Pinus contorta Seeds | Lodgepole Pine
LATIN NAME: Pinus contorta
COMMON NAME: Lodgepole Pine
Plant Profile
The inland populations of this pine carry cones sealed shut with resin, and those cones may hang on the branches for years holding their seed. Heat from a fire melts the resin, the scales swing open, and the seed falls onto ground that has just been cleared of competing vegetation and enriched with ash. Coastal populations are far less serotinous, and their cones open on the tree as they dry, a difference that follows the fire regime of the two habitats. Serotiny in this species is not a single switch: it varies with the age of the tree, with altitude, and from one stand to the next.
A useful rule in the field is that the further a stand is from the coast and the more frequent its fire history, the higher the proportion of cones that stay closed. On the coast, where fire is rare and wind is the main source of mortality, keeping seed locked in a cone would be a mistake.
Lodgepole pine is a stand-replacing species. It colonises burned ground in enormous even-aged cohorts, grows quickly for a few decades, and then loses the light that its own dense canopy has taken away. Its thin bark gives it no protection from fire, so it does not survive a ground fire the way a ponderosa pine does; instead it relies on the seed bank held above the flames. Where the species has been planted outside its range, in northern Europe and New Zealand in particular, that colonising energy has made it a weed of open ground and a nuisance on grazing land.
The English name records a use rather than a botanical feature. The straight, slender trunks were cut by the peoples of the interior plains and used as the long poles of a conical lodge, and the same straightness suits the modern mill. Lodgepole logs go to sawmills for stud and board, to pulp mills, and above all into oriented strand board, in which thin flakes are glued into large panels. The species grows in dense, uniform stands, which makes harvesting cheap, and that economic advantage is exactly what makes the beetle outbreaks so damaging.
Science & Biotechnology
The wood of this pine is light, straight-grained and resinous, and it was one of the sources of naval stores in the American west. The resin ducts of the trunk and the needle oils of the species have been analysed repeatedly, and the volatile fraction is built around monoterpenes: alpha-pinene and beta-pinene, delta-3-carene, myrcene and limonene, with a sesquiterpene tail. Delta-3-carene is the compound that gives the crushed foliage of many two-needled pines their sharp, almost turpentine smell, and it is one of the reasons lodgepole pine foliage is unpleasant to handle in quantity. The seed, though edible in principle, is far too small to be worth collecting.
Uses & Benefits
No other North American pine is quite so willing to be several plants at once. Pinus contorta grows as a wind-hammered, salt-pruned shrub on the outer coast and as a straight forest tree two or three dozen metres tall in the interior, and the two have been treated as varieties of a single species since the middle of the twentieth century. Field botanists list four: var. contorta of the coastal fringe, var. latifolia of the Rockies and the interior plateau, var. murrayana of the Sierra Nevada, and the geographically restricted var. bolanderi of the Mendocino pygmy forest. The needles always come in bundles of two, the cones are small and prickly, and the bark on a mature tree is thin and scaly rather than thick and furrowed.
The species has an unhappy talent for growing in exactly the arrangement that suits an outbreak. Large, even-aged stands of similar diameter across a whole landscape give the mountain pine beetle a continuous supply of suitable bark, and the epidemic that swept British Columbia and spread into Alberta killed pines over an area without precedent in the recorded history of the region. White pine blister rust is a second pressure, since this pine carries little resistance to the fungus that alternates onto currants and gooseberries, and dwarf mistletoe thickens the crowns of infected stands.
Lodgepole pine has been planted so widely outside its natural range that seed production has become an industry of its own, particularly in Scandinavia, where it was introduced on a large scale and where seed orchards were established to supply the plantations. Seed orchards are made by grafting selected clones onto rootstock and letting the wind do the pollination, and the difficulty is that the orchard also pollinates whatever wild pine grows nearby. Trees in a seed orchard flower at a young age, and the seed crop is heavy, but the pollen cloud has to be managed so that the offsite genes do not contaminate the certified lots.
Growing from Seed
Sow in late winter or early spring on the surface of a coarse, free-draining nursery mix and cover the seed with a fine layer of grit, because light and moisture matter more than depth for a seed this small. Keep the seedbed shaded and evenly damp, and expect the seedlings to lean over until their first true needles harden. A commercial nursery will inoculate the seedbed with mycorrhizal fungi, and a garden sowing benefits from soil taken from under a healthy mature pine. Plant out into the open ground once the seedling is a hand span tall and the root collar has thickened; lodgepole hates being held in a pot, where its roots circle.
Seed from the coast planted inland will fail, and interior seed moved far south will grow badly. The safe rule is to use seed collected from a stand within a few degrees of latitude and a few hundred metres of elevation of the planting site, or to buy material of known provenance.
Our Take
This is a tree for a large site or a shelterbelt rather than a small garden, and it is at its best where the soil is thin and the wind is real. I sow it in deep tubes, plant it out small, and never let it stand in grass. For other pines of the same sort, see our pages on ponderosa pine, Austrian pine and Scots pine.
Related Reading
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