You can build a square quadrat frame out of PVC tubing
or meter sticks. One method involves fastening sections of PVC tubing using elbows.
To make the quadrat frame easier to slide under vegetation, you can construct
the two halves separately using PVC tubing and sleeves. Another method used to
construct quadrats is tying 1 m long pieces of string between both ends of two
meter sticks. This method is best for short vegetation as the strings may get
caught on taller plants.
Make sure that your quadrat can be taken apart
or folded up for carrying. It is best to leave one corner of the quadrat unattached
so you can unfold the quadrat and slide it under the vegetation into place. If
all four sides are fixed, you must place the quadrat over the vegetation, which
can be difficult with tall plants such as purple loosestrife.