Only to complete your answer...
Joseph Zorzin <redoak at forestmeister.com> escribió en artículo
<35DD19B6.B65E17A at forestmeister.com>...
: Tony Holt wrote:
: > I understand that (in the UK at least) yield class is the amount of
: > biomass created per annum - eg. YC12 means 12 cubic
: > What exactly does this include - is it the total biomass including all
: > the foliage and/or branches or does it refer to the economically useful
: > timber?
According to our rules in Chile this class yield means the usable volume
(that means the stem) up to certain limiting diameter in most of the cases
this limit diameter is 10 cm ( 4") to pulplogs.
: > Ps. How much of a tree is ecomically useable as say sawtimber? I
: > this is a broad question, but are there any rules of thumb?
: > For example, what percentage of an 18 inch white oak might be utilised
: > as plank/fencing material? 50 per cent or substantially less?
This point depends of another factor, this parameter must be associated
with the taper curves and with that is possible calculate the total volume
to be used for sawtimber and for pulplogs.