VALUE AND USE
SPECIES: Robinia pseudoacacia | Black Locust 



WOOD PRODUCTS VALUE : 
Black locust wood is close-grained,strong, hard, heavy, and durable
[12,45].  Past and present uses of black locust wood include fenceposts,
fuelwood, mine timbers, poles, railroad ties, insulator pins, tool
handles, boxes, wooden novelties, and pulp [45].  Black locust is not an
important commercial timber species in the United States, largely
because of its poor growth form and frequent locust borer infestations
[45].  In Europe, however, black locust products include paneling and
construction boards in addition to uses already mentioned [50].  Carey
and Gill [18] rated black locust as excellent (their highest rating) for
firewood.  Black locust has the highest heat equivalent of any North
American woody species.  One cord of black locust wood (at 20 percent
moisture) yields as much heat as approximately 1.12 tons of anthracite
coal [9,20].



IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
In Illinois black locust provides excellent food and cover for northern
bobwhites where it invades old fields or burned sites [32].  Despite its
hard wood, black locust is susceptible to insects and rots, and is
therefore a good nest-cavity tree, particularly for woodpeckers [45].
Black locust trees have a disproportionate number of cavities (with
nests) in an oak-hickory forest in West Virginia.  Most of the black
locust trees in this forest are suppressed, showing poor vigor, or dead
[17].  In Kentucky, fledged eastern screech owls roost on black locust
branches during the summer at a frequency higher than expected based on
availability.  Screech owls are rarely found in cavities in the summer,
but fall and winter use of cavities is frequent [7].  Black locust is
more prone to snag formation than is red maple (Acer rubrum), American
beech (Fagus grandifolia), or red oaks (Quercus, subgenus
Erythrobalanus) [58].

Carey and Gill [18] rated black locust as only fair (their lowest
rating) in browse value for all species of wildlife.  However, young
growth is browsed by white-tailed deer and cattle [15].  In Georgia,
black locust is rated as choice browse for white-tailed deer [41].
Rabbits eat winter twigs of black locust [12].

Young growth is nutritious livestock forage, although all parts of the
plant contain substances toxic to livestock [15].  Horses are more
sensitive to the toxic substances than are other livestock species
[15,76].  Black locust poisoning is rarely fatal [52], and small amounts
of black locust materials are apparently acceptable.  Feeds containing
up to 20 percent black locust meal have been used for poultry, rabbits,
and ruminants [15].  In Europe, black locust is planted and mowed as
livestock forage [50].

Black locust seeds are eaten by northern bobwhites and other game birds
and squirrels, but do not constitute an important food source [45].  The
flowers are a source of nectar for honeybees and hummingbirds [31].


PALATABILITY : 
Palatability ratings of black locust in Utah are fair for cattle and
horses and poor for sheep [29].


NUTRITIONAL VALUE : 
Black locust is rated fair in energy value and poor in protein value
[29].  However, black locust has relatively high leaf nitrogen levels
[10].  It is planted in Europe as a nutritious livestock forage,
rivaling alfalfa in nutritional value [50].


COVER VALUE : 
Cover value of black locust in Utah is fair for elk, mule deer, and
upland gamebirds, poor for pronghorn and waterfowl, and good for small
nongame birds and small mammals [29].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Natural revegetation of mined sites in southwestern Virginia and
northeastern Tennessee includes black locust, usually as root sprouts
from adjacent forests [65].  Volunteer black locusts can modify sites to
favor forest reestablishment [78].  Black locust vegetatively colonizes
mined sites that have been reclaimed to grassland [40].

Black locust was the most frequently and widely used tree for mine soil
plantings in the United States as of 1981 [79].  It is also planted in
some areas of Ontario, Canada [83].  Black locust is planted on mine
spoils to ameliorate poor soil conditions and to stabilize mine soils
and/or badly eroded or gullied land [45,65,72].  It is adapted to a wide
range of minesoil types [79].  Its habit of sprouting has been a cause
of concern where its long term occupation of a site is undesirable [78].

Surface-mined lands that are otherwise unproductive may produce good
economic returns if planted for short-rotation, woody biomass fuels
[9,20].  Black locust may be productive for this purpose, since it
exhibits rapid early growth, and sprouts after cutting [9].  Biomass
yields were measured for black locust for various planting spacings
[37].


OTHER USES AND VALUES : 
Black locust is planted in shelterbelts, as an ornamental, for nectar
production for honey, and for fuel [31,50].

Black locust flowers have been used to make tea [76].  Tonic, purgative,
and emetic properties have been reported for the inner bark and roots
[24].


MANAGEMENT CONSIDERATIONS : 
The popularity of black locust for reforestation and revegetation of
mined lands in the United States is waning, primarily because of its
weedy habit and because of locust borer infestations. Herbaceous
perennials are more often selected for reclamation [78].  It is still
widely planted, however, and as of 1984 there were over one million
hectares of black locust plantations worldwide [10].

Black locust increases soil nitrogen through relatively high rates of
nitrogen fixation and accretion [39,63].  Acetylene reduction rates
(indicating nitrogen fixation) have been determined for nodulated black
locust roots [59].  A heavy litter layer is created early in stand
development.  The litter is subject to rapid decomposition, improving
soil structure and fertility [3].

Sapling stands of black locust (with other species) can grow out of
reach of white-tailed deer in as little as 10 years, reducing available
browse.  Browse can be increased by intensive silvicultural cleaning
(mechanical removal of aboveground portions of nondesirable stems),
which encourages black locust sprout formation [27].

Studies on the effects of interplanting black locust with other
hardwoods [34,71] or conifers [35,49] have reported improved growth of
the interplanted species.  Black locust-conifer interplantings show
greater success when conifer are planted from 5 to 8 years prior to
black locust [49].  Prior occupation of a site by black locust is
beneficial to planted hardwoods [19].  Decadent (due to locust borer
infestation) black locust stands (12 to 15 years old) were underplanted
with black walnut and yellow-poplar.  When the black locust trees died
out, the underplanted trees were left in good condition [78].  This use
as a nurse tree is not without drawbacks; black locust's thorny branches
can cause leader and bark damage to planted stems.  It is therefore
recommended that black locust make up no more than 25 percent of a
hardwood mixture [79].

Black locust can be hydroseeded with fertilizer and mulch.  This
treatment results in dense stands that provide rapid and fairly complete
site protection and stabilization [84].  On acidic mined sites, black
locust performance is improved by additions of lime to increase soil pH
[43].  Black locust plantings can be inoculated with Rhizobium bacteria
specific to black locust for improved performance [16].  Black locust
plantation failures have been attributed to poor site conditions,
including eroded, compacted, or clayey soils, low soil fertility, and
locust borer infestations [45].  Black locust planted on poor soils
(such as mine spoils) is often subject to locust borer infestations that
severely affect form and vigor [10,78].  Seedlings show positive
response to fertilizer [78].  

Prairie remnants along railroad rights-of-way in Wisconsin are
threatened by black locust invasion [42].  

Dense thickets of black locust root sprouts are sometimes produced after
clearcuts [45,55] or open shelterwood cuts [38] in stands previously
occupied by even minor amounts of black locust.  Black locust can be a
serious competitor on these sites for many years [55].  Black locust is
not detrimental when sprouts are scattered or in small clumps [85].  In
addition, its short lifespan, coupled with its nitrogen-fixing
character, may facilitate forest growth later in succession [10].

Control:  Hill prairie remnants in Illinois that were being invaded by
black locust were treated (and retreated where necessary) with 2,4-D
[51].  Bovey [11] lists 2,4,5-T as effective against black locust.
Other herbicides at least partially effective against black locust
include triclopyr [60,61], picloram [66], and glyphosate [81].  [61].
Herbicide treatments do not always control root sprouting [55].  Black
locust root sprouting can be prevented with auxin application [73].  Oak
seedling stands that are in danger of being overtopped by black locust
are improved by silvicultural cleaning [22].

Diseases: Black locust is susceptible to heart-rot fungi, witch-broom
virus, root rots, and Nectria fungi [45].

Insects:  The major pest of black locust is the locust borer, which
causes severe damage to form, wood quality and overall vigor in many
plantations.  Older trees that are already low in vigor are particularly
susceptible to locust borer infestation [20,45].  Other insect pests
include locust leafminers and locust twig borers [45].  A summary of
damaging agents listed by type and by black locust size class attacked
is available [2].

Other silvicultural concerns:  Black locust is subject to clipping by
rabbits, and deer browsing is sometimes severe in Los Angeles County,
California [69].

Related categories for Species: Robinia pseudoacacia | Black Locust