Update: March 7, 2014
Daylight Savings Time is here and it is prime mountain biking season for the warmer parts of the country. Mtbr is based in Northern California and we’ve had the driest January and February on record. Poison oak shoots are already exploding in their red, juicy glory. This is a good time to brush up on your poison knowledge as identification and prevention is key.
“causes severe itching, evolves into inflammation, colorless bumps, and then blistering when scratched.”
We are not botanists but it is our business to understand this evil weed as it affects our mountain biking. No other trail hazard out there can be as damaging and bothersome to our riding. The problem is, it doesn’t have barbs or jagged edges that will cut us and let us know that damage has been done. It is like a seed that will incubate over the next day or two. And when it’s ready to do damage, it can fester for weeks and months. It is not just an itch. It is a burning, skin eating disease that can stop us from riding, getting out in the outdoors, drinking beer. Basically, it can land us in the hospital. So read on and be informed.
What is it?
Poison oak, poison ivy, and poison sumac are plants that contain an irritating, oily sap called urushiol. Urushiol triggers an allergic reaction when it comes into contact with skin, resulting in an itchy rash, which can appear within hours of exposure or up to several days later. A person can be exposed to urushiol directly or by touching objects — such as bike clothing, gardening tools, camping equipment, and even a pet’s fur — that have come into contact with the sap of one of the poison plants days or weeks earlier
Urushiol oil is found in all parts of these plants, including the leaves, stems, and roots, and is even present after the plant has died. Urushiol is absorbed quickly into the skin. It can also be inhaled if the poison plants are burned. The smoke may expose not only the skin to the chemical but also the nasal passages, throat, and lungs. Inhaled urushiol can cause a very serious allergic reaction and can surely land a person in the hospital as no topical cleaners or ointments can reach the body’s internals.
What does it look like?
Poison Oak is highly variable in appearance. It varies from shrub to vine. The leaves vary from red to green. It has long stems, leaves in threes, small greenish flowers, and smooth seeds that are about 1/4 inch across. It is often lush in coastal canyons, but sparse in the mountain woodland. It is deciduous, and often looses its leaves in late summer, leaving it hard to recognize. But the long, straight branches give a clue.
Poison-oak is usually a shrub, though it sometimes becomes a vine several inches in diameter that grows high into the oak trees attached by air-roots. The leaves DO come in threes. They are shiney, without prickers, and the middle leaf has a distinct stalk. It is harder to identify Poison Oak in the winter, when it loses its leaves and looks like erect bare sticks coming from the ground. In the spring, it is easy to detect as the baby leaves shoot out in their full reddish glory. This is when the urushiol is most potent and the slightest contact with these reddish stacks will result in bad exposure.
Where is it found?
It is found in damp, semishady areas near running water and also thrives in direct sunlight, requiring water only in early spring. Any trail leading to a waterfall on California’s coast may likely be home to western poison oak; it can also be found in some inland mountain ranges, such as the Cascades.
It needs sunlight though so very shady places like redwood forests minimize the growth of these plants. Also, at higher elevation like over 6000 feet, they are not able to thrive.
The plant toxin produced by members of the genus Toxicodendron, called urushiol, is known for causing an uncomfortable, and sometimes painful, skin reaction. Urushiol is the main component of the oily resin that is found on the stems and leaves of poison ivy and several other related species (Hogan, 2008). It causes contact dermatitis — an immune-mediated skin inflammation (Kalish et al, 1994) — in four-fifths of humans.
What does it do?
Effects of poison oak are similar to those of poison ivy. It first causes severe itching, evolves into inflammation, colorless bumps, and then blistering when scratched. In late fall or winter, there are no leaves on the plants, so they can be difficult to recognize.