Dunes Wonderland Trail #12: Suckering Super-Spreader
The final cache in this 12-cache series, a small screw-capped camo-taped tube, is hidden in a small tree at a quiet, shady corner of this part of Clovelly adjacent to the golf course. See GCA3BT8 DWT#1 for details of the trail.
As with DWT #11, if wished, the cache can be done as a quick Park 'n' Grab, in which case the terrain would be 1.5.
As I was completing hiding the cache, the owner of the adjacent house came along walking his dog. So, after exchanging greetings I asked if he knew what plant it was – he replied that it was ‘an acacia’.
Later, after some searching, I discovered it was not (quite) an acacia but rather a pseudoacacia . . .
The black locust or false acacia (Robinia pseudoacacia) is a medium-sized hardwood deciduous tree, in the legume family Fabaceae. British colonists at Jamestown discovered this species in 1607 and named it for its resemblance to the Carob or Old World Locust (Ceratonia siliqua). Posts of its durable timber served as corner posts for the colonists' first homes.
It is endemic to a few small areas of the USA but has been widely planted and naturalized elsewhere in temperate North America, Europe, Southern Africa and Asia and is considered an invasive species in some areas. It needs careful planting planning and subsequent management to avoid rampant spread.
It typically reaches 12–30m with a trunk diameter up to 1.22m. It is a very upright tree with a straight trunk and narrow crown that grows scraggly with age. The dark blue-green compound leaves with a contrasting lighter underside give this tree a beautiful appearance in the wind and contribute to its grace.
It is shade-intolerant species and therefore typical of young woodlands and disturbed areas where sunlight is plentiful and the soil is dry. In this sense, it can be considered a weed tree. It also spreads by underground shoots or suckers, which contributes to the weedy character of this species.
Young trees are often spiny, but mature trees often lack spines in early summer it produces large flowers in intensely fragrant clusters reminiscent of orange blossoms. The leaflets fold together in wet weather and at night (nyctinasty), as some change of position at night is a habit of the entire leguminous family.
The number of spines varies - some trees are densely prickly and other trees have none. Its wood is pale yellowish brown, heavy, hard, strong, close-grained, and very durable/rot resistance in contact with the ground.x`
It reproduces both sexually via flowers, and asexually via root suckers. The flowers are pollinated by insects, primarily by Hymenoptera (eg, bees, wasps, ants). Root suckers are an important method of local reproduction of this tree. The roots may grow suckers after damage (by being hit with a lawn mower or otherwise damaged) or after no damage at all. The suckers are stems which grow from the roots, directly into the air and may grow into full trees.
The main trunk also has the capability to grow sprouts and will do so after being cut down. This makes its 
removal difficult as the suckers need to be continually removed from both the trunk and roots or the tree will regrow. The suckers allow it to grow into colonies which often exclude other species. These colonies may form dense thickets which shade out competition.
The tree was identified in 1607 at Jamestown by British colonists, who used the timber to build houses. It was introduced into Britain in 1636. The genus is named after the royal French gardeners Jean Robin and his son Vespasien Robin, who brought the plant to Europe in 1601, in what may be regarded as a reintroduction. A black locust planted by Vespasien Robin still exists in the Square René Viviani in Paris.
Its range has been continually expanded by distribution for landscaping and now includes Pakistan, India, Australia, Canada, China, Europe, Northern and South Africa, temperate regions in Asia, New Zealand, Southern South America.
It is an interesting example of a plant species considered invasive even on its native continent. Because it can dominate and shade open habitats it will for example convert grassland ecosystems into a forested ecosystem where the grasses are displaced. It is listed as an invasive in parts of the USA, Australia (an environmental weed). In South Africa, it is regarded as a weed because of its suckering habit.
When growing in sandy areas this plant it can enrich the soil by means of its nitrogen-fixing nodules, allowing other species to move in but it may replace other vegetation which cannot fix nitrogen.
It is a typical early successional plant - a pioneer species growing best in bright sunlight and does not handle shade well. It specializes in colonizing disturbed areas and edges of woodlots before it is eventually replaced with taller or more shade-tolerant species
It hosts numerous lepidoptera and provides valuable cover when planted on previously open areas. Its seeds 
are eaten by birds and squirrels and some birds may nest in the trunk with are often infected by heart rot in older trees.
Uses: Bees love the flowers and it is a major honey plant in some countries and the source of the renowned acacia honey. It is easily propagated from roots, softwood, or hardwood. Cultivars may be grafted, ensuring that parent and daughter plants will be genetically identical.
It is excellent for growing in highly disturbed areas as an erosion control plant. Its shallow, aggressive roots help hold onto the soil, and nitrogen-fixing bacteria on its root system allow it to grow on poor soils, making it an early colonizer of disturbed areas. Obviating the need for mass application of fertilizers, it and other nitrogen-fixing trees and shrubs have become import in managed forestry.
It is planted for firewood, as it grows rapidly, is highly resilient in a variety of soils, and grows back rapidly after harvest from the existing root system. Note that the cache tree has been coppiced – trimmed at about head height – promoting new growth.
In Europe, it is often planted along streets and in parks, especially in large cities, because it tolerates pollution well. Numerous cultivars are available – of which the cache tree may be one.
Food and medicine: In Indian traditional medicine, parts are used as laxative, antispasmodic, and diuretic. In Romania the flowers are sometimes used to produce a sweet, perfumed jam (see here for a recipe from a forager’s blog).
In France, Italy and Romania, its flowers are eaten as beignets after being coated in batter and fried in oil. They are also eaten as tempura in Japan.
See here for more information on this fascinating tree.
Videos: see here (description), here (use in small garden), here (a forgotten tree – overview) and here (benefits).