Consider
a major industrial raw material that utilizes solar energy
almost exclusively in its production... One that is converted
to its final product form with minimal amounts of additional
energy... A material that can store carbon throughout
its useful life... And one that is renewable on a predictable
cycle. A material like this would seem to be in high demand
for its environmental benefits. Yet this material, wood,
is often at the center of controversy because it often
comes from lands that are also highly valued for their
other benefits. Although debates over land use focus on
extraction of the resource and the resulting environmental
issues, they seldom deal with the environmental impacts
of substitution of other materials for wood. However,
wood has some significant environmental benefits, especially
as related to energy. Consider that wood represents nearly
half of the tonnage of industrial raw material consumed
in this country... more than steel and plastic combined...
yet it requires only 4% of the net energy consumed in
producing our raw materials.
Some would suggest replacement of wood fiber with the
fibers of other crops, such as kenaf or hemp, especially
in the production of materials such as paper. There will
likely be applications for other fibers, but crops grown
specifically to replace wood fiber require land, fertilization
and often irrigation to produce yields that can make them
competitive. They also require land currently used for
other crops or that currently grow trees. The annual cycle
of planting, fertilizing, irrigating and harvesting some
of the suggested crops has its own set of environmental
issues. Intensive cultivation techniques applied to fast-growing,
genetically-improved wood species, such as some poplar
and cottonwood, can produce the same or higher yields
per acre as alternate fiber crops with fewer entries onto
the land. Intensively cultivated tree plantations are
now being successfully demonstrated in several areas.
One of the challenges facing the wood resource may be
one of respect. It is so common and so widely used by
consumers ranging from those in construction to the do-it-yourself
builder that we lose connection with its real value and
often with the source of the final product. We take our
homes, our newspapers, our library collections, our computer
paper, for granted and fail to connect them with a remarkable
fiber that is both diverse and complex.
Sawmills are often viewed as outdated manufacturing
facilities that belong in an earlier century. A look inside
a modern mill, however, will show a computer based manufacturing
process where the emphasis is on maximum recovery of lumber
from each log. New technology and higher recovery have
allowed more efficient manufacture of lumber from small
diameter trees and have increased the level of utilization
of the wood fiber dramatically. The history of the forest
products industry in the 20th century has been of history
of increased efficiency in processing, increased life
of the products that are produced, and increased utilization
of the wood fiber. The development of paperboard and the
resulting cardboard boxes that replaced wooden crates,
plywood that replaced boards, particle board that utilized
sawdust and other leftovers from the manufacture of lumber,
treatments for products such as railroad ties that greatly
extended their service life... these are just examples
of innovations throughout this century that have increased
utilization of our wood fiber and extended the wood resource.
Today, when a log reaches a sawmill or processing plant,
all the wood fiber and most of the bark is utilized in
some fashion.
Today's technological developments extend the concepts
of greater utilization and quality into the next century
and provide better potential for a match with the construction
products of tomorrow and the expected characteristics
of the wood resource. Engineered wood products like laminated
veneer lumber, oriented strand board, and I-joists, products
that use the minimum amount of wood to meet engineering
specifications needed in construction they represent wood
products that are stable and predictable in their performance,
and they can also be manufactured from the smaller diameter
trees. The technologies that have allowed improvement
in sawmill yields can also improve timber harvesting efficiency
and effectiveness. The ingenuity and capability of the
people on the ground in harvesting are often ignored,
but they have been innovators and equipment developers
for as long as they have been in the woods. Once they
understand the management objectives and the constraints,
they are usually adaptable enough to find systems that
can achieve those objectives.
Although wood products represent environmentally sound
building materials that are being steadily improved in
performance and predictability, the issues associated
with extraction of the trees from the forest have not
been resolved. Some advocate no harvest of trees, some
suggest specific areas dedicated to production of wood
and other areas dedicated to preservation, and others
suggest that we can extract wood while sustaining other
values and amenities. Still others look to crops of trees
that can mature in 5 - 7 years. In the final analysis,
the solution will likely include wood fiber from a combination
of these management strategies. New technologies, new
sources of wood fiber, better understanding of ecosystem
processes, people willing to take a risk with new approaches
to land management, some measure of consensus... this
combination can allow us to continue to enjoy the environmental
and societal benefits of our most common raw material.....
wood.
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Dr. Johnson is a Professor of Forest
Engineering at the University of Idaho and Department
Head of the Forest Products Department. He has been
involved in teaching and research in the area of timber
harvesting since 1970, with an emphasis on harvesting
costs and production. His early research looked at
harvesting systems to revover small diameter material
and forest residues. More recently the work has focused
on combinations of harvesting equipment that might
be used to decrease impacts on the harvested site
without increases in harvest cost.