GIRTH INCREMENT OF HEVEA BRASILIEN8IS. 
81 
development of new leaf respectively. Generally speaking, 
this occupies from four to six weeks. Within a week after 
the change of colour all the leaves have fallen and the tree is 
bare. In another week the buds are shooting. A week 
later the new leaves are evident, but another two or three 
weeks elapses before they are fully formed and rigid. As 
an example, the records of tree No. 3 for 1912 may be quoted. 
These are as follows : — 
January 28 : Leaves changing colour. 
February 4 : Leafless. 
February 11 : Buds just shooting. 
February 18 : Leaves just developing. 
February 25 : Leaves hah normal size. 
March 3 : Leaves full size but limp. 
March 10 : Leaves rigid. 
These records were, as previously stated, taken only at 
weekly intervals, and the exact date of the final change may 
lie anywhere between the last two dates. 
In 1913 the period occupied by these changes was greatly 
extended, in one case to ten weeks. This was due chiefly 
to the irregular “wintering” of the trees, the different 
branches of the same tree shedding their leaves at different 
times, so that several trees were never entirely leafless. For 
example, the upper branches of tree No. 6 began to lose their 
leaves on January 5, and on February 23 their new leaves 
were fully formed, but the leaves on the lower branches were 
then just beginning to fall, and these branches did not com- 
plete the change until March 16. The total change of leaf 
was spread over ten weeks, but the tree “ wintered ” in 
two distinct halves. This individuality of different branches 
on the same tree is often a marked feature in the leaf -fall 
of deciduous trees in the tropics, as has been previously 
recorded by Wright and others, but it is not usually so 
pronounced in the case of Hevea hmsiliensis as it was in 
this abnormally wet season. 
In 1914 the period occupied by these changes was shorter 
than usual, being only three to four weeks. 
In general no increase in girth occurs during the change 
of leaf. Some exceptions to this rule will be noted in the 
