c. Fiora Watts

Battling Dutch Elm Disease

September 2, 2014

The Prospect Park Alliance is currently battling a serious threat to one of its most majestic species of trees, the American elm. American elms used to be one of the predominant trees in American streetscapes and public parks, but over the course of the last century a bacteria called Dutch elm disease has had a devastating impact on these national treasures. The elms of Prospect Park are no exception, including a few significant specimens on the Long Meadow such as the knoll near Dog Beach, and a number in the Park’s woodlands.

“This is one of the oldest and most resistant tree diseases in the country,” said John Jordan, director of Landscape Management at the Alliance. Carried by beetles, Dutch elm disease is a fungus that enters the soft tissue beneath the bark. It blocks nutrients from circulating through the tree, eventually resulting in the tree’s decline. Dutch elm disease can overcome a tree in a single growing season. Prevention requires diligent monitoring to catch the symptoms before they claim the life of the elm.

Early detection is critical. The Alliance’s Landscape Management crew looks for the premature browning of the leaves, which eventually spreads throughout the branches. When symptoms are spotted, Alliance arborists attempt to prune infected wood before the disease can reach the tree’s root system, and in some cases, an anti-fungal agent is applied. Unfortunately, Dutch elm disease is often a losing battle. For those beyond healing, the Alliance works with the New York City Parks Department to properly remove the infected trees, which are then replaced with new plantings.

Love the Park and its 30,000 trees? Learn more about the Park’s commemorative tree program and how you can help support their ongoing care.