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Agroforestry is the interaction of agriculture and trees, including the agricultural use of trees. This comprises trees on farms and in agricultural landscapes, farming in forests and along forest margins and tree-crop production, including cocoa, coffee, rubber and oil palm. Interactions between trees and other components of agriculture may be important at a range of scales: in fields (where trees and crops are grown together), on farms (where trees may provide fodder for livestock, fuel, food, shelter or income from products including timber) and landscapes (where agricultural and forest land uses combine in determining the provision of ecosystem services).

Agroforestry is agricultural and forestry systems that try to balance various needs:

1) to produce trees for timber and other commercial purposes;

2) to produce a diverse, adequate supply of nutritious foods both to meet global demand and to satisfy the needs of the producers themselves; and

3) to ensure the protection of the natural environment so that it continues to provide resources and environmental services to meet the needs of the present generations and those to come.

https://tinyurl.com/pnv4wjx8%20Acesso%20em:%2004.03.2023.

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    The Amazon rainforest is now emitting more carbon dioxide than it is able to absorb, scientists have confirmed for the first time. The emissions amount to a billion tonnes of carbon dioxide a year, according to a study. The giant forest had previously been a carbon sink, absorbing the emissions driving the climate crisis, but is now causing its acceleration, researchers said.

    Most of the emissions are caused by fires, many deliberately set to clear land for beef and soy production. But even without fires, hotter temperatures and droughts mean the south-eastern Amazon has become a source of CO₂, rather than a sink.

    Growing trees and plants have taken up about a quarter of all fossil fuel emissions since 1960, with the Amazon playing a major role as the largest tropical forest. Losing the Amazon’s power to capture CO₂ is a stark warning that slashing emissions from fossil fuels is more urgent than ever, scientists said.

    The research used small planes to measure CO₂ levels up to 4,500 m above the forest over the last decade, showing how the whole Amazon is changing. Previous studies indicating the Amazon was becoming a source of CO₂ were based on satellite data, which can be hampered by cloud cover, or ground measurements of trees, which can cover only a tiny part of the vast region.

    The scientists said the discovery that part of the Amazon was emitting carbon even without fires was particularly worrying. They said it was most likely the result of each year’s deforestation and fires making adjacent forests more susceptible the next year. The trees produce much of the region’s rain, so fewer trees means more severe droughts and heatwaves and more tree deaths and fires.

(Damian Carrington. www.theguardian.com, 14.07.2021. Adaptado.)

TEXTO:

                
    When Sudan, the last northern white rhino bull, died
in March 2018, that left alive only two females of
the subspecies once common in Central and East
Africa.Both are descendants of Sudan and live in Kenya,
[5] and were considered infertile. But now, new hope is
emerging that extinction of the species can still be
prevented. Researchers have successfully created living
embryos in the laboratory from frozen sperm of the
northern white rhinoceros and egg cells from the southern
[10] white rhinoceros. It’s the most closely related
subspecies, with more than 20,000 southern rhinos living
in the wild.
    Although such hybrid embryos are not pure northern
white rhinoceros, the researchers are optimistic. They
[15] plan to take egg cells from the still living northern
rhinoceros females in autumn of this year, and to fertilize
them with stored sperm from the same species.They
then intend to implant the oocytes into fertile southern
rhinoceros females in early 2019. This method is also
[20] used in human reproductive medicine.
    Even if healthy rhinoceros calves can be
produced, whether the northern white rhino can be saved
in the long term remains unclear. As the sperm comes
from a few rhinoceros bulls, limited genetic diversity could
[25] endanger the health of a newly bred northern white rhino
population. Due to the smaller gene pool, such inbreeding
typically leads to higher rates of recessive disorders,
translating into higher death rates and poorer overall
health.
[30]    Still, the research unit is hoping that stem cell
technology can create more eggs and sperm from the
skin cells of 12 northern whites, increasing the supply
and genetic variety. If the scientists pull it off, they’ll
both rescue a seemingly doomed animal and provide a
[35] blueprint for protecting other animals teetering on the
edge of oblivion.

WHEN SUDAN...Disponível em: https://www.dw.com/en/researcherscreate-hybrid-northern-white-rhino-embryos/a-44527410. Acesso em: 1 nov. 2018. Adaptado.