ensure transparency in funds and performance measures. Ek Kadam Sansthan's campaign One Tree My Duty is working with technology-enabled tree plantation work. Israel See: Jewish National Fund#Afforestation; List of forests in Israel. Tree-planting is an ancient Jewish tradition. The Talmudic rabbi Yohanan ben Zakai used to say that if a person planting a tree heard that the Messiah had arrived, he should finish planting before going to greet him. Due to massive afforestation efforts, this fact echoed in diverse campaigns. Israeli forests are the product of a major afforestation campaign by the Jewish National Fund (JNF). The largest planted forest in Israel is Yatir Forest, located on the southern slopes of Mount Hebron, on the edge of the Negev Desert. It covers an area of 30,000 dunams (30 square kilometers). It is named after the ancient Levite city within its territory, Yatir, as written in the Torah: "And unto the children of Aaron the priest they gave Hebron with its suburbs, the city of refuge for the manslayer, and Libnah with its suburbs, and Jattir with its suburbs, and Eshtemoa with its suburbs" (Book of Joshua 21:13-14). In 2006, the JNF signed a 49-year lease agreement with the State of Israel which gives it control over 30,000 hectares of Negev land for the development of forests. Research on climate change is being carried out in Yatir Forest. Studies of the Weizmann Institute of Science, in collaboration with the Desert Research Institute at Sde Boker, have shown that the trees function as a trap for carbon in the air. Shade provided by trees planted in the desert also reduces evaporation of the sparse rainfall. Yatir Forest is a part of the NASA project FluxNet, a global network of micrometeorological tower sites used to measure the exchanges of carbon dioxide, water vapor, and energy between terrestrial ecosystem and atmosphere. The Arava Institute for Environmental Studies conducts research that focuses on crops such as dates and grapes grown in the vicinity of Yatir forest. The research is part of a project aimed at introducing new crops into arid and saline zones. The JNF has been criticized for planting non-native pine trees which are unsuited to the climate, rather than local species such as olive trees. Others say that JNF deserves credit for this decision, and the forests would not have survived otherwise. According to JNF statistics, six out of every 10 saplings planted