Snag Appeal

by Laura Reeves

In 2008, I bought 160 acres with a homestead that had been abandoned for 25 years. The old houses and barn were starting to cave-in, the grass was long and matted, and the yard was dotted with giant 100-year-old Manitoba maples. These trees were spectacular, their trunks too big to wrap my arms around. Some had large limbs that ran along the ground for a time; others were within reach of an outstretched arm – perfect for climbing. I imagined all of the stories they could tell.

 

Dramatically, in 2011, a wildfire raged through the farm, taking the barn, houses and shed. The heat from the burning buildings was so intense that it killed or permanently damaged trees a fair distance away. Including all but one of the giant maple trees.

 

 

I could have cut the damaged trees down right away, or at any time, but I was adamant they be left for their historic value – a reminder of the family that settled here and made their living on this land. This family did drop by one time to see the old place. Unfortunately, it was after the fire. As they walked around, I heard them reminiscing about their childhood days, pointing to the different trees and remembering the specific branches that were their favourite hangouts.

 

Most people would see “dead” written all over these trees, but they are far from that. 15 years post fire, they still sport a few live branches or have sprouted new trunks, but the life they contain goes far beyond these few holdouts.

 

For several years elm oyster mushrooms (Pleurotus ostreatus) emerged from wounds on the damaged trees, and pidpankes (Armillaria spp, also known as honey mushrooms) have appeared every year on the ground around the trees when conditions are right. The previous landowner told me her family always used to pick pidpankes around these trees. Had I cut the trees down, I’d have missed out on both of these delicious parasites.

 

About 10 years ago while working in the yard, I became aware of a faint chittering sound. Always curious, I dropped what I was doing to find the source. My search led me to one of the fire-damaged maple trees whose leaning trunk had twisted and cracked in the wind. Zeroing in on the sound, I peered into the crack and discovered a nest of squirming baby red squirrels holed up in the hollow core of the tree.

 

As the trees have aged, dead branches have gradually weakened and broken off. Those that remain are preferential lookout towers for all manner of birds and squirrels. The phoebes especially like to use them to scan the area for insect prey.

 

 

13 years after the fire, a couple of flickers took a keen interest in one of the snags. I watched them chip out a hole 10 feet up the nearly barkless trunk and raise four kids there. I could hear the persistent vocalizations of the invisible nestlings, which resembled the hum of a hydro wire, every time I walked by. A month or two after they fledged, a strong wind caused this tree to break off at the next cavity, but that didn’t deter the parents from reclaiming the tree the following year and hollowing out a new cavity just below the old one. A cavity that a northern saw whet owl later claimed as its own.

 

At the same time, pileated woodpeckers took to tearing the same tree apart looking for round-headed wood borers and flat-headed wood borers (aka metallic wood borer larvae). These beetles lay their eggs in the bark, after which the larvae tunnel into the wood, emerging as adults one or two years later. That is, if the ichneumon wasps don’t get them first.

 

 

“The what wasps?” you may ask? “Ick-noo’-mon” wasps are parasitic insects that hunt down the same food as the pileated woodpeckers. What looks like a long stinger that trails behind the female wasps as they fly, is actually an ovipositor (egg depositor) that they use to drill into the wood-boring larvae (and other insects) and inject a paralysing venom before laying their eggs. For the last few years, I’ve watched both giant ichneumon and black giant ichneumon wasps laying their eggs in wood-borer holes within the cavities created by pileated woodpeckers. When the eggs hatch, the wasp larvae feed on the wood-borer larvae, eventually killing them. They pupate inside the tree over winter and emerge in early spring – so long as pileated woodpeckers don’t get them. These wasps are really neat to watch!

 

(FYI, the stingers of bees and wasps are actually modified ovipositors. Ovipositors are not stingers – they are only used to lay eggs.)

 

It’s amazing how much has gone on in these seemingly dead trees over the years. Even one standing snag will benefit a plethora of wildlife, both seen and unseen, for many years – even decades. If you have a snag in your yard, consider leaving it be. You’ll be rewarded in spades.