The Smithsonian Tropical Research Institute (STRI) instrumented the Agua Salud (AS) Experimental Catchments as part of an ongoing series of land‐cover related experiments in the steep, saprolitic, lowland, seasonal tropics of central Panama. The sites include tree plantations, rotational grazed pastures, native forests from 10 to over 80 years old, and a monoculture grassland. This data note provides a brief description of the instrumented catchments, rainfall and discharge data collection methods, data processing, and online availability.

In the southwestern United States, precipitation in the high mountains is a primary source of groundwater recharge. Precipitation patterns, soil properties and vegetation largely control the rate and timing of groundwater recharge. The interactions between climate, soil and mountain vegetation thus have important implications for the groundwater supply. This study took place in the Sacramento Mountains, which is the recharge area for multiple regional aquifers in southern New Mexico. The stable isotopes of oxygen and hydrogen were used to determine whether infiltration of precipitation is homogeneously distributed in the soil or whether it is partitioned among soil-water ‘compartments’, from which trees extract water for transpiration as a function of the season. The results indicate that “immobile” or “slow” soil water, which is derived primarily from snowmelt, infiltrates soils in a relatively uniform fashion, filling small pores in the shallow soils. “Mobile” or “fast” soil water, which is mostly associated with summer thunderstorms, infiltrates very quickly through macropores and along preferential flow paths, evading evaporative loss. It was found that throughout the entire year, trees principally use immobile water derived from snowmelt mixed to differing degrees with seasonally available mobile-water sources. The replenishment of these different water pools in soils appears to depend on initial soil-water content, the manner in which the water was introduced to the soil (snowmelt versus intense thunderstorms), and the seasonal variability of the precipitation and evapotranspiration. These results have important implications for the effect of climate change on recharge mechanisms in the Sacramento Mountains.

J.M. Gomez et al., 'Efectos de las rasgos morfologicos y ecofisiologicos de arboles neotropicales en laransferencia de agua y nutrientes al suelo (Effect of morphological and eco-physiological traits of neotropical tree species on water and nutrients transference to soil)', Agroforesteria en las Americas, pp.p. 69-75, 2014

The objective of this study was to evaluate the "Caja de Agua" urban forest of 3.06 ha located in the district of San Juan Lurigancho in the province of Lima, Peru, using the i-Tree Eco and i-Tree Canopy programs. A forest census was conducted in the study area in which all tree and arborescent individuals with a diameter at breast height (DBH) greater than 2.5 cm at 1.30 m from the ground were measured. In total, 765 individuals were recorded, grouped into 43 species, 40 genera and 22 botanical families. With the i-Tree Eco program, the environmental services provided by the "Caja de Agua" trees were estimated, which were the elimination of 256.9 kg/year of air pollutants (CO, O3, SO2, NO2, PM2.5 and PM10), the annual capture of 16.44 metric tons of carbon, the storage of 172 metric tons of carbon and the production of 43.83 metric tons of oxygen per year. It was determined that the forest species that provided the greatest environmental services were Eucalyptus camaldulensis Dehnh., Ligustrum lucidum W.T. Aiton, Fraxinus americana L. and Ceiba speciosa (A. St.-Hil.) Ravenna, influenced by their abundance and leaf area. The i-Tree Canopy program was used to classify four types of cover in the "Caja de Agua" urban forest (arboreal/shrub, bare soil, herbaceous and constructions) by photointerpreting satellite images available in Google Earth, which determined that there has been a decrease in tree cover in the last 14 years. The results indicate that the "Caja de Agua" urban forest provides environmental services for the city, which should be conserved for the benefit of the local community. | El presente estudio tuvo como objetivo evaluar el bosque urbano “Caja de Agua” de 3.06 ha, ubicado en el distrito de San Juan Lurigancho, en la provincia de Lima, Perú, utilizando los programas i-Tree Eco y i-Tree Canopy. Se realizó un censo forestal en el área de estudio en el cual se midieron todos los individuos arbóreos y arborescentes con un diámetro a la altura del pecho (DAP) mayor a 2.5 cm a 1.30 m del suelo. Se registraron un total de 765 individuos, agrupados en 43 especies, 40 géneros y 22 familias botánicas. Con i-Tree Eco se estimaron los servicios ambientales proporcionados por el arbolado de "Caja de Agua", los cuales fueron la eliminación de 256.9 kg/año de contaminantes del aire (CO, O3, SO2, NO2, PM2.5 y PM10), la captura anual de 16.44 toneladas métricas de carbono, el almacenamiento de 172 toneladas métricas de carbono y la producción de 43.83 toneladas métricas de oxígeno al año. Las especies forestales que otorgaron los mayores servicios ambientales fueron Eucalyptus camaldulensis Dehnh., Ligustrum lucidum W.T. Aiton, Fraxinus americana L. y Ceiba speciosa (A. St.-Hil.) Ravenna, influenciadas por su abundancia y área foliar. Utilizando el programa i-Tree Canopy se clasificaron cuatro tipos de cobertura en el bosque urbano "Caja de Agua" (arbórea/arbustiva, suelo desnudo, herbácea y construcciones) mediante la fotointerpretación de imágenes satelitales disponibles en Google Earth, determinando una disminución de su cobertura arbórea en los últimos 14 años. Los resultados indican que el bosque urbano “Caja de Agua” proporciona servicios ambientales para la ciudad, el cual debe ser conservado para el beneficio de la comunidad local.

Farmlands have gradually been replaced by apple orchards in Shaanxi province, China, and there will be a risk of severe soil-water-storage deficit with the increasing age of the apple trees. To provide a theoretical basis for the sustainable development of agriculture and forestry in the Loess Plateau, soil water content in a 19-year-old apple orchard, a 9-year-old apple orchard, a cornfield and a wheat field in the Changwu Tableland was investigated at different depths from January to October 2014. The results showed that: (1) the soil moisture content is different across the soil profile—for the four plots, the soil moisture of the cornfield is the highest, followed by the 9-year-old apple orchard and the wheat field, and the 19-year-old apple orchard has the lowest soil moisture. (2) There are varying degrees of soil desiccation in the four plots: the most serious degree of desiccation is in the 19-year-old apple orchard, followed by the wheat field and the cornfield, with the least severe desiccation occurring in the 9-year-old apple orchard. Farmland should replace apple orchards for an indefinite period while there is an extremely desiccated soil layer in the apple orchard so as to achieve the purpose of sustainable development. It will be necessary to reduce tree densities, and to carry out other research, if development of the economy and ecology of Changwu is to be sustainable.

Using a water balance to estimate groundwater recharge through the use of remotely sensed evapotranspiration offers a spatial and temporal density of data that other techniques cannot match. However, the estimates are uncertain and therefore ground truthing of the recharge estimates is necessary. This study, conducted in the south-east of South Australia, demonstrated that the raw water-balance estimates of recharge had a negative bias of 45 mm/yr when compared to 190 recharge estimates using the water-table fluctuation method over a 10-year period (2001–2010). As this bias was not related to the magnitude of the recharge estimated using the water-table fluctuation method, a simple offset was used to bias-correct the water-balance recharge estimates. The bias-corrected recharge estimates had a mean residual that was not significantly different from an independent set of 99 historical recharge estimates but did have a large mean absolute residual indicating a lack of precision. The value in this technique is the density of the data (250-m grid over 29,000 km²). The relationship between the water-table depth and net recharge under different vegetation types was investigated. Under pastures, there was no relationship with water-table depth, as the shallow roots do not intercept groundwater. However, under plantation forestry, there was a relationship between net recharge and water-table depth. Net recharge under plantation forestry growing on sandy soils was independent of the water table at around 6 m depth but, under heavier textured soils, the trees were using groundwater from depths of more than 20 m.