METALS-Aluminium hits three-month low as stocks ramp up, tariffs loom

* Aluminum hits weakest since Dec. 19 at $2,085/T

* LME/ShFE arb: http://bit.ly/2wZSAEz

* GRAPHIC-2018 asset returns: http://tmsnrt.rs/2jvdmXl (Updates with official prices)

LONDON, March 15 (Reuters) - Aluminum slid to a three-month low on Thursday, hurt by a rise in stocks, the specter of U.S. import tariffs and expectations that supply from China will rise as its winter pollution controls expire.

As well as their direct effect on aluminum, which could be a supply surplus if exporters to the United States are obliged to sell their metal elsewhere, the threats of tariffs hurt metals more broadly by sparking fears of a trade war.

"If you look at the impact, the trade tariffs will, in the end, be deflationary globally," said Julius Baer's head of macro and commodities research, Norbert Ruecker.

"We see the end of the capacity cuts to China, with the end of the winter heating season ... Production has been holding up better than expected; supply, looking at inventories, has been increasing and these earlier fears that we could have some tightness have just not materialized."

* ALUMINIUM: London Metal Exchange aluminum touched its weakest since Dec. 19 in early European trade at $2,085 a tonne. It was untraded in official midday rings but was last bid at $2,085, down 0.2 percent.

* HEATING SEASON ENDS: China's winter heating season ended on Thursday. Aluminum smelters in 28 northern Chinese cities had been told to reduce output by at least 30 percent from Nov. 15 to March 15, though the actual volume cut was below expectations and applied pressure on prices.

* STOCKS: Aluminium inventories in LME warehouses <MAL-STOCKS> rose by 16,275 tonnes, data showed on Thursday. Headline stocks have risen by 24 percent since early February. ShFE aluminum <AL-STX-SGH> stockpiles held at exchange warehouses are within a whisker of record highs near 850,000 tonnes.

* OUTPUT: China's aluminum production eased by 1.8 percent in January-February from a year earlier, squeezed by the country's pollution crackdown and supply-side reform. An estimated 4.4 million tonnes of new capacity is expected to be completed this year.

* TECHNICALS: LME aluminum could bounce into a range of $2,108-$2,131 a tonne before falling, as suggested by its wave pattern and projection analysis, Reuters technical analyst Wang Tao said.

* COPPER: LME copper was untraded in official rings and was last bid down 1 percent at $6,920 a tonne, paring the previous session's gains.

* OTHER METALS: LME zinc and nickel were also untraded in official rings. Zinc was last bid up 0.2 percent at $3,233 a tonne while nickel was bid down 1 percent at $13,700. Lead was down 0.7 percent in official trading at $2,387, while tin fell 1.9 percent to $20,750.

(Additional reporting by Melanie Burton in Melbourne Editing by Mark Potter and David Goodman)