Dead planet, living planet

Mekong Delta mangrove forest restoration

CASE STUDY #23

The costs to successfully restore both the vegetative cover and

ecological functions of a mangrove forest have been reported

to range from USD 225/ha to USD 216,000/ha (Lewis, 2001).

Mangrove restoration projects have been classified into three

categories (Lewis, 2001; 2005): (1) planting alone, (2) hydro-

logic restoration, with and without planting, and (3) excavation

or fill, with and without planting. The first type, planting only,

although inexpensive (e.g.: USD 100–200/ha) usually does

not succeed due to a failure to appreciate the physiological tol-

erances of mangroves to tidal inundation. The second type,

hydrologic restoration, can be done for similar costs, and with

proper planning has a high success rate. Successful restora-

tion of abandoned shrimp aquaculture ponds is an example

of this method. Planting should only be done if natural recolo-

nization fails, and can double the cost of a project. Scientific

data indicates that using this method, ecological functions are

quickly restored, with fish populations typically reaching refer-

ence site diversity and densities within 5 years. The third type,

excavation and fill, is the most expensive due to the high costs

of large scale earthmoving.

Large-scale restoration of mangrove forests are feasible and

affordable. The largest mangrove restoration was that of the

mangrove forest in the Mekong Delta completely destroyed by the

US Air Forces in the 1970’s (above) and subsequently restored by

the Vietnamese government.

Black and white insert: “Results of Defoliation Operation”, illustration from

‘Vietnam Studies: Tactial and Material Innovations’, by Lieutenant General

John H. Hay, Jr.;

Colour im-

age: Professor Nguyen Homg, Universidad de Hanoi, Vietnam.