You can see some hopper damage to the leaves in the photo I just took, but I've never seen a castor bean tree completely defoliated or even seriously damaged.
I had no idea castor bean trees could survive so well in dry, sandy soil. It's been about a month since there was any significant rainfall here, and I've seen potted castor bean plants go all droopy if I wait too long between waterings. It's very strange -- everything I can find on the Web about castor bean trees says the have shallow roots, and I've observed the same thing when I pull them up (in my garden in San Antonio, they tend to be a bit overly fecund). This article [An Assessment of Alternative Perennials For Use in Agriforestry Systems of Smallholder Famers] says that castor plants are drought resistant. Maybe they store water in their trunks and stems?
A 1937 article in St. Petersburg FL Independent says that grasshoppers love to eat castor bean leaves and die after eating them. http://news.google.com/newspapers?id=ZuNPAAAAIBAJ&sjid=M1UDAAAAIBAJ&pg=3470%2C286829
If only!
There's an article on the same page of the newspaper about a guy who moved into a condemned lower east side apartment in NYC and rented out rooms for 5 cents per day. In addition to the space, the tenants received firewood and candles. http://news.google.com/newspapers?id=ZuNPAAAAIBAJ&sjid=M1UDAAAAIBAJ&pg=4921%2C286509
Here's an article about the various commercial uses of castor beans:
http://nceed.com/Spilling_the_Beans.pdf
It says the main use of castor bean oil is in making nylon. Castor oil is also used as a component of lithium grease and other types of grease; as a component of plastic polymers; and corrosion inhibitors. Researchers in Israel are working on selectively breeding castor bean plants for the production of bio-fuel from the oil. Castor bean oil is ideal becuase:
- it is soluble in alcohol, and does not require heat to be transformed into fuel
- Oil makes up about 50% of the weight of the castor seeds
- The castor-oil plant is easy to grow and drought- resistant
- The castor bean can be grown on marginal lands, which are not usable for food production
- The castor plant can be adapted to large scale mechanized production
Castor oil certainly makes a LOT more sense than corn oil for making fuel.