Lynn Canal biogeographic province is 42% glaciated, second only to Fairweather province, northwest of Glacier Bay. It has the most precipitous mountains and deepest waters of the Inside Passage, testament to erosive power of the glacier that once filled its namesake fiord. It has the fastest rate of glacial rebound of any province except Glacier Bay. As one result, uplift meadows and parkland are more abundant here than anywhere in Southeast (and the world). Major estuaries at Mendenhall, Herbert/Eagle, Cowee and Berner’s Bay are critical stopovers for migratory birds, and magnets for resident fish and wildlife.
Below is an aerial tour up the watery heart of this province, and a sampling of one of my favorite interpretive tools, repeat photography.
Flight to Haines with SEAL Trust
On June 5, 2013, I flew to Haines for surveys in Mud Bay with the Southeast Alaska Land Trust. Then-director Diane Maier generously allowed our charter pilot to detour off course so I could attempt retakes of several early Navy aerial obliques. As usual, I linked my photos to a GPS track in Robogeo.
Asx’ée, twisted tree (Eagle River) is the square mile where I became a naturalist in the 1980s, and is probably the reason for my obsession with detecting change. In the 1929 original, no spruces were yet visible on the outer ridge. Today they’re beginning to close ranks into a solid line, but meadow-capture may retard final closure into the 22nd century.
Asx’ée rebounded about 5 feet in the interval between these photos. But while river-influenced sloughs on the left migrated like a whipped rope, those within the goosetonge flats have remained remarkably stable. This can probably be attributed to the tenacious and often deep rhizome mat of salt-marsh halophytes, which binds the banks and “locks-in” the lacing channels.
This was Jilkáat Kaagwaantaan country, trapped all the way to the headwaters (Goldschmidt & Haas, 1998); however, Thornton (2012) Our grandparents’ names on the land, gives no Tlingit name. My retake is at lower elevation and farther to the north than the original.
Former USFS forester Tom Pence told me back in the 1980s that cottonwoods were growing 5 feet per year on the Endicott delta, and in logged karst on the upland point enclosing its north end (not shown in retake). In addition to forest advance in the foreground fan and beach ridges, there’s been dramatic colonization by cottonwoods on the distant flood plain. At Endicott Gap, ~15 miles west on the border with Glacier Bay National Park, Glacial Lake Adams once spilled over into Endicott River. The largely barren flood plain in 1929 was probably a legacy of this glacial dominance, healing over during the subsequent 8 decades.
Oddly, Thornton (2012) gives no Tlingit name for the Davidson—one of the most photographed glaciers in Southeast Alaska. My retake is considerably south of the 1906 and ~1960 views, but serves to show how much the terminus has receded since its Little-Ice-Age march to tidewater. On the 1906 photo by Wright I’ve added dotted lines on the right-side trimline. When ice reached this elevation, it also extended out to the farthest moraine. Because land was depressed several feet at that time, high tides probably lapped the ice on the northeastern front..
Considerable reforestation has occurred not only on deglaciated ground, but on raised former tideland. The outwash channel shifted north between 1948 and 1960. In the 1894 image by McArthur, ice had receded only a little from the LIA maximum. The same pattern prevailed in Juneau-area glacial retreat—slow at first, then accelerating ~1910.
Wulix’áasi Héen, cascading river, is fed by Meade Glacier—like the Davidson a major ice feature for which, unfortunately, I can find no Tlingit name. The Lukaax.ádi must have been intimately familiar with this northernmost ice-river draining the Juneau Icefield, because it advanced about to the corner visible in the distance on the 1929 oblique. Hiking up valley for trapping and goat-hunting would have been easy on the barren river bars, at least during low flow.
My retake lines up the opposing points fairly well, but was at lower elevation. Although considerable recession has occurred, this is still an active glacial river, with a mostly-barren flood plain. Only in a few protected side pockets and on some point bars has substantial reforestation occurred. An example is the cottonwood stand marked in middle distance.
In contrast, the glacially rebounding estuary has seen about 400 acres of more uniform forest advance. Unlike the river bars, this uplifted delta is now entirely free of water-related disturbance.
My retake of this classic early Haines scene is just slightly south of the original. The most dynamic area is Sawmill Wetland, site of today’s airport, visible way upriver. In 1929 there was apparently little vegetation anywhere on the flats, which were all swept by Chilkat River during high flows. What was then an overflow channel became Sawmill Creek, heading near the Lukaax.ádi village of Yandeist’akyé.
Dan and Gretchen Bishop and I studied succession on this wetland in the early 1990s, in relation to proposed taxiway construction. I’d love a chance to go back and revisit those studies.
Showing all 2 results