Question: Which tree species is found in Nevada County, California and is the most widely distributed pine species?

Context paragraphs:
Tecomella: Tecomella undulata is a tree species, locally known as rohida in Urdu "روہیڑا" found in Thar Desert regions of India and Pakistan.  It is a medium-sized tree that produces quality timber and is the main source of timber amongst the indigenous tree species of desert regions of Shekhawati and Marwar in Rajasthan.  The trade name of the tree species is desert teak or Marwar teak.

Wolf Creek (Nevada County, California): Wolf Creek is a waterway in Nevada County, California, US.  The creek is 25 miles long.  The watershed, approximately 78 sqmi , is heavily mined.  Most of the creek is situated in the lower montane zone.  Its altitude ranges between 3000 ft (headwaters at Banner Mountain, also known as Banner Hill) to 1200 ft (confluence with the Bear River).  Vegetation in the valley varies from alpine pines at higher elevations, to blue pines at mid elevations, and ponderosa pine mixed with evergreen forests at lower elevations.  From 1850 to 1950 gold was mined in the rich formations of the Mother Lode in the heart of Banner Mountain.

Pinus taeda: Pinus taeda, commonly known as loblolly pine, is one of several pines native to the Southeastern United States, from central Texas east to Florida, and north to Delaware and southern New Jersey.  The wood industry classifies the species as a southern yellow pine.  U.S. Forest Service surveys found that loblolly pine is the second most common species of tree in the United States, after red maple.  For its timber, the pine species is regarded as the most commercially important tree in Southeastern US.

The Jack Pine: The Jack Pine is a well-known oil painting by Canadian artist Tom Thomson.  A representation of the most broadly distributed pine species in Canada, it is considered an iconic image of the country's landscape, and is one of the country's most widely recognized and reproduced artworks.

Nevada County Narrow Gauge Railroad: The Nevada County Narrow Gauge Railroad (NCNGRR) (nickname: "Never Come, Never Go") was located in Northern California's Nevada County and Placer County, where it connected with the Central Pacific Railroad.  The Nevada County Narrow Gauge Railroad Company incorporated on April 4, 1874, and was headquartered in Grass Valley, California.  After two years of construction, passenger and commercial rail services began in 1876 and continued until 1943.  The 22.53 mi line ran from Colfax, north through Grass Valley to Nevada City.  At one time, the railroad was notable for having the highest railroad bridge in California, the Bear River Bridge, built in 1908.

Pinus rigida: Pinus rigida, the pitch pine, is a small-to-medium-sized (6 - ) pine, native to eastern North America.  It can be found in two pockets along the St. Lawrence River in southern Quebec and Ontario and more prominently occurs from central Maine south to Georgia and as far west as Kentucky.  It is found in environments which other species would find unsuitable for growth such as acidic, sandy, and low nutrient soils.  This species occasionally hybridizes with other pine species such as loblolly pine ("Pinus taeda"), shortleaf pine ("Pinus echinata"), and pond pine ("Pinus serotina"); the last is treated as a subspecies of pitch pine by some botanists.

Nevada County Air Park: Nevada County Air Park (ICAO: KGOO) is a county-owned public use airport in Nevada County, California, United States.  The airport is located three nautical miles (6 km) east of the central business district of Grass Valley, California.  It is also known as Nevada County Airport.

Pinus ponderosa: Pinus ponderosa, commonly known as the ponderosa pine, bull pine, blackjack pine, or western yellow-pine, is a very large pine tree species of variable habitat native to the western United States and Canada.  It is the most widely distributed pine species in North America.

Doris Foley Library for Historical Research: The Doris Foley Library for Historical Research (formerly, Nevada City Free Public Library and Nevada City Library; colloquially: Carnegie Library or Foley) is a reference and research library in Nevada City, in Nevada County, California.  Built in 1907, the Romanesque Revival style building is currently a branch of the Nevada County Library System.

Janzen–Connell hypothesis: The Janzen–Connell hypothesis is a widely accepted explanation for the maintenance of tree species biodiversity in tropical rainforests.  It was published independently in the early 1970s by Daniel Janzen and Joseph Connell.  According to their hypothesis, host-specific herbivores, pathogens, or other natural enemies (often referred to as predators) make the areas near a parent tree (the seed producing tree) inhospitable for the survival of seedlings.  These natural enemies are referred to as 'distance-responsive predators' if they kill seeds or seedlings near the parent tree, or 'density-dependent predators' if they kill seeds or seedlings where they are most abundant (which is typically near the parent tree).  Such predators can prevent any one species from dominating the landscape, because if that species is too common, there will be few safe places for its seedlings to survive.  However, because the predators are host-specific (also called specialists), they will not harm other tree species.  As a result, if a species becomes very rare, then more predator-free areas will become available, giving that species' seedlings a competitive advantage.  This negative feedback allows the tree species to coexist, and can be classified as a stabilizing mechanism.

Supporting paragraphs: Wolf Creek (Nevada County, California) Pinus ponderosa
Answer: ponderosa pine