Western Hemlock is the most abundant tree species in Southeast Alaska. It can reach an age of over 1,200 years, a height greater than 70 m (230 feet), and a diameter over 2.7 m (9 feet).
Wind is the primary cause of disturbance in the Pacific Coastal Temperate Rainforest of Southeast Alaska. Wildfires are infrequent and generally small due to the high rainfall, which ranges from 127 cm (50 inches) to over 508 cm (200 inches) per year.
Storms can windthrow large patches of timber, but in old-growth forest (generally over 300 years old), most openings are very small, averaging less than 0.8 hectares (2 acres). With small openings, the pattern of trees in mature forest is a mixture of sizes and ages.
The Western Hemlock tree in the photo has been broken by wind. Because bedrock is close to the surface resulting in thin soils and shallow roots, trees often are uprooted by the wind. Since this tree broke, we know its roots were strong.
It’s easy to focus only on the beautiful green forest of living trees when we walk in the woods. But both standing dead trees and logs on the ground are extremely important ecological parts of the forest.
Many wildlife species depend on dead wood for food, shelter, nesting, perching, and escape from predators. As you hike through the forest, take time to observe the many forms of dead wood. Look for the evidence of use by wildlife.
Like so many of the features of the forest, the values of dead wood also create high quality fish habitat.
Winter Sunrise: Gossamer cobwebs of mist rise from Gastineau Channel, floating south in the early morning air flow. View from the Douglas Bridge, that connects downtown Juneau to Douglas Island (see previous post for more about the bridge and cities).
The sun will rise another few degrees above the horizon, then drift west to disappear behind the Douglas Island mountains to the right by noon. A cloudless winter day, minus 5 C (23 F). Froze my fingers taking this vid.
It’s low tide: along the right side of the view, Douglas Island’s exposed tideflats show as a black shadow between the sunlit water and the snow above the high tideline. Gulls and shorebirds will be feeding here among the blue mussel-kelp beds, just as they do below the Douglas Bridge.
Dark, weighty clouds in the distance nearly hide the mountains of Admiralty Island. Although the wind is light here, the thinly banded clouds between the dark bank and the blue sky look like they could be shaped by higher winds, probably coming down Taku Inlet.
Gulls feeding on salmon eggs and carcasses, Juneau, Alaska. Chum Salmon (aka “Dog Salmon”) and Pink Salmon (aka “Humpies”) spawning in Sheep Creek estuary. CLICK THE PHOTO BELOW TO SEE VIDEO: 10 seconds into video, a chum salmon with red and purple stripes thrashes into shallows. Past this chum salmon out in the channel, see the humped backs of pink salmon in spawning frenzy.
Pinks and Chums are the only two species of salmon whose fry (newly hatched young) migrate immediately back to saltwater. They become “smolt”: their bodies and metabolism change so they can live in saltwater. The young of the other 3 species (Chinook, Coho, and Sockeye) stay in streams and lakes for 1 or more years before they go out to sea.
Once in the ocean, their life histories diverge. Pink salmon spend only 1 year feeding in saltwater, migrating back into the streams as 2-year-old adults, the smallest of the salmon at 2.2 kg (4.8 lbs.). Chum Salmon remain in the ocean for 2-4 years, so return as 3 to 5-year-olds. Their longer life of feeding and growing results in weights of 4.4 to 10.0 kg (9.7 to 22.0 lbs.)
The high protein-high fat salmon and their eggs are super-foods for predators like gulls, shorebirds, bears, and humans. As they die, the nutrients from their bodies feed aquatic and terrestrial plants and invertebrates from crab to insects in the Coastal Temperate Rainforest. These are critical habitats and migratory passages that require protection from pollutants, destruction, and blockage.