Adored for its beauty and ease of growth, and despised for its harmful, everlasting effects, the tree of heaven truly is glorious. Although deserving of our admiration, Rhode Island is one of a handful of states that must hop on board to regulate the distribution of this invasive tree, to combat its negative impacts within diverse ecosystems.
With a name like “tree of heaven,” one could form a mental picture of a gorgeous, heavenly tree. One with luscious budding flowers, attractive bark and magnificent leaves extending from a sky-piercing trunk. These imaginative assumptions are true for tree of heaven’s appearance. Its godly strength and resistance to disturbance allows it to stand out as a glimpse of a life form within a concrete jungle.
While in a city setting this tree is able to thrive, but its ability to also thrive in environments holding an abundance of native plants makes this tree destructive. What lacks from its physical appearance is this species’ inner demons that are far more damaging than its exterior suggests.
Within a diverse ecosystem, this tree will not only outcompete surrounding species for resources, it will actually poison and kill them.
The tree of heaven, known also as Chinese sumac and stinking sumac, is an aggressive invasive species taking over the United States state by state. According to the U.S. Department of Agriculture, tree of heaven has invaded 41 of the 50 states and has extended its reach through much of Canada, since its introduction in 1784.
First planted on an estate in Pennsylvania by William Hamilton, it was introduced to New York City some 40 years later. Since its preface to city streets, tree of heaven has been able to establish itself as a pioneer species, successfully surviving amongst minimal resources where other species cannot. It has the ability to tolerate saline soils, air pollution, a range of soil pH and drought, making it a perfect tree for city habitat.
Where air pollution is highly concentrated and natural flora is scarce, it's incredibly important to find a species that can withstand such conditions. In a flourishing, diversified area with optimal resources for many species to live, such as Rhode Island, this plant becomes a noxious invader. A characteristic of some highly invasive species is allelopathy: a host of chemicals a plant releases into the environment that act as a germination and growth inhibitor.
According to The Nature Conservancy, the bark, roots and leaf litter of tree of heaven contain an allelopathic chemical known as ailanthone. The tree uses this biochemical to prevent other plants from establishing and also disrupts the growth rates of existing native plants.
Like many invasive species, tree of heaven likes to establish itself in disturbed areas such as forest edges, roadsides and waste lands. This is a cause for concern because if it has established itself in an area such as a forest edge, it will most certainly encroach on the native flora, and over time reduce the diversity of plant life in the area.
A change in plant diversity will alter the abundance and diversity of wildlife within the area, because natural food sources will be removed. Not only will it kill the surrounding species, by releasing up to 400,000 wind-dispersed seeds a year, according to the U.S. Forest Service, this tree will be able to further establish itself in the disturbed open areas where it had previously killed off native plants.
Although tree of heaven is registered as an invasive species, Rhode Island has failed to prohibit the human distribution of this invasive species. The state of Rhode Island is in essence allowing greater potential for the tree to invade vital ecosystems that Rhode Islanders hold dear, and putting native species in danger.
I urge the Rhode Island Department of Environmental Management to list the tree of heaven as not only an invasive and noxious plant, but to also prohibit the possession, transport, planting and propagation of the tree to further ensure the safety of Rhode Island’s native plants.
Maggie Kimball is a University of Rhode Island student studying wildlife conservation and biology.