Dr C. G. G. J. VAN STEENIS, 
HERBARIUM, BUITENZORG, 
JAVA, N. E. I. 
; 
Buitenzorg, Nov.2ij.th, 1958 
Dear Henderscn, 
I have still not yet answered your letter of Oct.2^. I 
have not been lazy but there were several urgent duties and I am miles behind 
with my work. 
■^he passage on the nan61ia«TiBpyi>^ occurrence of lightning, Maleische Vegetatie- 
schetsen in Tijdschr.^on.^ed.Aardr.Ganootschap vol.52, 1935* P«lj-8 (separate 
p.2M reads as follows in English: 
Bire through struck of lightning seems to occur locally more frequent that 
one might think. It was communicated to me that in teak f orests some spots 
suffer often and regularly from lightning, possibly above underground water 
veins. I myself described ( Tropische Natuur 2ji,193ll-*p.l66) * bum-vegetation 
consisting of grasses on a steep conical andesite peak, Mt Aseupan in iiwwaaa- 
Krawang fchieh probably suffers probably regularly from struck of lightning. 
F.E.Endert (Midde^B^rneo expeditie 1925# 1927#P.226-227) mentioned struck 
of lightning on steep limestone hills in Central East Borneo, where 
after fire firstly Epitheroa, ees a snail fleshy herb, later ferns (among 
others Nephrolepis and Pteridium aquilinum, the latter a typical fire-plant) 
and at last shrubs gained ground. H.N.Ridley ^wrote me that he had found 
plenty traces of lightning struck on the sandstone plateaux of G.Tahan, Malay 
Peninsula. 
I may add that later the forester Dr.D.Burger wrote an article entitled 
Bliksem als oorzaak van boschbrand (Tectona 29* 193&* p.881-895) 
♦ 
I mention the following translated passages from this article of which the 
title is in English Lightning as a cause of forest fires. 
p.88l.Ritsema van Eck, C.R.S.,(in Tectona 15,1920,p.336-358) says s 
Forest fire originates in the Javan mountain forests only by man 1 s influence 
Struck of lightning which can cause fire is here always accompanied by 
heavry rains, lightning occurs only iuring the West monsun (the wet season , 
v.St.) and then there is no fear for forest fires. 
confirms 
Burger-ftaflumes that he also has seen numerous traces of struck of lightning 
in teak forests but denies that this has caused forest fires. 
Burger also found that in the very inflammable Ca mountain casuarina forests 
of East Java numerous traces of lightning struck occur. The centre of I£ t 
Andjasmoro - a ridge with inf lammable grass-Casuarina savannah - is called 
poesoeng gelap, which means lightning-ridge. Traces of lightning are found 
along the Casuarina stems, but there has occurred no fire during the period 
1929-1933. ■ : ?i t W 'i W?. - t*>, ^ v"-.--; ^ ' 
p.§81-882. Burger went through reports of 2602 fires.In only 1 case 
fire was reported as being caused by lightning. This fire which burned down 
ca 1 sq.hm of mounta info rests was extinguished by rain. (The argument is not 
very convincing as I4.8/0 of the reports,that is nearly one half or 1300 fires 
did not mention any cause known, better said : cause unknown. Among these 
1500 fires there must have been certainly more caused by lightning as this 
cause easily escapes observation at reiaore spots such as mountain tops and 
-ridges are I v.St.) 
p.882. Burger also concludes from tha fact that in well-preserved areas 
fire does not occur any more , that lightning can be negllcted as a 
cause of forest fires. 
p.883* Burger mentions, however, that contarily in Finland and California 
a large percentage of forest fires is caused by lightning, in Oregon and 
Washington more than 50$ of all fires 1 In Holland, Belgium, South Africa 
and Russia only a small percentage is due to lightning. Braak, the meteorlo- 
|ist has the impression that tropical lightning is less powerful that it is 
in temperate regions, and, moreover, is always accompanied of followed by 
heavy rain. 
