Overall vulnerability of trees in the Chicago region can be estimated by considering the impacts on individual trees using model projections or changes in heat or hardiness zone, together with the adaptive capacity of trees as described in the previous section. Two vulnerable species are nonnative (Japanese red pine and Katsura tree). Vulnerable species tend to be native to mountainous or northern areas. Examples include black cherry, red and white pine, balsam fir, quaking and big tooth aspen, white spruce, gray and paper birch, and Douglas fir. Common invasive species considered to have low vulnerability are European buckthorn, Amur honeysuckle, tree-of-heaven, and glossy buckthorn. Several common native trees are also considered to have low vulnerability including boxelder, hackberry, bur oak, and black locust. Species that are often used in cultivated settings that had low vulnerability were Freeman maple, littleleaf linden, maidenhair tree, and European hornbeam.