86 MANGROVE SWAMPS 
is toothed. The flowers are light blue and are in dense heads 
arranged in compact inflorescences at the ends of branches. The 
fruit is minute and crowned with white hairlike projections. 
STANDS IN MANGROVE SWAMPS 
The present condition of the mangrove swamps in the Philip- 
pines is very variable. In places close to centers of population. 
as in the immediate vicinity of Manila, Iloilo, and Cebu, the 
Swamps have been so closely cut over as to make them almost 
valueless. In many other places the most valuable trees have 
been largely removed, in other areas the swamps yield a large 
quantity of good material, and still others are practically un- 
touched. The largest remaining virgin swamps in the Islands 
are probably in Palawan and Mindanao, although in both of 
these islands a considerable amount of cutting and bark collecting 
has been carried on. 
A careful study of the swamps near Port Banga, Mindanao, 
has been made by Dr. H. N. Whitford and Forester W. I. Hut- 
chinson. The following extracts from their report describes 
this forest: 
The mangle forests of the Port Banga tract cover an area of 2,463 
hectares (6,086 acres). The largest continuous body of swamp, varying 
in width from 0.5 to 2 kilometers (0.31 to 1.42 miles), extends from the 
head of Balon Bay northward to the Baluan River. Scattered areas, some 
of considerable extent, also occur near the Tungauan River, and in Ticbucay 
Bay and Port Banga. 
Light cuttings have been made in these swamps for many years, and 
since 1902 certain situations have been heavily culled for posts and poles. 
Tanbark has also been extensively exploited, many areas being practically 
stripped of Tangal, the species from which the bark is obtained. 
The mangle forest is made up of a dense stand of small and medium- 
sized trees, many of which are raised on stilt roots from 1 to 3 meters 
(3 to 10 feet) above the ground. The characteristic species of the stand 
are Pagatpat, Bakauan, and Pototan. In certain localities Piagau and 
Langarai form pure stands, to the practical exclusion of all other trees. 
Tangal and several minor species occur scattered throughout all the swamps. 
The soil is soft, black mud of unknown depth. Underbrush and litter 
are entirely absent. The only method of travel through many of the 
swamps is by climbing along on the stilt roots of the trees. 
In the area surveyed, Pagatpat and Bakauan formed over 90 per cent 
of the stand. The average diameter of all trees over 40 cm. (16 inches) 
is 47 em. (18 inches). The largest tree is Pagatpat, which reaches a 
maximum diameter of 80 centimeters (31 inches) or more, with a maximum 
clear length of 17.50 meters (57 feet). The clear length of Bakauan 
almost equals Pagatpat, and that of Pototan exceeds it, but the greater per- 
centage of these species falls below 40 centimeters (16 inches) in diameter. 
