Most everyone knows that we use proteins, carbohydrates and fats for energy. Calories are measurement of a unit of heat or food energy. For example, we can achieve four calories per gram of proteins and carbohydrates, and nine calories per gram from fats.
Tree Variety. Virginia pine (Pinus virginia) is the major Christmas tree species for the acidic soils found in East Texas. A grower can produce a 6- to 8-foot Virginia pine Christmas tree in 3 to 5 years, depending on soil and climatic conditions.
Species in the Pine and Spruce genus are also used well used as Christmas trees, see list of Christmas tree names below. Some natural trees are sold as Living Christmas trees. They are sold live with roots and soil, often from a tree farm or nursery.