The park’s Tree of heaven is at least 57 years old. It has smooth gray bark, and produces a strong unpleasant odor. Our tree is unfortunately an invasive species, but luckily it’s a male that no longer produces seeds. 

How did this happen? Trees of heaven were established in the United States before gardeners realized how dangerous they are to our native ecosystems. These trees damage ecosystems by producing too many seeds, resprouting after being cut down, and producing a chemical called ailanthone, which stops the growth of other plants nearby.

Before its first introduction to the United States in 1784, they had been extensively cultivated in China. In its native land, the roots, leaves, and bark are used for traditional medicines. While in America, it quickly became popular for its incredible durability. Even during the industrial revolution, when coal soot and sulfur dioxide were poisoning urban trees, the Tree of heaven was indestructible. It can withstand cement dust, toxic fumes, and even high concentrations of mercury. The author Betty Smith even used their resilience as the basis for her novel A Tree Grows in Brooklyn.