Jug Handle Cove, Ecological Staircase

Jug Handle Cove, Ecological Staircase

by | Jan 17, 2022

Jug Handle Cove is a California State Natural Preserve consisting of a series of ancient marine terraces called the Ecological Staircase at the mouth of Jug Handle Creek that exhibit different stages of ecological succession, about 5 miles (8 km) south of Fort Bragg and 5 miles (8 km) north of Mendocino, California. The cove is named after Jug Handle Gulch, which was named in 1941 because the old road that crossed it made a turn in the shape of a jug handle. Marine terraces are prominent landforms along the Pacific coast of northern California and while these are common features, erosion has rendered them indistinct except in rare places like Jug Handle State Natural Reserve. Marine terraces are elevated wave-cut platforms formed as a result of sea-level fluctuations superimposed on tectonic uplift. The principal driver of regional tectonic uplift at Jug Handle Cove is the seismically active plate boundary between the North American Plate and the Pacific Plate at the San Andreas Fault which lies about 3.5 miles (5.6 km) offshore. The North American Plate initially overrode the oceanic crust of the Pacific Plate, and the subduction zone then shifted motion and is now a dominantly right-lateral transform fault. However, slight variation in plate motion vectors gives rise to a small amount of compression perpendicular to the fault which is responsible for the ongoing uplift of marine terraces along much of the California coast. The exposed bedrock is part of a terrane called the Franciscan Complex that was scraped, bent, buried, exhumed, and eventually smeared against the North American continent. The bedrock consists mainly of a partially metamorphosed sandstone called greywacke composed of quartz and feldspar grains incased in a clayey matrix that was heated and compressed. This segment of coastline has been uplifting for about 500,000 years at an average rate of 0.8-1.2 inches (2-3 cm) per century. During the Pleistocene, sea level fluctuated with the growth and decay of continental ice sheets so that sea level was lower during periods of glaciation and higher during interglacial periods. Waves are constantly eroding the shoreline and gradually developing nearly horizontal wave-cut platforms. Over millennia, these platforms were uplifted creating the terraces now visible along the coast. Each terrace at Jug Handle Cove has been above water about 100,000 years longer than the level below it.

The terraces have been inhabited by humans for thousands of years and evidence of the Mitom Pomo, or Mtom-kai Pomo, on the North Coast dates back 3,000 years. Although the main Mitom villages were located near present-day Willits, the Mitom made periodic visits to the coast to gather food. They hunted large and small game, caught fish and shellfish, and gathered seaweed and various seeds. Beginning in the 1850s, the Mitom lifestyle changed drastically with the influx of American settlers following California statehood. Diseases took a heavy toll and logging camps displaced seasonal villages situated at the mouths of rivers. The Mitom were forced to give up their lands and move to reservations. In 1850, the San Francisco-bound brig Frolic sank north of what is now Point Cabrillo, and the salvagers noticed the endless stands of redwood forests. Two years later, a sawmill was built near the mouth of Big River and settlers started arriving. The first Euro-American settler in the area was Siegfried Caspar, a German trapper who lived and worked near what would later become known as Caspar Creek, about 1 mile (1.6 km) south of Jug Handle Creek. In 1860, William H. Kelley and William T. Rundle bought 5,000 acres (2,023 ha) of forest land in the Caspar Creek basin, founded the Caspar Lumber Company, and built a second sawmill at the mouth of Caspar Creek. In 1861, Jacob G. Jackson was taken on as a partner, and by 1864, he had taken over the lumber company. Jackson bought more timberland along Jug Handle Creek, and under his leadership, Caspar Lumber Company became one of the most successful logging enterprises on the Mendocino coast. In 1874, the company built a mule-drawn tramway between the sawmill at Caspar and Jug Handle Creek. The tramway was later converted into a standard-gauge railroad that became the Caspar Creek Railroad. In 1884, a wooden trestle 160 feet (49 m) high was built over Jug Handle Creek. The trestle collapsed in the earthquake of 1906 but was soon rebuilt and remained in operation until 1945. By the mid-1940s,  the old-growth timberlands were severely depleted and in 1947, the State of California bought nearly 50,000 acres (20,234 ha) of forest land from the Caspar Lumber Company. During the 1960s, conservationist John Olmsted worked with Dr. Hans Jenny on a conservation campaign to protect the area. In 1962, a forest reserve of 250 acres (101 ha) was established to protect the pygmy forest growing on the 3rd marine terrace above Jug Handle Creek, and in 1969, it was designated a National Natural Landmark by the National Park Service. However, Jug Handle Creek displayed the whole evolutionary history of this part of the northern California coast, and land developers were aggressively pursuing access to the lower terraces. In 1970, the non-profit California Institute of Man in Nature purchased the land with borrowed funds and in 1975, the land was transferred to the state and along with parcels owned by Caspar Lumber Company, the Pacific Holiday Lodge Corporation, Save the Redwoods League, and others became Jug Handle State Natural Reserve in 1977.

The marine terraces at Jug Handle State Natural Preserve represent an example of soil development and ecological succession famous among plant ecologists. Although each terrace has evolved from the same parent rock of greywacke sandstone, each has been weathered for different lengths of time creating different soil types, and consequently are supporting different plant communities. All 5 terraces form what is known as the Ecological Staircase and a trail of 2.5 miles (4.0 km) traverses the first three terraces. The lowest terrace supports three plant communities including the North Coast Bluff Scrub, the Coastal Prairie, and Bishop Pine Forest. This entire terrace was formed at the same time and the three vegetation types reflect differences in the physical environment based on distance from the ocean. The North Coast Bluff Scrub community found along the edge of the seacliff consists of perennial low-growing shrubs adapted to strong winds and ocean salt spray by growing low to the ground. The Coastal Prairie is dominated by grasses, wildflowers and blackberries. Most of the common grasses were introduced and have dominated the landscape due to past history of plowing and grazing livestock by early settlers. The Bishop Pine Forest is not common in California. Unlike most conifers, this pine does not open its cones and distribute its seeds when they are mature. They release their seeds only when the cones are exposed to intense heat. The second terrace is away from the salt-laden breezes of the ocean and is dominated by redwood trees. Redwoods have a limited distribution, occurring only along the coast between southern Oregon and central California where summer fog and moderate temperatures prevail. This tree can live for about 2,000 years and the tallest redwood measures 368 feet (112 m) tall and 12.5 feet (4 m) in diameter. The third terrace exhibits a unique pygmy forest of 5-10 feet (1.5 to 3.0 m) tall cypresses and pines and dwarfed shrubs of rhododendron, manzanita, and huckleberry. This rare plant community occurs only in a few sites where marine terraces and their soil surfaces have remained flat during half a million years of geological uplift. The soils here are 1,000 times more acidic than soil found in the redwood forest. Heavy winter rains have leached iron and other soil nutrients from the surface of the ground and washed them down to the subsoil. The iron, soluble under acidic conditions, combines with eroding bedrock to form a dense hardpan 18 inches (46 cm) below the surface. Extremely acidic conditions and poor soil fertility, coupled with shallow hardpan formation, contribute to the stunted, sparse growth of the Pygmy Forest. Read more here and here. Explore more of Jug Handle Cove and the Ecological Staircase here:

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About the background graphic

This ‘warming stripe’ graphic is a visual representation of the change in global temperature from 1850 (top) to 2021 (bottom). Each stripe represents the average global temperature for one year. The average temperature from 1971-2000 is set as the boundary between blue and red. The color scale goes from -0.7°C to +0.7°C. The data are from the UK Met Office HadCRUT4.6 dataset. 

Credit: Professor Ed Hawkins (University of Reading). Click here for more information about the #warmingstripes.

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