A Northwoods Almanac for 2/17 – 3/2/23
Sightings – Hikes and a Porcupine
Mary and I led two snowshoe hikes in recent weeks for the North Lakeland Discovery Center; one to an unmarked old-growth white pine site off of Cty. J near Mercer, and the other to the Beaver Creek Hemlocks, a 267-acre forest a few miles southwest of Springstead off of Hwy. 182. After the hikes, we all sat down to a homemade lunch and shared our stories of how we came to love the Northwoods, a sharing that in my mind was every bit as beautiful as the hikes themselves.
The Beaver Creek Hemlocks site was purchased by the Northwoods Land Trust via a trade with the Board of Commissioners of Public Lands in 2021. The property was identified as a priority for acquisition as part of the Trust’s Old-Growth Forest Initiative (full disclosure – I’m on the Board of the Land Trust). The Initiative aims to protect mature and old-growth forest habitat in the Northwoods, and educate landowners and the general public about the importance of these forests.
The Beaver Creek site now protects 8,160 ft of creek shoreline; 950 ft of bog shoreline; mature and old-growth hemlock-hardwood forest; black-spruce tamarack swamps; vernal ponds, and poor fen and wetlands. Trails and a parking area were constructed last summer, and are meant for low-impact public recreation, including hiking, snowshoeing, backcountry cross country skiing and nature observation. Traditional uses also include fishing and hunting according to state regulations.
One of the highlights of the Beaver Creek hike was discovering a porcupine den in an old yellow birch, and then finding the porkie in a nearby tree.
Porcupines always impress me by their girth – they are chunky (average weight is 20+ lbs.)! Some of that bulk is due to their winter diet of inner tree bark, which has only 2 to 3 percent crude protein, compared to new leaves and buds in spring, which may contain 20 percent crude protein. Despite ingesting large volumes of woody matter every day in winter, porcupines often lose weight continuously.
The stomach and small intestine of porkies contains microorganisms that work to digest wood’s ultra-high fiber, but the limited amount of nutrients, particularly nitrogen, in inner bark makes for a less than ideal diet. During years when spring comes late, some individuals die of malnutrition because of dwindling amounts of nitrogen, even though their stomach may be full.
As spring warms, a porcupine’s diet and behavior changes rapidly as they now feast on swollen buds. They chew off a branch, hold it with their forepaws, and nip off the buds. You can find these nipped twigs littering the ground below a porcupine feeding tree in spring and in winter, too.
Porkies particularly like to forage in spring on the buds and leaves of sugar maple, the leaves of ash, and the catkins of quaking aspen. As summer comes on though, these trees, and others, defend themselves by producing and accumulating tannins in their leaves. Tannins inhibit the digestion processes of porcupines, forcing them to find other sources of food.
Most trees also exhibit a highly effective line of defense against leaf-eaters like porcupines by concentrating nearly 300 parts of potassium for every part of sodium in their leaves. The problem for porcupines arises in that their body requires an even ratio of both sodium and potassium. Eating the leaves transfers the mineral imbalance to the porcupines digestive system which must rid itself of the tremendous excess of potassium because too much potassium disrupts muscle and nerve functions. The porcupine's kidneys remove the surplus potassium, but some of the sodium is inadvertently swept away as well, leaving the porkie in need of either a different food source or a sodium supplement.
This is why porkies are famous for their profound affinity for salt. Since natural supplies of sodium are scarce, sodium-laced human implements and artifacts receive homage well beyond what we might imagine as their worth. Porkies have been known to go to extreme lengths in their search for salt, eating old camp pots for the salt imbedded in the aluminum, canoe paddles for the salt on the handles, plywood walls in a ski shelter, or committing the socially stigmatizing sin of chewing away outhouse seats.
A Barred Owl
We also were treated with relatively close-up views of a barred owl, which stayed put at some length on an upper branch despite all of us ogling it from below.
The Beaver Creek Hemlocks site supports many older patches of forest, which barred owls appear to prefer due to the greater availability of potential nest sites, easier hunting in the more open understory, and the closed canopy which helps with thermoregulation while offering protection from mobbing crows. Barred owls typically require a good-sized tree cavity for their nest site, though they may use stick nests built by hawks, crows, ravens, or squirrels.
Courtship calling between the male and female increases in late winter and early spring, and in addition to its distinctive 8-note hooting call (often rendered as "Who cooks for you? Who cooks for you all"), barreds may project a loud series of spectacular dueting vocalizations during courtship that sound like maniacal laughter or a tree full of monkeys on a PBS broadcast.
If you live near or in an older forest, you might consider putting up a nesting box – barred owls readily take to nest boxes.
Hemlock Wooly Adelgid – The Ill-fated Future for Eastern Hemlocks
Whenever Mary and I hike in a forest comprised in large part of eastern hemlocks, like the Beaver Creek Hemlocks, we are always reminded of how lucky we are to still be able to view healthy hemlocks. Over the last couple decades, an invasive insect, the hemlock wooly adelgid (HWA), has devastated most of the hemlocks in the eastern U.S. from North Carolina to Maine. The adelgids have also been moving inexorably west in recent years, and is now confirmed in numerous Michigan counties bordering Lake Michigan. So, I’m afraid it’s only a matter of time before it reaches us – very likely within the next decade.
The hemlock woolly adelgid is a native of Asia and only 1/32 inch long – perhaps the size of a period in one of these sentences – but it’s accidental arrival in Virginia in the mid 1950s doomed millions of Eastern hemlocks. The adelgid feeds on the sap at the base of hemlock needles, sucking the tree’s juices and injecting a toxic saliva which disrupts nutrient flow and causes the needles to eventually fall off. Without needles, the tree starves to death, usually within three to five years of the initial attack. White, woolly masses, which resemble tiny cotton balls at the bases of hemlock needles, indicate an infested tree.
Without any native predators to keep it in check, this aphid-like insect spreads at a rate of 15 to 20 miles per year, blown by winds, and carried by birds and other wildlife. It can also be moved on equipment, clothing, vehicles, infested nursery stock, and when infested branches are trimmed and disposed of improperly.
Winter is the best time to look for evidence of a hemlock woolly adelgid, because cooler temperatures trigger feeding activity. We all need to keep an eye out for this insect, because in its early stages, it can be treated with an insecticide. Branch dieback progresses from the lower branches to the top of the tree, so look low first.
In 2016, HWA was first found in the Upper Midwest in Ottawa County, MI. Michigan is home to an estimated 170 million eastern hemlock trees, all of which are at risk.
In Wisconsin, hemlock was once our most common tree, but it now represents 1 or 2 percent of our forests. Hemlock’s major loss occurred during the tanbark era of the late 1800s and early 1900s. What little still thrives, however, provides unique dark, moist, conifer habitat for many wildlife species. And its beauty is revered by most who have taken the time to know it. Donald Culross Peattie described this beauty in terms of sound in his A Natural History of Trees: “When the wind lifts up the Hemlock’s voice, it is no roaring like the Pine’s, no keening like the Spruce’s. The Hemlock whistles softly to itself. It raises its long, limber boughs and lets them drop again with a sigh, not sorrowful, but letting fall tranquility upon us.”
Since the early 1990s, scientists have evaluated host-specific insects to control HWA. Several predatory beetles and fly species from the HWA native range are currently being studied and released at hundreds of locations with some promising results, but overall they have not been able to keep up with adelgid reproduction.
Insecticides are effective in settings from urban landscapes to smaller managed forests. However, the cost and effort associated with insecticide treatments make them impractical for treating large, forested areas.
The real key to keeping them at bay may be cold, hard winters. Extreme cold temperatures, below -15 degrees, cause widespread HWA mortality. Minus 30 degrees is better yet, killing 99% of hemlock wooly adelgids. But as climate change marches ever onward, we’re increasingly unlikely to see extreme lows.
Plus, consider that the few individuals that are able to survive extreme cold events will likely pass along that ability to their offspring in their DNA.
When the adelgids arrive and thrive, how will we describe to someone 100 years hence what the feel of a dark hemlock forest was like, what it smelled like, and what the sound of the breeding birds was like?
New Book From Local Author
Joe Hovel from Conover has just published his memoir entitled From Barbells to Spruce Grouse. He chronicles a life dedicated to land and water conservation, and the many battles he had to fight along the way, and continues to fight to this day. Highly recommended! See https://www.northwoodalliance.org/books to purchase.
Celestial Events
February 20 marks the 61st anniversary of John Glenn first orbit of the Earth in 1961. The new moon occurs the night of 2/20 as well.
On 2/22, look after dusk for Saturn and Jupiter to be a degree or two above the moon.
We hit 11 hours of sunlight as of 2/27!
On the 1st of March, our average high temperature will be 32°. The Minocqua area averages 269 days with average high temperatures above 32° - about ¾ of our year.
Thought for the Week
“I think when you’re young you want to learn the names of everything. This is a beaver, this is spring Chinook, this is a rainbow trout, this is osprey, elk over there. But it’s the syntax that you really are after. Anybody can develop the vocabulary. It’s the relationships that are important.” - Barry Lopez, Syntax of the River
