The Staircase, a strip about 0.8 kilometer (0.5 mile) wide extending from the shore inland along Jughandle Creek some 5 kilometers (3 miles), is a series of five marine terraces that demonstrate, as nowhere else on the North American continent, long-term coastal landscape evolution. The first and lowest terrace is approximately 100,000 years old; the fifth is probably older than 500,000 years.
Carved by the sea during the interglacial periods, the terraces were elevated by gentle earthcrust movements. In other parts of the State further south, where marine terraces were formed nearer the San Andreas fault, most have been tilted and eroded away. Though the five terraces are more or less in evidence along a 32-kilometer (20-mile) stretch of the Mendocino coast, at Jughandle Creek the terraces are roughly of the same width and well-preserved.
On the upper terraces, weathering and the leaching action of the percolating rainwater have impoverished the soil and made it highly acidic. In level areas where an impervious iron-hardpan has developed at a depth of 45 to 50 centimeters (18-20 inches), it restricts root growth and impedes the flow of nutrients and water, resulting in the dwarfing of the vegetation. Trees dwarfed are the Mendocino cypress, Cupressus pygmaea, Bolander pine, Pinus contorta var. bolanderi, and Bishop pine, Pinus muricata. A cypress one meter (3 feet) tall may be 100 years old. Other dwarfed species include California rose-bay, Rhododendron macrophyllum, salal, Gaultheria shallon, Fort Bragg manzanita, Arctostaphylos nummularia, and California huckleberry, Vaccinium ovatum.
On the first terrace, 15-25 meters (50-80 feet), grassland predominates, with local stands of Bishop pine, giant fir, Abies grandis, and Sitka spruce, Picea sitchensis. (The wind-dwarfed Picea stand on the headlands is the southernmost seaside occurrence.) These trees are found on the forepart of the second terrace, 40-55 meters (125-175 feet), as are localized grasslands. In the level center portion there is a "proto-pygmy forest" with full-sized Bolander pines and cypress and an acid-tolerant undergrowth. On the dunes backing the terrace, redwood and Douglas fir, Pseudotsuga menziesii, predominate. The third terrace, 70-90 meters (225-300 feet), marks the transition to the pygmy forest which covers half the terrace. On this terrace, as on the fourth, 105-130 meters (350-425 feet), and fifth, 175-200 meters (575-650 feet), full-size trees grow on the slopes and dunes adjacent to the pygmy forest.
Jughandle Creek has the features of a drowned valley. At the northeast boundary of the Staircase there is a sphagnum bog. Plants endemic to the Staircase are the cypress, Bolander pine and manzanita. The rare sedge, Carex californica, is found here too. There is an endemic insect, Heifer's blind weevil, Raymondinemis helferi. Along the coastline there are a number of rich and varied tidepools.
Integrity: Logging and grazing have occurred during the past 100 years. Efforts are being made to have the entire Staircase declared a National Monument. Currently some 120 hectares (300 acres) lying within the Jackson State Forest have been designated a National Landmark.
Use: Research, educational, observational.
Ref: Jenny, Hans, 1973. Pygmy Forest Ecological Staircase. Privately published.
Inventory of California Natural Areas
Revision © 2009 Steven Louis Hartman