Melia azedarach -- Arizona

Chinaberry is considered native to southeastern Asia, specifically central and western China, northern India, the Himalayan region, Burma, and Malaysia. It is also native to tropical Australia. Because chinaberry has been extensively cultivated around the world, its native distribution is uncertain. Chinaberry readily escapes cultivation and spreads to disturbed sites and wildlands. Chinaberry is a nonnative tree in North America. It occurs throughout the southern United States north to Virginia and west to central California. It also occurs in Utah, Oklahoma, Missouri and New York, Hawaii and Puerto Rico. In southern forests, its estimated cover is greatest in Georgia, Alabama, Mississippi, and eastern Texas. In addition to North America, chinaberry occurs as a nonnative in Mexico, Argentina, and other warm-temperature parts of the world (Waggy, 2009).

Chinaberry is naturalized in areas with a climate match to Arizona, such as Argentina, central Australia, and southern and northern Africa (GBIF, 2022).

Melia azedarach has become invasive in a number of locations in the Americas, the Pacific and Africa, and has been classified as an invasive species in some countries including South Africa and Hawaii, USA. It is difficult to control because of its ability to resprout from stems and suckers, and the expense of chemical techniques (CABI, 2022). Chinaberry displays a wide range of occurrence across warm parts of the Globe (GBIF, 2022). The significance of chinaberry invasion is shown in the prioritization it has been given in studies of biological control (Ding et al, 2006), ecological assessments (Rowntree, 1991) and listings of invasive species (Oswalt & Oswalt, 2013). Though a prioritization study gave it a lower ranking than expected for South Africa (Robertson et al, 2003).

Chinaberry has not been included on any state or federal Noxious Weed list. However, it is listed as an invasive species by the Texas Invasive Species Institute (2014). Its significance as invasive is supported by impacts caused by the plants' toxicity and tendency to form thickets, and ability to travel by seeds consumed by birds (Texas Invasive Species Institute, 2014). While Melia can be expected to be a more common problem in east Texas, outside the climate-matching zone, Melia is widely occurring in the Southwest, present in New Mexico, Utah, and California, other states adjacent to Arizona with large climate-matching areas. Chinaberry has been noted as common along streambanks and roadsides in semiarid savanna in the norther Cape of Africa, but its abundance declined in arid regions. Also reported from Australia (Waggy, 2009).

Melia is a small genus with no other species with noteworthy invasive tendencies (Wikipedia, 2022). No other species in the genus Melia are listed in the Global Compendium of Weeds (Randall, 2017).

Chinaberry is a widespread species which is present in areas which are a climate match to Arizona, plus many more areas. These additional areas include Central America and the Northwest portion of South America, Brazil, Central Africa, Southeast Asia and New Zealand (GBIF, 2022).

Rated as forming dense thickets, but not having a climbing or smothering habit (PIER, 2004). In Georgia, Chinaberry is ranked as a Category 1 invasive species: nonnative plants that pose serious problems in Georgia natural areas by "extensively invading native plant communities and displacing native species." In parts of Texas "often forms dense stands that reduce light to other
understory vegetation" (Waggy, 2009).

Chinaberry sprouts from roots and stumps when damaged suggesting it may sprout after fire. Vegetative regeneration is more likely than sexual reproduction in chinaberry after fire; however, chinaberry seedlings may establish from buried seed or from off-site seed sources soon after fire. A publication from Virginia on firewise landscaping techniques gave chinaberry a low flammability rating however, no details were provided on how this determination was made. (Waggy, 2009).

Chinaberry is listed as toxic and unpalatable to animals (PIER, 2004). Melia azedarach intoxication has been observed in humans and domestic animals due to the ingestion of leaves or, mainly, fallen fruits, although they have a bitter taste; clinical signs in humans include nausea, vomiting, diarrhea, thirst, sweating, grinding of teeth, sleepiness, and convulsions. Chinaberry poisoning has been reported in horses, cattle, sheep, goats, pigs, dogs, rabbits, rats, guinea pigs, and poultry. Toxicity of the fruits is found within the pulp, whereas the shell and kernel are quite harmless. Most poisoning occurs in autumn and winter, when the berries ripen (Ferreiro et al. 2010).

Rated as forming dense thickets, but not having a climbing or smothering habit (PIER, 2004). Forming dense thickets (Tourn, 2000). In one instance, chinaberry formed impenetrable patches of vegetation in combination with pokeweed (Phytolacca sp.) and boneset (Eupatorium sp.) on an island off the coast of Texas. Can form dense stands, as has been observed in Florida and Texas (Waggy, 2009). Because this is a tree species, by inference these thickets will have capacity to block livestock and humans.

Chinaberry typically reproduces by seeds, but may exhibit clonal growth following disturbance (e.g. fire, herbivory, animal injury).
Root buds were produced in all (fire treated and control) plagiotropic root cuts when incubated under controlled conditions. Root suckers developed from the differentiation of parenchymatous cells produced by meristematic activity in the cambial zone. Results from ongoing experiments indicate that the chances of a root sprout to survive into a new individual are much higher than those of a seedling (Tourn et al, 2000)

Chinaberry can reproduce vegetatively from root suckers. However a study of chinaberry clonal growth (Tourn, 2000) did not describe a capacity for the plant to disperse detached fragments.

Typically reproduces by seeds (Tourn, 2000).

Rated as "no" for prolific seed production (>1000/m2) (PIER, 2004). However, described as prolific producer of seeds by CABI (2022). Each fruit contains one to six seeds (Waggy, 2009). Forms a tree suggesting high seed potential, but under dry conditions these are smaller trees where the maximum height is 10-15 m (CABI, 2022).

Seed germination of the species is very poor due to seed dormancy (Azad et al, 2010). However in a study of seed germination, the control group consisting of cleaned and dry seeds showed a 39% germination rate, while treatments such as scarification and submersion in hot water or acid yielded higher germination rates. (Azad et al, 2010).

This woody species is rated as having a minimum generative time of four years (PIER, 2004). May begin flowering in the seedling stage (Waggy, 2009).

Chinaberry flowers from March through April or May. Fruits and seeds are produced by July and ripen from September to October (Waggy). In Florida chinaberry flowers from March through April or May. Fruits and seeds are produced by July and ripen from September to October. In Japan, chinaberry fruits ripen autumn through winter. Fruit often remains on the tree until the leaves fall, or longer (Waggy, 2009). Noted as flowering March - July in California (Preston & McClintock, 2012).

In North America, chinaberry seed is dispersed by animals, gravity, and possibly water. Birds and mammals eat chinaberry fruit and disperse its seed. Cattle egrets in Texas use fruitbearing twigs of chinaberry for nesting material, thus dispersing its seed. Seedlings emerge in abundance near the parent plant, suggesting that much of the seed is gravity dispersed. In Hawaii, chinaberry does not appear to have a natural dispersal agent and is thought to be dispersed by humans. In Africa, chinaberry is
dispersed by water and birds (Waggy, 2009).

In North America, Chinaberrytree seed is dispersed by animals, gravity, and possibly water. In Africa, chinaberry is dispersed by water and birds (Waggy, 2009).

Propagules not likely to disperse as a produce contaminant (PIER, 2004).