1082 
THE TROPICAL 
AGRICULTURIST. [June i, 1882 
Hybkidity of Cinchona. 
Sik.— A letter of Mr. Wm. Smith of Mattakellie appeared 
in the columns of your evening contemporary the other day, 
which contained an interesting account of the writer's ex- 
perience regarding the grafting of Ledger cuttings and 
shoots on to succirubra stocks, and also some arguments 
of his in support of the theory that cinchonas d<5 not 
hybridize. It is only the latter subject which I wish to 
speak of here; and with all due deference to the opinion 
of one who has had so much experience of the cinchona 
tree, I cannot help arriving at a different conclusion, as 
du the great majority of my brother planters. How does 
Mr. Smith account for the presence of hybrids or Robustas 
011 estates, where no other seed but that gathered from, the 
trees on that estate has been sown, and where no Robusta 
tree old enough to give seed is to be found ? 
On this estate there were 103 succirubra and 44 officin- 
alis trees [unfortunately cut down and sold in London in 
1879] growing alternately along a road when 1 took charge, 
and a tew sell-sown trees in the coffee, but they were cert- 
ainly not older than two years then, and the original trees 
were 11 years old, having been planted as far as I am able 
to ascertain in 1867. I am certain there was not one solitary 
Robusta among the original trees, which have since been 
coppiced and have thrown out fine, healthy, tall shoots, 
and anyone can satisfy himself that the succirubra are 
pure and the officinalis too : the latter of course should be 
called Oondaminia. 
Until last year no other seed but that from my own trees 
has been sown here, and I have many thousand hybrids 
growing all over the estate ranging in age from one year 
to six. Now the question naturally arises where these 
hybrids, and particularly the oldest of them, six years old, 
come from ? I have one or two Micrantha plants about 
a year old, but I have no Micrantha tree, I feel con- 
fident. Where did they come from ? 1 am certain that most 
practical planters have adopted the hybridization theory — 
not without sufficient proof — and are not to be perverted 
even by so great an authority as Mr. Smith. 
Any opinion of Mr Smith is entitled to great consideration 
at our hands, but, if he is so confident, a's he expresses 
himself to be, that no hybridization can take place, why 
has he had his valuable Ledger trees enveloped in muslin 
whilst in flower, as I have heard he had done ? 
Does not this look as if he thought it was just as well 
to be on the safe side ? It is useless to dismiss the many 
facts that go to support the hybridization theory with 
generalisations such as " that the hybrid theory is repug- 
nant to my every sense, moral and material." 
I will ask him are there no cases of hybridization or 
cross-bxeeding in nature, as he seems to imply ? 
H. H. Capper. 
Broughton Estate, Haputale, 25 th April 1882. 
INFLUENCE OF FOBESTS ON 
CLIMATE. 
It is perhaps, from a feeling that the continuance 
of our present, or rather, our late, system of forest 
conservancy is in serious danger, owing to the break- 
ing up of the Forest Board, that Dr. Schomburgk, 
the Director of the Botanical Gardens has added to 
his recently issued report a lengthy appendix on the 
subject of the influence of forests on climate. The 
object of this paper is to prove that the destruction 
of forests usually has the effect of reductiug the 
rainfall, while on the contrary, the planting of trees 
broadcast over a country is one of the best methods 
which can be adopted for ameliorating its climate 
and increasing the annual fall of rain. It cannot, 
indeed, be proved that the climate of South Australia 
is altering for the worse in this respect. In fact, a 
comparison of the meteorological records will show 
that the annual average rainfall for the colony during 
the past ten years has been 21*1 inches, as compared 
with 20'1 inches for the previous ten years. The fact 
is that in the agricultural districts of the colony, and 
especially in those which were not originally timbered, 
the bringing of the land into cultivation has had the 
f fleet of slightly favouring the fall of rain. Ploughed 
land attracts moisture to a much greater degree than 
the unbroken soil. In considering the effect which the 
removal of forests per se has, in altering the climate 
in South Australia, the only direct test that could 
be taken from the records issued by the Govern 
ment Astronomer is the experience of the neigh 
bourhood of Adelaide. If we divide the time which 
lias elapsed since 1839, the year in which observ- 
ations were commenced, into two periods, we find 
for the first an average rainfall of 28-8 inches and 
for the second one of 21 "7 inches. It will thus be 
seen that on the whole the rainfall at Adelaide 
is diminishing, though very slightly, and, perhap?, the 
iliminution in the amount of timber may have some- 
thing to do with the change. There is, however, a 
comparison which is much more interesting than 
this, namely, that between the results obtained at 
the Obseiva'orv, at which there are very few trees 
of any size, but which is near to the sea, and those 
observed on East-terrace, at which ihey are more 
numerous, and which is nearer to the hilk There 
is a difference in the average rainfall of about three- 
fifths of an inch between these two places. This, 
of course, is in itself very slight, and would be scarcely 
worthy of notice but for the curious fact which is 
observable, that the advantage at East-terrace is en- 
tirely in the winter and spring months, while West- 
terrace has the greater amount in the summer months. 
Dr. Schomburgk, in searching for illustrations of 
the effect of trees on climate goes further afield, 
and brings forward some striking historical instan- 
ces, in which it is evident that loss of forests means 
loss of rainfall, and vice vena. He recalls to memory 
how the Russians by burning down some of the Trans- 
Caucasian forests at the time of their struggle with 
the brave Circassians converted the country from a 
fertile land into a desert, simply through the cutting 
off of the supply of rain. Similar instances of rain 
having deserted a country denuded of forests have 
occurred in the Mauritius, in Jamaica, the Azores, 
and it may also be added to a still more remarkable 
extent in several of the smaller We3t-India islands. 
No sooner had the forests of these places been destroyed 
than the springs and rivulets ceased to flow, the rain- 
fall became irregular, and even the deposition of dew 
was almost entirely checked. On the other hand it is 
generally accepted as an historical fact that the great 
Mehemet Ali, the most remarkable of the rulers of 
Egypt, increased the fertility of his country enormously 
by planting trees. He alone planted some 20.000,000 on 
the Delta; his successors followed up the work and it is a 
noteworthy circumstance that the rainfall rose from 
six to forty inches.* Planting has also, it would seem, 
produced remarkable effects in France and Algiers! 
Extensive regions have been planted with gums and 
other trees, which, for the most part, grew to about 
tbirty or forty feet in height, and it is noticed that the 
quantities of rain and dew which now fall on the adjacent 
land are double what they formerly were. To the French 
Government is due the honour of having made experi- 
mental tests, which placed the matter, at least as re- 
gards the European climate, almost beyond a doubt. In 
the historical method of research one must take the con- 
ditions as he finds i hem, and may very often be deceived 
by overlooking some fact of material consequence But 
when experiment is possible the conditions in one case 
can be rendered exactly similar to those in the other, 
and the test is then one of scientific exactness. Rain- 
gauges were erected under the supervision of the 
Forest Academy of Naiioy, some being placed in 
the neighbourhood of forests and others in the 
same districts, but sorrounded by open plains, 
and the strikin g fact was established that the 
* If this is ti ue, there is an end to discussion, 
but is it true ? We utterly discredit the wild state- 
ment. Who kept the Egyptian records ?— Ed. 
