Invasive Species Mayhem in the Forests of the Anacostia River

You may have wondered why are there so many leafless trees in mid-summer along the Anacostia River. The short answer is EAB. That is, Emerald Ash Borer. It is a beetle scientifically known as Agrilus planipennis, first detected in North America in 2002. It was accidentally introduced from Asia most likely as a hitchhiker in wood packing materials. If you ask us what’s our worst invasive species in the Anacostia River watershed, EAB is definitely on top of that list. EAB is the poster child of a highly invasive species, a nonnative species that causes ecological and economic harm, and in the case of EAB the impacts are evident and well documented. 

A neat little beetle in the wrong place has caused significant environmental damage to the forests of the Anacostia River watershed. Photo: USGS Bee Lab, Sam Droege.

EAB has killed millions of ash trees (Fraxinus spp.) in forests and cities in America. The epicenter of the invasion is located in southeast Michigan, there, more than 99% of the ash trees with stems greater than 1 inch in diameter have been extirpated. Unfortunately, we are certain that the riparian forests of the Anacostia River, with a high abundance of ash trees, are undergoing the same ordeal as the forests in Michigan. All the ash tree species in North America are vulnerable to this infamous forest pest.

These are the riparian forests at Bladensburg Waterfront Park taken from the west banks (Colmar Manor Community Park) in the summer of 2011 (top photo) pre-EAB invasion, however, chances are the beetle was already present but its damage was still not evident. The bottom picture was taken earlier on this month (June 12, 2017). All those leafless trees are dead or dying! as you can see EAB has been devastating to the watershed's forests. 

Six years ago we blogged about the triangular purple boxes hanging from trees. Those purple boxes were traps set in ash trees to attract and catch the invasive beetles to detect their presence. Now the pest has been detected almost all over the state of Maryland. In Virginia, it was first detected in 2003 in Fairfax County where an eradication effort was attempted. In 2008, there was another report, since then, it has spread to 25 counties! The pest has already reached the Shenandoah National Park which is why park goers are not allowed to bring firewood to the park’s campsites.

This year we decided to take action! We have planted 100 native trees of 9 species in a 2-acre area (the effected area in the photo above) to replace the dead ash trees with species not affected by the pest. Some of the tree species planted are: Swamp white Oak, Sweet bay Magnolia, River Birch, Black Willow, Paw paw and other species. Special thanks to volunteers from The World Bank who were instrumental in putting those trees on the ground during the spring. Also to the great volunteers from Monumental Sports and Entertainment for helping us maintain those trees and for planting lots of native swamp roses to help enhance these forests so badly affected by EAB. With so much sunlight available as a result of less tree canopy, habitat conditions have improved for invasive plant species which we are controlling around each of the trees planted. Species like Porcelainberry, Japanese Clematis and Multiflora Rose being the worst offenders so far. 

Top photos show fallen dead ash trees with the nasty galleries created by the EAB larvae in the tree's sapwood. The bottom photos show our awesome volunteers from The World Bank planting the new generation of trees and preparing tree shelters for each tree planted. 

With your support, we will follow up with this efforts to recover the riparian forests of the watershed with reforestation and invasive plant control.   



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