VALUE AND USE
SPECIES: Toxicodendron diversilobum | Poison-Oak 



WOOD PRODUCTS VALUE : 
NO-ENTRY


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Black-tailed deer and all classes of livestock browse poison-oak [53].
It is the most important black-tailed deer browse in some areas of
California [5,6].  Birds eat poison-oak fruits [53].


PALATABILITY : 
Poison-oak palatability is rated good to fair for horses and deer; and
fair to poor for cattle, sheep, and goats [53].


NUTRITIONAL VALUE : 
Percent crude protein in poison-oak foliage collected throughout
California averaged 24.2 in March, 20.6 in May, 10.1 in July, and 6.5 in
September [5].  Poison-oak is relatively high in phosphorus, sulfur,
and calcium as compared to other browse species [24].  The following
mineral content (percentage basis) was reported for the foliage [54]:

                   Ca     P     K     Mg     S
                 1.00   0.23  1.13  0.59   0.19


COVER VALUE : 
The federally endangered least Bell's vireo uses poison-oak for nest
sites in oak woodlands [25].  

Fremont cottonwood (Populus fremontii)/poison-oak woodlands contribute
to bird diversity and density in California [28].  A rare colony of
ringtail was found inhabiting a Fremont cottonwood/poison-oak woodland
on the Sacramento River [3].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Poison-oak has been recommended for use in restoration projects.
Information on propagation and handling methods to "minimize risks" to
planting crews is available [23].  Having worked on field crews in the
Sierra Nevada foothills, however, this author recommends using native
shrubs other than poison-oak for restoration.


OTHER USES AND VALUES : 
Urushiol has been found to mediate DNA strand scission.  This activiity
may have application in DNA sequence studies [70].

Native Americans used the stems to make baskets and the sap to cure
ringworm [15,60].  Chumash Indians used poison-oak sap to remove warts,
corns, and calluses; to cauterize sores; and to stop bleeding.  They
drank a decoction made from poison-oak roots to treat dysentery [60].


MANAGEMENT CONSIDERATIONS : 
Safety/Medical:  The entire poison-oak plant is covered with oily resin.
Human dermatitis results when skin comes in direct contact with the oil,
either by touching the plant or touching something that has contacted
it, such as clothing or firewood.  Urushiol is the poison present in the
oil [46].  Poison-oak does not cause dermatitis in wildlife or
livestock, but pets may react to it [53]. (See FIRE MANAGEMENT.) American
folklore holds that drinking the milk of poison-oak-fed goats bolsters
the immune system against poison-oak because the poison is present in
the milk in trace amounts.  Drinking the milk probably does not grant
immunity, however.  Analysis of milk from does fed a straight poison-oak
diet for 3 days showed no trace of urushiol.  Some urushiol was present
in the does' urine, but most was apparently catabolized [40].

Control:  Poison-oak is controlled by glyphosate, triclopyr, or 2,4,5-T.
Used alone, 2,4-D is ineffective.  Goats are an effective biological
control [40,50].

Other:  Poison-oak vines sometimes kill their support plant by
smothering or breaking it [46].

Poison-oak iblossoms are a source of good quality honey [46].

Related categories for Species: Toxicodendron diversilobum | Poison-Oak