Trees play an important role in the hydrological cycle to maintain the existence of water. Through the roots of trees, rainwater will seep into the ground and be stored as groundwater reserves. The fewer trees the less potency for rainwater to be 'captured' in the soil and the lower the ability to absorb water into the soil. This causes an area to tend to be arid and lose soil absorption, and during the dry season, there are no longer any water reserves that can be utilized.

However, not many people understand the role of trees in the hydrological cycle, so they tend to ignore the existence of trees, especially trees that have a water conservation function such as banyan and gayam which do not have high economic value compared to other cultivated plants such as sengon, teak, acacia, and mahogany. Awareness of water conservation needs to be continuously promoted in the community until a joint movement can be realized, as did Stube HEMAT Yogyakarta in the Water Security program. This program enriches students' experience through planting trees that function for water conservation with the Resan Community of Gunungkidul on Tanjung river bank, Bleberan village, Playen district, Gunungkidul (Saturday, 11/12/2021).

The students of Stube HEMAT Yogyakarta learned the philosophy of the Resan Community movement, observed the geological area of ​​Gunungkidul, identified plant species, and planted trees on riverbanks. Edi Padmo, the pioneer of the Resan Community expressed his concern, “I feel sorry for the loss of springs in Gunungkidul and want to pay attention to water sources in the Gunungkidul area. This movement is a space for people from various backgrounds to take action who care about water conservation. I am sure, slowly but sure, more and more areas of springs, spring catchments, and village forests are getting the 'touch' of the Resan community together with local community groups”. Meanwhile, Irsyad Martias, from Anthropology lecturer at Brawijaya University explained the reality of water problems in Gunungkidul has not become a regional development priority, as proved by the development focus directed at developing tourist areas and road facilities rather than the construction of quality clean water supply installations and access to make it easier for the community to get. Meanwhile, Budi, an organic farming practitioner, guided Stube HEMAT Yogyakarta students to identify plant species that have a water conservation function, such as Nyamplung, Gayam, Banyan, Loa, and several other species. He also explained that each member of the community played a role in establishing a tree nursery.

In the action of planting trees in the area along the Tanjung riverbank, Stube HEMAT students did not hesitate to mingle with other participants who came from various elements of society such as community members, inhabitants, village officials, and community networks around Gunungkidul. They walked along the riverbank, crossed the river, dug planting holes, planted plant seeds, and installed support poles. This collaboration is even more impressive by exchanging experiences related to water problems in various areas where students come from, such as the floods that occurred in Sintang, West Kalimantan, and difficulties in accessing clean water during the dry season in Manggarai and Sumba.

It is true that concern for water is not just a discourse, but must be realized in action, even though it seems simple the act of planting trees will provide benefits and preserve water. It is time for young students to take part in joint action to conserve water.***