Photographs from Fixed Points

Photographs taken from fixed points around a transect usually convey additional information. In forest only the understorey can be photographed satisfactorily and here it is essential to be able to relocate the photo-point with respect to ground position, height and exact direction of the camera. Slight changes in the position of the lens between photographs can give a false picture of changes in the height of plants. A 2 m graduated pole can be used to overcome this difficulty of obtaining a vertical scale. Ideally the boundaries of part of the transect should be included in the photograph and the field of view can be centred on a permanent marker. Sometimes it is possible to photograph a transect from a nearby vantage point or tree; this is particularly useful when future understorey growth is expected to obscure the field of view on the ground.