Christmas is still eight months away, but Lling Ping is already worried about a bad holiday season. >> Many customers, she says, are holding off on orders. Low makes artificial trees for the US and Europe.The Iran war has disrupted shipping and hiked oil prices, raising her costs per tree by 10%. This is the material used to make Lowe's artificial trees. It's PET plastic derived from oil.For these bags alone, the price is up 15%. And the PET in these needles rose around 5%. She tells me her revenue is down ...