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Saving The Sugar Pine

Harvesting cones from a rust-resistant Soper-Wheeler tree
Harvesting cones from a rust-resistant Soper-Wheeler tree

Harvesting cones from a rust-resistant Soper-Wheeler tree

Once threatened with extinction, Sugar Pines now have a fighting chance.

Growing to heights of over 200 feet, Sugar Pines (Pinus lambertiana) are the tallest of the world’s 100 species of pine. Their large cones, often exceeding 12 inches in length, are the hallmark of this truly magnificent tree that naturalist John Muir called the “king of the conifers”.

Road to Extinction

In the early 1900’s, a non-native fungal disease, white pine blister rust, was accidentally introduced into British Columbia by an infected seedling shipment from France. The foreign pathogen quickly spread unimpeded, killing off tens of thousands of Sugar Pines and threatening extinction of the species.

Lifecycle of the Pathogen
Sugar Pine cone on collection bag

Sugar Pine cone on collection bag

White pine blister rust propagates itself via a host plant- currants and gooseberries in the Ribes family. It grows on their leaves, forming fruiting bodies which release a type of spore that attack white pines. The spores infect the pine’s needles, and the fungus ultimately travels into the trunk of the tree, where it produces ugly cankers, killing the tree. A second type of spore is released from the dead tissue which infects other Ribes plants, and the cycle is repeated.

Failed Cure

In 1923 The US Forest Service started a program to control the fungus by eliminating its host, Ribes, from the landscape. Thousands of men from the Civilian Conservation Corps and the Public Works Administration uprooted and burned Ribes plants throughout the 1930’s. This program continued unsuccessfully over millions of acres of National Forest until 1970 when the project was halted. Ribes is a quick-growing shrub, and the area was too vast and rugged to contend with the spores that can travel hundreds of miles on the wind.

Soper-Wheeler Research
Newly planted rust-resistant Sugar Pine seedling

Newly planted rust-resistant Sugar Pine seedling

During this time, the same issues were affecting Soper-Wheeler lands. Between 1953 and 1971, the company worked cooperatively with the USDA Bureau of Entomology to conduct trials with fungicides and pruning regimes. During that period, Soper-Wheeler made numerous attempts with different Sugar Pine seedling trials. Unfortunately, the pathogen always killed the seedlings. By 1971, plantings were curtailed and the future of the Sugar Pine looked bleak.

Breakthrough

In 1977, a Forest Service geneticist, Bohun Kinloch, found a genetically resistant line of Sugar Pine. This led to a screening test for resistant trees. In 1988, the Forest Service made the test publicly available.

The Sugar Pine Co-Op
Soper-Wheeler forester Jason Warshawer harvests Sugar Pine cones

Soper-Wheeler forester Jason Warshawer harvests Sugar Pine cones

Soper-Wheeler helped form a cooperative with other timberland owners, and immediately collected cones from ten likely candidates on our lands. Several were found to be resistant, and these were cross-pollinated with other pines to produce resistant seed stock. Since then, the Company has tested more than 400 candidates and has added 37 resistant trees growing on company lands to the cooperative seed bank.

Bright Future

Today we plant a genetically diverse supply of rust-resistant sugar pine seed in our mixed-conifer regeneration sites, ensuring the future of the Sugar Pine for future generations to come.

See the video below for how we harvest the cones without harming the tree.

 

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