an INQUA Terrestrial Carbon Commission resource

Estimates of preanthropogenic carbon storage in global ecosystem types.

Compiled by Jonathan Adams, Environmental Sciences Division, Oak Ridge National Laboratory, TN 37831, USA

Link to Introduction to the carbon storage inventory

References directly cited in these pages (does not at present include secondary citations)

This section of the inventory aims to give information and opinion on per-unit-area carbon storage for specific ecosystem types in their 'natural', relatively non-anthropogenic state such as existed up until the mid-Holocene in many areas. Under each broad ecosystem type the present range of opinion is discussed, and a 'recommended' value is put forward. The recommended value is that which, on the grounds of this discussion and repeated checking with authors, is suggested by the present author as being the most plausible for the preagricultural/Late Quaternary state of each biome. Note that the purpose here is not to estimate 'present actual' (i.e. 1997) carbon storage, but instead the most likely state at various times in the prehistoric past. This is a state that present-day areas of anthropogenically disturbed ecosystems may tend to return to (even with climatic changes and alterations in the natural disturbance regime) if they are left unmanaged over future decades and centuries. Such estimates are important, therefore, in understanding the future potential fluxes of carbon into terrestrial biomes; they need to be taken into account in the carbon budgeting of planting and forest management policies, in long-term planning of fuelwood resources, etc.

Units

Units are presented here in tonnes of carbon per hectare (t/ha C). This unit is standard in the forestry and forest ecology literature, and is also often used in ecology in general. For conversion into Kg/m2 (a unit quite widely used in soil carbon studies, and in non-forest vegetation carbon studies), divide by 10.

Ecosystem components

For each ecosystem category, the values are broken down as follows; litter and debris (dead trees, dead roots, fallen wood, dead fallen leaves and twigs) t/ha C, vegetation (leaves, stems, trunks, branches, roots) t/ha C, and soil (organic matter below the litter layer and excluding living or dead roots and underground stems) t/ha C.

Each of the vegetation types is described in relation to categories used in the Olson et al. (1983) ecosystems map, although many modifications to this framework have been necessary.

Maps of hypothetical potential ecosystem distribution for present climates in the absence of anthropogenic disturbance (compiled by Jonathan Adams from a range of sources).

Africa present-potential vegetation

Australasia present-potential vegetation

Eurasia present-potential vegetation

Europe present-potential vegetation

North & Central America present-potential vegetation

South America present-potential vegetation

Key to the vegetation classification system used in this inventory and in the above maps

Link to Olson et al.'s map of present-actual ecosystem distribution and carbon storage

Version of the Olson et al. map with 'zoom-in' option

WCMC's map of present-actual global forest distribution

Key to the vegetation classification system used in this table and in the above maps

A summary of suggested average carbon storage in preanthropogenic ('prehistoric') ecosystems. Note that modern-day ecosystems are often depleted in carbon relative to this reconstructed state, due to agriculture and wood-cutting. An error range of approximately +/- 30% is suggested on each value.

Ecosystem type	Vegetation tC/ha	Soils tC/ha	Litter/Debris tC/ha	Total tC/ha
1. Tropical Rain Forest	210	100	10	320
2. Monsoon Forest	150	100	10	260
3. Tropical Woodland	85	70	10	165
4. Tropical Thorn Scrub	40	21	4	65
5. Tropical Semi-Desert	5	14	0	19
6. Tropical Grassland	12	42	0	54
7. Tropical Desert	1	0	0	1
8. Savanna/Forest Mosaic
9. Tropical Savanna	35	55	0	90
10. Warm Temperate Forest	190	145	36	371
11. Giant Conifer Forest	350	256	120	726
12. Tropical Montane Forest	130	130	15	275
13a) Mediterranean Forest	100	80	8	188
13b) Mediterranean Scrub	40	60	5	105
14. Cool Temperate Forest	160	140	25	325
15. Southern Taiga	140	135	15	290
16. Main Taiga	82	219	15	320
17. Open Boreal Woodland	50	129	15	194
18a) Temperate Woodland	95	97	15	207
18b) Temperate Scrub	45	45	5	95
19a) Montane/Dry Tundra	5	50	0	55
19b) Lowland Tundra	10	210	0	220
20a) Steppic Steppe-tundra	5	55	0	60
20b) Tundric Steppe-tundra	5	55	0	60
21. Polar/Montane Desert	1	0	0	1
22. Temperate Desert	1	0	0	1
23. Temperate Semi-Desert	4	56	0	60
24a) Moist Steppe	10	250	0	260
24b) Dry Steppe	6	70	0	76
25. Forest Steppe	10	220	11	241
26. Forest-Tundra	11	166	20	197
27. Bog/Swamp	20	N.A.	0	20 (+ peat)