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| Calculation of Woodmiles< Calculation of Woodmiles > |
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‘ Global environment issues and timber
Following is a demonstration of how we calculate Woodmiles indexes of a local timber house:
1, The volume of timber used
First, we need to assess the volume of timber used to build the applicable house. A wooden house is usually built with 5 kinds of timber--- structural materials, semi-structural materials, sheathing, backing materials, finish materials, and millwork materials. It is desirable to take all of these into calculation, but it is also possible to calculate only with structural materials. Referring to gkibiroihyo purchase orderh, we will demonstrate the calculation of the volume of timber used to build the applicable house. In this case, all 5 kinds of timber are assessed. The total volume is 20 m3.
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2, Collecting information of transportation
Next, we need the information of logistics routes of each timber----the volume, the distance, the form of transportation, the reliability of the information. As for the form of transportation, because Woodmiles Forum use only 5 kinds of coefficients of CO2 emission by its form of transportation---road, rail, coastal shipping, oceangoing bulk shipping [roundwood], and oceangoing container shipping [sawn timber], we investigate which form of transportation was taken. As for the reliability of the information, we decide if the information of logistics routes is reliable or if it is based on assumption and provision through research. In reality, however, it is extremely difficult to trace the history of each single log in the downstream direction. So, with cooperation of sawmills and timber market operators, we first calculate the average procurement distance per year of timber which was transported to them, referring to the invoices. Then we use it for calculation of Woodmiles. In such cases as the above, when average distance of timber transportation per year is available through field research done by sawmills and market operators, we consider this as reliable data to assess Knowledge level of logistics stops for appreciation of their effort toward traceability.
In this demonstration, just to simplify the calculation, let us suppose that all the timber was transported through 1 route as following even though it is unthinkable in reality.
Now all the information is available to calculate Woodmiles indexes.
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3, Calculation of Woodmiles indexes
‘ Woodmiles/Woodmileage
Woodmileage from the place of harvest to the sawmill is: 20 (m3)~20 (km) = 400 (m3E). Woodmileage from the sawmill to the construction site is: 20 (m3)~30 (km) = 600(m3E). The total of 1,000 (m3E) is the Woodmileage of the applicable house. Woodmiles of this house is calculable by dividing it by the total volume of timber: 1,000 (m3E)20 (m3) = 50 (km). In this case, where the route taken by the timber transportation is one, we come up with the same figure by simply adding each distance of the transportation.
‘ Woodmileage CO2
Woodmileage CO2 of the applicable house, in this case, is calculated by multiplying the total Woodmileage by the CO2 emission coefficient of road transportation: 1,000 (m3E)~0,13225(kg/m3E) = 132,25kg. This is the Woodmileage CO2 of the applicable house.
‘ Knowledge Level of Logistics Stops
Knowledge level of logistics stops refers to the ratio of the volume of timber whose logistics history is traceable to the total volume of timber used. In this case, logistics route is only one. So, the volume of timber whose transportation distance is a certainty is calculated by multiplying the ratio of Woodmiles of a certain logistics history (30km/50km = 0.6) by the applicable volume of timber (20kg)---12m3. So, the ratio of the volume of timber of a certain logistics history to the total volume of timber is: (12m320m3 =60 (%). This is the knowledge level of logistics stops pf the applicable house.
The distance of major imported timber is provided by Woodmiles Forum as provisional data. Those come very handy. But because they are provisional, we handle them as assumed and/or unclear data.
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Woodmiles indexes
Woodmilege (m3*) 