This article is part of
Wilderness Way
VOLUME 14, ISSUE 2.
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Making Use of Dutch Elm Diseased Trees
by Barry Keegan
The peeling of elm trees, making a bark wikiup, as well as an elm bark canoe were all part of classes taught in our programs at Hawk Circle. For more about these classes, please visit www.HawkCircle.com. Other uses were strips of bark used as medium strength lashings on the wikiup project. Much of the wood was used in benches at our camp, throwing sticks for our students of survival, and the leftovers made firewood.
Dutch elm disease has some similarities to other elm infections, but is recognized by the yellowing leaves on parts of the tree’s crown. “Elm yellows” affects the entire crown at once. “Bacterial leaf scorch” also affects portions of the tree’s crown, but is different in that the leaves will “brown” along the leaf margins with a yellow halo. Dutch elm disease causes leaves to wilt and turn yellow, then turn brown. Dutch elm disease symptoms appear any time during the growing season where as the other two, from mid summer to early fall.
Testing the Tree’s Bark Before Peeling
The best way that I have found to see where
to peel the best remaining bark is to entirely girdle the
tree. Then I remove a 3-inch wide strip of bark from around
the whole tree’s circumference. This is the test strip.
The tree was dying slowly and in vertical stripes. You often need to peel in between these stripes. Test strips often stick very tightly there, because the bark is dead in those areas. The wood beneath is much darker or obviously discolored. Despite the disease, sometimes the tree will still allow you to peel its entire circumference, sticking more as you peel farther up toward its branches. Sometimes this is as easy as peeling a healthy tree, and sometimes you work much harder, hence the test strip. Most of the time you will be greeted by a foaming, hissing ooze of bad smelling, fermenting sap and gasses, escaping through your initial cut. Elm tea, from the bark of a healthy tree, has a pleasant taste. The difference is notable. Often you will see yellow leaves on some of the lower branches. This can be spotted from far away. If more than half of the branches are entirely dead, you will likely have been too late.
Over the past ten years I have had good luck peeling bark from dying elms. This works best in peeling season, which starts around June 1st and ends around August 1st in New York State. Dry weather is a contributing factor and can cause the bark to stick, even during the peak of peeling season— June.
Peeling Bark with Spuds
We felled both trees over about a week long period. Student,
Mark Kessler, and I wished to drop one large tree using only
hand tools. We used two felling axes to take out a wedge and
a two-man saw to notch the back. The tree dropped very close
to where we wanted it. Then we used a chainsaw to drop the
other one, which was a more difficult tree to drop
accurately. Originally all of the elm bark we could peel was
designated for Mark’s shelter project. The lower section of
the first tree was easy to peel and it was huge.
We were able to remove the 4-1/2 feet wide by 13 feet long sheet with four peelers (students) using antique iron spuds. The sheet came off without any splits at all. This piece was so good that we decided to use it to build a bark canoe later in the fall. We shaved off most of the outer bark and rolled the big sheet up into a roll of a 3 feet diameter and 4-1/2 foot width. This was stored on the lower floor of our barn as it was too heavy to haul up the narrow stairs to the attic. The rest of the bark sheets were dried flat upstairs, stacked up in layers, with 2 to 5-inch diameter wood poles in between, used as “stickering.” The logs left over are the new camp benches. Mark later built a 10-feet high elm bark wikiup, which he stayed in through parts of our wet summer. I emphasize the “wet” part, which requires more details affecting the storage part.
Drying Bark Slabs and Building Mark’s Wikiup
Drying bark without it molding is difficult even in a dry
summer. If we used a fan in the attic we would have had less
mold. Once the bark is on the shelter, we could have built a
fire inside, which would have dried as well as smoked the
bark. The smoke is a big help with keeping mold away, but
flattening the bark helps when we place it on the shelter,
so we do not have to push so hard to keep it in place. The
upstairs bark storage was our only option, since much of our
help was needed soon with preparing for the summer camp
programs. The molded parts were hardly noticeable, until it
was time to build the canoe in September. The smaller,
straight branches gave us bark sheets to use in
basket-making classes throughout the summer. Those we let
dry in their natural tube shapes in our barn attic.
Most of what Mark used on his shelter had little to no mold on it 3 weeks later. He put up a cedar pole frame and lashed the elm’s branches to it, using bark strips for rope. The bark strips were peeled from the same elm branches that were the horizontal poles, wrapping around the wikiup’s conical pole frame. Elm wood is pretty tough and does not rot as fast as hickory or hornbeam. More of these poles, maple too, were needed to hold the bark onto this frame from the outside.
These were lashed to more cedar poles, poked into the ground and then tied to the top where the smoke hole is. This outer frame compressed the bark onto the inner frame. You can see this, and the bark-hat, which serves as a rain-proofing over the smoke hole that is also of elm.
The bark sheets that were on the bottom of the drying pile fared the worst. Two of those lower sheets were useless. We had humid 90˚F weather and left the door of the upstairs open for ventilation. Perhaps if we made lower bark piles, it would have allowed for more air for drying? The bark that was stored downstairs was the worst. We were still able to use the big sheet in the building of a canoe. Half of the bark problems came from the mold, but there was a another problem inside of the bark.
Larval Damage
Dutch elm disease is a fungal infection. The fungus alone
does not pose such a great threat to the elms. Their host, a
bark beetle, bores into the bark, carrying fungal spores
from one tree to the next. The beetles lay eggs in these
holes under the bark and their larvae eat tunnels through
the bark as they mature into beetles. These larvae lived in
our canoe sized bark roll all summer long, despite all of
the outer bark that we shaved off.
I saw many beetles fleeing from the bark as we vigorously shaved it thinner with antique “in-shaves” and “scorps” (chair and bucket maker’s tools). Mark’s shelter fared better, with beetle damage also. He soaked the dry bark before placing it on the shelter, to get the best fit. The bark was weighted down with stones, likely drowning the beetles and possibly the larvae.
Building the Elm Bark Canoe
Building the elm bark canoe was a project for the 2006 fall
semester of a class that we held called “Earth Skills.” Our
first step required sinking the bark roll entirely under
water, with stones, for three days.
We had to find a deep part of the Cherry Valley Creek to do this and hoped for no floods. We hauled the bark out while standing on our bridge, which nearly washed away during a June flood.
This same river will serve as a waterway to this canoe in the future. The bark roll was then transported to a flat, shady piece of lawn. We chose to be under a white pine and beside our tipi, for maximum shade. This kept us from rewetting the bark until the boat was about complete.
We shaved the bark even thinner in the 4 areas that were to be tucked (folded), and also where the bow and stern were to be folded and sewn shut. We wet the bark shavings and spread them on the parts that were drying fastest. Then we measured the width to form a row of stakes at a 3 feet long. This was for the center part, between where each end tapers to points that are slightly excurvate. Two students lifted gently on the bark to raise up one side while I drove in stakes about every foot or so. Each side rose about a foot. There was some taper that got trimmed later.
Next, we formed the four tucks, all of which face to the stern. One person lifted the bow or stern and another used the Jim Dina “ tweeker” tool to crimp and form each fold of the tuck. Using a stick to burnish these folds also helped where the bark was thicker or less flexible. This was the most delicate part of the process, even without the beetle grub damage. The largest holes and voids made by the grubs clustered in the area of two tucks. There was no getting around this and large patch pieces were sewn in these places.
The gunwales were of American hornbeam saplings, two poles per side. We then lashed them to each other with wet strips of basswood and hickory bark. Then we placed both outer wales and inner wales and began lashing them to the bark, starting at the center and working out toward each end. A hole was carefully reamed just below each wale and wooden-pole pliers were used to clamp the wales as they were lashed.
The placement was important because the thwarts were placed at the tucks and one just off center. The thwarts were just temporary notched ended poles of 3 feet length that were arranged for maximum space to accommodate 3 paddlers. This sounds simple and it basically is if your bark is perfectly flat and gunwales are perfectly straight. Both ends curve up the bow a little more than the stern.
Both of the inner and outer gunwales cross at each end of the canoe. They are arranged to where they interlock neatly and are tied with a bark strip. A spacer, of a round log about 6 inches high, is placed under each end. These take strain off of the upward bends of the gunwales at each tuck area. The tucks are mainly to create a “rocker” effect, or the rise of each end of the boat. This aids in maneuverability, especially with steering the boat, and allows the bottom to remain less damaged when the boat is paddled into a sandy shore.
The gunwales are flexible, but strong and often need to be coerced into remaining bent. If necessary, stone weights can be placed upon these lashed poles to help facilitate the bending at those spots. Next, all bark is trimmed from above the gunwales so that the lacing of the gunwales together, around the top edge of the bark, can be continued. Before the last lacing was done at the very ends, a split stick is laced on each outer side of the folded bark forming each end of the canoe.
These are the stem pieces, which are placed vertically and any irregular edges are first trimmed to the shape of these split sticks. Holes were made so from the top, down to the lower fold. Traditionally: pulverized inner bark of the elm tree was placed between the folded faces of the bark at each end. This was done so that both stem pieces clamped this mucilaginous paste of wet bark fiber, which oozed through the holes of the stitching, as the stem pieces were clamped and stitched shut. The stitching was done with long laces of basswood bark. Any splits in the bark that required patching were handled in a similar fashion. Pounded wet bark was crammed into the split and sewn around small splits. Larger holes had an inner piece of bark for a patch and the pulverized bark went in between the patch and the bark hull. It is easiest to lace these patches tight with at least one helper. One holds the patch down with some pressure and the other does the sewing. Pine pitch was also used as a sealer.
Before sealing the boat it is good to fit the ribs into it. There should be a rib about every foot or so. The lacing around the gunwales corresponds to the rib placement. We selected about 16 thumb-thick saplings of viburnum (nannyberry) for our ribbing. Each end was beveled at about a 45-degree angle. These angles were shoved up under/ between the inner gunwale and the bark walls.
The thick ends are alternately placed so that every other rib end (on one side) is a thick end, (thin, thick, thin, etc). This distributes the forces evenly and there is plenty of force in these few scrawny looking ribs.
Only with much experience can you shape a rib around your knee without putting a crease into it. Your knee is too tight a bend and a creased rib is no longer useful. Using a larger diameter tree is safer to bend around. You leave all of the stakes in the ground while setting the ribs if you have not yet put in the thwarts. This prevents the combined force of all of these ribs from blowing out the bark walls of the boat. Start at the middle, angle the rib so both tips are snug under the inner gunwales, and push the sagging middle along the bottom until it takes a snug fit to the inner boat, forcing it into a more vertical position. You tighten them all in about three sequences by tapping them tight with wooden mallets. This gives the bark shell some time to adjust to the stretching so that it will not tear.
The temporary thwarts still need to be replaced with permanent ones. We used two inch thick hornbeam. These were as straight as possible and cut to 2 feet longer than the width of the canoe. The end of each thwart, was cut most of the way through a foot from each end and we then split off and/or chopped off the excess wood, so that it was left with foldable tabs at both ends. Each tab is a foot long and no thicker than your pinky. They should be carved smooth enough to bend nicely around the inner gunwale and then bent back on itself and lashed tight with bark strips. Thwarts cannot move about and should allow you to lift the boat overhead for portaging, without moving, tearing, etc. Despite their strength, you should never sit upon them. Bark boats are a breed unto their own. The lower that you keep your center of gravity, the less swimming you and your crew will do. Sitting on the floor or kneeling were the traditional ways to sit in these boats.
Once all of the ribs are tight, you may think that you are done. You could take the boat out to test it, but when you are done, the boat will shrink as it dries. This is especially true if you soaked your bark to rehydrate it. If this boat is left to dry, without adjusting the ribs daily during this process, tears will result from the shrinkage. After about two weeks of drying, it is safe to store it. I once had 40 new tears in a new boat’s bark because of shrinkage during drying. If the ribs are left too loose the upper edges of the bark will curl so much that it will become nearly impossible to fit a rib under the gunwale. Watching the boat is the key. Seal holes as needed.
The last thing you will need is an inner floor. Left over bark slabs work well for this, but a latticework of lashed sticks will also do just fine. If you climb into the bark boat and step directly onto the outer bark skin, you will likely split or tear through the bark.
The slabs that you put on the inner floor will distribute your weight more evenly, keeping all of your weight on top of only the ribs and never the bark. For this I have put extra ribs in the areas where the paddlers sit or kneel.
We chose to use pitch as our sealer. We used a mixture of about 5% deer tallow to 95% spruce pitch on the ends and patching. This is best done once the bark has dried for a few days. Pitch does not stick well to wet bark.
The bottom of the boat is only bark. You must remember that when paddling into shore. It is traditional to step out of the boat in a foot of water, and empty it by carrying the load to shore before placing the canoe on dry land. Scraping the boat wears away the bark and makes the boat eventually leak. Also when the boat is not in use it needs to be dry. Remove the inner floor when not in use and place the boat in the wind or sun to dry. Mold will destroy this boat. Beware that sunlight will melt your pitch sealer, so if you used pitch, keep it out of the sun when it is not in the water.
These
boats are tougher to handle than our sleek modern canoes
with keels on them. They require more diligent paddling to
steer on a windy lake. Bark canoes were used on rivers that
most would not even consider paddling on, poling up stream
and then paddling back down.
Happy paddling.
