Relatively few Asian trees were available for planting when the first edition of Downing's Landscape Gardening book came out in 1841, including: Ailanthus altissima
, Broussonetia papyrifera, Ginkgo biloba, Gleditsia sinensis, Magnolia denudata and liliflora (and their hybrid, x soulangeana), Morus alba, Platycladus orientalis and Salix babylonica.
Moreover a strong threat is represented by alien species that occupy considerable surfaces, especially Opuntia ficusindica (1534 [m.sup.2], 6%) and Ailanthus altissima
(590 [m.sup.2], 2%).
Interactions between Albizia julibrissin and Ailanthus altissima
: two co-occurring invasive trees.
Our previous study demonstrated increased nodulation in Trifolium exposed to root leachates from the Asiatic invasive tree Ailanthus altissima
An IVI of 56.06, 39.27 and 34.57 was recorded in Populus deltoides, Ailanthus altissima
and Ulmus wallichiana, respectively.
Jeong, Ailanthus altissima
swingle has anti-anaphylactic effect and inhibits inflammatory cytokine expression via suppression of nuclear factor-kappa B activation, In Vitro Cell.Dev.Biol.-Animal, 46, 72-81(2010)
The most abundant of those include chinaberry (Melia azedarach), tree-of-heaven (Ailanthus altissima
), and Japanese ligustrom (Ligustrum japonicum).
The forest cover is mixed, primarily consisting of maples (Acer), European black alder (Alnus glutinosa), black locust (Robinia pseudo-acacia), tree-of-heaven (Ailanthus altissima
), autumn-olive (Elaeagnus umbellata), sycamore (Platanus occidentalis), and red oak (Quercus rubra).
Invasive Scotch broom Cytisus scoparius Invasive Scotch thistle Onopordum acanthium Invasive Spotted knapweed Centaurea maculosa Invasive and noxious Tree of heaven Ailanthus altissima
Invasive Yellow star-thistle Centaurea solstitialis Invasive Yellow toadflax Linaria vulgaris Invasive TABLE 10-2 Seed Longevity of Some Weed Seeds NUMBER OF NAME SPECIES YEARS VIABLE Annual bluegrass Poa annua 100 Chickweed Cerastium spp.
Two hundred years ago, a Philadelphia gardener imported the Chinese tree of heaven (Ailanthus altissima
), and Chinese immigrants later introduced it on the West Coast.
douglasii 5b tulip-tree Liriodendron tulipifera 5b sycamore Platanus occidentalis 5b horsechestnut Aesculus hippocastanum 6 European beech Fagus sylvatica 6 tree-of-heaven Ailanthus altissima
6 redbud Cercis canadensis 6 goldenchain tree Laburnum X watereri 6 yellow-cedar Chamaecyparis nootkatensis 6 western redcedar Thuja plicata 6b eastern flowering dogwood Cornus florida 7 sweetgum Liquidambar styraciflua 7b Douglas-fir Pseudotsuga menziesii var.