| 摘要 |
The present invention is composed of: a synthetic resin board (1); and coupling protrusions (4) installed on the board (1) at predetermined intervals vertically and horizontally. The coupling protrusions (4) are formed as hollow protrusions, which protrude in a hollow type by thermally pressing the board (1). The coupling protrusions (4) have a catching element (42) at the middle portion thereof, and thus, when one coupling protrusion (4) is inserted into a hollow inside of another coupling protrusion (4), the catching element (42) prevents the separation of the coupling protrusion (4) inserted into the hollow inside. The frost damage on a fruit tree can be prevented by putting the board (1) around the lower portion of the trunk of the tree, connecting both ends of the board (1) through the tight fit of the coupling protrusions (4); and filling a heat insulator, such as rice husks or sawdust, between the tree and the board (1). |
