Google News USA: what are the plants and trees at risk of extinction
by | VIEW 968
In the USA, plants and trees of various species are seriously threatened, and would risk extinction. According to a study published in the journal Plant people and planet, 100 US plant species are dangerously close to extinction.
Among these, the redwood, the American chestnut, the black ash, the white pine. These trees are mainly threatened by attacks from invasive insects, the proliferation of deadly diseases and climate change. Insects and invasive pathogens are among the main causes of plant extinction risk.
Even though the immune system of plants is well developed and evolved, they are easily overwhelmed by these diseases, never encountered before. Murphy Westwood, one of the study's lead authors, said: "Conservation research rarely focuses on plants."
USA: What are the plants and trees at risk of extinction
The trees are clearly stressed by extreme weather conditions, making them easily attacked by insects and fungi.
Prolonged drought deprives trees of the water they need to produce, for example, resin, which is essential for defending themselves from external attacks and healing wounds. As environmental conditions worsen, threats will risk not only being alien but could transform organisms into possible killers.
Another example, in nature the severgreen sequoia grows spontaneously along the coast that goes from California to Oregon, within a radius of 60 km from the Pacific Ocean. In fact, the plant prefers a type of temperate oceanic climate rich in humidity, however it does not tolerate continental climates and temperatures that are too rigid.
It is widespread up to altitudes of 1,000 m above sea level, but generally grows at altitudes below 300 m. Sequoias prefer soils of alluvial origin where they form pure or mixed forests with other species of local conifers such as Pseudotsuga menziesii and Picea sitchensis.
However, the fires of recent months have destroyed a large area. In the Rosaceae family, which includes hawthorn and apple, more than a quarter of species are threatened, endangered or critically endangered. Half of all ash species are threatened by the invasion of the emerald borer, an invasive insect whose larvae feed on the tissue beneath the bark.
