This is an update of instructions originally published March 2001.
First, let’s look at what this is for, so the steps will make sense.
A standard protocol in some vegetation surveys is “percent cover” in a one-meter area. You are supposed to visually estimate the percent of plant species or other things. This vegetation frame we are going to build is to help with that.
The four sides (or “legs”) of the frame are marked in 1/10 meter (10 cm) increments. This makes it easy for you to mentally grid up the ground inside the one meter square. These are the pink dashed lines in the picture above. Each small square is 1%.
In this example you might estimate the tree trunk as about 25% (purple solid line), or a little less. The exact way you do this would depend on your study protocol, but this post is about the equipment.
You have to carry the frame around in the field, so it is as light weight as possible. Each leg is shock-corded in pieces, like the tent poles of a dome tent. This lets you fold the frame up small for easy packing. Also, as shown here, if there is some obstruction, you can just fold part of a leg out of the way.
In a day’s work, you typically take the frame apart and put it back together a lot. So the leg ends stick together with Velcro. You can just fish the legs through the brush, touch the ends together, and they stick. One end of each leg is visually distinct from the other, so you can see at a glance which ends will connect. You don’t have to fuss with trying them all different ways.
The core of the design is the fiberglass tent pole sections. You can buy them from:
Tentpole Technologies (“TT”)
Explain that you want sections that will be one meter long, and will fold up in thirds. If TT can look up previous orders from me (rickshory.com) you can order the same thing.
If you’re really pinched for cash, ask if they will sell you the raw materials, the fiberglass pole sections and the shock cord. You can save some money by putting in the labor to assemble them yourself.
TT typically makes the poles with one white end, and the rest black. This is all to the good, for making the two ends visually distinct. If you are assembling them yourself, take note of how they will finally fold up, so as to be most compact.
In order to apply the colored bands, mark the poles at 10 cm intervals. It is rather tedious to make the marks one at a time, each successively 10 cm from the last. Below is an easier technique.
Lay out a strip of tape, such as blue painter’s tape (as shown below), or masking tape. Use tape at least two inches wide, or improvise from narrower strips laid parallel. Two inches will give you enough width to arrange all four poles side by side.
If you plan to do this a again, you can make a jig by applying the tape to a 4-foot-long board, as shown. Then you can put this arrangement away between uses. If you are only going to do this once, you can put the tape directly on a table and discard the tape when done.
Now, you only need a short ruler to lay out marks on the tape at 10 cm intervals. (The tape saves marking up your table.)
When you line up your poles, the ends may not align exactly. However, having the whole meter length at once lets you get them as even as possible. The ends may go part of a centimeter beyond the furthest marks, but this is OK. It’s well within tolerance.
Now, you can mark all four poles at once. Where marks fall on the white and silver sections, you only need a tiny dot to find the location later.
However, on the black sections, the mark will only appear as a faint glint of a slightly different color quality (this is ink from a black Sharpie pen). Although you may have to hunt a bit for these marks, this will still be quicker than, say, sticking temporary bits of tape to mark the places.
Below is an example of a pole after the color bands are on.
I use two easily distinguishable colors, the “main” color (red here) and a “tip” color (violet in this example). The widths of the bands help visualize percent cover, but the colors themselves help keep you from losing the poles in the woods.
The main color is most important because there’s more of it. I use a color that will stand out in the environment. In leafy green vegetation, a hot color like red, orange, or yellow would be good. However, in a red desert, I might use violet for the main color instead. You may not realized how easy it is to lose equipment like this until you are actually out in the field.
The material to make the color bands is vinyl electrical tape. Various colors are available at most hardware stores. Bright fluorescent “DayGlo®” tape would be better, but I have never found it in a field-durable form. There is a product called “gaffer’s tape” in fluorescent colors, but this is much like masking tape, and would not last long in field work.
I put the tip colors on first, to avoid mixups. You want the two ends of each pole readily distinguishable from each other, but all four poles the same. It’s easy to get confused if you start applying the color bands at random.
In all the banding, wrap the tape onto the pole tightly enough that it stretches. There are a few details that will increase field durability.
At the start and end of each wrap, you overlap the tape somewhat. If you start with the tape tip torn at an angle (as shown), the overlap will not bulge out so much, and will abrade less. (This example wrap will go up to the next mark on the silver section, above and to the right.)
At the end of the wrap, if you tear the tape at an angle, this end also will be more neat.
The tape will then naturally break leaving an angled tear, ready to start the next wrap.
For pole junctions that will not need to pull apart, you can just continue the tape up or down from fiberglass pole sections to aluminum ferrule. However, at junctions that do need to pull apart, make two tape wraps, one on each side of the junction.
If you want to add a label, now is the time, before putting on the Velcro ends. In this example, I show my web domain. You may want to put a barcode for inventory, or some contact information so lost equipment can be returned if found.
You want your label to still be readable, even after years out in the weather. Otherwise, it’s not worth taking the trouble. In field conditions, a label just stuck on would soon be damaged or gone, from moisture, abrasion and dirt.
A paper label would quickly degrade. I use these weatherproof labels, item number OL1825LP, from onlinelabels.com. Note that these are very small labels. You do not have much room on a slim tent pole.
Even these tough labels would break down or wear off if left exposed. I cover the labels with transparent “heat shrink tubing”, often used in electronics to insulate wires. The size is 0.375″ (9.53mm) diameter. It is available from DigiKey, part number A038C-4-ND. A piece 2.4″ long is good for covering each label.
Apply a label and slide the shrink tubing over it.
Heat the tubing to shrink it in place. Using a candle, as shown here, you can “roll” the pole as you gradually feed it past the flame. Start from the larger aluminum ferrule end to avoid trapping any air bubbles. If you take care to keep the tubing above the tip of the flame, you will not have any black soot.
I use two different colors of sticky-back Velcro, to accentuate visual contrast.
The hook Velcro of one color goes on one end of each pole, and the pile Velcro of the other color goes on the other end. It does’t matter which goes on the “tip” end, as long as you are consistent for all four legs. That way, you know at a glace “opposite” ends will always stick together.
If you cut one length of Velcro 5.5 inches long, this will supply all four pieces you need for the legs.
You can fold this and cut it in half, then cut each of those in half again.
The Velcro backing is pretty sticky. However, in the dirt and wet of field work, it would come loose. Hold it on with small 4-inch cable ties. It is convenient to prepare these by partially inserting the tail, to make small loops. Then, they will be ready to use when you stick on the Velcro.
Wrap the Velcro sections around the ends of the poles. The Velcro will overlap slightly. Note that the exact point of one-meter length on the pole is about a centimeter in from the end. This lines up with the center of the width of the Velcro.
Slip on a cable tie, pull it tight, and cut off the tail.
The finished set is convenient to be bundled up with a rubber band.
While you’re using the frame, you can put the rubber band around a leg end. There, it will be handy when you pack up.
The entire set weighs only about 275 grams, less than 10 ounces.
I developed this design while working on federally funded research grants, so is in the public domain. You can build a set for about $35 in parts.
I was surprised to get inquiries, asking to buy frame sets from me. I guess that makes sense if you are in an agency and can’t justify the setup overhead. My price, including labor, is currently about $175 per set, plus about $45 shipping for up to 4 sets.