Discovery siteFrom the Discovery Site
Sweeney Ridge Hiking Trails

Christine Case, Skyline College


You will experience the "good tidings" of nature if you take a few precautions for your walk. Dress for the weather which can range between 60°C fog and 80°C sunshine within a few hours and carry water and a snack. Stay on the trails to avoid destroying vegetation and to avoid poison oak and ticks.

poison oak


Poison Oak
Poison oak is plentiful in the coastal scrub. It is one of the few deciduous (sheds its leaves in winter) plants in this region. In the fall, its leaves turn red. In winter it appears as leafless, reddish twigs. New buds appear in February and mature to bright, shining green leaves in summer. The plant has white flowers and white berries. The lobed leaves are in threes - poison oak lacks spines on the leaves and stems while blackberries have spines. This plant produces chemicals called catechols. Many people are allergic to catechols and contact with the plant or clothing that has touched the catechols produces a skin rash .



Ticks wait on bushes for passing rabbits and deer. The tick attaches to a host with its mouth and eats blood. If you walk through the brush, check your clothing for ticks. Ticks are arachnids like spiders because they have 4 pairs of legs. A hungry tick is about 4 mm long. A tick engorged with blood may be 5 times that size (to 2 cm). The Western Black­legged tick can transmit Lyme Disease

In the United States, ticks transmit more vector-borne diseases than any other arthropod. In 1995, Lyme Disease was the ninth most frequently reported of the 52 diseases that are reportable to the Centers for Disease Control and Prevention, with 3.7 cases per 100,000 people.

Click on the ticks to
DiseasesSee the 9 most common tick-borne diseases in the U.S.
ProblemTry a medical problem about ticks.