At Manulife Financial Corp.’s asset-management business, a slow and steady investment with some novel revenue sources is proving lucrative for the Canadian insurer: timber. The firm has amassed more than US$16 billion of timberland and agricultural assets under management in countries including the U.S., New Zealand, Australia and Brazil as it sought alternative investments to help diversify both its own portfolio and those of its clients. When held over decades, the investments help Manulife match the longer-duration liabilities of its life-insurance policies and offer opportunities for extra revenue, its executives said. “Timberland is not correlated to the fate of equities,” Paul Lorentz of  the company’s wealth- and asset-management division, said. “There are also opportunities to generate other income,” he said, pointing to carbon-offset credits, renting the land out and selling forestry products such as pine straw.