Boxelder

 

 

Common Name: Boxelder, Ash maple, Three-leaf maple, Sugar ash, Manitoba maple (Canada), American maple (Russia and Italy), Water maple (UK) – The incongruous common name given to this maple family tree is due to the similar attributes of its white wood to that of the box or boxwood and due to its pinnate compound leaves like the elder.

Scientific Name: Acer negundo – Acer is the generic name for maple trees with good reason; it is the Latin word for maple tree. It is also the Latin word for ‘sharp,’ the etymological rationale is that maple leaves have sharp points. The species name is more abstruse, deriving from the Sanskrit nirgundi which is the name for plants of the grape vine genus Vitex. More particularly, Vitex negundo is a shrub that is native to south Asia also called the chaste tree with three to five leaflets similar in appearance to the leave arrangement of A. negundo. The scientific name is in essence “a maple tree with leaflets.”

Potpourri:  The boxelder tree is one of the many curiosities of North American botany which confronted the pioneer Old World naturalists with the enigmatic diversity of New World plants. This eventually led to the taxonomic system devised by Carolinus Linnaeus to sort things out according to physical similarities. The Linnaean taxonomic system is still in use today though upset by the real relationships revealed by DNA sequencing. Common names preceded the systematics of science to create some peculiar nomenclatures; the boxelder is a case in point. The early settlers had never seen this native North American shrubby tree but evidently noted that it had the white wood of the shrub they knew as box (Buxus sempervirens) and opposite and pinnate leaves like their native elders (Sambucus spp). Since both of the familiar plants were shrubs and since the new plant seemed to have the characteristics of both, boxelder was not a illogical choice. The name stuck; a maple tree called boxelder the result. The confusion is somewhat justified in that the leaflets have only a marginal resemblance to the standard maple leaf. The three to five opposite leaflets are marginally lobed and not consistent; some of the leaflets are nearly smooth around the edge.

The boxelder has the broadest range of all the maples native to North America, extending from the Atlantic seaboard westward to California and from Canada south to Central America. The USDA recognizes six subspecies based on relatively minor variations in leaflet numbers and branch coloration that are associated with geographic regions; the California variant of the west differs subtly from the Texas variant in the south-central midlands. The profligacy of the boxelder is a direct result of its successful adaptations that promote growth in marginal habitats, notably wet bottomlands. Tolerant of near anaerobic conditions, the boxelder thrives in heavy, wet soils; it can survive flooding for up to a month and is among the first colonizers (called pioneer species) of alluvia. This is in part because of its shallow, fibrous root system, advantageous in adsorbing the higher levels of oxygen of the near surface soil. For the same reason, boxelders thrive in heavy clay soils of disturbed areas. A second factor in boxelder profligacy is the production of legions of seeds with a high germination rate. The indehiscent (not opening) seeds are at one end of long, aerodynamically curved wings that promote wind dispersal distant from the parent tree. The fruits are paired and hang in groupings that look like a set of keys; this type of seed is called a key for that reason. The winged seed is also called a samara which is the Latin word for the similar elm seed.

 

Due to its shallow roots and fecund seeds, the boxwood grows and spreads with celerity in marginal soil conditions; it has historically been used in remediation of deforested waste areas. Wind breaks called shelterbelts were widely planted in the Great Plains to reduce soil erosion. Boxelders were also useful in urban and suburban settings for watery riparian habitats and in the disturbed corridors of road access cuts; cultivars were even developed to accentuate fall colors. The boxelder was introduced to Eurasia in the late 17th Century as an urban park curiosity, spreading through wind borne seed dispersal to the extent that it is considered a nuisance, invasive species in some regions of central Europe and China. The boxelder is not an economically important tree, as its wood is too soft for structural applications. However, as a burgeoning shrub that can be planted in otherwise barren ground, it is used as a source of wood fiber for plywood and fiberboard.

Native Americans had a number of interesting uses for the boxelder, most notably as a source of sugary sap. This was particularly true for the western tribes, as the boxelder is the only maple tree that grows extensively west of the Mississippi River basin; red, sugar and silver maples are predominantly eastern species. The Apache, Chiricahua and Mescalero boiled the inner bark to collect the crystallized sugar, saving the inner bark shavings as a winter food source. Cheyenne of the upper Midwest not only used ash maple sap to make candy, but also burned the wood as incense during ceremonies and as fuel for cooking. Navaho from the southwest in the Four Corners area used the wood for tubes, an apparent vestige of Anasazi who preceded them in this region between 200 and 1300 CE. Four flutes were discovered in an archaeological excavation of an Anasazi site in the Prayer Rock District in central Arizona in 1931. After a detailed evaluation, it was determined that they were all made from boxelder sometime between 354 and 769 CE based on a combination of dendrology and radiocarbon dating techniques. While boxelder would not be a particularly appropriate wood for this application – it is not ver durable and has solid heartwood that would be difficult to bore – it was very likely the only wood readily available.

The boxelder has the dubious distinction of having a namesake parasite that feeds on its sugary sap – the boxelder bug (Boisea trivittata). It is a true bug of the Order Hemiptera (half-winged) that is closely related to the stink bugs in a distinct family called the scentless plant bugs. This is fortunate, as the boxelder bug, like the ladybird beetle, has the propensity to seek warmth during winter inside houses often in pestiferous numbers; if it smelled it would be an even more unwelcome guest. True bugs are so named to distinguish them from the generic bug that is often applied a variety of other insects. True bugs are taxonomically categorized as having fore wings called hemelytra that fold flat over the back, rear wings for flying and a conspicuous triangular shield called a scutellum (little shield in Latin) mounted between them. The life cycle is typical of all metamorphosing insects. The eggs hatch into nymphs in the late spring that feed on the boxelder shrubs on which they were laid by inserting sucking mouthparts to remove fluid from the leaves. Thus nourished, they grow to adulthood, and depending on the weather and season, lay the eggs of a second generation before the cold of autumn drives the adult females into hibernation. In that their adaptive behavior is inexorably linked to the boxelder, over-wintering adult females do not lay eggs indoors, as the nymphs on whom species survival depends would starve.