Relative age is used an indicator for how close in time a stand is from the growth culmination, which is assumed to be 10 % higher that the minimum final felling age. The relative age definition is obtained from Hugin, the predecessor to RegWise. The relative age is used in age conditions for how how late a thinning can be done. Other conditions that limits how late a thinning may be done is the height of the stand (see chapter Thinning for more info).  By default, the maximum relative age allowed for a thinning is 0.9. It is also used in RegWise as an explanatory variable in priority functions and calculation of harvest levels.


Formula: Relative age = Basal area weighted mean age (excl overstory trees), divided by k*MFA*1.1,



MFA = Minimum final felling age according to the Swedish Forestry Act. For Lodgepole pine (Pinus contorta) and for common broad-leaves such as birch the MFA is set in control table Treatment Model: see Min Final Felling Age Contorta and Min Final Felling Age Deciduous (figure 1) parameters.


k        = Rotation Age Adjustment Factor (kontrolltabellen Treatment Model) (figur 2).




Figure 1. Contorta has no MFA according to the Swedish Forestry Act, but is set in control table Treatment Model. For stand dominated by common broad-leaves (such as birch, aspen and alder) the actual MFA is 35 år, but in Heureka this can be modified and is by default set to 55 years, as requested by users of Heureka.




Figur 2. The Rotation Age Adjustment Factor parameter affects Relative Age value.




See also: Mnimum final felling ages





Author: Peder Wikström. Created with Help & Manual 6 and styled with Premium Pack Version 2.31 © by EC Software