IKEA is working to wield more control over its most important raw material: wood.

The Swedish furniture giant earlier this month bought a forest in Romania, marking the first time that the company will manage its own forest operations.

IKEA said owning and operating forests would help it secure long-term access to sustainably managed wood at affordable prices. The retailer used the equivalent of about 530 million cubic feet of round wood last fiscal year—or about 14 Empire State Buildings—excluding paper and packaging.

Timber prices are expected to increase globally as population, the use of biomass for energy and U.S. housing sales are on the rise, said George Krempels, a fund manager at FIM Services Ltd.

IKEA said it would use some of the wood from its 83,000 acres of Romanian forest to locally make furniture for its store in Bucharest, with plans to open a second store. The acquisition comes as IKEA has also been investing in renewable energy and biomaterials.

IKEA in 2012 set a target to double sales to €50 billion ($55 billion) by 2020. That involves more than doubling the volume of products it sells, said IKEA’s head of sustainability, Steve Howard, since the retailer tries to lower overall prices slightly every year. Despite this, IKEA is aiming to increase the wood it uses by only about 50%, Mr. Howard said in an interview.

To do this, the company has been working on optimizing its product designs to make the best use of trees.

IKEA designs some of its Norden series tables so they use the tops of trees and irregular-looking bits that wouldn’t otherwise be used, according to a spokeswoman. The company’s Skogsta product line—which will become available in August—is made of acacia, a type of tree that is light blond in the middle and darker on the outside. IKEA now makes products that use both shades of the wood, rather than just the dark wood, which the furniture industry has historically favored.

IKEA also has been tweaking the density of the particleboard used for the backs of products like wardrobes and dressers. Rather than use one sheet of particleboard of standard thickness, the company designs its boards to be thicker around the hinges and corners, and thinner toward the middle, which needs less support.

For the tops of certain coffee tables, such as its Lacka product, and increasingly for wardrobe doors, IKEA uses a board on a frame rather than a thicker piece of solid wood. Mr. Howard said that allows producing three or four times as much with the same raw material.

“We’ve been progressing through our range of products and mapping where we need solid wood,” Mr. Howard said. IKEA’s Mockelby table is made of pieces of wood connected with joints, but a layer of veneer helps give it the appearance of a solid piece of wood. “This lets us use logs that would otherwise be thrown away,” Mr. Howard said.

IKEA is increasingly relying on recycled wood for its furniture. By 2020, the company wants all the wood its uses to be either recycled or certified by the Forest Stewardship Council, a nonprofit group that promotes responsible forestry. So far, about 50% of the wood it uses meets either criteria.

IKEA also has its own foresters, who strive to ensure it is buying from well-managed forests. However, the company—which buys much of its wood in Scandinavia, Poland, Romania, China and Russia— has run into problems on its sustainability practices.

Early last year, the company was briefly banned from cutting trees in Russia’s Karelia forest by the Forest Stewardship Council, which had found that IKEA’s Swedwood subsidiary had violated its logging agreement. IKEA appealed, and the FSC lifted its suspension a month later after reclassifying some of IKEA’s alleged deviations.

Viktor Säfve, chairman of the Swedish nonprofit Protect the Forest, called IKEA’s practices in Russia “very brutal” and said the company has logged old forests that have high conservation value. Mr. Säfve also said the FSC is paid by the organizations it certifies, making for a “dysfunctional system.” The FSC said its policy is to cut all ties with a company in the event of “major illegal activities,” which didn’t need to be applied to IKEA’s case in Karelia.

An IKEA spokeswoman said, “We are committed to responsible forestry and to the principles of the FSC. In accordance with our forestry standards, we do not harvest in high-conservation-value forests—as defined by the FSC—unless they are certified as responsibly managed.”

Richard Donovan, vice president of forestry at Rainforest Alliance—which audited IKEA in Russia for the FSC—said the organization found no evidence that IKEA logged old trees in Karelia.

IKEA has since divested its operations in Karelia. In Russia, it still operates in Veliky Novgorod and Tikhvin.

IKEA said it recently had bought forests in Estonia, Lithuania and Latvia, totaling nearly 10,000 acres, but had no plans to harvest them at this point and isn’t managing those forests itself. It also said it is considering buying forests in several other markets.