PORTLAND — Damage estimates to Oregon’s nursery stock industry from late December storms suffered by 160 growers in 12 counties range from $18 to $31 million in a survey conducted by the Oregon Association of Nurseries.

“It’s now clear that damage to nursery and greenhouse structures and crops was widespread and extensive,” said OAN President Tom McNabb of Yule Tree Farms of Canby.

Hardest hit were greenhouses and other structures used in the production of nursery and greenhouse crops. Growers reported the total estimated cost to repair or replace damaged greenhouses and structures at $10.8 million.

The nursery industry is Oregon’s most valuable agricultural producer, with sales topping $1 billion last year. About 81 percent of the output goes out of state, nearly 50 percent east of the Mississippi River.

The losses come as sales are reportetd down across the board because of the housing slump and sinking economy.

OAN spokeswoman Elizabeth Peters said the damage is probably not long-range or systemic, but will show up mostly in the costs of replacing buildings and plastic-covered “hoop houses”’ cheaper than glass greenhouses, used to protect young plants. Peters said there are no immediate indications that the state Christmas tree crop, which is included in the $1.1 billion total, suffered serious damage.

The association asked members to provide low and high estimates for crop damage because many plants are still in winter dormancy.

“Given the nature of our industry, the full extent of crop damage may not be fully known until spring, when plants begin to show new growth,” said McNabb. The reported low and high estimates for nursery and greenhouse crop damage ranges from $6.8 to $19.9 million.

The top-producing counties, Washington, Clackamas, Multnomah, Marion, and Yamhill, produce 86 percent of the state’s nursery crops and were the hardest-hit.

Damage prompted the OAN to seek agricultural disaster declarations in Benton, Clackamas, Columbia, Douglas, Jackson, Lane, Linn, Marion, Multnomah, Polk, Washington and Yamhill counties, possibly in the form of low-cost loans.

“Our growers are self-reliant and unaccustomed to government assistance,” said McNabb. “But, during these tough economic times, when banks are more cautious about making farm loans, we need access to federal assistance. This could not have come at a worse time for Oregon nursery and greenhouse growers.”