100 Disease-Resistant Trees Planted in the Presidio

Presidio of San Francisco (November 15, 2004) — Foresters and volunteers began planting one hundred Monterey cypress and pine trees this week in a key historic Presidio stand in the Fort Scott area of the 1,491 acre park.

The pine clones, which were selected for their resistance to Pine Pitch Canker, and the cypress seedlings, could grow to a height of 100 feet. Pine Pitch Canker is a fungal disease that killed about 80% of the Monterey pines around the town of Santa Cruz alone, and tends to disfigure some of the Presidio pines. The disease ultimately leads the death of the trees.

There are some 70,000 trees in the forests of the Presidio and about 17% of them are Monterey pines. The Presidio Trust is obligated to replace the aging forest, which was planted by the U.S. Army at the same time some 120 years ago or so. Chief forester Peter Ehrlich says it was necessary to find Pine Pitch Canker resistant trees in the Presidio’s forest.

“We had some clones of the trees that showed resistance rooted in Monterey last year, Ehrlich says. “These are cuttings taken from trees that showed tolerance or resistance to the disease in a University of California Davis study.”

The Presidio forests are considered even-aged, because they were generally planted at the same time. The Presidio forestry program currently reforests from 2 to 2.5 acres of forest a year, so that an uneven aged forest can begin to form. This year it will be 2.1 acres.

The Kobbe planting is part of the Kobbe Key Historic Stand. There are four Key Historic Stands in the Presidio: the Kobbe, Arguello, Presidio Gate and Park Boulevard.

These stands are not only contributing factors to the Presidio’s Historic Landmark Status, but they (the Key Historic Stands) are called “Character Defining” in that they embody the visual qualities that most people associate with the forest here.