* Aluminium hits weakest since Dec. 19 at $2,086/T
* LME/ShFE arb: http://bit.ly/2wZSAEz
* GRAPHIC-2018 asset returns: http://tmsnrt.rs/2jvdmXl (Updates throughout, adds LONDON dateline)
LONDON, March 15 (Reuters) - Aluminium slid to a three-month low on Thursday, hurt by a rise in stocks, the prospect of looming 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 aluminium, which may see 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 be in the end deflationary globally," Julius Baer's head of macro and commodities research Norbert Ruecker said.
"We see the end of the capacity cuts to China, with the end of the winter heating season .... (and) you also see increasing inventories across this segment," he added. "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 materialised."
ALUMINIUM: London Metal Exchange aluminium fell to its weakest since Dec. 19 in early European trade at $2,086 a tonne, and by 1030 GMT was at $2,088.50 a tonne, little changed from Wednesday.
* HEATING SEASON ENDS: China's winter heating season ended on Thursday. Aluminium smelters in 28 northern Chinese cities had been told to reduce output by at least 30 percent from Nov. 15 to March 15, although the actual volume cut was below expectations, putting pressure on prices.
* STOCKS: Aluminium inventories in LME warehouses <MAL-STOCKS> rose 16,275 tonnes, data showed on Thursday. Headline stocks have risen 24 percent since early February. ShFE aluminium <AL-STX-SGH> stockpiles held at exchange warehouses are within a whisker of record highs near 850,000 tonnes.
* OUTPUT: China's aluminium production eased 1.8 percent in January-February from a year earlier, as the country's pollution crackdown and supply-side reform kicked in. An estimated 4.4 million tonnes of new capacity are expected to be completed this year.
* TECHNICALS: LME aluminium may bounce into a range of $2,108-$2,131 a tonne before falling, as suggested by its wave pattern and a projection analysis, Reuters technical analyst Wang Tao said.
* COPPER: LME copper was down 0.5 percent at $6,956 a tonne, paring the previous session's gains. Prices are expected to rise as industrial production in the seasonally strongest second quarter ramps up.
* OTHER METALS: LME zinc was up 0.3 percent at $3,235.50 a tonne, while lead was 0.3 percent lower at $2,397.50 a tonne. Nickel was down 0.7 percent at $13,745, and tin was down 1.9 percent at $20,750.
(Additional reporting by Melanie Burton in Melbourne; Editing by Mark Potter)