Environmental Engineering Reference
In-Depth Information
potential, especially in North America and South America. Therefore, increased woody biomass
use is possible in most countries.
Although most wood currently used for bioenergy comes from natural forests, the greatest poten-
tial for increasing bioenergy production is in establishing plantations, which currently are only
5% of the world's forest area (Table 15.1). Forest plantations have dramatically increased for the last
25 years, mainly in Asia. The area of productive forest plantations increased by 2 million ha/year
from 1990 to 2000 and by 2.5 million ha/year from 2000 to 2005. Eucalyptus , Pinus , and Populus
species are particularly suited for short rotation woody crop (SRWC) plantings, although many other
forest species may also be used. Accordingly, we review current activity with, and the potential of,
the main species in these three genera, with additional focus on the role and potential of biotech-
nology to increase Eucalyptus biomass production and enhance conversion to bioenergy products.
15.2 eucAlyptuS
Many of over 700 Eucalyptus species, native primarily to Australia, have potential as biomass crops.
Eucalypts are successful exotics because of their fast growth and environmental tolerance because
of attributes such as indeterminate growth, coppicing, lignotubers, drought/fire/insect resistance,
and/or tolerance of soil acidity and low fertility. Many eucalypts have desirable wood properties,
such as high density, for bioenergy production.
With 19.6 million ha of plantations in some 90 countries (Trabedo and Wilshermann 2008;
Figure 15.1), Eucalyptus is the most valuable and widely planted hardwood worldwide. Eucalypts
FIGure 15.1 (see color insert) Worldwide Eucalyptus planting. (From Trabedo, G.I. and Wilshermann,
D., Eucalyptus universalis . Global Cultivated Eucalypt Forests Map, 2008, available at www.git.forestry.com)
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