Wednesday, August 24, 2016

Ancient Trees, Young Trees, the Forest Abides

Kathleen Sayce, August 22, 2016

Last Saturday I walked in the ancient red cedar grove on Long Island. I first saw this grove in the 1970s while timber cruising on the island for the refuge. Forty-one years later, these trees are as magnificent as they were then. Their habitat is as complex and multilayered. This stand is a climax forest, and it richly expresses the diversity of a climax forest in a coastal temperate rainforest biome.  

What has changed most is the forest around the cedar grove. 

This stand along the trail from the beach at Smokey Hollow was too dense with young western hemlock to see into 40 years ago. Today, you can see sky among the canopies, and there are mosses and ferns on the ground, with young shrubs starting to grow in some spots. 

In the 1970s, most of the island had been logged and was regrowing as naturally sprouted western hemlock trees in dense 'dog hair' stands. These were young, many less than forty years old, and they lined the roads like green walls. No sunlight reached the forest floor. One could not see into the stands from the roads. I cored a few of those hemlocks four decades ago, and their growth rings were tiny, a few millimeters per year or less. 

Forty-one years later, natural loss has thinned the hemlock stands by more than seventy-five percent, leaving behind more widely spaced living trees that are three times as tall with trunks correspondingly bigger. Ferns and shrubs are scattered on the ground. Mosses now carpet the ground. Another two hundred years, and these young stands will be approaching solid middle age. Western hemlock trees live around four hundred years. 

As the stands of hemlock age, other trees will seed in, including Douglas-fir, red alder, Sitka spruce and, of course, western red cedar. When we walked these roads last weekend, it was easy to see more than one hundred feet into the forest all along the road.

The trail into the cedar grove has also opened up in the past 40 years. Sunlight reaches the forest floor. Ferns are lush. Some trees are more than 12 inches dbh (diameter at breast height, 4.5 ft from the ground) now. 

In the cedar grove, meanwhile, a few trees have died, one or two snags have fallen, and otherwise, the grove looks very much as it did then. There are abundant mosses on the ground, on logs and in the trees. There are layers of ferns and shrubs. Some of the shrubs are more than ten feet tall. There are young trees, many are hemlocks, with a few others. There are dozens of mature cedars, 850 to 900 years old. The oldest living trees are around 1200 years old. Study these trees, and you can see the signs of old nurse logs, where living trees now seem to be on their toes, hollows showing at the ground level where their supporting nurse logs have rotted away. Lightning scars are visible on many trees, signs of historic damage. 

Every tree species has a different feel as an elder, and when in groves. Here in the island cedar grove, the ancient trees are each distinctly different in shape, but all have multiple dead tops, showing the candelabra form that is distinctive to the coast.

More strikingly, these trees live close to the coast, a few miles from the Pacific Ocean, and this proximity shapes their form. They aren’t very tall, around 200 feet in height. Cedars can grow more than 300 feet tall. Winter storms, high winds and salt in the air kill the growing tips. Cedars respond by growing new tips, forming in time a crown of dead and living tops in the shape of a complex candelabra––candelabra cedars. The large trunks, often more than ten feet in diameter, rise in huge columns to these woody crowns. Shrubs, ferns and young trees sprout from pockets of soil and moisture, often one hundred or more feet in the air. 

A refuge manager here in the 70s, Joe Welch once told me that he was worried that there were so few young cedars in the stand. Dr. Jerry Franklin, a forest researcher who visited the grove soon after, told him not to worry. The cedars live such long lives that to them, the hemlocks are just passing through. Sitka spruces live eight hundred years or more, as do Douglas-fir, so the tree species  balance is not skewed to hemlocks over millennia. Cedars have been here for thousands of years, and will remain a major presence in this grove. 

Cedars may stand dead for many centuries before they fall to the ground, and then take more centuries to decompose. Living around one thousand years, the decomposition process also takes around one thousand years. There are logs in the grove that have been on the ground for hundreds of years, and still have bark firmly attached. 

A magnificent western hemlock snag, with pileated woodpecker holes, and polypore fungi fruits.

It is satisfying to know that natural forest processes are dominant here as they have been for at least four thousand, perhaps eight to ten thousand years. These aren’t sequoias or bristlecone pines, to individually live several thousand years, nor are they redwoods, which can resprout from the ground after fire, and live on after major wildfires, growing a new trunk and fresh canopy of leaves on old roots. 

During my own lifetime, I have watched logging trucks on the road, first with old growth, then with old second growth, and then, younger and younger trees. The average age of a conifer log on a logging truck now is less than thirty years. Knowing that this small grove, less than 300 acres, is preserved, intact, functional forest is also comforting. The cedar grove abides.  

Monday, August 15, 2016

Red Tide on the Columbia River

Kathleen Sayce, August 15, 2016

In mid summer on the Columbia River Estuary a color change appears in the water, red to purple, and persists into early fall. It’s a natural red tide, when billions of single celled animals, ciliated protozoans, called Myrionecta rubra (also called Mesodinium rubrum) bloom.  The bloom is particularly striking from the high span over the shipping channel, on the south end of the 101 bridge near Astoria. It is not toxic, but it is very red. 

The band of purplish-red water is a colorful streak of Myrionecta rubra cells, seen from the Astoria-Megler bridge on August 14th, 2016. 

The cells are less than 100 micrometers long, and have two rows of cilia between two round body sections, which give this tiny animal the swimming dexterity of a jet fighter. They look like two round balls of different sizes stuck together. The beating rows of cilia allow it to jump ten to twenty body lengths in one movement, which would be like a 6-feet-tall human jumping sixty to one hundred twenty feet. 

Seen under the microscope, they spin, dash and turn with amazing speed. The red color comes from a red alga that lives inside the cell.  The algae cells are not permanent residents; each cell lives around 30 days inside the protozoan. There may be several algae cells in each Myrionecta organism, and carbon fixed through photosynthesis by the algae feeds the protozoan. 

During warm, sunny weather the blooms form in long streaks in the Columbia River Estuary between the jetties to above (east) of the Astoria-Megler bridge. Sometimes they also form in Youngs Bay, and can be seen on that causeway and bridge. In some years, the entire river looks like it’s running with blood instead of water. Most years, the bloom is in streaks surrounded by otherwise normal-colored water, green to gray to blue. 

One spectacular year in the 1990s, the Myrionecta bloom in local waters coincided with a dinoflagellate bloom, of Ceratium species. Dinoflagellates are often golden to warm red in color. That year, the dinoflagellates were golden orange. The combination of strong red-purple and gold  from billions of organisms of different colors in different parts of the river gave the water a very weird red-orange color combination. Ceratium organisms gathered in warmer shallow water, and Myrionecta tended to the deeper waters of the main channels, so the colors were blended together in some areas, and distinctly separate in others. Both blooms stopped as the storm season got underway that fall.  

This species prefers lower salinity water, and warm weather. August and September are the usual months to see the long red to purple streaks. Cool storms disrupt the bloom in fall, and by mid to late October, unless weather has been unusually calm, it’s gone again for the year. Individual cells turn up in plankton samples throughout the year, however, it's only late summer to early fall when their numbers rise into the billions and become visible to us. 

Myrionecta has been seen and collected in the surf zone along the north coast beaches in Oregon and south coast beaches in Washington, on each side of the river. It’s also been found in Willapa Bay, and the Willapa and Palix Rivers. 

In Alaska, residents say that when the fireweed blooms, summer is almost over. Here, when we see the red tide of Myrionecta rubra on the Columbia from the Astoria-Megler Bridge, we know fall is going to arrive in a few weeks.