April, 1928 
The Queensland Naturalist. 59 
life in open situations. They are late arrivals in the 
plant colonisation of a country, depending on the pro- 
tection afforded by densely packed trees. The dominant 
trees of the rain forest, however, are not shade loving. 
From across a valley we look at the/ forest on the opposite 
side, and see the crowns of the trees, fitted into each 
other, the leaves arranged in a leaf mosaic, so that a 
continuous canopy of green is presented to the full sun- 
light. So efficient are the crowns in intercepting the 
sun’s ray a that only stray beams stab the shade beneath. 
The trunks of the tallest trees, too, are bare of limbs,, 
and this is largely, a result of the tree’s love of light. 
Where light is insufficient the branches gradually die 
and , fall off, leaving a clean trunk. Out in the open, the' 
branches would persist as in the familiar case of the 
hoop pine, which in the rain forest has a bare columnar 
trunk. I11 Malayan countries mangroves are cultivated 
for tanbark, and are planted close; self-pruning takes 
place, and the stripping of the bark is made easier. 
Rain forest trees are not all sun-loving. The heights 
of the species composing a forest vary greatly, and 
,many never* reach the top story. The lower ones prefer 
shade. Young trees of the dominant species, however*,, 
have to be able to stand a considerable amount of shade, 
or they would never be able to reach the sunlight. It is 
no uncommon, thing in the forest to find numerous small 
trees apparently at a standstill, their stems weak, and 
their leaves few. When an opening occurs, as when a 
cyclone tears a gash through the forest or a tree falls 
and makes a clearing, these small plants shoot up rapidly. 
They, have the faculty of enduring a long Suppression 
period in their youth, and so can spend a long time 
attaining their objective — a place in the sun. Brandis 
hasi shown that the sal (Shorea robusta) is very tolerant 
of shade when young, and Brown finds that another 
dipterocarp (Parashosea malaanonan) may in the forest 
be seventy years in attaining a diameter of two inches, 
though it grows rapidly to an enormous size afterwards. 
The gum trees are different. They are sun lovers, and 
when cultivated in countries where the amount of sun- 
light is limited they are weakly. They have no long 
suppression period, and in their young state very few of 
them can tolerate such shade as occurs in the rain forests. 
Their place is not in dense formations except in the case 
of a few rapidly- growing columnar-trunked species such 
as Eucalyptus saligna, E. regnans, and E. gonio calyx. 
