As you may have noticed, as part of the #OptOutside movement, a pretty significant movement of people around the nation chose to be outdoors this year rather than shopping on Black Friday, the day after Thanksgiving.

The movement started when the outdoors retailer REI declared in October that on Black Friday its 143 stores would be closed, most of its 12,000 employees would be off, and the company would not process online orders.

REI encouraged people to post photos of their outdoor experiences with the hashtag #OptOutside, and created a website and Twitter page for collecting outdoors options for the day. More than a million people became involved, and the states of Arizona and Colorado offered free entry to state parks. Alabama offered discounted camping. Save the Redwoods League, a nonprofit in California, offered free passes to the 49 state parks there; those ran out during the day on Friday. In Washington, Mt. Rainier and Olympic national parks were free as well.

If you'd like to see some of the notices posted on Twitter with the hashtag #OptOutside, go here.

Local municipalities across the nation offered ranger-led hikes, free outdoors events, or other promotions. In New York City, Nature World News went on one of several ranger-led hikes sponsored by NYC Parks, in the 2,800-acre Staten Island Greenbelt, an area of open space, forest, ponds, and 35 miles of trails at the center of the island.

On the 8-mile hike, we walked among many types of oaks, sweet-gum, and white pine, and heard about several invasive species, including multiflora rosa, which forms a green lattice-work of prickly vines over whole sections of landscape; and we saw long white pine cones sticky with sap. We also saw trees marked by bucks (male deer) attempting to scrape off the velvet that they wear on antlers in the spring, summer and early fall. Right now the deer are in "running season," our rangers explained. That is when bucks spar with one another and compete for mates. Rubbing their velvet on the trees also leaves behind their scent markings, which carry messages to does of their status in the herd and their viability as a mate.

While the rest of us were just hanging out and having a brisk walk after a very big meal the day before, it was a refreshing fall day in the woods.

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-Follow Catherine on Twitter @TreesWhales