Lack of rain forests affect recovery work in São PauloWednesday April 15th, 2015
São Paulo, April 15, 2015 – forest plantations are usually made in the summer period with the forecast of rain between October and March. But in the last two years it has rained less than usual, which affected several forest restoration projects undertaken by the Green Initiative as Planting Waters, implemented in São Paulo. It was initially planned to plant 20 hectares of riparian forests and 30 hectares of agroforestry systems in early 2014 in the municipalities of Iperó, Itapetininga, Piedade, Porto Feliz, Salto de Pirapora and São Carlos. Due to the drought, these crops had to be made in the season the end of 2014 and early 2015.
Unfortunately, the planting of trees that will help recover the water resources of the state was hampered by the very lack of water. They were postponed because the plants require a lot of water distributed in the first months of their lives on growing after inserted on site. This period is crucial for the establishment of trees in the field. Long periods of drought compromise the rooting of cuttings, and leave them more susceptible to problems related to plantations dry like fire.
“Typically, plantations are performed with the application of hydrogel (material that retains moisture in soil) in the cradle (hole) where the seedlings are placed. This product guarantees their survival in short periods of drought, but their use does not replace the need for irrigation or perform planting at the time of occurrence of rainfall, “says Pedro Barral, forestry director of the Green Initiative. In addition, the hydrogel also needs water. It needs to be hydrated prior to its application to gradually release water to the plants.
In some places in the interior of São Paulo, as the case of the Ribeira Valley (BNDES Atlantic Forest Initiative project), the plantations hired by the institution might have continuity with the use of a greater amount of hydrogel. But besides the increased volume of material used, there was the need for greater care than ever spent the plantations in places where it was possible to implant the seedlings. “Like, for example, plant only in areas closest to rivers,” says Julianna Colonna, environmental management.
Blame it on St. Peter?
The year 2014 was the 13th rainy season (October-March) drier since the Weather Station (MS) of the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) of the University of São Paulo (USP) in 1932 began to measure precipitation (amount of water that falls from the sky) in the Metropolitan Region of São Paulo, according to the expert in precipitation, Augusto José Pereira Filho, a professor at IAG / USP. “The weather forecast for summer 2014 indicate near-normal rainfall. The nearly 20 models that are used in prognosis failed to climate assessment, “he explains.
Despite the surprise, this is a climate variability. “The climate changes, what is normal,” says Pereira Filho. For example, according to the expert, since measurement began, the rainy season of 1941 was the driest. “Therefore, it makes sense to say that this drought was a record for three thousand years. Incidentally, the rainy periods of the last four years are among the ten wettest of the entire series of 81 years, “he says.
According to the meteorologist, which caused the recent drought was a common phenomenon called the high pressure of the South Atlantic system that has greater or lesser intensity and spatial extent depending on the atmospheric circulation patterns. This high pressure system will South Africa to the northeast and sometimes occupies an even larger area and leaves São Paulo under that drier air and warmer, as occurred earlier in the year. As this air weighs more and is more stable than the humid air, the humidity caused no rain in the region. In December 2013, the rains were concentrated further north causing floods in the Holy Spirit and in Rio de Janeiro. “We have to be aware of these changes and prepare for them,” he points out.
“The drought of 2014 was very intense as a result of decrease in rainfall associated with longer precipitation systems (called the South Atlantic Convergence Zone),” says Pereira Filho. This zone extends from the Amazon to the South-Central Atlantic. The humid air goes from the Atlantic Ocean toward the Amazon basin. There, the water is recycled with rain and moisture transport to the South and Southeast of Brazil. Rain in the Amazon back to the ocean by rivers. Some factors such as the Earth’s rotation and the Andes prevent rain spread westward. “In that sense, we are citizens of the Atlantic. If Amazon were deforested whole, research indicates that there would be a reduction in rainfall in the Amazon and, therefore, in the South and Southeast of Brazil, “he adds.
This lack of rain affecting over 2015. As the soil is drier, it takes longer for the moisture back to average conditions, even with the rain that has fallen in the Southeast. Therefore, the volume of water from the dams takes to rise. Hence the importance of planting native trees.
The Green Initiative recovers degraded riparian forests as Joanópolis (photo), one of the municipalities that are part of the Cantareira System – work that, in future, will bring benefits to the reservoir because the vegetation contributes to the regulation of the local water system. “The trees Planting Water and the Green Initiative in general, of course, will decrease the erosion of areas, ensuring greater protection of rivers. Also increase the infiltration of rain into the soil. Even if they are few, these plants will help to store more water in the soil and thus recharge the river in the dry season. Most vegetation also increase the humidity, which is beneficial to the microclimate, “says Colonna.
* Report originally published in the second issue of the journal “Planting Waters.” The complete issue can be read in the Green Initiative website .