Oct 24 (Reuters) - U.S. forest products firm Weyerhaeuser reported an 88% fall in third-quarter profit on Thursday due to low demand for its products amid a weakness in the housing market. U.S. existing home sales declined to a 14-year low in September, hurt by high mortgage rates and house prices.

Though house supplies have improved, entry-level homes remain scarce in most regions of the country, keeping home prices at an unaffordable level for first-time buyers and hurting sales of companies such as Weyerhaeuser. Net sales in its wood products unit, the largest in terms of revenue, declined by 19.6% to $1.24 billion, also hurt by higher manufacturing costs.

In the fourth quarter, the company forecast sequentially higher core profit for the wood products segment. Sales in the Timberlands segment also declined by 5.4% to $493 million in the third quarter, hurt by lower harvests due to wildfire risks in its northern assets and wet weather in the south. The company reported a net income of $28 million, or 4 cents per share, for the quarter ended Sept. 30, compared with $239 million, or 33 cents per share, last year.

(Reporting by Sourasis Bose in Bengaluru; editing by Alan Barona) ((mailto:Sourasis.Bose@thomsonreuters.com))