Tree of Heaven’s Dampening Effect on Biodiversity

Tree of Heaven (Ailanthus altissima), an invasive tree endemic to Eastern Kentucky’s Appalachian Mountains.

Tree of Heaven Overview

  • OverviewTree of Heaven is a small tree of up to 80 feet but usually less than 50. It grows rapidly and produces low fiber quality. It has large leaf scars on the twigs.
  • FoliageFoliage is one of the best identifying characteristics for this species. The leaves are pinnately compound and 1-4 ft. (0.3-1.2 m) in length with 10-41 leaflets. Ailanthus altissima resembles native sumac and hickory species, but it is easily distinguished by the glandular, notched base on each leaflet.
  • FlowersSpecies is dioecious and flowering occurs in early summer when large clusters of yellow flowers develop above the foliage.
  • FruitFruit produced on female plants are tan to reddish, single winged and can be wind or water-dispersed.
  • Threat SummaryRemove dumping sites

Tree of Heaven: A Super Adaptable Invader

The invasion of Tree-of-Heaven (Ailanthus altissima) from Asia has been documented in disturbed landscapes throughout much of the world, leading to biodiversity loss and degradation of ecosystem function. The effect has been marked and pervasive throughout much of North America, including the Appalachian region.

Tree of Heaven is hearty, it grows rapidly and takes to a wide variety of climates and ecosystems. It seems especially adept at growing in Eastern Kentucky and as such, is one of the primary invasive species on our list of non-native plants requiring chemical and mechanical control.

What makes Tree of Heaven particularly troublesome is its affect on the microscopic biome—Tree of Heaven is so good at adapting to non-native ecosystems, that it outcompetes native species, depleting the soil on a microscopic level and disrupting the native symbiosis between the micro and macro biomes.

Tree of Heaven has spread readily beyond it’s native habitat of China and Taiwan to thrive on nearly every continent on earth.

Ailanthus interferes with the restoration of native species by its aggressive growth habit, alteration of nutrient cycles, and allelopathic chemical production. Recent studies suggest that allelopathy has a negative effect on the growth of red oak. Though the exact mechanism of this negative effect isn’t precisely known, it is in part believed due to Tree of Heaven interfering with the symbiosis of beneficial fungi (ECM).

Two-year-old oak seedlings growing among mature Tree-of-Heaven produced significantly less biomass, specifically in root production, than the oaks growing without the invasive tree, according to current research.1

Management and control efforts for this species continue across the United States at great economic cost. At ArP we are pioneering innovative, cross disciplinary approaches and practices to create novel strategies for the control of this invasive species.


1: Bauman, Jenise M. Ailanthus altissima (Tree-of-Heaven) interferes with beneficial symbionts with negative impacts on oak regeneration. American Society of Mining and Reclamation.