Fire promotes exotic pine invasions in Patagonia.

RAFFAELE E Y ENERSTROM J.

Bariloche

Simposio; VI Southern Connection Congress- Simposio: Pine Invasion in South America: patterns, process and lessons to be learned.; 2010

Pines have caused problems by invading natural communities in many places, especially in the southern hemisphere, when planted outside of their natural range for commercial forestry. In Patagonia, several pine species including species with adaptations to cope with and regenerate vigorously after fire, have been planted in areas that were formerly open woodland or steppe, where lack of fuel continuity was an important limitation to fire spread. Natural wildfires have been a recurrent disturbance for as long as 41 / 150 there have been humans in this region. The fires are intensified in areas with poorly managed pine plantations where the increased fuel load creates fast spreading crown fires. We studied the establishment of pines after fires, suspecting that the establishment success of pines both inside and outside of the plantations would be high. Field studies were conducted in 17 sites where pine plantations had been burnt in fires between 1985 and 2002. We recorded pine establishment inside and outside burnt plantations to study the pine establishment after fire in 2002 and 2009 at the same sites. In 2002 establishment of pines outside the old burnt plantations was found only in two sites. However, in 2009 we recorded high densities of pines outside in at least 10 sites. Inside the old plantations the establishment of pines was much higher than outside of the plantations, both in 2002 and in 2009. We concluded that there is a risk that pines will become invasive in Patagonia.