Deer on the Right, No Deer on the Left


It’s an odd word.  If you’ve never seen it in print, it just looks wrong.  Still, you’ve probably already guessed what it means.  If an enclosure keeps deer in, then an exclosure keeps them out.

Botanists use exclosures to measure, among other things, the effects of overabundant deer on the forest ecosystem.  Although the measuring and analysis can get complicated, the concept is simple: Exclude deer from a small area (or sometimes a large one covering several acres), and then watch to see what happens.  But be patient.  This could take a while. 

Eventually, if those overabundant deer are still present on the outside of the exclosure, the areas inside and outside the fence will begin to look very different.  The exclosure in the photo was built over ten years ago, and the area inside still isn’t quite back to normal.  Already, however, it looks very different from what’s on the outside.  That’s what a normal, healthy forest looks like—a forest, that is, with a normal, healthy number of deer.

This particular exclosure is on a 6,000-acre preserve in northeastern Wisconsin called, oddly enough, “Dairymen’s.”  The club was started back in the 20s by a small group of wealthy dairy magnates who wanted a private playground in the north woods.  (Yes, they were the “big cheeses” of the dairy industry.)  They also wanted Dairymen’s to be a wildlife refuge where no hunting was allowed. 

Deer had been almost totally eliminated from northern Wisconsin, and they pretty much had been eliminated from the southern part of the state.  So back then a wildlife refuge was a great idea.  By the 40s, however, Dairymen’s had a new problem.  It actually had too many deer.  Looking for answers, the club’s Conservation Committee invited a consultant up from the University of Madison, a professor named Aldo Leopold.  He told them they had four times as many deer as the land could support, and advised them to open Dairymen’s to hunting.

They thanked him for his advice, and then ignored it.  Instead, they decided to solve the problem by feeding the deer.  That way, they figured, the land could support more deer.  As you can imagine, this only made things worse.  Eventually deer densities exceeded 100 per square mile.  The deer ate everything they were fed, but they also ate every bit of vegetation they could reach.  The closer to the lodge, the worse the overbrowsing.

In the 90s, members of Dairymen’s began working with Dr. Tom Rooney, a botanist from Wright University in Ohio.  This sort of thing is his specialty; he’s one of the world’s leading experts on the effects of overabundant deer on the forest ecosystem. 

Here, he’s standing next to an eastern hemlock that’s just outside another exclosure.  This sad little sapling looks like it just hopped out of a Dr. Seuss story.  It’s one long, skinny trunk with a single tuft of needles at the top.  Deer have been hitting this tree hard for a long, long time.  It’s finally tall enough so it’s about to break free and begin growing normally.

After a clearcut, an aspen sapling could reach this height over a single summer.  But this tree is probably older than you are.  The technical term botanists use to describe a tree that’s been browsed in this pattern is “lollipop tree.”  (This describes its shape.  Unfortunately, lollipops don’t actually grow on it.)

Here, Dr. Rooney and I are about to break into a larger exclosure down the road.  He’d misplaced the key, and we didn’t want to crawl under the fence.  Normally it’s a bad idea to mix botanists, beer, and boltcutters.  But in this case, I made an exception.

Next time: more about the deer of Dairymen’s—how bad things got, why they’re getting better, and what lessons this story holds for the rest of us.

© 2011 Al Cambronne

This Bud’s Not For You

This bud’s not for you.  Not if you’re a deer, it isn’t.

And that’s the explanation behind an apparent mystery.  Who knew that red pines had such lovely white flowers, and that they’d be blooming before the snow has even melted?

But no.  These blossoms are actually little scraps of paper that have been carefully stapled to thousands upon thousands of seedlings.  It was the only way to prevent their tender new growth from being nipped off by hungry deer.

If you think it must be a lot of work to do that, you’re right.  It has to be done in a way that doesn’t harm the tree, and yet is still tight enough so deer can’t easily nuzzle it off.  It’s done with paper that breathes, but is still quite durable.  These trees received their bud caps three or four years ago, and the caps are still there.  Here’s a close-up:


Most of these trees have grown to the point where they’re relatively safe from deer.  Plus, local deer populations here in northwest Wisconsin are now down significantly.  Deer hunters are mad as hell about that.  They blame wolves, the DNR, bears, and each other—in roughly that order.  (But that’s a whole other story.)

When these trees were planted, however, deer were so plentiful that tender new seedlings without bud caps didn’t stand a chance.  After repeated replantings, it was time for the last-ditch bud cap strategy.  Remarkably, a wildlife biologist told me that during this same period he received a phone call from an angry citizen who hunts less than a mile from here.  The hunter said there were no deer left for miles around, and it was his worst year of hunting ever. 

Meanwhile, frustrated foresters were telling a different story.  Bud caps are a very labor-intensive solution, but there was no other option.  The labor was provided by migrant workers from Mexico, the same crews that come every spring to plant these seedlings. 

Every spring, one of these crews stay at a resort down the road from us.  The contractor gets a special rate, and the resort gets extra business during the weeks before fishing season.  In anticipation, our local IGA stocks extra tortillas, beans, hot sauce, and similar items that have been moving more slowly all winter.  These guys work hard, dark to dark, six days a week.  They’re hungry when they get back.

Occasionally, these crews are here at other times of year.  They arrive in the night, quietly and unannounced.  Their secret mission: To protect vulnerable pine seedlings by battling deer with office supplies.  Instead of being issued a shovel, each worker is given small scraps of paper and a loaded stapler.  It’s a dirty job, but someone’s got to do it.

© 2011 Al Cambronne

The Last Happy Hour: Instant Winter Severity

Winter Severity Index

During the past 24 hours, we’ve been getting walloped by our first major snowstorm of the season.  We’ve received at least a foot of new snow on top of what we already had.

Meanwhile, today is the last day of Wisconsin’s gun deer season.  Bow season began back in September, and continues until January 9.  In October, gun hunters in some deer management units had an early four-day antlerless season.  In November, we had the regular nine-day gun season, followed by a ten-day muzzleloader season that just ended Wednesday.  Thursday morning, persistent hunters could head back out with their breechloaders for a four-day late antlerless season that will end later this afternoon.

It’s not easy being a deer.  True, all this new snow will keep most hunters out of the woods today.  But sometime early this morning, we crossed a threshold.  The weather officially became severe—doubly severe.  Last night the temperature was around ten below, and we now have over 18” of snow on the ground.  If this keeps up, we’ll have a long, severe winter. 

Wildlife biologists measure such things with a tool called the Winter Severity Index (WSI); according to the WI DNR, it’s calculated by “…adding the number of days with 18 inches or more of snow on the ground to the number of days when minimum temperatures were 0 degrees Fahrenheit or below between December 1 and April 30.  If you think of it as adding up points, a day when both conditions occurred would get two points.  At the end of the winter all the points are added up, resulting in the WSI number for the whole winter. A winter with an index of less than 50 is considered mild, 50 to 79 is moderate, 80 to 99 is severe and over 100 is very severe.”

The WSI isn’t perfect; 17” of snow topped by an icy crust doesn’t earn that day a second point–no matter how unpleasant conditions might be for cold, hungry deer.  Similarly, there’s a big difference between one below and forty below.  Still, the WSI at least allows rough comparisons from one winter to the next.

So far this month, it’s been below zero about every other night.  Five points right there.  Just checked the forecast; more subzero nights on the way.  Looks like we’ll be racking up two points a day until later in the week.  By then, we could be getting more snow.