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In the northern California coast, nature has created her own forest of bonsai trees. Instead of pots, she used iron cemented hardpan for containers. Instead of scissors for pruning, she stunted the trees with a highly acid, infertile soil and a layer of hardpan that holds too much water in the winter. Her tools were ocean waves, heavy rainfall, and uplifting caused by the grinding together of continental plates.
The story of the pygmy forest is part of a larger story of an ecological staircase. It's a story best told at the Jug Handle State Reserve, 2 miles south of Fort Bragg on State Route 1 in Mendocino County. Here a 2-1 / 2 mile nature trail leads visitors on a self-guided tour up nature's terraces from the seashore.
From the headlands of the first terrace, you can gaze down upon the ocean as it deposits sand and gravel on a future terrace. The earth has been steadily uplifting this coast. "What's so rare is that the land was uplifted flat, so you have soils that are a million years old," says Teresa Sholars, Professor at the College of the Redwoods in Fort Bragg. During this time, sea level has lowered and risen with advances and retreats of continental glaciers. As the sea lowers, it drops sediments on a level beach. As it rises, the sea pounds away at the now-higher beach that will have formed sea cliffs. Each of the five terraces along Jug Handle Creek is about 100 feet higher and 100,000 to 200,000 years older than the one below it.
On the lowest terrace, grasses and wildflowers like California poppy and coast lupine have enriched the old beach sediments. This coastal prairie is maintained by salt spray from the ocean that keeps trees at bay.
By the second terrace, the soils have nurtured coniferous forests. Then a leaching process called podzolization, common to coniferous rain forests, depletes the soil.
Rainwater draining slowly on the flat terraces picks up acids from falling needles and carries iron and alkaline minerals down through the soil, forming a hardpan.
"The acid soil and the hardpan are really creating the pygmy forest," says Sholars. In fact, this soil is almost as acid is vinegar – the most acidic soil in the world.
By the third terrace, after 300,000 to 600,000 years of leaching, the contrast is startingling. As you walk through a luxuriant forest of towering redwoods and Douglas Firs, you'll see an incredible shrinking act by the trees around you; you've finally arrived at the pygmy forest.
Here the ground is an ill-clad dingy white, with little more than lichens and sparse leaf litter for clothing. Rarely found wild outside the pygmy forest, pygmy cypresses and bolander pines, along with the widespread bishop pine, eke out their livings in this depleted soil. Where the hardpan is less than a foot deep, a 2-foot high, half-inch diameter cypress may be a mature 80 to 100 years old. Other vegetation in the pygmy forest consists mainly of shrubs of the acid-loving heath family, including showy pink rhododendrons and huckleberries.
Another good place nearby to explore pygmy forests – especially with young children – is in Van Damme State Park. Here also a self-guided tour brochure provides interpretation along a short trail.
Perhaps the oddest thing about the pygmy forest is that it is a climax community. On the terraces, the process of ecological succession – the gradual replacement of one plant community by another – proceeds from grassland to pine forest to pygmy forest. But it ends there – with the pygmies. No other plant community will take its place as long as conditions stay as they are, the ecological staircase will bear its forests of bonsai trees through time.
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