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boom had been expected. It might have materialised but for these improve: 
ments in tyre manufacture. Instead of a boom came a slump, however, 
and the planting industry has not yet quite recovered from the effects 
of that slump. There was practically no new planting from 1920 to 1922, 
There was a little in 1923 and in the early part of 1924. In the last 
three months of 1924 came a considerable rise in price and a tremendous 
rise in 1925. That started new planting, especially in the Dutch East 
Indies, and in 1925, 1926 and 1927 there was a very large amount of 
planting by the natives. This is not altogether new planting, because the 
native not infrequently taps his holding in a most drastic manner without 
consideration of the life of his trees. Thus a good deal of the new planting 
done by matives in the Dutch East Indies is to replace trees which will 
sooner or later cease to produce. It takes from five to six years from 
the time of planting of the trees before a commercial crop can be harvested. 
The output of a tree increases up to 12 to 14 years. After that, it remains 
stationary for a while, and then ‘it probably declines. The average pro- 
ductive life of a rubber tree is really not known since planters have had 
only about 25 years’ experience of the plantation industry. 
Wild rubber from Brazil and Africa is now practically negligible, being 
less than 5 per cent. of the total world’s marketable supplies. In 1900 
Brazil, Africa and Central America supplied all the world’s rubber, Brazil 
roughly two-thirds of it. The highest output of wild rubber was in 1910 
and 1911, when it reached 60,000 tons, dry weight, per year. In 1928 
not more than 25,000 tons of dry rubber will be obtained from those places. 
It is doubtful whether even with a higher price, of 1s. 6d. or 2s. a Ib., 
these countries would produce more than 30 to 85 thousand tons of dry 
rubber. In Brazil, the more accessible trees have been tapped for many 
years and are rather exhausted. Tt does not pay to work the numerous 
trees in the more. inaccessible regions. In Africa the wild rubber has 
been dying out since 1910 owing to the destructive methods adopted in 
tapping the trees. Thus wild rubber is not an important factor to-day. 
The 1920 slump. 
In spite of a good demand in 1918 for rubber in America and other 
countries, falls in the local prices of rubber in the East occurred, owing 
to the scarcity of shipping, which was required for transporting troops 
and war material. Thus, whilst during 1917 and 1918 the London prices 
were from 2s, 6d. to 3s. a Ib., local prices in the East were below 1s. 
par lb. With the release of shipping after the Armistice, tue situation 
improved, and during 1919 large quantities of rubber were shipped. The 
demand was encouraging and no one foresaw that in less than two years 
the plantation industry would be experiencing the worst slump it has had 
to face. The slump was partly due to general trade depression in 1920, 
but was largely due to the improved manufacture of tyres. In the days 
of the old fabric tyre, five tyres a year were required for each car. By 
1920 the new cord tyre was in use; only three per car were required 
each year. Cord tyres contained more rubber than the old fabric tyres, 
but were much more durable. In the middle of 1920, manufacturers found 
themselves with large forward commitments of crude rubber at prices 
ranging from 2s. 6d. to 3s. per Ib. and with stocks of manufacturers’ 
goods largely in excess of the current demand, Manufacturing activity 
was drastically curtailed, the demand for crude rubber dropped, and the 
resulting fall in price was intensified’ by the re-sale of criide rubber by 
manufacturers. Owing to the multiplicity and diversity of the nationality 
of the producers, it was impossible to effect an immediate curtailment of 
shipments, and it proved impossible, for the same reasons, to get a 
sufficient amount of support for any effective voluntary scheme of restriction 
of output.