Ailanthus

There is an urgent need to explore and utilize naturally occurring products for combating harmful agricultural and public health pests. Secondary metabolites in the leaves of the Tree of Heaven, Ailanthus altissima L. have been reported to be herbicidal and insecticidal. The mode of action, however, of the active compounds in A. altissima are not understood. In this paper, we report the chemical characteristics of the herbicidal and insecticidal components in this tree, and will discuss the effect of light on the bioactivity of the active components. Extracts from the fresh leaves of A. altissima showed a strong plant germination/growth inhibitory effect in laboratory bioassays against alfalfa (Medicago sativa). The effect was dose-dependent. The growth inhibitory components were in the methylene chloride soluble fraction of the extract. The effect was greater in the light than in the dark. Other fractions had plant growth enhancing effect at lower concentrations. The extract was sl...

The hypoglycemic activity of a 70% methanol extract from the leaves of Ailanthus excelsa Roxb. (Simaroubaceae) was studied in normal, transiently hyperglycemic and streptozotocin (STZ)-induced diabetic rats. Oral administration of the extract at doses of 14, 70 and 350 mg/kg body weight caused no significant changes in fasting blood glucose levels of normal rats. In an oral glucose tolerance test, the extract produced a significant decrease in glycemia 90 min after the glucose pulse. Daily administration of A. excelsa extract for 60 days produced a significant hypoglycemic effect in diabetic animals. In addition, this treatment improved the altered renal function observed in diabetic control rats. This study suggests that Ailanthus leaf extract could be potentially useful for post-prandial hyperglycemia treatment. Copyright © 2007 John Wiley & Sons, Ltd.

We have specifically carried out a greenhouse experiment to assess relationship between samara weight and seed success. Relationship assessed as dispersal potential, germination level, germination rate and early seedling mass for the invasive species Ailanthus altissima. For this purpose, we considered two close stands as seeds source. We found no correlation between samara size and neither germination level, germination rate, nor seedling mass, but a positive correlation with samara projected area. These results suggest that samara weight is not directly related to germination, dispersal and invasion potential neither. Nevertheless, stands differed in the invasion potential of their samaras; one stand presented samaras with higher projected area per weight unit whereas the other one presented samaras that produced heavier seedlings. Whatever the origin, (genetic or environmental) of this differences it should be advantageous for a colonizing invader species such as A. altissima sin...

Ailanthus altissima is an invasive species for the native flora of Greece and it could pose a serious threat to the biodiversity and the functioning of ecosystems. The purpose of this study was to investigate the spreading of Ailanthus altissima in urban and non urban areas of North and Central Greece and also to evaluate the effects of its spreading on species composition and floristic diversity in natural ecosystems. The spreading of Ailanthus altissima in urban areas is very intense, mainly in abandoned places (35.29%). It is commonly found in non urban areas of Greece, especially in hedgerows of arable lands (36%) and adjacent wetlands (17%). It is less common in forests (4%), shrublands (11%) and grasslands (9%). The spread of Ailanthus altissima in urban and natural ecosystems is relatively recent. Although it has been recorded at altitudes of up to 640 m, it usually appears at low altitudes of up to 200 m. Floristic diversity was found to be higher in the stands that it domin...

Ailanthus altissima (tree of heaven) is a non-native invasive tree spreading within central Appalachia. This dioecious, deciduous, and allelopathic species copiously produces samaras, capable of traveling at least 200 m through primary wind-dispersal. Removal of A. altissima individuals prior to timbering and other forest disturbances may help prevent spread into forest interiors. To aid in species management, this study investigated the use of remote sensing to identify the location and abundance of samaras in mixed mesophytic forests through supervised classifications. From empirical measurements, the estimated number of seeds per classified unit area was determined and the relationship between quantified propagule sources and individual seed primary dispersal was spatially modeled using a cellular automata model. The predicted seed dispersion pattern was compared to empirical seed trap measurements. Secondary seed dispersal, germination and seedling survival parameters were determined through field experiments. Specifically, I found that remote sensing can be successfully used to distinguish A. altissima samara clusters from surrounding closed canopy vegetation. The identified total area of classified A. altissima samara clusters was determined to be linearly related to total canopy seed yield, however model predictions of seed dispersal patterns generally predicted greater numbers of seeds per seed trap compared to measured outcomes. Seed dispersal predictions using all classified A. altissima samara clusters provided no positive relationships with observed values (Site II, p=0.2997; negative relationship at Site III, p=0.0053). Manually delineating seed sources through photo interpretation resulted in a positive relationship between model estimates and observed seed rain (Site II, p=0.0225), but may still contain commission errors (Site III, p=0.7002). Microsite survey observations of seed germination indicate the frequency of safe sites was high in disturbed environments (canopy gaps), but seedling survival was negligible in the year this study was performed. Measurements of secondary dispersal on land and water (hydrochory) indicate the species can be dispersed with multiple dispersal agents. Hydrochory was shown to be able to contribute greatly to the species’ long distance dispersal, as seeds can reach water bodies, stay viable for long periods of immersion, and can be dispersed downstream distances more than two orders of magnitude greater than primary dispersal. This was the first demonstration of hydrochory in this species. From these studies, it appears that polychory may contribute greatly to this species dispersal and I can infer the same polychory occurs in other terrestrial species, and may contribute to invasive success.

There was no written documentation when, where and how the invasive alien plant species Ailanthus altissima was introduced to the Malesh Region in FYR Macedonia, yet only assumptions for the early 20th century as a species suitable for erosion control, and in certain urban areas for ornamental purposes. This article represents the first research on this species in the mentioned region. Most of the research activities were conducted in 2016 during the preparation of a MSc thesis titled: ‘Predicting the potential distribution of invasive species A. altissima due to climate change in the Bregalnica Region’.
At all sites of A. altissima in the Malesh Region, GPS coordinates were taken. Basic bio-ecological features of the highest individual trees were noted, and core samples for determining the age were taken for laboratory analyses. All collected data were imported in an attribute database to be displayed on a map using QGIS software, thus giving us a detailed picture of the current distribution of the species in this region.
The principal findings show that the Municipality of Pehchevo has a larger area covered with A. altissima than the Municipality of Berovo, both settled on the Maleshevo Mountains. The invasive alien plant was found in urban and peri-urban areas, as a part of the ruderal vegetation (pioneer species), along main roads, introduced as an ornamental species, afforested for erosion control or planted by mistake by local population instead of other species (Juglans sp.). The largest specimen (with DBH of about 51 cm, a height of 15 m, and age of about 65 years) was found in the village of Pancharevo. The species appear to thrive up to the elevations of about 1000 m a.s.l.