Coppice

1
Woody Bioenergy Crops for the Southeastern United
States
Mark Coleman1 and Keith Kline21USDA-Forest
Service, 241 Gateway Drive, Aiken, SC 29803
coleman.m_at_earthlink.net2Oak Ridge National Lab,
Oak Ridge, TN 37831-6038 klinekl_at_ornl.gov
Short-Rotation Woody Crops Production Systems
Introduction

• Southern Pines
• Hardwoods
• Coppice

Coppice
Biomass is an important alternative energy
resource that can offset greenhouse gas emissions
from fossil fuels, provide crop options for
marginal farmlands and improve rural economies.
Forests cover nearly 60 of the southeastern US.
Woody energy crops include fast growing native
species that have shown large productivity gains
from improved genetic resources and cultural
practices. Woody feedstocks offer many
advantages compared to other types of biomass and
options for conversion to various types of energy
(liquid fuels, electric power, and other
bio-products) are possible. Here we summarize
accumulated learning from southeastern
practitioners experiences with woody cropping
systems and discuss examples of many of the most
promising woody energy crop species.
Pine
Willow
Cuttings for planting

• Vegetative propagation
• High density planting
• (6000 trees/acre)
• Cut every 3 to 4 years
• Replanting required after 25 years
• Efficient harvesting equipment

• Elite genetic selections
• Adapted to wide range
• of sites
• Variety of selective
• herbicides
• Developed operations

• Experience to date has been with northern
  temperate culture
• Willow native to southern US,
• merits research
• Sycamore coppice yields twice
• that of seedlings

Hardwood
Enhanced Pine Production Potential

• Poplar, Eucalyptus, Sycamore, Sweetgum
• Large growth potential
• Forest operations equipment
• Genomic resources

After cut
Advantages of Using Woody Crops for Bioenergy
Late in year 2

• Provide diversity of feedstocks
• Location and geographic distributive advantages

• Relatively low input crops
• Genomic Resources
• Multiple market options

Year 3
Environmental Benefits
Process Benefits
Harvester
Sampling soil - sweetgum

• Adaptability of species to regional areas
• Lower ash content
• Year-round availability
• Stable, consistent feedstock supply
• High density products
• Easy to store
• Easy to handle
• Mix with the other woody feedstocks

• Protect soil, water and air quality
• Sustainable production systems
• Sequester carbon
• Create wildlife habitat
• Increase diversity
• landscape
• biological
• soil microbial and mesofauna
• Improve productivity of marginal farmland

• Orlando, FL
• 2 ½-year-old Eucalyptus
• Grandis
• Growth Rates of 2 to 3 diameter/year
• 7.2 dry tons/acre/year

Eucalyptus
Sycamore
E. amplifolia E. viminalis E. nova-anglica E.
macarthurii E. camphora

• Bainbridge, GA
• 4.5-year-old
• survived gt 150 freezing
• nights
• 1.7 2.7 diameter per year
• 7 dry tons/acre/year

Pine Sweetgumtrials - year 12
Practitioners Survey

• Numerous forestry practitioners were interviewed
  about the potential for
• woody energy crops in the southeastern US.
• In total, over 250 person-years of southeastern
  forestry research experience.
• Each was asked to name potential crop species,
  management requirements,
• expected productivity rates and factors
  impacting yields.
• The table summarizes results.

Table 1. Summary of practitioner survey of
potential for woody energy crop species for
southeastern US.
Energy Conversion of Woody Biomass
Conclusions

• Combustion boilers
• Gasification
• Synthesis gas 20 H2, 20 C0, 5 CH3
• Pyrolysis Bio-oil Char
• Bio-Oil is a crude containing high value
  chemicals
• Biofuels
• Biochemical processes requiring
• Cellulosic enzymes
• Distillation energy
• Thermochemical process
• Catalytic conversion of synthesis gas
• Alcohols and diesel

• Several woody crops offer high growth potential
  in the southeastern US under proper silviculture
  but costs for hardwood plantations may be
  prohibitive.
• Loblolly pine has the most developed
  infrastructure. It can be grown at lower cost
  and at higher rates on the largest variety of
  sites.
• Bottomland hardwoods such as cottonwood and
  sycamore are limited by site and soil
  requirements and disease.
• Eucalyptus out performs other species in biomass
  output/year but is limited by frost to Florida
  and a narrow band along the gulf coast.
• Coppice crops offer potential to rapidly expand
  production but require research to identify the
  best species and cultivars for a given locale and
  to develop appropriate cultural practices and
  operational equipment.
• Extensive natural hardwood and mixed forest
  resources in the southeast also merit further
  study for potential contributions to bioenergy.

Woody Plantation Expected Production Production
Crop (dry Mg/hectare-yr) Costs Advantages Disadva
ntages Low
Avg. High (dry/Mg)
Cottonwood and 6 9 12 15-95 Broad genetic
resources Narrow site requirements Hybrid
Poplars Disease susceptible Sycamore 7
9 11 15-95 Rapid early growth Narrow site
requirements Disease susceptible Sweetg
um 4 6 8 15-65 Broad site requirement
Relatively slow growth Disease
resistance Eucalyptus
18 22 25 15-65 Broad site requirement
Restricted by frost High growth Hybrid
Aspen 9 10 12 no data Broad site requirement
Undeveloped genetic material Loblolly Pine 8
9 10 10-40 Operational infrastructure
Broad genetic resources