An invasive species is one that is non-native to the ecosystem of the area, which can cause environmental harm or even pose a human health risk. These species are often difficult to remove because they have no natural predators or competitors in the new ecosystem and so they quickly spread and overwhelm the area.
Because of this growth, these alien species can take over the ecosystem they have entered and threaten the survival of native species. Unfortunately, many of the trees growing on Long Island are highly invasive, most commonly these are Chinese exotics brought here over 200 years ago. These include the tree-of-heaven, Japanese angelica, Norway maple, and sycamore maple, and some newcomers such as glossy buckthorn and Callery pear, as well as thorny multiflora rose and autumn olive shrubs.
Unless we can reduce or stop the spread of invasive species, they will continue to cost significant amounts of money to control and even more to repair the damage they cause. And they may cause even more harm to the natural ecosystems of our area.