The rehabilitation or intensified use of Imperata grasslands will requ
ire a much better understanding of their area, distribution, and chara
cteristics. We generated estimates of the area of Imperata grasslands
in tropical Asia, and suggested a typology of Imperata grasslands that
may be useful to define the pathways toward appropriate land use inte
nsification. We conclude that the area of Imperata grasslands in Asia
is about 35 million ha. This is about 4% of the total land area. The c
ountries with the largest area of Imperata grasslands are Indonesia (8
.5 million ha) and India (8.0 million ha). Those with the largest prop
ortion of their surface area covered with Imperata are Sri Lanka (23%)
, the Philippines (17%), and Vietnam (9%). Laos, Thailand, Myanmar, an
d Bangladesh evidently all have similar proportions of their land area
infested with Imperata (about 3 to 4%). Malaysia(< 1%), Cambodia(1%),
and the southern part of China (2%) have but a minor proportion of th
eir total land area in Imperata. The species was found widely distribu
ted on the full range of soil orders. It occupied both fertile (e.g. s
ome of the Inceptisols and Andisols) and infertile soils (Ultisols and
Oxisols) across a wide range of climates and elevations. Imperata lan
ds fall into four mapping scale-related categories: Mega-grasslands, m
acro-grasslands, meso-grasslands, and micro-grasslands. The mega-grass
lands are often referred to as 'sheet Imperata'. They are the large co
ntiguous areas of Imperata that would appear on small-scale maps of sa
y 1:1,000,000. We propose that this basic typology be supplemented wit
h a number of additional components that have a key influence on inten
sification pathways: land quality, market access, and the source of po
wer for tillage. The typology was applied in a case study of Indonesia
n villages in the vicinity of Imperata grasslands. We propose an inter
national initiative to map and derive a more complete and uniform pict
ure of the area of the Imperata grasslands, This should include select
ed studies to understand conditions at the local level, These are crit
ical to build the appreciation of change agents for the indigenous sys
tems of resource exploitation, and how they relate to local needs, val
ues, and constraints.