Development of New Method for Field Survey of Stand Parameters on Mangrove Forest □ A Prototype and Application Test □

摘要

It is difficult to measure tree height, trunk volume and so on for many trees in mangrove forest. But it is necessary for calculation of stand parameters such as average of them. We have calculated trunk volume of a tree by conventional ways that are to measure diameter at each height with intervals of some meter by climbing a tree or cutting down a tree. If it is not allowed to cut down trees, we measure diameter at each height by climbing. But the measurement is hard, riskful and not expected with accuracy. We tried to develop a new method with combination a pole composed of drawtubes and a digital camera operated by remote control. Six laser pointers were parallelized in a box fixed bellow the camera, and the unit composed the box and camera was fixed at the top of drawtubes, could be panned horizontally. Red points on a trunk with laser pointers functioned as scales. It was useful against many trees at different distance, and it became possible to know a diameter at any height on a taken imagery zoomed in. This method is a type of remote sensing in the forest. The usefulness should be increased with some devices and improvements. And it will become easier to collect data for stand parameters of mangrove forest combined to the satellite data.