What it is
Pines that produce edible seeds large enough to bother harvesting.
Out of roughly 120 pine species, about 20 are commercially harvested for nuts. The big four for temperate food forestry: stone pine (Pinus pinea), Korean pine (Pinus koraiensis), pinyon (Pinus edulis and P. monophylla), and Siberian cedar pine (Pinus sibirica).
Pine nuts pack 670 calories and 14 g of protein per 100 g. They store for years in the shell. The trees live for 200 to 1,000 years and tolerate ground that almost nothing else can crop.
Why it works
Pines partner with ectomycorrhizal fungi. The hyphae extend root reach 100 times and trade phosphorus and water for sugars. Many edible mushrooms (porcini, Lactarius deliciosus, matsutake) only fruit under specific pine species. You get nuts above ground and mushrooms below.
Pine needles drop year-round and build a deep slow-decomposing duff layer. That layer holds water, suppresses weeds, and slowly acidifies the soil. Under stone pine you get a self-mulching system that needs no input after establishment.
The nutrition is dense. Indigenous people of the Great Basin lived on pinyon for 10,000 years. The Korean pine zone of northeast China and the Russian Far East supported Tungusic peoples whose calendar revolved around the autumn cone harvest. Stone pine fed Roman legions. These are not garnish crops. They are staple food.
The species
Stone pine (Pinus pinea). Mediterranean. The umbrella pine of Italy. Hardy to about -15 C. Tolerates poor sandy soil and drought. Starts bearing at 15 to 20 years. Mature trees produce 5 to 10 kg of nuts annually. Cones take three years to mature. The pine nuts sold in Italian and Spanish supermarkets come from this tree.
Korean pine (Pinus koraiensis). Northeast Asia. Hardy to -40 C. Slow start, but a mature tree at 50 years drops 25 to 50 kg of cones, each cone holding 130 to 200 large kernels. The most productive nut pine on earth by mass. Russia, China, and Korea export Korean pine nuts globally.
Pinyon (Pinus edulis, P. monophylla, P. cembroides). Southwestern US and northern Mexico. Drought specialists. P. edulis survives on 250 mm of annual rainfall. Slow growth, but small mature size (5 to 10 m) makes them workable on tight sites. Pinyon nut shells are thin enough to crack by hand. The harvest was the basis of Numic, Puebloan, and Diné food systems.
Siberian cedar pine (Pinus sibirica). Boreal Russia. Hardy to -60 C. Direct relative of Korean pine, similar nut, slightly smaller. Tolerates short summers and acidic soil. The Siberian taiga harvest still supports villages from the Urals to the Pacific.
Swiss stone pine (Pinus cembra). Alpine. Hardy to -40 C. High-altitude specialist (1,500 to 2,800 m). Small nuts but a beautiful slow-growing tree to 25 m. The basis of the zirbenschnaps tradition in Austria and Switzerland.
Plant them
Pick by climate. Mediterranean: stone pine. Cold continental: Korean or Siberian. Hot desert: pinyon. High altitude: Swiss stone. Pick wrong and the tree sulks for 30 years.
Plant grafted stock if you want nuts in your lifetime. Seedling stone pines bear at 20 to 25 years. Grafted cultivars bear at 7 to 10. The same applies to Korean pine. Italian and Spanish nurseries supply grafted Pinus pinea; specialist North American nurseries (Burnt Ridge, Oikos) carry grafted nut pines.
Space wide. Stone pines need 8 to 12 m between trees. Korean pines need 6 to 10 m. Crowded pines compete for light and produce few cones. Better to plant fewer and let them spread.
Underplant after establishment. Pine duff is acidic and dry, but blueberry, huckleberry, and certain Vaccinium shrubs thrive. Mushroom inoculation under pinyon and stone pine can produce Lactarius deliciosus (saffron milk caps) within 4 to 8 years.
Harvest by laying a tarp and shaking branches in late summer, or collect fallen cones. Dry cones in sun for two weeks until they open. Shell by hand or with a small grain mill.
When it goes wrong
No nuts after 15 years. Seedling stock, not grafted. Wait, or graft scions from a productive tree onto your stand.
Cones drop empty. Poor pollination. Pines are wind-pollinated and need at least three trees within 30 m of each other to set seed reliably. Plant in clusters.
Mountain pine beetle. Dendroctonus ponderosae has killed millions of pinyons and other western US pines. Healthy trees resist. Drought-stressed and crowded trees do not. Thin stands, water deeply during severe drought, watch for pitch tubes on the trunk.
Pine nut weevil. Conophthorus species drill into developing cones in spring. Pheromone traps and removing infested cones in summer cut populations. Most damage shows in the second year of cone development.
Soil too rich. Pines, especially pinyons and stone pine, sulk in heavily fertilised ground. Plant on poor soil and they thrive. Save the rich beds for chestnut and walnut.