Tea production in the northern coastal provinces of Gilan and Mazandaran has dropped 40 percent on a year-to-year basis as rainfall has diminished and overall temperatures have risen, the head of the Tea Organization, Ali Moharar, told ISNA on Friday.The decrease in precipitation and the unprecedented heat since last June have severely damaged tea gardens facing farmers with major challenges. Around 100 thousand tons of tea leaves were expected to be harvested. However, the plants yielded no more than 62,500 tons, worth 870 billion rials, Moharar said.The official also noted that during the current farming year of 2013-2014, 86 percent of all the farmers were not able to insure their gardens. Moharar had previously urged farmers to insure their landed property. He argued that the damage caused by the recent drought will now be estimated by filming and monitoring the gardens with cameras. The imagery and footage that has so far been gathered was sent to the national disaster management organization. Annual tea consumption in Iran ranges between 110,000 to 120,000 tons.Iran exports tea to Germany, the United Arab Emirates, Russia, Azerbaijan, Georgia, Tajikistan, Afghanistan and Turkmenistan.