Single-leaf Pinyon and Bristlecone Pine State Trees of Nevada

The state trees of Nevada are the Single-leaf pinyon (Pinus monophylla) and Bristlecone pine (Pinus longaeva).

The single-leaf pinyon is also known as the nut pine and the piñon. The pinyon is found in isolated mountain ranges in southern Idaho, western Utah, and northwestern Arizona, as well as throughout Nevada, eastern and central California, and areas bordering the Mohave. Pinyon is used to make fence posts. The trees are popular locally for Christmas trees.

Singleleaf pinyon reaches 20 to 40 feet in height. The growth pattern is rounded to flat-topped with upward reaching branches. Pinyon has a strong lateral root system that helps the tree compete for soil nutrients and water. Pinyon grows in a wide variety of soils, but prefers a pH of 6 to 8. Pinyon is monoecious, having both male and female strobili.

The needles grow as singles with some spacing between each leaf. Pinyon needles persist on the tree for a dozen years or more. Fallen needles are combustible. The cones are less than an inch in length than ripen, dry, open, and fall in the winter or spring months. Pinyon can live for many hundreds of years if there is no wild fire to kill them. There are many trees that are over 200 years old in the wild. A tree in Nevada was crossdated to 1106 AD.

Pinyon reproduces by seed. Cones are viable when the tree reaches 35 years of age. The small animals who store food for the winter are the best known agents of germination. Pinyon is a slow grower. It can reach 6 feet after 60 years. It grows best on rocky slopes, in dry soil, and with full sun. Pinyon is the most drought tolerant pine in the United States and the only one with the single needle habit. It is usually the dominant tree when growing in the wild. Pinyon is available in the trade.

Pinyon seeds are a food source to mice, squirrels, chipmunks, deer, bear, sheep and birds. The inner bark is browsed by porcupines, raccoons, rabbits, coyotes, and foxes. The pinyon also has a long history with the early people of the western United States. They used the pitch for caulking and to strengthen paint. Pinyon seeds were (and still are) a food source and a commercial crop.

The pinyon has predators. It is susceptible to the larvae of the mountain pine beetle, rust, sawflies, and gall midges.

The bristlecone pine is also known as Great Basin bristlecone pine, intermountain bristlecone pine, and western bristlecone pine. The tree is found growing in the wild in California, Nevada, and Utah at the timber line. The tree is extremely drought tolerant.

Trees at lower elevations can reach 60 feet in height and are quite straight, while trees at higher elevations are stunted, contorted, and may be only 30 feet. The roots adapt from branched and shallow to widely lateral depending on the soil conditions in which they grow. The number and size of pine colonies is shrinking. Stands facing south tend to be larger than those facing north.

Bristlecone pine needles range from 1 to 1.6 inches long, with 5 needles in a cluster. The needles can persist on the tree for 35 years. The tree is monoecious with both male and female cones.

Bristlecone pine is considered endangered. It is long lived, with some trees dated to 4,789 years, but it is difficult to propogate. Seeds are the means of propagation with pollination dependent on wind.

Bristlecone pine is highly drought tolerant and grows in nutritionally poor and rocky soils. The trees can withstand the cold winter temperatures and strong winds.

The dead wood of Bristlecone pine is slow to decay. Some of the dead wood has been dated over 10,000 years old. Scientists use this pine to calibrate the radiocarbon timescale.

Sources
Pinus monophylla, http://www.fs.fed.us/database/feis/plants/tree/pinmon/all.html
Pinus monophylla, Gymnosperm Database, http://www.conifers.org/pi/pin/monophylla.htm
Pinus monophylla, Las Pilitas Nursery, http://www.laspilitas.com/nature-of-california/plants/pinus-monophylla
Pinus longaeva, http://www.fs.fed.us/database/feis/plants/tree/pinlon/all.html
Pinus longaeva, Gymnosperm Database, http://www.conifers.org/pi/pin/longaeva.htm