Tag: terrain

A landscape of widely spaced trees with grazed grassland beneath — neither forest nor field but the ancient hybrid of both. Created by centuries of grazing and pollarding. Wood-pastures contain some of the oldest trees in Europe because the trees were never felled, only pollarded.

A stream that flows only in the wet season, when the water table rises high enough to feed it. In summer the bed is dry chalk or gravel. Common in the chalk country of southern England, where villages named Winterbourne line valleys that are rivers half the year and footpaths the other half.

The entire area of land that drains water to a single point — a river mouth, a lake, a confluence. Every drop of rain that falls within a watershed eventually reaches the same destination (or soaks into the ground trying). Watersheds are the natural units of hydrology: they are defined not by political boundaries but by topography — the ridgelines that divide one drainage from the next. The word also means a turning point, which is fitting: a watershed ridge is the point where water decides which way to go.

A broad, flat, sandy channel in the desert through which water flows intermittently — wider and less defined than an arroyo, often braided, with a surface of loose sand and gravel. Washes are the rivers of the desert, present in form even when absent in flow. Desert plants concentrate along their edges, drawing on the subsurface moisture that lingers after floods. A wash is a river's ghost, or its promise.

A shallow, seasonal wetland that fills with winter rain on top of an impermeable hardpan layer, holds water through spring, and dries completely by summer — leaving a cracked, bare depression that gives no sign of what it held. In the weeks between filling and drying, vernal pools support an extraordinary community of life found almost nowhere else: fairy shrimp, tiger salamanders, specialized wildflowers that bloom in concentric rings as the water recedes. Most of California's Central Valley vernal pools have been destroyed by development and agriculture. The ones that remain are among the most endangered ecosystems on the continent.

The slow, large-scale rising of a portion of the earth's crust — driven by tectonic compression, magma intrusion, or the removal of weight (such as the melting of an ice sheet). Uplift is the force that builds mountains, raises coastlines above the sea, and exposes marine fossils on mountaintops. It operates on timescales that make it invisible to any single human life, but its evidence is everywhere: tilted sedimentary layers, raised beaches, river terraces perched high above the current channel. The Himalayas are still rising. Scandinavia is still rebounding from the weight of ice that melted 10,000 years ago.

An earthquake. The word carries a different weight than its English equivalent — less clinical, more physical, closer to the body's experience of the ground shuddering beneath it. In California and the American Southwest, temblor is used interchangeably with "earthquake" in both journalism and conversation, a linguistic inheritance from the Spanish-speaking culture that named the landscape first.

 A field of broken rock that has fallen from the cliff above and accumulated at its base. Larger than scree — individual rocks range from grapefruit-sized to refrigerator-sized. Crossing a talus field is an exercise in choosing which rocks to trust.

The vast belt of boreal coniferous forest that encircles the Northern Hemisphere — spruce, fir, larch, and pine stretching from Scandinavia across Siberia and from Alaska across Canada. The taiga is the largest terrestrial biome on earth, and its interior is among the least populated landscapes outside the polar ice. Winters are long and brutal; summers are brief, warm, and plagued by insects. The word names the immensity.

 A shallow, elongated depression in the landscape — either natural or human-made — that collects and infiltrates water. In permaculture and land management, a swale is a ditch dug along a contour line with a berm on its downhill side, designed to capture rainwater and let it soak into the soil rather than running off. The word applies equally to natural low spots in coastal dunes and to carefully engineered earthworks.