Gov. Jerry Brown is on a prospecting trip of his own this week. He arrived Tuesday in China, seeking a vein of investment gold for California.

"They've got $400 billion or $500 billion they're going to invest abroad, so California's got to get a piece of that," he told an Associated Press reporter before departing on a seven-day trip to Beijing, Shanghai and four other cities.

There are reasons for caution. The line between government and private enterprise is blurry in China, and serious allegations of officially sanctioned industrial espionage, copyright piracy and cyberattacks can't be ignored. Neither can the desires of a growing middle class in the world's most populous nation or the foreign currency reserves at the disposal of Chinese investors.

During his trip, Brown will sign an agreement limiting Chinese greenhouse gas emissions and announce various partnerships. You can count on the governor taking every opportunity to showcase China's extensive high-speed rail network. But that won't mean much unless Brown's hosts invest in his vision of a bullet train linking San Francisco and Los Angeles.

California ports are a primary point of entry for Chinese imports, but Brown's goals include sending more products the other way. About 90 business and economic development executives and public officials are accompanying him on a trip that marks a return to the international stage for a state that, by various measures, has the eighth or ninth largest economy in the world.

Beginning in the 1980s, California established a dozen trade offices around the globe to promote exports. Faced with a budget deficit as well as questions about the return on state's $6 million annual expenditure for the trade offices, the Legislature closed them all in 2003.

In Shanghai, Brown will preside over the reopening of an investment and trade office.

Unlike the state's last venture in international business, this office will be privately funded<NO1> and operated<NO>. Supporters say it will boost sales of wine, produce and other California products in China, which is already the state's third largest trading partner, trailing only Mexico and Canada. The other goal is to match Chinese investors with opportunities in California.

"We're going to facilitate billions of dollars of investments," Brown said in a speech before his trip. "Not overnight, but over time."

California isn't the only state trying to claim a larger share of the rapidly expanding Chinese consumer economy and tap into its deep pool of savings. This month alone, governors from three other states and the U.S. territory of Guam are visiting China to talk about trade and environmental issues. Several other states already have opened trade offices in China.

By one estimate, Chinese investment abroad could reach $2 trillion by 2020. By one estimate, Chinese investment abroad could reach $2 trillion by 2020. California must stake a claim if it wants to secure a share of that gold.