X1V INTRODUCTORY, 
The dry season divides fats a or one from November to Feb- 
ruary, with a temperature of 57-60° in the morning to 85-88° in 
the afternoon, with a minimum of 52- ‘54° ; and a hot one commencing 
towards the end of February and continuing to the middle or end of 
May, showing a temperature of 70-74° in the morning to 95-100° 
in the afternoon e maxima observed range from 104-106°, while 
the minima go ‘down as far as 69° Fahrenheit. Rain is ‘scanty 
during the whole dry season, being restricted to one or a few 
showers, which usually occur in March, but heavy dew in the cold 
and haze in the hot season act beneficially upon vegetation generally. . 
The greater part of the country is hilly or mountainous, and 
thus favourable to the existence of forests, which therefore cover 
the whole of the terrain except where the axe of the native has 
destroyed them. In those extensive alluvial plains which are 
formed by the Irrawaddi, Sittang, and partially by the Salween and 
other rivers, the forests gradually give shin to extensive savanna 
which spread out along the rivers themselve 
The greater the difference of me acne, the greater is also 
the influence of exposure ; and thus we see in Burma the deep valleys 
and the shady slopes of the hills more as less covered with evergreen 
tropical —— while the more ep slopes and plains are studded 
with | dding forests. An exception form here the forests 
growing in swampy depressions sed the mangrove forests which 
occupy the sea coasts, 
The area of tropical evergreen forests (which form the bulk 
of vegetation between the tropics towards the equator) is greatest 
in the southern provinces, as in Tenasserim and the Andamans, 
but it becomes more and more restricted and circumscribed as we 
- proceed northwards, where these forests retreat jo jhe valleys and 
favourably exposed se of the hills, owing to the dryness and 
heat fore the hot On the other hand, the leaf-shedding 
forests become of bass iter and = more ¢ircumscribed south 
wards, until they disappear altogether or become restricted to cer- 
_ tain substrata, or still more Setuonily ihe leaf-shedding trees mix 
_ with the evergreens and form no more conspicuous forests for 
themselves. 
Socialism of trees of the same species is a characteristic. of 
the temperate zones and recurs partially in the higher regions 
of our Indian mountains, as is shown by the pine forests ; but in 
te ee zone this socialism of conspecific trees is ereatly re- 
There prevails a continuous struggle for supremacy between 
such a large number of different trees that one often becomes 
press bewildered. An evergreen tropical forest consisting of 200 
to 300 species of trees alone to the square mile is almost the 
rule, and leaf-shedding forests (excepting the very poorest of 
a — are still composed of a eet number of trees than any 
