A Low-Salt Diet
by Barbara Walvoord
Originally published in the Lathrop Lamp Post Jan. 13-19, 2018
Walking in the east campus woods recently, some friends and I came upon several trees gnawed like this one in the photo. After some debate and research (is it bear? termites? pileated woodpecker? Bigfoot?) we decided it’s porcupine. Just because the bark is up in a tree, no problem. Porcupines are great tree climbers.
The problem with trees, though, is that they are a low-salt food. Matthew Miller of the Nature Conservancy, says, “North American porcupines (Erethizon dorsatum) feast on a high-potassium, low-sodium diet of foliage, causing them to excrete high levels of sodium. This creates a sodium-potassium imbalance,” so porcupines crave salt. https://blog.nature.org/science/2015/03/30/believe-porcupines-eat-bigfoot-bones-outhouses-myths/
Human sweat is high in salt, so porcupines eat wooden-handled tools (with human sweat on them), car hoses that have been splashed with road salt, and any wooden shed or box that stores salt.
But what’s the saltiest wood in the forest? The area surrounding the seat in a backwoods boy-scout camp outhouse. Human urine is high in salt, and boy scouts are boys. Miller, who leads boy scout camps, includes this photo of the inside of an outhouse, with the toilet seat precariously perched on some of the only wood that’s not been eaten, and the porcupine culprit right there gnawing away.
A porcupine finds a salty snack = urine + plywood. Photo by Education Specialist/Flickr through a Creative Commons license. File http::///C:/Users/Barbara/Pictures/porcupine%20Critter%20Damage%20_%20Porcupines%20are%20great%20except%20when%20they%20take%20…%20_%20Flickr.htm
In earlier days, the timber industry hunted porcupines because supposedly they would girdle trees and reduce the harvest. Turns out porcupine predation is not a factor in tree plantation productivity.
However, this gives me an idea. At Lathrop, we have some trees such as Norway maple, Amur cork, and Autumn Olive, all dangerously invasive in our forests. I wonder what would happen if we just rubbed some salt all around their trunks….