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一亩树林通过光合作用,每天能“生产”49公斤氧气,“回收”67公斤二氧化碳。而一个成年人每天大约需要0.75公斤氧气,呼出0.9公斤二氧碳。这就是说,一亩树林每天产生的氧气,足够65个成年人每天的需要量。如果在城市和工矿区大量植树造林,就能保持空气新鲜。一树林对灰尘具有很大的拦截,过滤和吸附作用。一公顷杉林一年可吸滞灰尘约320吨,一公顷松林一年可吸尘36.40吨。由于树林有很大的滤尘作用,所以林区空气中的含尘量比无林区要低得多。二一亩生长较好的天然林和人工阔叶林,每年可以生产1000公斤左右的有机物质,并从土壤中吸收30万到50万公斤水,其中99％以上的水分蒸腾到空中去了。在夏
A mu of forest photosynthesis, daily can “produce” 49 kilograms of oxygen, “recycling” 67 kilograms of carbon dioxide. An adult needs about 0.75 kg of oxygen a day and exhales 0.9 kg of carbon dioxide. This means that the oxygen produced by a mu of forest per day is enough to meet the daily needs of 65 adults. If the city and mining areas in a large number of afforestation, we can keep the air fresh. A forest of dust has a great interception, filtration and adsorption. One hectare of cedar forest can absorb about 320 tons of dust a year, one hectare of pine forest a year to 36.40 tons of dust. As the woods have a great role in dust filtration, the amount of dust in the air in the forest area is much lower than that in the non-forest area. Ermu natural forests and artificial broad-leaved forests, which grow well, can produce about 1000 kilograms of organic substances per year and absorb 300,000 to 500,000 kilograms of water from the soil, of which over 99% of the water transports into the air. In summer