Estudiando el balance hídrico de las Islas Canarias, y en concreto restando, a la precipitación, la escorrentía, la infiltración y la evapotranspiración, se obtienen valores negativos de dicha ecuación para las islas occidentales. Esto hace pensar que el bosque obtiene el recurso hídrico de alguna otra forma para superar este balance negativo. Este nuevo recurso, a integrar en la ecuación del balance hídrico, es la lluvia horizontal. En el presente documento se exponen los fundamentos, experiencias y métodos para su captación y aplicaciones en actividades forestales como el abastecimiento a zonas recreativas o el llenado de depósitos de agua para repoblaciones forestales.

En un area de repoblacion natural de Pinus patula, se estudio el efecto del control de la vegetacion competidora sobre la radiacion fotosinteticamente activa a nivel del suelo, el contenido de humedad del suelo y el potencial hidrico de los brinzales de Pinus patula. Se utilizo un diseno experimental completamente al azar con cuatro tratamientos (control manual de malezas cada dos, cuatro y seis meses, y testigo) y cuatro repeticiones. Las mediciones se realizaron mensualmente durante una estacion de crecimiento. Los resultados obtenidos indican que la presencia excesiva de malezas dentro del rodal provoca una fuerte reduccion de contenido de humedad del suelo, restringiendo a los brinzales de Pinus patula de este recurso. Por otro lado, la limitacion de humedad para las plantas de pino ocasiono una disminucion del potencial hidrico, sobre todo en los meses de menor precipitacion pluvial. La cobertura de malezas redujo drasticamente la cantidad de luz a nivel del suelo, ocasionando una menor oportunidad de los brinzales de pino para abastecerse de este recurso.

Resumo De grande valor comercial e ambiental, Enterolobium contortisiliquum (Vell.) Morong é uma espécie arbórea da família Leguminosae - Mimosoideae, utilizada para produtos madeireiros, arborização urbana e reflorestamento de áreas degradadas. Objetivando-se analisar a resposta da espécie ao lodo de esgoto compostado (LEC) em relação ao substrato comercial (SC), foram utilizadas 5 combinações de substratos: S1 (100 % SC); S2 (75 % SC + 25 % LEC); S3 (50 % LEC + 50 % SC); S4 (75 % LEC + 25 % SC) e S5 (100 % LEC), cada qual com 4 repetições. Essas 5 combinações de substratos foram submetidas a 3 lâminas de irrigação: L1 (36 mm/dia), L2 (72 mm/dia) e L3 (108 mm/dia). Foram mensurados parâmetros biométricos (altura, diâmetro do coleto e número de folhas), velocidade de crescimento, biomassa seca, Índice de Qualidade de Dickson e a relação altura/diâmetro das plântulas. A partir dos valores obtidos, e com base nas médias superiores para todos os parâmetros avaliados, recomenda-se o uso de S5, composto 100 % LEC mediante o uso da L1. | Abstract With high commercial and environmental value, Enterolobium contortisiliquum (Vell.) Morong is a tree species of the family Leguminosae - Mimosoideae, known as tamboril and used for civil construction, timber products, urban afforestation, and reforestation of degraded areas. In order to analyze the response of the species to the composite sewage sludge (LEC) in relation to the commercial substrate (SC), 5 substrate combinations were used: S1 (100% SC); S2 (75% SC + 25% LEC); S3 (50% LEC + 50% SC); S4 (75% LEC + 25% SC) and S5 (100% LEC), each with 4 replicates. These 5 substrate combinations were submitted to 3 irrigation slides: L1 (36 mm/day), L2 (72 mm/day) e L3 (108 mm/day). Biometric parameters (height, diameter, number of leaves), growth speed, dry biomass, Dickson Quality Index, and height/diameter ratio were measured. Based on the values ​​obtained and on the upper averages for all the parameters evaluated, it is recommended to use S5, composed of 100% LEC with L1.

The “Bosque de Agua”, to the west and south of Mexico City, which is the fifth largest city in the world, has historically suffered disturbances in forest cover, with a consequent reduction in the environmental services provided. Changes in the state of the forests between 1994 and 2017 are here analyzed in terms of the annual net change in area of the different cover densities and the different change processes. In general, the net change was favorable in all cases: forest improvement vs. forest degradation, reforestation vs. deforestation, and afforestation vs. land use change. There were changes in 16.03% of the Bosque de Agua: recovery in 11.09% and disturbance in 4.94%. This marked recovery is the result of the protected status of two-thirds of the forest, the payment for hydrological environmental services in 29.33% of the forest, as of 2003, and the continuous programs of reforestation, fire control and surveillance by the local communities, circumstances that have allowed the recovery to exceed the disturbance in most of the Bosque de Agua. One-third of the forest disturbance is concentrated in six of the 35 municipalities in the southern region, caused by clandestine logging by organized gangs, due to the state of ungovernability that reigns in these municipalities.