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Black Locust

Robinia pseudoacacia

Summary 6

Robinia pseudoacacia, commonly known as the black locust, is a tree of the genus Robinia in the subfamily Faboideae of the pea family Fabaceae. It is native to the southeastern United States, 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. A less frequently used common name is false Acacia, which is a literal translation of the specific epithet.

Associated forest cover 7

Black locust develops and grows best in cove or mixed mesophytic  forests of the central and southern Appalachian Region. These  forests are usually highly productive and characterized by a  large and variable number of species. The species is often a  component of mature forest on such sites but is seldom very  abundant. Black locust is listed as a component of the Mixed  Mesophytic Forest (6). In the Cumberland Mountains of Kentucky,  it made up about 1 percent of the mixed mesophytic forest on  north and south slopes but is considered as more properly  belonging to other communities and as a relict from preceding  stages or accidentals from nearby unlike communities. It is not  listed as a component of oak-hickory forest in the Ozark and  Ouachita Highlands or of oak-chestnut forest in the southern  Appalachians but is listed as an associate of shortleaf pine (Pinus  echinata) and Table Mountain pine (P. pungens) in the  oak-pine communities of the oak-chestnut forest region.

    In the forest cover type Black Locust (Society of American  Foresters Type 50) the species is in pure stands or makes up the  majority of stocking (15). Black locust is listed as an associate  in only two other types: Yellow-Poplar (Type 57) and  Yellow-Poplar-White Oak-Northern Red Oak (Type 59). Black locust  is a pioneer type, usually man-influenced, and temporary. It  follows disturbances and may be natural or planted. The type is  found locally throughout the Eastern United States and in  southern Canada. Black locust makes up a majority of the stand  during early stages but is short lived and seldom matures to a  sawtimber stand. A wide variety of species become associated with  black locust and usually replace most of it. On good sites,  single trees or small groups may persist, grow to a large size,  and form a small part of the ultimate canopy layer.

Associations 8

Foodplant / saprobe
immersed in bark, in clusters of 2-5, stromatic pseudothecium of Aglaospora profusa is saprobic on dead twig of Robinia pseudoacacia
Remarks: season: 10-1

In Great Britain and/or Ireland:
Foodplant / parasite
fruitbody of Agrocybe cylindracea parasitises branch of Robinia pseudoacacia
Other: minor host/prey

Foodplant / pathogen
Armillaria mellea s.l. infects and damages Robinia pseudoacacia

Foodplant / internal feeder
larva of Bruchidius cisti feeds within pod wall of Robinia pseudoacacia
Remarks: Other: uncertain

Plant / associate
adult of Bruchidius varius is associated with Robinia pseudoacacia
Remarks: season: (late 7-early 10, late 4)5-6

Fungus / saprobe
pycnidium of Camarosporium coelomycetous anamorph of Camarosporium robiniae is saprobic on dead wood of Robinia pseudoacacia

Foodplant / saprobe
clustered or linear, subiculate pseudothecium of Cucurbitaria elongata is saprobic on dead twig of Robinia pseudoacacia

Foodplant / saprobe
immersed, plurilocular stroma of Cytosporina coelomycetous anamorph of Cytosporina ludibunda p.p. (Robinia form) is saprobic on branch of Robinia pseudoacacia

Foodplant / saprobe
immersed, in small groups perithecium of Diaporthe oncostoma is saprobic on dead twig of Robinia pseudoacacia
Remarks: season: 12-2

Foodplant / saprobe
fruitbody of Ganoderma australe is saprobic on dead trunk of Robinia pseudoacacia

Foodplant / parasite
fruitbody of Ganoderma lucidum parasitises live stump of Robinia pseudoacacia
Other: minor host/prey

Foodplant / saprobe
sometimes effuse Gliocladium anamorph of Gliocladium roseum is saprobic on wood of Robinia pseudoacacia

Foodplant / saprobe
fruitbody of Meripilus giganteus is saprobic on dead trunk (large) of Robinia pseudoacacia

Fungus / parasite
Microsphaera pseudacaciae parasitises Robinia pseudoacacia

Foodplant / saprobe
stromatic perithecium of Nectria pallidula is saprobic on dead twig of Robinia pseudoacacia
Remarks: season: 8-1

Foodplant / open feeder
larva of Nematus tibialis grazes on leaf of Robinia pseudoacacia
Other: sole host/prey

Foodplant / gall
larva of Obolodiplosis robiniae causes gall of rolled leaf margin of Robinia pseudoacacia

Foodplant / parasite
fruitbody of Perenniporia fraxinea parasitises live trunk (base) of Robinia pseudoacacia
Other: minor host/prey

Foodplant / spot causer
amphigenous, numerous, very small, scattered, immersed, pallid acervulus of Phloeospora coelomycetous anamorph of Phloeospora robiniae causes spots on live, fading leaf of Robinia pseudoacacia
Remarks: season: autumn

Foodplant / feeds on
gregarious to linearly arranged, covered, then raising and bursting pycnidium of Phomopsis coelomycetous anamorph of Phomopsis oncostoma feeds on branch of Robinia pseudoacacia
Remarks: season: 1-7

Foodplant / feeds on
crowded or solitary, embedded in rows, then erumpent pycnidium of Phomopsis coelomycetous anamorph of Phomopsis petiolorum feeds on branch of Robinia pseudoacacia

Foodplant / gall
Phytoplasma (ined) causes gall of twig of Robinia pseudoacacia

Foodplant / saprobe
fruitbody of Rigidoporus ulmarius is saprobic on dead, white-rotted stump (large) of Robinia pseudoacacia

Foodplant / pathogen
Robinia Mosaic virus infects and damages mosiaced, deformed leaf of Robinia pseudoacacia

Foodplant / hemiparasite
haustorium of Viscum album is hemiparasitic on branch of Robinia pseudoacacia

Biology and spread 9

Black locust reproduces vigorously by root suckering and stump sprouting to form groves (or clones) of trees interconnected by a common fibrous root system. Physical damage to roots and stems increases suckering and sprouting, making control difficult. Black locust clones easily spread in quality and restorable natural areas. Although black locust produces abundant seeds, they seldom germinate.

Climate 10

The native range of black locust is classified as humid, with two  local areas of superhumid climate (43). The range includes the  cool temperate moist forest, warm temperate montane moist forest,  warm temperate montane wet forest, and warm temperate moist  forest life zones (38).

    Native black locust appears under the following ranges of climatic  conditions (45). January normal daily temperatures: maximum, 2°  to 13° C (36° to 55° F); minimum, -7° to 2°  C (20° to 36° F); average -4° to 7° C (25°  to 45° F); August normal daily temperatures: maximum, 27°  to 32° C (81° to 90° F); minimum, 13° to 21°  C (55° to 70° F); average, 18° to 27° C (64°  to 81° F); mean length of frost-free period, 150 to 210  days; normal annual total precipitation, 1020 to 1830 mm (40 to  72 in); mean annual total snowfall, 5 to 152 em (2 to 60 in).  Black locust has been successfully introduced into many parts of  the world where the climatic conditions are different from those  of its native range.

Damaging agents 11

Black locust is severely damaged by  insects and disease, probably more than any other eastern  hardwood species. Ubiquitous attacks by the locust borer (Megcallene  robiniae) and by the heart rot fungi Phellinus rimosus  or Polyporus robiniophilus make growing black locust  for timber production impractical. Locust borer larvae construct  feeding tunnels throughout the wood, and the holes serve as entry  points for heart rot fungi that cause extensive wood decay.

    Locust borer attacks can begin at a young age and damage can be so  extensive that trees are not suitable for fence posts. Many  plantations planted in reclamation projects were seriously  damaged, but more trees could be used if cut as soon as they  reach post or mine-prop size. Slow-growing trees on poor sites  are most susceptible to borer attack. On sites where tree vigor  is low, repeated attacks often reduce black locust to sprout  clumps. Damage to the sprouts is often as severe as in the  original stem (37).

    Outbreaks of the locust leafminer (Odontota dorsalis)  occur almost yearly. Black locust trees throughout an entire  region are often defoliated, and during years of low rainfall  many are killed. Attacks by the locust twig borer (Ecdytolopha  insiticiana) occur over a wide area and in heavily infested  areas seedling mortality may be high. Black locust is attacked by  a wide variety of other insects that cause some degree of damage  (3).

    Common diseases are heart rot and witches' broom disease, caused  by a virus, Chlorogenus robiniae. In the southern  Appalachians most large trees are infected with heart rot and  decay of trunk wood is extensive. In the Texas root-rot belt,  black locust is extremely susceptible to Phymatotrichum  omnivorum (21). In New Brunswick, plantings of black locust  are not recommended because of high mortality and dieback of  branches caused by Nectria cinnabarina and because of  superior performance by conifer species (40).

    Although black locust is moderately frost hardy in the southern  and central Plains, cold weather damage has occurred in the  colder parts of its range (37). In the Appalachian region, it is  highly susceptible to frost damage (44). Although the species has  been reported to be very susceptible to fire damage, researchers  concluded that parts of a study area in Illinois would be rapidly  converted to black locust thickets if fire was the only  management tool used (2).

Description 12

Black locust has a shallow, aggressive root system. The bark of black locust is deeply furrowed and is dark reddish-brown to black in color. It has an alternate branching pattern, which creates a zigzag effect. A pair of sharp thorns grows at each node. They are ½ to ¾ inches long, and very stout.

The pinnately compound leaves are 8 to 14 inches long, with 7 to 19 short stalked leaflets. These dull green leaflets are ovoid or oval, 1 to 2 inches long, thin, scabrous above and pale below.

The separate male and female plants have sweetly fragrant flowers that are creamy white with five petals (bean-like) arranged in a pyramidal spike. They usually bloom in May or June. Heavy seed production can be expected annually or biannually. The legume type seed is produced in a flat, brown to black pod, which is 2 to 4 inches long. There is an average of 25,500 seeds per pound. Although black locust is a good seed producer, its primary means of spread is by both rudimentary and adventitious root suckers.

History in the united states 13

Black locust has been planted extensively for its nitrogen fixing abilities, as a source of nectar for honeybees, and for fenceposts and hardwood lumber. The clonal pattern of growth and connected roots are promoted for erosion control. It is also used for mine soil reclamation. Black locust is susceptible to some damage from two native insects, the locust borer (Megacyllene robiniae) and the locust leafminer (Odontota dorsalis).

Sources and Credits

  1. (c) TCDavis, some rights reserved (CC BY-NC-ND), http://www.flickr.com/photos/30556912@N00/509950940
  2. (c) laurent.breillat, some rights reserved (CC BY-NC-ND), https://www.flickr.com/photos/laurentbreillat/4641237419/
  3. (c) Steven J. Baskauf, some rights reserved (CC BY), http://bioimages.vanderbilt.edu/baskauf/29725
  4. (c) 2008 Keir Morse, some rights reserved (CC BY-NC-SA), http://calphotos.berkeley.edu/cgi/img_query?seq_num=265027&one=T
  5. (c) 2008 Keir Morse, some rights reserved (CC BY-NC-SA), http://calphotos.berkeley.edu/cgi/img_query?seq_num=265029&one=T
  6. Adapted by Jonathan (JC) Carpenter from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Robinia_pseudoacacia
  7. (c) Unknown, some rights reserved (CC BY-NC), http://eol.org/data_objects/22779463
  8. (c) BioImages, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22923963
  9. (c) Unknown, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22948831
  10. (c) Unknown, some rights reserved (CC BY-NC), http://eol.org/data_objects/22779461
  11. (c) Unknown, some rights reserved (CC BY-NC), http://eol.org/data_objects/22779471
  12. Public Domain, http://eol.org/data_objects/1393224
  13. (c) Unknown, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22948830

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