Non-native invaders

They can wipe out a forest in a few decades

They have invaded our farms, ranches, parks, waterways, forests, rangelands, and even our backyards. They prey upon our grasses, crops, trees, fish, birds, snails and, in the long game, even threaten to destroy us. Invasive species are non-native species that disrupt healthy ecosystem functions from the bottom up, causing a chain reaction which leaves nothing unaffected. When invasive pests and pathogens attack trees, they degrade forest health and increase fire frequency. Damaged forest ecosystems heavily impact natural resource-dependent industries such as logging, hunting, fishing, hiking and wildlife watching.

How Invaders Killed the Western White Pine in Idaho

White pine, long ago considered the “King Pine,” once dominated the moist inland forests of northern Idaho. So dominant and useful was the species in Idaho, that it was named the state tree in 1935. By that time, the mighty white pine was already in steep decline. With over-logging in the 19th and early 20th centuries and an invasive species known as blister rust disease – a fungus native to Asia – the sun-loving giant barely survives in the forests of Idaho’s panhandle today.

White pine blister rust was introduced from Europe to North America in shipments of infected pine seedlings during the decades around 1900. This invasive species wiped out forest and industry in just a few decades.

Other forests in Idaho are plagued by invasive species, such as the gypsy moth, that eat needles and foliage. Asian gypsy moths are a serious threat to western forests. This insect consumes both old and new needles on conifers which are not able to re-foliate.