Firewood was the primary source of fuel until the 1800s, when it was displaced by coal and later by oil. Firewood is a renewable resource, provided the consumption rate is controlled to sustainable levels. A natural resource qualifies as a renewable resource if it is replenished by natural processes at a rate comparable or faster than its rate of consumption by humans or other users Today firewood is usually obtained from timber or trees unsuitable or unwanted for building or construction. In the fields of Architecture and Civil engineering, construction is a process that consists of the Building or assembling of Infrastructure In the United States, firewood is sold by the cord, and is therefore also called cordwood. The cord is a unit of measure of dry Volume used in Canada and the United States to measure Firewood and Pulpwood.
Of all of the renewable resources, only biomass, including wood, and geothermal need to be carefully managed in order to prevent depletion.  The shortage of suitable firewood in some places has seen local populations damaging huge tracts of bush thus leading to further desertification. Desertification is the degradation of land in arid and dry sub-humid areas resulting primarily from human activities and influenced by climatic variations On the other hand, proper forestry practices applied to firewood allow the usage of a carbon-neutral, or even carbon-negative, energy source, since the carbon dioxide released by the burning of the firewood was previously absorbed from the ambient atmosphere through photosynthesis. Because of this, firewood can be considered to be a form of solar energy.
Some firewood is harvested in "woodlots" managed for that purpose, but in heavily wooded areas it is more usually harvested as a byproduct of natural forests. A woodlot is term used in North America to refer to a segment of a Woodland or Forest capable of small-scale production of forest products such as A forest is an area with a high density of Trees There are many definitions of a forest based on various criteria Deadfall that has not started to rot is preferred, since it is already partly seasoned. Wood drying (also seasoning lumber or timber seasoning) refers to reducing the Moisture content of wood prior to its use Standing dead timber is considered better still, as it is both seasoned and has less rot. Harvesting this form of timber reduces the speed and intensity of bushfires. Ladysmith-RFSJPG|right|thumb| Ladysmith NSW RFS fire fighting tanker]]A Bushfire is a Fire that occurs in the bush (collective term for Harvesting timber for firewood is normally carried out by hand with chainsaws. A chainsaw (or chain saw) is a portable mechanical motorized Saw. Thus, longer pieces - requiring less manual labour, and less chainsaw fuel - are less expensive and only limited by the size of their firebox. Prices also vary considerably with the distance from wood lots, and quality of the wood.
Normally wood is cut in the winter when trees have less sap so that it will season more quickly. Most firewood also requires splitting, which also allows for faster seasoning by exposing more surface area. Today most splitting is done with a hydraulic splitting machine, but it can also be split with a splitting maul.
In the metric system, firewood was normally sold by the stère (= 1 m³ = ~0. The metric system is a decimalised system of measurement. It exists in several variations with different choices of base units, though the choice of base units does The stère is a measurement unit for Volume of wood and equals one Cubic metre. 276 cords). The cord is a unit of measure of dry Volume used in Canada and the United States to measure Firewood and Pulpwood. Currently it is also sold to consumers by the kilogram.
In the United States, firewood is usually sold by the cord, 128 ft³ (3. The United States of America —commonly referred to as the A foot (plural feet or foot; symbol or abbreviation ft or sometimes &prime – the prime symbol) is a non-SI unit 62 m³), corresponding to a woodpile 8 ft wide × 4 ft high of 4 ft-long logs. The cord is legally defined by statute in most states.
It is also common to see wood sold by the "face cord", which is usually not legally defined, and varies from one area to another. For example, in one state a pile of wood 8 feet wide × 4 feet high of 16"-long logs will often be sold as a "face cord", though its volume is only one-third of a cord. In another state, or even another area of the same state, the volume of a face cord may be considerably different. Hence, it is risky to buy wood sold in this manner, as the transaction is not based on a legally enforceable unit of measure.
The only measurement of firewood that is regulated is a cord. The cord is a unit of measure of dry Volume used in Canada and the United States to measure Firewood and Pulpwood. All other measurements including 1/3 cord, half cord, and truckloads are not regulated. Also, firewood can either be seasoned or unseasoned and that can affect the price.
Firewood needs to be seasoned for 8 months, so the best time to buy firewood would be in the spring. It is also the cheapest time to buy firewood. The term seasoned is not regulated, so a reseller can claim that they are selling seasoned firewood, but it may not be seasoned for a full 8 months.
Using 4 mil plastic it is possible to create a greenhouse effect and decrease the amount of time needed to season the firewood. See the link below.
The energy content of a cord of wood depends on the type of wood, and ranges from 15. 5 to 32 million Btu per cord. 
There are several methods for stacking firewood.
Under a roof: Here are no concerns about the wood being subjected to rain, snow or run-off. The methods for stacking depend on the structure and layout desired. Whether split, or in 'rounds' (flush-cut and unsplit segments of logs), the wood should be stacked lengthwise, which is the most stable and practical method.
Outdoors: Firewood should be stacked with the bark facing upwards. This allows the water to drain off, and standing frost, ice, or snow to be kept from the wood. When possible, a tarp or water-proof cover may be placed over the top of the pile. This can be a large piece of plywood or an oiled canvas cloth, although cheap plastic sheeting may also be used.