Fact Sheet No. 16: Photo Points as a Monitoring Tool

Introduction

Establishing a photographic collection to monitor vegetation changes does not generate the kinds of intense data that are gathered using methods to determine cover, density, production, etc. However, they do surpass these data in their ability to portray changes on a large scale and to transfer this information to audiences of different backgrounds.

Strengths

The strengths of repeated photographs in monitoring vegetation changes are:

• a complete inventory of the landscape is encapsulated in the picture,
• rates of vegetation change and events associated with that change are documented,
• and the field portion of the process can be executed rapidly and easily.

Weaknesses

The weaknesses of repeated photographs in monitoring vegetation are:

• Observable changes in the species composition are limited to obvious species such as woody plant invasion, large herbaceous species replacing small species, etc.;
• photographs can represent a biased selection of the conditions present in the entire area when photographed;
• and alterations in the photographs to enhance the artistic aspect of the image can misrepresent conditions.

Creating the Photo Point

Establishment of a basic photo point requires a steel fence post, a two-to five-pound hammer, a set of metal letters and number stamps, a compass, and a camera.

The post can be cut in half for ease of handling. The photo point number, date, and observer's initials are stamped into the spade. The bottom of the post will be inverted so that the spade will be exposed when the post is driven into the ground. The top half of the post can then be used to locate the close-up photo center.

The long view photo should be a representative view of the area and have a distinctive landmark in the background (peak, rock outcrop, tree, etc.) to aid in repeating the photo in the future. The remaining top of the steel post will act as the center of focus for the close-up photo. If the vegetation is relatively complex, additional steel post tops may be needed as reference close-up photo centers. A compass bearing from the photo point to the center of focus must be recorded for both long view and close-up photos.

A 35-mm camera with color slide film is the best combination for taking photos, but any camera with appropriate film, used carefully, will produce useful photos.

The process of developing a photograph collection includes:

• the retrieval of old images and the relocation of photo points,
• the establishment of new photo points,
• a systematic method of recording information about each photo,
• and methods for the storage and use of the collection.

One difficult obstacle to rephotographing photo points is the lack of accompanying records describing the location, time of year, and time of day the photograph was taken. Develop a field data form to systematically record this and other information concerning the photograph and the photo point.

For each photo point there should be a description of each photo point, including:

• Photo point number or name
• Name of photographer
• Date of photograph
• Date established
• Time of day
• Magnetic declination
• Location: specify, if possible, township, range, 1/4 of 1/4 section, altitude, and description of area, including notation of prominent landmarks so that the plot can be found easily by others.
• Comments and notations on vegetation and other conditions.

Have a place for keeping photos. This could be an envelope or prints attached to notebook sheets. Each photo must be identified on the back of the print or on the edge of the slide. Successful storage can be measured by ease of retrieval.

Photo Point Placement

To determine the location for photo points for water quality monitoring, consider the following:

• Locations that capture the perceived problem and/or landscape
• Locations that area easily relocatable with easy access
• In areas where you have knowledge of what you are photographing:
• to show cause and effect
• to show change over time
• to show impact of a major event (fire, flood, etc.)

Monitoring California's Annual Rangeland Vegetation, UC/DANR Leaflet 21486, Dec 1990.