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一、在城乡绿化中,要把住“以树为主”、“以森林为主”的原则,几棵树一片草的绿化格局不宜提倡,其理论依据是: 1.同化效益低。据测定,温带阔叶林同化能力为1200克/平方米/年,而温带草原500克/平方米/年,草原的同化能力不足森林的一半。 2.净气效益低。净气以供氧为核心,供氧量的多少由植物的叶量和生物量而定。据测定,森林叶量大,生物量为34公斤/平方米,放氧量为31.2吨/公顷/年,而温带草原生物量只有1.6
First, in the afforestation of urban and rural areas, it is not advisable to advocate the principle of “taking trees as the mainstay” and “taking forests as the mainstay”, and the afforestation pattern of several trees and grass should not be advocated. The theoretical basis is: 1. Low assimilation benefits. It has been determined that the assimilation capacity of temperate broad-leaved forest is 1200 g / m 2 / year, while that of temperate steppe is 500 g / m 2 / year. The assimilation capacity of grassland is less than half of the forest. 2 net gas benefits. Net gas to oxygen as the core, the amount of oxygen supply depends on the amount of plant leaves and biomass. According to the determination, the forest leaf is big, the biomass is 34 kilograms / square meter, the oxygen release amount is 31.2 tons / hectare / year, and the temperate grassland biomass is only 1.6