Tuesday, December 31, 2013

Building A Foot Bridge In The Wilderness.

Are you one of those lucky people who have a few acres of land with a small stream running through it? Well this post is for you! If not, join the crowd and read on anyway, maybe you will learn a new skill set. With the help of some friends, I will show you how to construct a foot bridge in the woods with mostly hand tools. Some of you may know that I have been a member of the Red River Gorge Trail Crew for going on a decade now. The RRGTC is a group of dedicated volunteers who meet once a month in the beautiful woods of east central Kentucky. The RRGTC helps keep the trails, bridges and back country of the Gorge safe and accessible for the general public to enjoy. 

Okay so first things first, you will need a large tree. What part of the country you are in will dictate the type of tree you will use. In the Gorge we use the eastern hemlock. The hemlock grows very straight and tall making it ideal for use as a bridge. Used properly the wood will last a long time in the elements. Once you have selected your live tree and felled it, with good sawyer techniques I hope, you need to strip the bark off. If you leave the bark on you will create an area for moisture to rot out your bridge.

Sad side note: The eastern hemlock is under attack in the US by the woolly adelgid. The woolly adelgid is a small insect that sucks the sap of the hemlock, desiccating the tree, causing the tree to lose needles and not produce new growth. After a hemlock is infested it typically takes 4-10 years for the tree to die. Even if it lives, it will be weakened and susceptible to disease. Unfortunately the woolly adelgid has made its way to the Gorge. Most of the Red River Gorge is going to have a completely different ecosystem in 20 years.

Okay after you have dried your eyes for the eastern hemlock you will need to find a lot of wedges. It helps to have friends with tools. You want to split the log so you have two equal and usable pieces. After you have figured out where you want to split the tree, mark it with a line of chalk or a string. Now start pounding the wedges in along the line.

This takes a while and it helps to have a lot of people around to switch off when you get tired, which you will. Even though hemlock is considered a "soft" wood, this stuff is pretty tough.

Once you get the metal wedges in a ways, you need to switch to wood wedges. Our sawyer cut up a bunch of them on the job site. As long as you keep applying pressure with the wedges you will eventually get the log to split.

The wooden wedges are just small diameter trees or limbs with an angle cut on one side. The bad thing about them is they break up pretty easily when beaten with a sledge hammer, the good thing about them is we could make as many as we needed.

Eventually you will win the battle if you keep at it. I have a lot of respect for the people who had to do this back in the day. We only split one log, with a lot of help and modern tools.

Ideally you want to get two usable sides out of each split log. This one split weird so we could only use one side for the foot bridge. I don't have a picture of it, but we used the other half to make a bench near the bridge.

Like I said you need to get all the bark off so the bridge doesn't rot. Having a bark spud is key to doing this fast. It is basically a chisel with the correct angle to peel the bark off in strips.

Okay so I said mostly hand tools. Our sawyer is cutting down into the log to specific points on both sides of the log. We measured the lowest points on the log and marked the sides. He then cut down to the marks with the chain saw.  Because he couldn't see the other side of the log, I sat across from him, and by using my hands, showed him how far away he was from the line. When my hands touched, he was at the line, and stopped cutting. It was raining off and on the whole day, so we did not bring out the crosscut saw. You could do this all by hand if you wanted to, and had the correct tools. 

The reason for notching the log with the chainsaw was so we could use this useful tool called an adze. This is an ancient style of tool dating back to the stone age. You can see this person using the proper technique of having one foot over the other and chopping towards them. This allows you to be pretty precise without worrying about adze-ing your shin. If you can't imagine the jokes around a tool called an adze, let me give you a few. "Get your hands of my adze" or "You sure know how to work an adze" or "Your mama's so fat her adze was made out of a manhole cover"... moving on.

You can see how smooth this log is getting. You don't want it completely smooth. You want to leave some grooves and imperfections for tread when it is wet. You can also knock the wood off with a pulaski, shown above.

Here is the other end. When you have a good adze in your hand, you can do amazing things...

We used these log movers to bring in the base of the bridge. Out in the wilderness, simple tools and manpower get most jobs done.

After the bases were striped of bark we used a brace to drill some pilot holes for re-bar "nails". You want to drill them at an angle so the base has less of a chance of moving in a large water event. Another hole was drilled on the opposite top side of the log with the same angle but going the other way. This pins the base into the ground with the re-bar going down like this ^ .

One of the best lubricants for pounding re-bar into wood is kerosene. We also use kerosene when we use the crosscut saws. It helps dissolve any saps in the wood and lubricates the blade.

Here we are setting the bridge in place. We then marked it so we could cut out divots on the bottom. This allows the bridge to sit snug on the base.

You would think that with how much wood you have to work with in the base you would notch it instead of the thinner bridge. If you were to do that, you would create a depression for water to collect where the bridge meets the base. This would slowly rot out the base and all your hard work would be for naught.

You can see how smooth you can make the wood with the proper tools. You might even say it is as smooth as a babies adze...

We repeated the brace and re-bar technique for the bridge. This thing is not going anywhere. The re-bar we used was about 4 foot long.

So here is the final product. An inviting foot bridge in the middle of the woods, crossing a small stream. If you are interested in seeing this for yourself, just hike the Whittelton branch trail east from the camp ground and you can't miss it.

Thanks to all the volunteers who come out month after month, year after year, in the rain, snow and cold. And a special thanks to our fearless leader Charlie, the forest service is lucky to have you and so are we. So I didn't have to fool around with getting everyone's permission, all photos are headless and taken by me. 

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