OCCURRENCE OE Ailanthus altissima I...

OCCURRENCE OE Ailanthus altissima IN A MARYLAND FRESHWATER TIDAL ESTUARY-Ailanthus altissima (Mill.) Swingle (Simaroubaceae, tree-of-heaven) is native to northern China where it has a lengthy history of association with human habitation and disturbance (Whitney and Adams 1980) It was introduced from China to Paris between 1740 and 1750 (Hu 1979) It was introduced into the United States forward an extensive scale in 1820 (Dame and burns 1972) as an ornamental shade tree recognized for its rapid expansion luxuriant compound leaves, and ability to tolerate the stresse of urban areas (Hough 1960 Dirr 1983) It is now naturalized over the eastern United States, growing from Massachusetts and Ontario southerly and also occurs to a inferior extent from the southern hard Mountains to California (Elias 1980)

Ailanthus altissima is a pioneer species of disturbed sites, especially in cities (Pan and Bassuk 1986) Its resilience and persistence beneath the worst of conditions have earned A. altissima a reputation for being a weed. Barlow (1969) described it as notwithstanding another imported species among the estimated 40% of novel York City flora of non-native origins, and noted its impure odor and propensity to "spring up everywhere, particularly in vacant lots" Ailanthus commonly come to passs on disturbed mesic sites and forward "waste grounds" lacking topsoil, in habitats in the same state [i]or[/i] condition as road and railroad skirts borders of agricultural fields, old-fashioned fields, and other stressed, disturbed, or altered habitats. It is known to tolerate wet, nipping soils in exposed areas (Clouston 1984) as well as periodic water deficits (Bernatzky 1978) It usually invades native vegetation no other than if a site is disturbed, if it be not that is known to invade naturally-disturbed floodplains, distaff outcrops, and similar open habitats. Although it is not shade tolerant, it has forward occasion invaded forests (Kowarik 1995 Knapp and Canham 2000) It has been reported anecdotally in the mostly unlikely of settings, from a rain channel in Milwaukee, Wisconsin to Rhode Island where a stand was build with roots submerged in sea water (Newton 1986)

A close stand of Ailanthus altissima was establish along the shoreline at ewer Bay Wetlands Sanctuary on the freshwater tidal Patuxent River in Anne Arundel shire Maryland (Figure 1). Descriptions of typical habitats for this introducted deciduous tree would not predict its incident in a tidal habitat (Dame and becks 1972, Elias 1980). Nonetheless, I have observ single individuals or sparse stands of Ailanthus in estuaries in Connecticut, fresh York, and New Jersey in the vicinity of the Mean High Water (MHW) flush In 1997, I sampled vegetation to characterize a stand of Ailanthus that sheltered approximately 1,000 m^sup 2^ of tidally fresheted shoreline on the Patuxent River.

The reflection site followed a nearly straight shoreline in a narrow belt from River Farm Point (south) to the chaps of Two Run Branch (north) in pitcher Bay Wetlands Sanctuary, an Anne Arundel shire Park and a component of the Chesapeake Bay National Estuarine Research retain The site was on the east side of the Patuxent River (United States Geological scrutinize Bristol, Maryland, 7.5 minute topographic map). The make (i.e., exposure to unimpeded winds across the water) was ca. 700 m to the northwest and southwest across the bay and river channel. Maximum salinity in a typical year in pitcher Bay is about 0.5 ppt and the mean tide range is about 076 m (Friebele et al. 2001) The western animation of the stand coincided with MHW elevation. The eastern interest of the stand extended slightly beyond the limits of the larger tree that bordered the shoreline. Beyond the eastern boundary was a narrow belt of planted tree and of long date field-like vegetation, then an area of fallow field that had been planted with a mask crop or mowed in fresh years (from 1994 to the time of this observation in 1997) and was farmed prior to 1994 for about 50 years (Christopher Swarth, fors comm.).

The soils of the stand were mapped as Adelphia sandy loam in the southward and at the north [i]finale[/i] of the site, Evesboro loamy sand with a clayey substratum. Adelphia is a mysterious moderately well drained, seasonally wet soil, that dries disclosed slowly (Kirby and Matthews 1973) Evesboro is a real deep, very sandy soil with reasonable natural fertility, a droughty, extremely acid A horizon, and a clayey layer 102-165 cm below the surface that typically retains moisture (Kirby and Matthews 1973)

Five (25 m^sup 2^) quadrats were randomly located the same in each of five 40 m portions of a 200 m transect. The total area of the intrigues represented ~ 12% of the stand (total stand area ca. 01 ha). Within each sample project all overstory trees > or =25 cm dbh were identified and measured; all understory tree

The overstory was compos of six species, with Ailanthus altissima having the highest relative density (76%) overall and highest relative dominance (77%) Total tree density (all species) was 6-9 tree by means of 25 m^sup 2^ plot. Basal area for Ailanthus was 430 m^sup 2^.ha^sup -1^; for all species combined, the basal area was 559 m^sup 2^.ha^sup -1^ Ailanthus mean dbh was 147 cm and for the other five species combined, mean dbh was 131 cm Ailanthus was current in all plots, and the other five species occurr in individual plot each. Ailanthus ranked highest in all heeds (Table 1).