Program Features
Forest
Health Indicators
Vegetation Indicator
The Vegetation Indicator is a set of variables
collected on the Phase 3 (forest health) FIA
plots. It is designed to assess the type, abundance,
and spatial arrangement of all trees, shrubs,
herbs, grasses, ferns, and fern allies (horsetails
and club mosses) occurring on the plots.
Measuring vegetation allows us to report on
the relative diversity of both native and introduced
species. Information about the abundance and
arrangement of species (structure) allows us
to classify plots into community types. By remeasuring
plots over time, we can monitor for change outside
expected rates.
Why is the Vegetation Indicator Important?
Information about forest vegetation diversity
and structure can be used to:
- Examine which forest types are most prone
to invasion by non-native species.
- Determine
which states, ecoregions, and forest types
are most diverse or contain
unique species.
- Assess tree diversity
on a plot more thoroughly than P2 measurements
allow. Among other
things, this allows us to predict
succession on a
plot.
The Vegetation Indicator also provides data
to classify plot vegetation into community types:
- Forest community types based on both
overstory and understory plant species are
highly correlated with ecosystem properties,
such as
productivity, response to disturbance, and
use by wildlife.
- This may allow us to extrapolate
other forest
health indicator results to broader areas
than the plots themselves, and with more
accuracy than by forest cover type.
With remeasurement, we can:
- Assess trends over time in relation
to other forest health indicators.
- Examine
forest communities’ resistance
to and resiliency following disturbance.
- Provide
an early warning indicator of forest response
to stresses like pollution,
certain
land uses, and disturbance events.
For more information about the Vegetation
Indicator view
the FIA
Vegetation Indicator Fact Sheet.
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