While vacationing recently in Puerto Rico, I visited El Yunque National Park which contains the only the rainforest within the National Park system. El Yunque encompasses 4,000-foot mountain peaks, numerous streams, rivers and waterfalls within a vast, tropical, evergreen rainforest. Other than its southern location, the park offers a fair equivalent of the Adirondack experience.
Over the peaks, I saw such familiar northern species such as broadwing and redtailed hawks soaring on the thermals. The journey provided a most unique reprieve after spending several days in the urbanity of the crowded, sprawling city of San Juan.
My perspective changed as I entered a forest filled with new and unique sounds, scents and freshness. I could feel an overall sense of relief, that same type of calmness that comes after a hike or a paddle at home.
Later, back at our hotel, I found an interesting article in Men's Health magazine that may explain why I felt that way.
The article began, "You may finally have a legitimate reason to hug a tree. A hike in the woods can boost your immunity, say Japanese researchers. They found that men who walked through a forest for a total of 6 hours over 2 days experienced a 46 percent spike in their blood levels of natural killer cells, which are part of your body's SWAT team against invading viruses. Apparently, all trees release airborne chemicals called phytoncides that not only protect their foliage from microbes, but also help to stimulate our own immunity systems."
In the thick green forest, trees emit phytoncides to kill germs and protect from various molds and bacteria. Coniferous trees emit more Phytoncides than broad-leaved trees.
This concept was revealed in this recent exchange among sportsmen. I knew an old timer who grew or collected much of the food he ate. Beside doing it because he was a depression-era skinflint, he used to say, "The plants I grow in my garden or collect in the woods have to fight the same vermin, [bacteria, molds, viruses] that I do - the ones that live around here. They've developed immunities over hundreds of years to survive, so when I eat them I get the benefit of that evolution."