A process for preventing the spread of vegetation from one area to another is disclosed. In the first step of this process, a vegetation-encroachment barrier is provided. The barrier preferably contains two halves 22, 26 which are joined at their bottoms 23, 27, whose tops are normally touching each other, but whose tops may be separated from each other. The two halves of the device are so shaped that, when their tops and bottoms are contiguous, a chamber 31 between them is defined; the chamber exists at a location intermediate the tops and bottoms of the halves. In the second step of the process, a furrow is dug around the area to be protected. Thereafter, the barrier is inserted into the furrow. <IMAGE>
