Wood has been an important construction material since humans began building shelters, houses and boats. Nearly all boats were made out of wood until the late 19th century, and wood remains in common use today in boat construction. Elm in particular was used for this purpose as it resisted decay as long as it was kept wet (it also served for water pipe before the advent of more modern plumbing).
Until the late 19th century, what vessels were almost always wooden?
boats

Schwarzenegger signed another executive order on October 17, 2006 allowing California to work with the Northeast's Regional Greenhouse Gas Initiative. They plan to reduce carbon dioxide emissions by issuing a limited amount of carbon credits to each power plant in participating states. Any power plants that exceed emissions for the amount of carbon credits will have to purchase more credits to cover the difference. The plan took effect in 2009. In addition to using his political power to fight global warming, the governor has taken steps at his home to reduce his personal carbon footprint. Schwarzenegger has adapted one of his Hummers to run on hydrogen and another to run on biofuels. He has also installed solar panels to heat his home.
What green technology did Schwarzenegger have installed at home to reduce his carbon footprint? 
solar panels

By the 2000 census, demographic changes including the end to slavery, immigration from Europe and Asia, assimilation of multiracial persons, and other factors resulted in a population in which 6.2% of the population identified as black, 40% as pardo, and 55% as white. Essentially most of the black population was absorbed into the multi-racial category by intermixing. A 2007 genetic study found that at least 29% of the middle-class, white Brazilian population had some recent (since 1822 and the end of the colonial period) African ancestry.
How much identified as white?
55%