophysical Institute

    Feb 6, 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. Cottonwood and Balsam Poplar | Geophysical Institute

    Feb 6, 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 …

  3. More on Why Tree Trunks Spiral | Geophysical Institute

    Feb 6, 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: Foliage …

  4. Tree Rings and History | Geophysical Institute

    4 days ago · 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 and thin …

  5. Burls - Geophysical Institute

    4 days ago · Burls, spherical woody growths on the trunks of spruce, birch and other trees, are commonly found throughout wooded parts of Alaska.

  6. Tropical Fossils in Alaska | Geophysical Institute

    4 days ago · 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 U.S. Geological …

  7. Trees as Earthquake Fault Indicators | Geophysical Institute

    4 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 …

  8. Witches' Broom | Geophysical Institute

    4 days ago · 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 pustules appear on the …

  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 millions of tiny …

  10. 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 …