A stack cubic meter of birch droplet (moisture content 20%) corresponds to a heating power of more than 150 liters of light fuel oil. No wonder throwing a beech into the nest is starting to interest the cent stretcher. The Internet brings together firewood applicants and firewood producers. This page contains information on assessing the quality of firewood at the time of purchase and how to store, dry, and burn firewood. In addition, links are provided to online firewood services.
Can It Be a Motto, a Stack Cube Meter, or a Loose Cube?
Firewood quantities are expressed in cubic meters, i.e., moths. When we talk about a stack cubic meter, we mean a stack of wood that is the size of a cubic meter in external dimensions. When we talk about a loose cube, we mean a box the size of a cubic meter into which firewood has been thrown. A loose cubic meter is sometimes also called a throw cubic meter. Loose and stack cubic meters come with different amounts of air.
Is Firewood of Good Quality?
Make Sure the Quality Before the Wood Shops. The condition and quality of firewood can be assessed on the basis of the mixing of wood species in the batch, the length and thickness of the logs, the evenness of the cutting surface, the moisture content, purity, color, and the number of rot and mold occurrences.
A high-quality firewood batch contains only a certain individual wood species. For example, a lot of birch wood of the highest quality grade must not contain any other wood species. The second-grade birch batch may contain 5% of other hardwood species, and the third-grade birch firewood may not contain more than 10% of other hardwood species.
High-quality firewood does not deviate too much in length from its guide size. For example, according to Finnbio’s quality guidelines, ice cubes 33 cm and 50 cm long must not deviate from their program size by more than two cents, or they will fall into a lower quality class. In the case of chips 25 cm long, no deviation of one centimeter in one direction or another is allowed in the highest quality class.
High-quality firewood is suitably thick. Eligible splits with a thickness of between 4 cm and 10 cm are eligible for the first quality class. The cutting surface of firewood in the first quality firewood is flat and straight. In lower-quality classes, uneven tree ends are allowed.
Humidity in the highest quality firewood does not exceed 20%. Dry firewood is recognizable by the fact that its bark or bark comes off easily, and there is a resonant squeaking sound when the trees are knocked against each other. It is also easy to remove slats from dry wood. There are no foreign substances such as soot, carbon, plastic, metals, pesticides, or other harmful foreign substances or objects in high-quality firewood; no snow or ice.
High-quality firewood does not contain rotting wood. In the highest quality class, no rot is allowed at all. In the second quality class, firewood may contain no more than 5% by volume of hard rot, while trees in the third quality class may also contain no more than 1% by volume of soft rot.
Firewood may have individual spots on the firewood. When present individually, they do not reduce the value in the use of firewood. The splitting surfaces of the chips may darken or have other color defects. Such color changes do not reduce the calorific value of the wood but reduce their value in the so-called experience trees.
How Should Firewood Be Stored and Dried?
The moisture content of felled, fresh wood is about 50%. When the chips are wet, they should be dried by storage. It takes time for the wood to dry. It may have taken a year or more before the firewood has dried to such an extent that the best possible combustion efficiency is achieved. A usable border drying takes at least two months in a normal summer outdoors under a canopy.
The drying rate is affected by the size and type of firewood. Of the three species, alder dries the fastest and birch the slowest. Dry firewood feels light, its surface looks grayed out, and when you hit the firewood together, you hear the sound of a slightly squeaky type typical of dry wood.
Firewood dries most quickly during the summer, well stacked, in a sunny, windy place sheltered from the rain. Firewood dries best when air can pass freely through the stack. To ensure this, it is a good idea to put underlays under the stack. Splitting wood speeds up drying because split wood has more evaporation surface from which moisture can evaporate.
During humid autumn, the humidity of firewood can easily rise again due to the effect of humidity. Before the onset of autumn rains, it is advisable to move the firewood to a wooden barn with adequate ventilation. A dense wood warehouse is not a good place to store moist firewood because in a small, dense warehouse, the air does not change, and the firewood easily starts to rot.
If you want to leave firewood out for the winter, you should cover it. Even then, care must be taken to ensure that the moisture can evaporate. It is good to leave a gap between the stack of wood and the cover that covers it so that air can circulate the trees.
In igniting everything, a and o are dry firewood. To keep the firewood as dry as possible at the time of ignition. It is advisable to bring it in a couple of days before use. When indoors, the moisture content of firewood can drop by a further 5-10% in a few days, which promotes ignition. Note, however, that drying firewood near a fireplace is not permitted due to the risk of fire.
Combustion requires a lot of oxygen. The air circulation in the combustion chamber is adjusted to the optimum by means of the oven hatches. Firewood is stacked so that air can circulate between the trees without obstructions. If the hatches are in the wrong position or too much firewood is trapped in the combustion chamber, the combustion process will not receive enough oxygen, and the firewood will not ignite.
In ignition, it is important that the firewood is ignited throughout. When using dry and thin ice cubes for ignition and placing them loosely in the fireplace, a good flammable “carpet” is created, from which the combustion starts well. Paper is also a great help when lighting firewood.
Evaluation of Firewood Combustion Efficiency
The combustion efficiency of firewood can be assessed by looking at the smoke coming from the chimney. Dark, unburned flue gases are a sign that firewood is burning uncleanly and with low efficiency. When firewood burns with high efficiency at the mouth of the barrel, only transparent thermal staining should be observed. Combustion efficiency is usually low for the quarter following firing and always for some time after new firewood has been added to the combustion chamber.
Firewood Sources Online
Halkoliiteri is a service operating in cooperation with Motiva, from which those who want firewood can apply for firewood producers operating in their area. The service already covers more than half of Finland.
Mottinetti is a service for the customers of Kymppivoima companies, ie its target area is Häme, Kymenlaakso, South Savo, South Karelia, North Savo and North Karelia. You can get firewood and information related to firewood from Mottinet. At the time of writing, the wood species offered in the service were aspen, softwood, birch, alder, and mixed wood.
Contact information for those selling firewood in Lapland has been collected at the Firewood Exchange. The Firewood Exchange is a project led by the Lapland Forest Center and provides a channel for buying and selling firewood. The service offers, e.g., birch, pine, or mixed wood in different lengths. In addition, there are pruned firewood logs.