The shape or branching habit of a tree can affect
its commercial value markedly. When assessing trees it is
useful to record any important aspects of form that may affect
marketability. The perfect "target tree" for saw
milling might, for example, have a very straight butt log
with a single leading stem.
Although most field recording sheets do allow
for comments against each tree, it is helpful to be able to
more quickly record a summary of each tree's form and suitability
for the intended use or market. There are many different methods
for doing this. As a minimum it is recommend that when measuring
trees farmers classify each tree as having either:
- Form 1: Perfect form for the intended use
or market (e.g. straight trunk or bole, fine branches, no
apparent defects etc)
- Form 2: Acceptable form for the intended
use or market but not ideal (e.g. some kinks in stem, evidence
of insect attack etc)
- Form 3: Unacceptable form for the intended
use or market (e.g. severe butt sweep, double leaders, evidence
of severe rot etc).
One of the most important form factors in the
production of sawlogs is straightness of the butt log. If
the tree deviates significantly outside a central axis (Form
3), then the form is likely to be unacceptable for milling
purposes or severely downgraded.
Straightness is an important form characteristic
in many situations. These examples show how farmers might
classify their trees based on stem form.
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