Dew Condensers for Reducing Drought Mortality of Tree Seedlings in Reforestation Projects.

High mortality of tree seedlings due to drought is a common cause for failure of reforestation projects. The problem is most severe for newly planted seedlings with poorly developed root systems, established in areas with prolonged drought periods and no access to irrigation water. We describe simple passive dew condensers capable of providing 100-250 ml of water per square meter of condenser surface on cloudless nights in the humid tropics. Even higher amounts of dew condensation occur in low humidity environments with greater atmospheric transparency to infrared radiation. Such amounts of water, dripped onto a single point near the trunk of young tree seedlings on a nightly basis, are often sufficient to keep seedlings alive during drought periods between growth-promoting rainfall events. The system is discontinued once tree roots develop sufficiently to exploit water deep in the soil. We show how our system is used to enhance performance of dew condensers already available on the market.