Yield, Land Area & Woodfuel Accessibility

Yield: For biomass resources and renewable energy forms, enter the annual availability of the resource. This can be specified either as a total annual value, or as an annual availability per unit of land area (click on Resource Properties to change this setting. When specifying yield per unit land area be sure to also enter data on land area (see below).
Land Area: for renewable energy specified per unit of land area enter data on land area, use this screen to enter the area of land devoted to producing the resource.
Woodfuel Accessibility: Several factors may make wood inaccessible and thus keep accessibility below 100%: First, wood resources may be far from demand centers or transport routes. Second, legal or tenurial constraints may restrict access to land (e.g., parks and reserves or protected private farmlands whose wood resources are held off the market). Finally, harvesting tools may be inadequate to utilize whole trees. For example, if for a given land type, only 60% is close enough to wood users to be exploited in the subarea and zone in question, and of that only 80% is legally accessible, and of that only 50% can be cut due to tool limitation, then the accessibility factor (A) would be the product of these three factors, or A = 0.6 * 0.8 * 0.5 = 24%. Typically, trees on agricultural land will have an accessibility close to 100%, while remote forest or bush areas would have a lower accessibility.

You may wish to make separate estimates of these three factors - referred to as the location access fraction (AL), the tenure access fraction (AT) and the management access fraction (AM) respectively. The overall access fraction (A) is thus calculated as:

A= AL × AT × AM

It is important to remember that these terms must be calculated sequentially. That is, AT is a fraction of AL and AM is a fraction of AL × AT.