ARBORETUM NEWS (NATURALISTSNOTES)

Thinking Like an Arboretum

SUNDAY, NOVEMBER 18, 2012

On an unseasonably warm November afternoon (not that I’m complaining, but it doesn’t feel NORMAL), we set out to “think like an Arboretum”. This annual tour takes its inspiration from Aldo Leopold’s essay “Thinking Like a Mountain”, published in 1949 as part of A Sand County Almanac, and a followup piece written in 1975 by Orie L. Loucks.

Loucks was a professor in botany at the UW, and a member of the Arboretum Committee, when he wrote “Community Integrity in the Arboretum”. He left the UW in the 1980s and went on to a distinguished career at Miami of Ohio, currently holding emeritus professor status there. The Nelson Institute for Environmental Studies at UW has a fellowship in his name.

Leopold wrote about killing a wolf, and later coming to a fuller understanding of the predator-prey relationship, since the removal of wolves allows an over-proliferation of deer, which in turn will defoliate trees and shrubs. Ultimately the habitat system deteriorates.

The broader concept, as Loucks argued, is to think like an ecosystem – to consider each organism’s place in the larger whole, and the consequences of removing or drastically reducing the population of any one element. He used the soil community as his example: tree roots and root hairs, mites, springtails, bacteria, fungi, and more. Each living thing plays its assigned role.

We’ve always timed our “Thinking Like an Arboretum” hike to coincide with the opening of deer hunting season in Wisconsin, since that’s a particularly appropriate time to be thinking about predators and prey, and questions of balance. This year it was even more topical, since for the first time, our state has a wolf hunt as well. Opinions are divided on the wisdom of that hunt, and how it’s being carried out; for purposes of these notes, suffice it to say that public attention has been focused on wolves and deer more than usual. As of the date of our tour, two of the wolf-hunting regions had already met their kill quota and had been closed.

I like to use a particular Wingra Woods route for this tour. I can’t come up with wolf habitat, since our acreage is not sufficient to support that animal; but there is a Wingra trail along which we can count on seeing deer sign every November.

First, we did a little diagonal across the southwest corner of Longenecker Gardens. Starting at the entrance arch, we angled through a few lilacs and magnolias and then passed under and around crabapple trees. The magnolias are showing fuzzy buds at the tips of their branches. Not to worry, this is normal. Unless the buds open early – and there is currently no sign of that—the new growth will not be harmed by winter temperatures.

A couple of squirrel dreys are visible in this area: large, leafy lumps near the tops of trees. Squirrels only build this type of nest in the wintertime. Using leafy branches provides extra insulation. In case you’re wondering, the entrance/exit hole is in the side of the structure, to prevent snow from getting in.

The crabapple trees, though leafless as usual at this time of year, are colorful with retained fruits. Our collection showcases many different sizes and colors of fruits; they’re an important food source for the Arboretum’s wildlife, including wild turkeys and many other species.

Leaving the garden through a gate in the fence that parallels the road, we crossed the paved drive and entered Wingra Woods at trail marker M-3. The first few hundred yards of this trail adjoin Nakoma Golf Course, and contain numerous invasive plants; but after that, the woods are of higher and higher quality and the sights get more interesting.

Like the dramatic, fresh “buck rub” visible on a tree on the right. A considerable amount of bark has been scraped off, leaving a bright-orange layer exposed. Here, a whitetail buck has scratched his antlers, removing the velvet covering from the antlers and leaving a blazing sign for all to see, proclaiming him sovereign of this section of the forest.

Farther along the trail there are many examples of buck rub from previous years. These have healed, and now blend in with the bark color, but can still be spotted. I have read that deer tend to frequent the same areas from season to season; that certainly seems to happen in Wingra Woods.

I’ve wondered how much buck rub hurts a tree. Apparently not too much, as long as the trunk isn’t girdled. Even though the scratches may be quite long, if they don’t go all the way around, the tree will likely recover.

Somewhere near the M-1 intersection, and on the left-hand side of the trail as you walk towards the Big Spring overlook, there formerly was a landmark I called the “Window Tree”. It was a very large standing snag, sufficiently decayed that there was a good-sized hole in it, through which you could see downhill towards the Wingra Fen. I always took note of it on my way toward the water, and if I had a camera with me, I couldn’t resist taking a shot through the “window”.

Then I didn’t guide tours in that part of the Arboretum for a year or two, and the next time I took that trail, I got all the way to Big Spring and realized I hadn’t seen my old friend. Had I simply passed it by? I retraced my steps – no Window Tree. It had finally decomposed to the point where it fell down. One of those piles of wood rubble used to be my waypost. So pass all living things, I guess.

On Sunday’s hike, we paused at the Big Spring overlook and I read Leopold’s words about shooting a wolf and watching “a fierce green fire” die in her eyes. The babbling water provided a backdrop of sound.

We continued eastward and eventually turned uphill, passing through hemlocks and yellow birches. With a nod to the Wingra Woods effigy mounds – which will be toured in detail on Dec. 2nd – we emerged in the parking lot. A long tangent through Longenecker Gardens returned us to our starting point.

Kathy Miner, Arboretum naturalist

Located between Lake Wingra and the West Beltline Highway at 1207 Seminole Highway, the University of Wisconsin-Madison Arboretum features the restored prairies, forests and wetlands of pre-settlement Wisconsin. This 1,260-acre arboretum also houses flowering trees, shrubs and a world-famous lilac collection. Educational tours for groups and the general public, science and nature-based classes for all ages and abilities, and a wide variety of volunteer opportunities for groups, families and individuals are available.