d44 
cutting over, it is taken by the undesirable Api-Api (vicennia). 
If this is kept out, the swamp may reproduce .itself in a com- 
paratively short time. It is claimed that a mangrove-tree will 
reach a diameter of about 2 dm. in 20 years. In places where 
there is opportunity for the swamp to move forward, as on 
the deltas of large rivers, the advance of the mangrove seems 
to be rapid. Natives of Borneo have often claimed that the 
mangrove at the mouths of their great rivers was advancing 
at a rate equalling five meters per year. 
It has been recognized at various times and places, that the 
mangrove-swamps offered an opportunity for simple and suc- 
cessful forest-management which is unique in the tropics. This 
has been attempted at several places. At one place on Manila 
Bay, the natives were found to have a definite system of mana- 
gement of the mangrove-swamp, on a ten year rotation, it 
being found that material large enough for firewood could be 
produced in that time. This system of management has been 
in operation for many years and has proved successful. It gives 
a remarkably even series of age classes. This is a remarkable 
instance of a definite bit of forest-management by natives. In 
the same region, the Miva is planted and handled on a regular 
crop basis. 
The largest area or swamp which I have seen under mana- 
gement is in the Federated Malay States, in the neighborhood 
of Port Weld, Perak. The tract which is under definite mana- 
gement, covers one hundred Square miles and additional area 
is being brought under management as rapidly as circumstances 
will permit. The time of rotation is twenty years, which would 
seem too short a time to permit full development of any but 
firewood. It is to be hoped that a great many more areas of 
mangrove-swamp will soon go under management; because, 
the mangrove seems the most natural and desirable firewood 
for this part of the world, and, unless carefully managed, it 
will be destroyed, leaving land which is waste and useless for 
agricultural purposes. 
