Table 2. Interim steps in the development of common-language indicators (CLIs) are shown here. Four indicators from forests are used for illustration. The steps listed for each column refer to Fig. 1. Small-group session numbers refer to which small-group sessions worked with which language iteration.

EMAP Indicator Name
(Step 1)
What each indicator measures
(Step 2)
What each indicator measures and indicates
(Step 3)
What each indicator conveys about the environment (Step 4)

(Presented to Small-Group Session 1)
(Presented to Small-Group Sessions 2 & 3)
(Presented to Small-Group Sessions 3 & 4)
Bio-indicator Plants - Ozone
Visible damage to plant leaves caused by air pollution.
Measures the visible damage to leaves of particular plants, which provides information about the level of air pollution in forests.
Air pollution effects on plants.
Photosynthetically Active
Radiation - Leaf Area
The amount of sunlight captured and used by a tree’s leaves for energy and growth.
Measures the amount of sunlight captured and used by trees for energy, which provides information about total leaf area and density, and how efficiently energy is being gathered by trees for growth.
How efficiently energy is being gathered by trees for growth, which helps to determine tree health.
Lichen Communities
The number and different types of lichens living on woody debris.
Counts the different kinds and total number of small, moss-like plants that live on trees and rocks in a forest, which provides information about one aspect of plant diversity in the forest, and about possible effects of air pollution on the forest.
The effects of some air pollution on the forest, including changes in the numbers and types of certain plants.
Root Ecology
The condition of trees at the root/soil interface.
Measures the condition of tree roots, which can help identify reasons for observed tree growth and vegetation structure, including soil condition (wetness, compaction, etc.), and disease and other stresses to trees.
How soil condition, vegetation structure, disease, and other stresses affect trees.