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Vegetation

Vegetation refers to plant life, including agricultural and developed vegetation, desert and semi-desert, forest, shrubs, herbs, and natural land cover. Drought can result in reduced growth rates, increased stress on vegetation, and alterations or transformations to the plant community and/or the entire ecosystem.

Vegetation and Drought

Tall, green trees with a mountain in the background

Water is necessary for every aspect of plant development, including gemination, cell division, and respiration. The stress of drought may induce complex changes in biochemical, physiological, and morphological aspects of plants, limiting vegetative health, growth, regeneration of the plant population, the vegetative community in a region, and/or the entire ecosystem. The exact nature of impacts to vegetation depends on the drought—its severity, spatial extent, seasonal timing, and persistence, and the capacity of the vegetation to absorb and adapt to disturbances, and vegetation management actions.

Data, Maps, and Tools

During periods of drought, plants increase their demand for water through increased evapotranspiration and longer growing seasons.

U.S. Vegetation and Drought

The Evaporative Stress Index (ESI) describes temporal anomalies in evapotranspiration (ET), highlighting areas with anomalously high or low rates of water use across the land surface. The ESI also demonstrates capability for capturing early signals of "flash drought," brought on by extended periods of hot, dry, and windy conditions leading to rapid soil moisture depletion. Learn more.

The Vegetation Drought Response Index (VegDRI) is a weekly depiction of drought's effects on vegetation stress across the contiguous United States, produced by the National Drought Mitigation Center, the U.S. Geological Survey’s National Center for Earth Resources Observation and Science, and the High Plains Regional Climate Center. Learn more.

NOAA's Center for Satellite Applications and Research produces satellite-based global vegetation health products, including the vegetation health index (VHI). VHI is a proxy characterizing vegetation health or a combined estimation of moisture and thermal conditions. Vegetation health is often used to estimate crop condition and anticipated yield. If the indices are below 40, indicating different levels of vegetation stress, losses of crop and pasture production might be expected; if the indices above 60 (favorable conditions), plentiful production might be expected. Learn more.

Standardized ET/PET Anomolies

The color with the hex code #722700 identifies:
-2σ <
The color with the hex code #ea0500 identifies:
The color with the hex code #fc762d identifies:
-1σ
The color with the hex code #f9d26d identifies:
The color with the hex code #fff identifies:
0
The color with the hex code #ddfe93 identifies:
The color with the hex code #a0f447 identifies:
+1σ
The color with the hex code #42cb01 identifies:
The color with the hex code #1c7001 identifies:
> +2σ

Drought Conditions

The color with the hex code #ffe500 identifies:
Pre-Drought Stress
The color with the hex code #e66900 identifies:
Moderate Drought
The color with the hex code #c81e32 identifies:
Severe Drought
The color with the hex code #6b0000 identifies:
Extreme Drought

Moist Conditions

The color with the hex code #87fac2 identifies:
Unusually Moist
The color with the hex code #53c289 identifies:
Very Moist
The color with the hex code #288233 identifies:
Extremely Moist

Other Conditions

The color with the hex code #fff identifies:
Near Normal
The color with the hex code #b2b2b2 identifies:
Out of Season
The color with the hex code #0070fd identifies:
Water
The color with the hex code #828282 identifies:
Other Landcover

Unfavorable Conditions

The color with the hex code #ff00a0 identifies:
0 - 6
The color with the hex code #f00050 identifies:
6 - 12
The color with the hex code #ff7878 identifies:
12 - 24
The color with the hex code #ffaa00 identifies:
24 - 36
The color with the hex code #ff5 identifies:
36 - 48

Favorable Conditions

The color with the hex code #5f5 identifies:
48 - 60
The color with the hex code #0a0 identifies:
60 - 72
The color with the hex code #55f identifies:
72 - 84
The color with the hex code #00a identifies:
84 - 100

Related Content

Data & Maps | Soil Moisture

Drought can affect soil chemical, physical, and biological activities that are essential for plant and soil health. Impacts may include lack of nutrient uptake by vegetation, increased soil temperatures, altered microbial activity, changes in organic matter decomposition, and increased release of CO2.

Data & Maps | Agriculture

In agricultural ecosystems, drought may affect the growth rate and development of crop production. Without irrigation, drought-induced crop losses may be extensive, resulting in significant economic losses.

Data & Maps | Fire

Drought stress on vegetation can include damage to forests and soils, which in turn may increase wildfire frequency, severity, and spatial extent. View datasets and maps on current and predicted outlooks for fire risk, potential, and occurrence.

Research & Learn | Ecological Drought

Ecological drought refers to extreme drought impacts that exceed the capacity of both human and natural systems to adapt. Thus, ecological drought could drive irreversible changes in vegetation ecosystems—for example, from forest to shrubs—thereby changing the ecosystem benefits and services once provided by forests.