INDIVIDUAL MACHINES
A series of studies
dating back to 1977 examined the performance of individual machines. Some of these involved new applications for
existing equipment and others examined prototype machines. One of the earlier publications tested the
forces required for the THX Tree Extractor to extract southern hardwood trees,
including the roots (Sirois
1977), to increase fiber recovery.
In cooperation with
the Tennessee Valley Authority and North Carolina State University, a prototype continuous feller-buncher
(Hyd-Mech FB7) (Curtin
and others 1985) was tested in a
3-year-old sycamore plantation. This
machine severed and accumulated stems, then unloaded the accumulated bunches
without slowing the machine. Other
publications (Frederick
and others 1986 and Stokes
and others 1986a) document the
detailed production data on this prototype machine. Because some short rotation woody crops rely
on coppice sprouting for regeneration, stump damage was also analyzed. A later publication (Woodfin
and others 1987a) reports harvest
systems, machines, and related costs for the three tests (1984, 1985 and 1987)
on the Alabama sycamore plantation. This publication (Woodfin
and others 1987a) included the
1987 testing which analyzed lower-priced machines and attachments that were
available on the market. The machine
descriptions and the system analysis provide a detailed description of why
certain system configurations are more productive than others.
Technical releases
(Mitchell
and Rummer 1999 and Mitchell
and Rummer 2001) document general
features, specifications and costs of two commercially available mulching
machines. The machines documented in
these two publications do not harvest energy wood; they support other land
management goals that can be realized by reducing biomass in the stand. Thompson
(2002) provides a summary of the
general types of mulching machines and their uses.
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