Deciduous
A shrub or tree that drops its leaves after the growing season; not evergreen.

Dendrochronology
The use of tree rings to establish the date of wood found in dwellings.

Desert Pavement
A natural residual concentration of wind-polished, closely packed pebbles, boulders, and other rock fragments, mantling a desert surface where wind action and sheetwash have removed all smaller particles, usually protecting the underlying finer-grained material from further erosion.

Desert Varnish
See rock varnish.

Detritus
Small particles of dead organic matter.

Dike
A tabular sheet of intrusive igneous rock that cuts across the structure of the intruded rock or cuts massive rock.

Disjunct
A local population geographically separated from other populations of the same species.

Diuretic
A diuretic increases water loss from body tissues and thereby increases the secretion and discharge of urine.

Diurnal
Active during the day.

Dome
A smooth, rounded mass of slickrock, often resembling a petrified sand dune.

Dome Tent
Dome tents come in many shapes, sizes, and pole configurations. Many have arched ceilings for greater headroom, freestanding setup, and quick pitching.

Domed Cup
A cup-shaped next completely covered or arched over.

Dorsal
Pertaining to the back or upper surface of the body.

Dorsolateral
Pertaining to the area at the junction of the back and the side.

Down Fill
A sleeping bag fill with maximum warmth for minimum weight and packed size. It is more expensive and slower to dry than synthetic alternatives.

Dryloft
Sleeping bag shell material that is windproof and highly water-resistant, but doesn't breathe (move moisture) as fast as most taffeta or microfibers.

Duck
Two or three small rocks piled one on top of the other to be used as a trail marker." See also Cairn and Monument.

Dugway
A road or trail carved into a cliff or steep slope. The Dictionary of the American West defines "dugway" as "a road or trail going through a high land form which is dug out of the land form or excavated into the land form or excavated into the land form to provide a path for transport." It is also described as a path scraped out of a steep hillside allowing cattle and wagons to travel the hillside.

Dutch Oven
A heavy metal pot with a cover used around camps to bake and prepare other delicious meals. There is an art to good Dutch Oven cooking and some spend their lives perfecting their tasty dishes. Often a complete meal can be prepared in one Dutch Oven.