On a rare rainy week in the Sonoran Desert, Kate Van Roekel juts out her tongue in concentration as she confidently navigates an upper section of the Explorer trail within Tucson Mountain Park.

The trail charts a path through stands of huge, impossibly stoic saguaro cactus, found only at certain elevations in and around the Madrean Sky Islands, a series of isolated, desert mountain ranges. Their shallow roots extend from a central stem in every direction, akin to spokes on a wheel. They reach out radially for water, for connection, for life. The desert is thirsty and the dirt is perfect. The sky has cleared and the sun is setting low behind the Tucson Mountains.

Mountain biking in Tucson has matured through grassroots trail development efforts, transforming strenuous and sparse routes into an expansive network that now serves a broad range of skill levels and terrain preferences.

Two miles long and surrounded by cacti, creosote and mountains, Explorer is one of dozens of mountain bike trails in the Tucson Mountain Park west of town. The park was established in 1929 to protect 20,000 acres of desert ecosystem and outdoor recreation resources.

As Van Roekel rides, a popping thwack sounds from the straining lugs of tires suddenly releasing their grip from the rocks. The loose dirt crunches. Most walk this steep and loose section of the technically demanding trail. Breathing deeply, Van Roekel maneuvers her front wheel between small boulders to corner around a saguaro, handlebars daringly close to the cactus’ spines. Yet, with ease, she makes it.