xu,¢,¢ Brown: Mount Banahao’s Podocarpus Imbricatus 327 
and South Carolina are averages of the figures given by Living- 
ston for stations in these states. 
The figures in Table V would not indicate that the temperature 
at the top of Mount Banahao is more unfavorable for growth 
than that in the northern United States. Such a conclusion 
must, however, be regarded as tentative. 
Owing to the prevalence of clouds the light conditions at the 
top of Mount Banahao are very unfavorable. It is usual for 
mountains on tropical islands to be frequently capped with clouds 
and the decrease in the intensity of light, due to this, is probably 
responsible, in a considerable measure, for the rapid dwarfing 
of vegetation as high altitudes are reached on such mountains. 
According to Wiesner’ sunless days are much more frequent 
at the tops of mountains than at lower altitudes. At the top of 
Mount Banahao the sun is obscured for a large part of most days, 
and this is probably a very important factor in causing a slow 
rate of growth. 
In fig. 1 is also shown a curve of growth of Parashorea 
plicata*® at an altitude of 300 meters on Mount Maquiling. This 
curve shows that the small individuals of Parashorea undergo 
a suppression period, but that after this period is passed Para- 
shorea grows much more rapidly than any of the four species 
of pines whose growth curves are given in the same figure, and 
very much more rapidly than Podocarpus imbricatus. 
In Table VI the rate of growth of Podocarpus imbricatus is 
compared with the rates of growth of some species of diptero- 
carps growing at low altitudes in the Philippines. This relation 
. TABLE VI.—Rates of growth of Podocarpus imbricatus on Mount Banahao 
as compared with rates of other species in the Philippines. 
[Figures represent annual diameter growth in centimeters.] 
fr Se Alti Diameter class in centimeters. 
anions Location. ‘2 
sie tude. | 5-10. |10-20, |20-30. '30-40, |40-50. |50-60. 
i oe ates es 
Meters. 
Parashorea plicata _______- Mount Maquiling-_.--- 300 | 0.28 0.40 | 0.62 | 0.92 | 0.83 |0.88 : 
| Shorea teysmanniana __..- Northern Laguna_-__-} 600 | 0.27 | 0.88 | 0.57 | 0.50 | 0.54 |0. 43 
Shorea polysperma.......-|----- * oe Te Se Bee 500 | 0.27 | 0.27 | 0.40 | 0.37 | 0.55 |0.34 
Shorea squamata .......---|----- Oe ee ee 500 | 0.82 ; 0.28 | 0.35 | 0.28 | 0.42 [0.26 
Shorea polysperma ____..-- Mount Mariveles -.--. 400-500 | 0.18 | 0.26 | 0.36 0.52 | 0.41 |..---- 
Dipterocarpus grandiflo- |... - pS eg eee ny ee 400-500 | 0.07 | 0.16 | 0.19 | 0.16 | 0.16 0.22 
rus. | 
Podocarpus imbricatus....| Mount Banahao ------ | 2,100 | 0.06 0,14 | 0.15 | 0.16 | 0.18 ‘ies 
: : wis 
* Wiesner, J. Der Lichtgenuss der Pflanzen (1907). 
* Brown, W. H., and Matthews, D. M., Philippine dipterocarp Forests, 
Philip. Journ. Sci. A, 9 (1914) 413-561. 
° Brown, W. H. and Matthews, D. M., loc. cit. 
