Like everywhere else in temperate Alaska, the vegetation is often a serious obstacle if not a downright nightmare. Ferns, alder, cow parsnip and berry plants are just a few of the many species of plant life that make off-trail hiking a real challenge. Even in Denali State Park where developed trails are the main routes for foot travelers, the trail is often overhung with three to five foot tall plants that are more than willing to reclaim the manmade swath. You don't really know what vegetation is until you've attempted to break the trail in Alaska.
Bear warning signs are posted throughout Denali State Park. Recent sightings are generally enough to fill the page, even though visitation is light and those taking time to report sightings are few and far between. Sows with cubs are dangerous adversaries at all times. Make sure to make plenty of noise while hiking the backcountry, travel in company whenever you can, and watch for fresh signs of bear activity.
Denali State Park is black and grizzly bear country. Even though the park's 300,000+ acres are wild and scenic, the bears are never averse to picking up scraps or marauding untidy campgrounds for a bite to eat. It is essential, especially when hiking in the backcountry, to keep your food odors to a minimum and to keep a clean camp. If foods are left out, bears will begin to associate easy meals with humans, and eventually become problem bears (i.e. to be either relocated or destroyed).