Trees are divided into two main categories: deciduous and coniferous. Forests are usually categorized as one or the other, or as a mix between the two.

Almost 50% of the biomass of a tree lies in the root system below ground. Here the roots, in symbiosis with various benign fungal growths, exchange carbon dioxide for soil-based nutrients such as nitrogen.

• deciduous
• coniferous
• Forest
• biomass
• root system
• symbiosis
• benign
• fungal
• carbon dioxide
• nutrient
• nitrogen