
Cottonwood and Balsam Poplar | Geophysical Institute
2 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 …
Northern Tree Habitats - Geophysical Institute
Mar 26, 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 …
More on Why Tree Trunks Spiral | Geophysical Institute
Mar 26, 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: …
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 …
Tropical Fossils in Alaska | Geophysical Institute
2 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 …
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 …
Burls - Geophysical Institute
Mar 12, 2026 · Burls, spherical woody growths on the trunks of spruce, birch and other trees, are commonly found throughout wooded parts of Alaska.
Bark Beetles in Spruce Trees | Geophysical Institute
Mar 26, 2026 · Bark beetles attack spruce trees in early summer. These brownish black beetles are common throughout Alaska and Yukon Territory where they kill trees by boring through the bark and …
Witches' Broom | Geophysical Institute
Mar 26, 2026 · 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 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).