SEATTLE — Hurricane Katrina destroyed thousands of homes, but it was the damage to timber and sawmills in the storm-ravaged region that immediately drove up the price of some construction materials nationwide.

Now, as the plants reopen and the focus switches to reconstruction, experts say prices should begin to stabilize. In the long term, some say the rebuilding effort will have a minimal effect on construction costs elsewhere in the country — and could possibly even lead to changes that make home-building somewhat more affordable.

"In terms of somebody buying a house in California, there's going to be some ripple effect, but it's not going to be overwhelming," said Michael Carliner, an economist with the National Association of Home Builders.

The devastation that Katrina wrought on homes alone is thought to be far worse than that of Hurricane Andrew in 1992, with perhaps hundreds of thousands of homes damaged or destroyed.

But experts say the rebuilding process could take years and could be spread over a wider geographic area if some residents choose never to return to storm-ravaged areas and settle elsewhere. Those two factors alone could help dampen any spikes in pricing, or at least make it more difficult to judge the impact.

"This is quite different from the typical hurricane already in that we're still trying to literally bail out the city of New Orleans," said Ken Simonson, chief economist with the Associated General Contractors of America.

"It's complex because there is much more damage to the region and more damage to the economy, but also more people moving out of the region."

Also, because rebuilding is expected to take so long, Simonson said it will be difficult to parse out the effect of the rebuilding from other factors that affect U.S. home prices, such as mortgage rates or the oft-predicted slowing of the nation's housing boom.

There are also some more subtle impacts of Hurricane Katrina that some say could actually help the U.S. housing market. The hurricane downed a large swath of trees that must now be harvested quickly before they rot, potentially putting more wood product into the market to meet any increased demand.

Also, the Bush administration has said it will consider eliminating or easing tariffs on imported timber to make rebuilding more affordable and to increase supplies. If that happens, Carliner said, it could possibly even help to lower home prices elsewhere in the country.

For now, however, the market is still reacting to initial panic.

The composite price for framing lumber has risen 13.5 percent, to $403 per thousand feet, since the hurricane hit, according to the trade publication Random Lengths. The price of structural panels is up 38 percent, to $499 per thousand feet, for the same period.

Shawn Church, editor of Random Lengths, said the structural panels market is already showing signs of calming. He expects wood products prices to stabilize as initial, emotional reactions are tempered. As rebuilding begins, he said, any increased demand could be felt regionally, "but nationwide it will be likely undetectable" because "the demand will just be folded into an overall market that is huge."

The hurricane also had an immediate effect on the cement industry, since imports bound for New Orleans had to be rerouted to areas including Florida and Texas. Ed Sullivan, chief economist with the trade group Portland Cement Association, said that in the short term, it will actually help the cement market since those areas were dealing with shortages.

Sullivan said that months from now, when the rebuilding process begins, he expects there to be a sustained increased demand for cement that could last several years. But he sees imports meeting that demand, which will have little effect on housing prices elsewhere in the country.

The impact on other building supplies is expected to be similar.

At this early stage, many forest products companies have become wary of predicting the long-term effect to their profits. That's partly because companies don't want to appear to be thinking about whether they will profit from a massive national tragedy. But it's also partly because, with many areas still shell-shocked by crisis, it's harder than expected to say how much demand there will be.

"A lot will depend on how the reconstruction takes place, the type of construction," said Bruce Amundson, a spokesman with Weyerhaeuser Co., the forest products company based in Federal Way, Wash. "Do people go in with concrete? Do they go in with wood? At this time it's just really too early to tell."

Analyst Steve Chercover with D.A. Davidson and Co. said one reason the impact is relatively low is that most larger companies are well diversified geographically. For example, Weyerhaeuser suffered some damage to timberlands in the area, but the company said that, overall, less than 1 percent of its U.S. acreage was affected.