Once a basic understanding of plant communities is obtained the rangeland manager must then decide which stable-state community is most desirable and possible to achieve on a given piece of land. The first step towards obtaining a desirable stable-state is to assess the condition, or health, of the range. This can be done by assessing the kinds of plant communities present. If we apply the color and meaning of traffic signals to range plants, we are able to group plants in a way that aids in assessing the condition of the range. These groups will be: 1) the ‘green-group’ plants; 2) the ‘yellow-group’ plants; and 3) the ‘red-group’ plants.

Plant groups

The green group. Plants in this group are the most desirable, the ones that provide the best combination of ecological services. When you see the green-group plants in abundance on rangeland, you know you management program is going well. The green-group plants consist of those that are plentiful in the potential natural community and are the first to decrease if rangeland is poorly managed or abused. Rangeland in the poorest condition has very few green-group plants on it.

The yellow-group. These are non-native or undesirable plants. They become more pronounced under improper grazing because they are short or because they are less tasty to livestock. Yellow-group plants are the ones to watch with caution. They increase in number as grazing becomes heavy. They replace the green-group plants that have become smaller and weaker. The range manager uses caution when the number of yellow-group plants increases on the range. If green-group plants are replacing them the range is improving. However, if heavy grazing continues, the yellow-group plants begin to weaken and die out. Their place is taken by the red-group plants.

The red group. These plants really do not need any explanation. They simply mean ‘danger’ to the range, so far as production is concerned. These plants are usually invasive weed species that have come in from other areas. These plants seldom, if ever, are as effective in controlling soil erosion and conserving water resources as the native plants that are more abundant when the range is in good or excellent condition. Soil and water losses cause nature’s plant and soil development process to go in reverse. The range becomes less able to provide the ecological services required by society.

Classes of range condition

Range sites vary in condition, so we judge and classify the condition of each site separately. Standard condition classes are: excellent, good, fair and poor.

Excellent. On excellent-condition range, the green and yellow-group plants are producing within 25 percent as much as they could possibly produce on the sit – within 25 percent of full capacity. Green-group plants make up the bulk of the forage. Red-group plants are either absent or are very minor components in the plant community. Litter cover is usually good, plant residue is abundant and the soil surface is loose and porous so that rain will soak in rapidly. There is no evidence of erosion.

Good. On good-condition range, the green and yellow-group plants are producing from 51 to 75 percent as much as the site is capable of producing. Green-group plants still produce the bulk of the forage, but yellow-group plants may have increased slightly in importance. The ground is well covered, litter is adequate, the plants are vigorous, the soil condition is still good and erosion is negligible. The green-group plants are still healthy and reproducing themselves. Red-group plants can be rated no higher than they were on the excellent-condition range.

Fair. On fair-condition range, the green and yellow-group plants produce from 26 to 50 percent as much as the site is capable of producing. Green-group plants are contributing less to the total amount, and yellow-group plants may be producing the majority of the forage. The green-group plants are in a weakened condition. Unpalatable forbs and shrubs (red-group plants) may have begun to increase. Some invasion of red-group annual grasses and forbs may be evident. Plant residue is low, more bare ground shows, total production is decreased, some water may be running off the trampled or compacted soil surface and erosion is evident.

Poor. On poor-condition range, green and yellow-group plants are producing form 0 to 25 percent as much as they could be producing under excellent condition. Green-group plants have been killed out except within the protective cover of shrubs. The bulk of the grazable yellow-group plants has been killed, and the red-group plants are most abundant. In extreme cases, even the red-group plants have been destroyed and soil is bare. In such cases, much water is lost through runoff, topsoil is often hard and compacted, and severe erosion may be evident.

Range condition scorecards

With the help of a range condition score card, a range condition guide and a little training, we can judge the condition of the range.
Scorecards or record sheets may be obtained from you extension agent or the Soil Conservation Service, Forest Service or Bureau of Land Management offices. Record sheets or scorecards may vary in format, but are designed for the same purpose – to help determine the condition and productivity of the range.

A range condition guide describes the kinds of plants, the kind of soil and other characteristics of a particular range site. Each kind of site has its individual condition guide, developed through research. The guide tells how to recognize various conditions on that type of site. A sample of the vegetation present is necessary to determine what percent of the different groups of plants are present, as described in the guide. Then the range site can be scored according to the condition classes described before. The first time you use the guide, it is best to receive assistance from an experienced person.

Trend of range

Trend means direction of change. The trend in rangeland condition can remain about the same, go down or go up. Trend changes quickly due to weather or management practices. Range condition changes more slowly. Therefore, it is important to determine the trend in range condition each year. Then management can be changed in time to prevent unwanted changes in range condition. It is best to set up permanent transects to measure the trend in range condition. Check these permanent samples every few years (approximately 5) to determine accurately whether the range condition is improving.

This might require the help of your extension agent, vo-ag instructor, forest ranger, BLM range manager or your SCS technician. They will be happy to talk with you about this. Ask them how to set up line transects to measure how much of the green, yellow or red plant species are present on the ranges you wish to score.