* Wheat falls as Black Sea supply concerns ease
* Soybeans edge lower after one-week high on export demand
* Firm dollar, approaching USDA report keep market subdued (Writes through after European trading, changes dateline)
By Gus Trompiz and Colin Packham
PARIS/SYDNEY, Dec 8 (Reuters) - U.S. soybean futures eased on Monday, after a three-day rally fuelled by exports, as attention turned to government forecasts this week that will show the extent to which strong demand has cut into record harvest supply.
Corn also edged lower for the first time in four sessions. Wheat tracked corn and soybeans downwards as worries about Black Sea supply that triggered gains a week ago continued to fade.
Chicago Board of Trade January soybean futures were down 0.5 percent to $10.31 a bushel by 1212 GMT. On Friday, the contract closed up 2.5 percent after touching a one-week high of $10.40-3/4 during the session.
"The strong export demand for U.S. soybeans is likely to prompt a downward revision of the envisaged U.S. soybean ending stocks for 2014/15," Commerzbank analysts said in a note.
"Nonetheless, we are sceptical about the future price performance, not least because new supply will soon reach the market from South America."
The U.S. Department of Agriculture will issue monthly supply-and-demand forecasts on Wednesday, in which analysts on average expect it to trim its forecast of U.S. 2014/15 soybean ending stocks and raise corn and wheat stocks.
Export sentiment in soybeans was boosted by higher-than-expected weekly U.S. sales last week, an additional 240,000 tonne sale to China reported on Friday, plus news that Chinese soybean imports rose 12 percent year-on-year in November.
CBOT March corn fell 0.1 percent to $3.94-1/2 a bushel, having closed up 1.3 percent on Friday.
Corn had also drawn strength from brisk weekly exports as well as market speculation that China might ease restrictions on imports of U.S. corn by-product distillers' dried grains (DDGs), which have been blocked for months by a dispute over genetically modified content.
However, corn and soybeans remained capped by record U.S. harvest production this year, and a continuing rally in the dollar that has traded at five-year highs since stronger-than-expected U.S> jobs data on Friday.
CBOT March wheat futures fell 0.7 percent to $5.90 a bushel, giving up similar-sized gains from Friday.
Milder temperatures forecast this week in winter grain belts in Russia and Ukraine have eased concerns about frost damage to crops while nervousness about potential Russian export restrictions has also subsided after last week's rally. (Editing by William Hardy)