Primary Productivity Table

                                     Units Nine and Ten --- Land Ecologies

World Builders

 Primary Productivity Table

 Ecosystem Type

 Net Primary Productivity
(Kilocalories / square meter / year)

 Approximate Kilocalories
per square meter per day
Growing Season # of Frost Free nights
 Rainfall per year in inches
Type of Land

% of Earth's Land Surface

Tropical Rain Forest



 365 days
 More than 60
Estuary (the place where a river meets the sea)




swamps lakes streams

Swamps and Marshes


Savanna (grass, scattered trees, little or no winter snow)  


Prairie and Savanna

Temperate Grassland (cold winters)


Deciduous Temperate Forest


more than 120 days
Temperate Forests
 Boreal Forest (Evergreen Coniferous Forest)


 less than 120 days
Polar Tundra


 Less than 10
Barren ice, sand tundra desert

 < 200

Less than 10

Cultivated Land, which has generally been forest or tall grassland before its cultivation, now covers 9% of the earth's land surface. It produces 14% of the land's biomass. Agriculture that supports humans requires at least 20 inches of rainfall a year, although sometimes, when rainfall is insufficient, the natural rainfall may be supplimented with irrigation.

The total primary productivity of the ocean is about 8 times the primary productivity of all the land surface. This is about three times as much production in the ocean as the average for dry land for the same area. This productivity varies widely from season to season and place to place.

This table is from online Geology course created by Dr. Michael Pidwirny at Okanagan College, British Columbia, Canada and Land Use and Net Primary Productivity
(Dr Viau's additions are in red.)

1999, 2003.  Elizabeth Anne Viau. All rights reserved. This material may be used by individuals for instructional purposes but not sold. Please inform the author if you use it at