Environmental Engineering Reference
In-Depth Information
for wood through poplar tree breeding. Stout and Schreiner (1933) reported on their pioneering
breeding effort in hybridizing poplars that was patterned after the classical work of A. Henry in
the United Kingdom (Henry 1914). Also, in the 1920s and 1930s Canadian poplar breeder pio-
neers Frank Skinner and Carl Heimburger began their pioneering poplar breeding programs in
Canada (Richardson et al. 2007). These four pioneering tree breeders laid the foundation for the
next 100 years of poplar breeding for biomass production in North America.
In the United States from 1900 to the 1940s, poplar plantations were mostly made up of native
poplar species, including eastern cottonwood (
Populus deltoides
) and black cottonwood (
P
.
tricho-
carpa)
(Bearce 1918; McKnight and Biesterfeldt 1968; Smith and DeBell 1973). In Canada during
that same period, there were thousands of hectares of abandoned farm land planted to native poplars
and imported hybrid poplars from Europe (Smith 1968). These plantations had varying degrees of
success depending upon conditions (Smith and Blom 1966). There were also thousands of hectares
of both native poplars and hybrids planted in shelterbelts and windbreaks during early settlement of
the Canadian and American west (Cram 1960).
Initially, these poplars were grown for shelter, but they were also used for fuelwood and other
wood products (Richardson et al. 2007). The multitude of hybrid poplars developed by Stout and
Schreiner (1933) were tested throughout North America during the 1930s and 1940s to determine
their adaptability to varying conditions including survival, growth, as well as pest and disease resis-
tance. These hybrids, known as Oxford Paper (OP) or Northeast (NE), showed varying degrees of
growth and survival largely because of climatic factors, cultural practices, and disease susceptibility
(Blow 1948; Smith and Blom 1966; Maisenhelder 1970).
In the 1950s, Ernst Schreiner, then with the U.S. Forest Service, distributed the better performing
NE hybrid poplars to cooperating landowners throughout North America to gain information on
their performance. He also shared the NE hybrid poplar clones with many other countries so they
might be tested under worldwide conditions (Garrett 1976). Many of them did not live up to their
expectations in Canada, Europe, and Eurasia (Pryor and Willing 1965; FAO 1980). Canadian poplar
breeders in the meantime were developing their own poplar hybrids for use in Canada (Smith 1968;
Richardson et al. 2007). Moreover, an active program of selection and breeding of eastern cotton-
wood was initiated in the eastern and southern United States in the late 1950s and 1960s (Wilcox
and Farmer 1967; Schreiner 1971). These breeding programs focused on improving adaptability,
growth and disease resistance with primary emphasis on producing wood for sawtimber and pulp
and paper (Thielges and Land 1976).
In the 1960s, there was a change in the focus on sawtimber and pulp and paper to biomass of
the forest. This change was largely due to the efforts of production ecologists interested in deter-
mining the primary production of the vegetation of forests including dry matter production and
energy accumulation. An initiative was known as the National Academy of Science, International
Biological Program (IBP) had one of their focal points on production of the eastern deciduous
forest biome (Newbould 1967). This program resulted in a number of studies of the standing crop
biomass and caloric values of native poplar stands and plantations (Peterson et al. 1970; Switzer
et al. 1976; Zavitkovski 1976; Crow 1978). The change in emphasis to weight of forest products
rather than volume prompted the U.S. Forest Service to start tallying biomass beginning in 1964
(LaBau et al. 2007). Also, there was recognition by many that intensive forest utilization required
an understanding of functional forest ecosystem processes, including dry matter, energy and chemi-
cals (Young 1973). Moreover, biomass studies were essential to realizing the full potential of the
forest for energy (Young 1971, 1973, 1976, 1977).
The concept of short rotation forestry or short rotation woody corps developed in parallel with
the biomass and bioenergy studies of forests (Larson and Gordon 1969; Gordon 1975). Schreiner
(1970) called it “mini-rotation forestry.” Short rotation forestry involves growing trees on short rota-
tions (i.e., <15 years) using agronomic principles including planting genetically improved stock,
fertilization, irrigation, weed and pest control (Drew et al. 1987; Dickmann 2006). Early efforts
to identify suitable species for short rotation forestry included many species (Dawson 1976), but
