**Description of Pinus monophylla**:
– Pinus monophylla is a small to medium-sized tree reaching 10–20m tall with a trunk diameter of up to 80cm.
– The leaves are usually single, stout, 4–6cm long, and grey-green to blue-green.
– The cones are acute-globose, 4.5–8cm long, ripening yellow-buff when 18–20 months old.
– Seed cones open to 6–9cm broad when mature, holding seeds on the scales after opening.
– Pine nuts are dispersed by the pinyon jay, with good seeds being dark brown.
**Subspecies and Genetics**:
– Three subspecies: monophylla, californiarum, and fallax.
– Differences in needle stoutness, color, resin canals, and stomatal lines among subspecies.
– Hybridization with Colorado pinyon and Parry pinyon observed.
– Classification based on single-needle fascicles sometimes challenged by environmental factors.
– Two-needled variant of single-leaf pinyon found in Mojave National Preserve and northern Baja California.
**Prehistoric Occurrence**:
– Fossil evidence shows distinctive ranges of single-needled pinyon over the last 40,000 years.
– Expansion of Pinus monophylla in Utah and Nevada since the Pleistocene.
– Presence of southern California variety in Joshua Tree National Park for the last 47,000 years.
**Uses and Symbolism**:
– Edible pine nuts collected by Native Americans and various animals.
– Roasted cones also edible; seeds harvested for personal use.
– Cultivated as an ornamental tree for native plant and wildlife gardens.
– Designated as Nevada’s state tree in 1959.
– Description attributed to John C. Frémont.
**Deforestation**:
– Pinyon groves cut down for charcoal production in the mid-19th century.
– Imported coal replaced locally produced charcoal with the advent of railroads.
– Efforts to clear woodlands for increased livestock forage peaked in the 1950s.
– Destruction of Pinyon woodlands seen as ecological and cultural vandalism by some.
– Concerns raised by cattle ranchers about decreased livestock forage in grazing rangeland.