Slash Pine Growth Potential

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Slash Pine Growth Potential
Slash Pine Symposium Jekyll Island,
Georgia April 24, 2002

• Bruce E. Borders, Professor
• D.B. Warnell School of Forest Resources
• The University of Georgia

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Slash Pine Growth Potential
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Slash Pine Growth Potential

• Slash pine (Pinus elliottii, Engelm) is a
  southern pine species that is near and dear to
  the hearts of many timberland owners and managers
  in the southeastern U.S.
• In the past 15 to 20 years a tremendous amount of
  effort has been put forth in the study and
  comparison of the productivity of slash pine
  compared to loblolly pine (Pinus taeda, L.)
• To the chagrin of many, loblolly pine always
  seems to come out on top in productivity
  comparisons

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Slash Pine Growth Potential

• In fact, traditional wisdom says that there are
  slash sites where loblolly pine can not compete
  with slash pine
• However, recent research indicates that this is
  not true (although there are undoubtedly
  exceptions to this general finding)

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Intensive Management

• Intensive management cultural treatments to
  ameliorate limiting growth factors on the site
• Vegetation control (herbaceous and woody)
• Fertilization as necessary to insure that all
  nutrients are in adequate supply
• Mechanical treatments (raking, bedding, ripping)
  to create adequate rooting volume for our crop
• Does slash pine fare better relative to loblolly
  pine in intensively managed stands?
  Unfortunately, the answer is no.
• In fact, loblolly is known to be even more
  responsive than slash pine when managed
  intensively

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Slash Pine Growth Potential

• So, we now know that slash pine is not as
  productive of a species as loblolly pine
• However, this does not mean that we always prefer
  loblolly
• It is well known that slash pine tends to have
  higher wood density and better wood properties
  than loblolly pine
• Therefore, it is possible that slash pine can
  produce more volume of a desirable end product
  than loblolly pine
• Even if this is not the case, landowners may
  prefer slash pine for their own personal reasons

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Slash Pine Growth Potential

• So, if we decide that we are going to grow slash
  pine an appropriate question to ask is what is
  the growth potential of this species?
• First we must realize that the inherent growth
  potential of any plant species is dependent on
  the underlying genetic makeup of the species in
  question
• This is just as true for slash pine as it is for
  corn
• We will never know the growth potential of a
  species until we have all growth factors present
  in adequate supply

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Limiting Growth Factors

• Growth of plants (including trees) is regulated
  by the following
• Physical Soil Rooting Volume
• Water Availability
• Nutrient Availability
• Light Availability
• Climate

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Limiting Growth Factors

• Physical Soil Rooting Volume
• The actual volume of soil that is available for
  the tree to occupy with its root system
• Can be limited by the texture of the soil (heavy
  soils), hardpans, level of the water table,
  amount and type of competitors
• Can be ameliorated with mechanical site
  preparation (ripping, bedding, disking, etc.) and
  competition control

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Limiting Growth Factors

• Water Availability
• The amount of moisture that is available to the
  plant
• Can be limited by the texture of the soil
  (sands), hardpans, level of the water table,
  amount and type of competitors
• Can be ameliorated with mechanical site
  preparation (ripping, bedding, disking, etc.) and
  competition control

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Limiting Growth Factors

• Nutrient Availability
• The types and amounts of nutrients available in
  the soil
• Can be limited by the history of the site as well
  as the competing vegetation on the site
• Can be ameliorated with fertilization and
  competition control

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Limiting Growth Factors

• Light Availability
• The amount of light available to the tree for
  photosynthesis to take place
• Can be limited by competing vegetation on the
  site
• Light has not been implicated as a major limiting
  growth factor in most plantation situations

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Limiting Growth Factors

• Climate
• The climate that the site is located in can not
  be changed
• We have to realize that if the other growth
  factors are not limiting we will run into the
  limit of the species/climate potential for our
  area
• When we reach this point we know we have arrived
  at the potential of our species in our locale

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Growth Comparison - Brazil
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Growth Comparison - Brazil

• Pisa Florestal - Parana State, Brazil
• Pinus taeda
• Potential productivity 615 cu.ft./ac/yr
• (approximately 6.8 cords/ac/yr)
• Pinus elliottii
• Potential productivity - 500 cu.ft./ac/yr
• (approximately 5.5 cords/ac/yr)

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Pinus elliotii - Brazil - Age 12
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Slash Pine Volume Growth - South Africa
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Slash Pine Age 34 South Africa
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Routine Cultural Practices Exotic Locations

• Intensive mechanical/chemical site preparation
• Mechanical/chemical competition control
• Fertilization
• Ripping
• Irrigation (primarily for survival)

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Slash Pine Growth Potential

• Clearly, the intensity of the management in these
  exotic locations are allowing the slash pine to
  show its inherent productivity potential in their
  climate and soils
• Thus, we know that this species has a great deal
  of potential that we have not routinely seen due
  to our extensive management practices

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Slash Pine Growth Potential

• What type of growth can we achieve in the
  southeastern U.S. if we use cultural treatments
  to remove limiting growth factors (i.e. when do
  we run into the limit of the climate and soils in
  our region?)

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Slash Pine Growth Potential

• Plantation Management Research Cooperative (PMRC)
  Slash Pine Site Preparation Study - established
  1980
• Treatments - various combinations of burning,
  bedding, complete vegetation control,
  fertilization (end of year 1, start of year 12)
• 20 locations throughout SE (16 remaining)

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Slash Pine Growth Potential

• After 20 growing seasons
• Complete vegetation control resulted in an
  average gain of 5.3 feet in height and 0.9 inches
  in diameter
• Fertilization treatment resulted in an average
  gain of 5.1 feet in height and 0.6 inches in
  diameter
• Average annual volume/acre production (dbh gt 4.5
  to a 3 top dob) of most intensive treatments 203
  cubic feet (2.25 cords) vs 98 cubic feet (1.09
  cords) for non-intensive mechanical site
  preparation

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Slash Pine Growth PotentialSlash Pine Site
Preparation - Age 4 - Complete Veg Control Fert
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Slash Pine Growth PotentialSlash Pine Site
Preparation - Age 13 - Complete Veg Control Fert
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Slash Pine Growth Potential CAPPS Loblolly Pine
Plots

• Four treatments were evaluated in each of these
  areas
• H - herbicide used to control all herbaceous and
  woody competitors (complete control)
• F - fertilize as follows First 2 growing seasons
  - 250 lbs/ac DAP plus 100 lbs/ac KCl in the
  spring, 50 lbs/ac DAP in mid-summer in each
  subsequent growing season 150 lbs/ac ammonium
  nitrate in the spring

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Slash Pine Growth Potential CAPPS Loblolly Pine
Plots

• Four treatments were evaluated in each of these
  areas
• HF - both H and F treatments
• C - check plots (treatments on check plots were
  intensive mechanical that varied by location -
  the objective of the treatment was to have the
  area free of all vegetation and to be well tilled
  at time of planting (no ripping was done)

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Slash Pine Growth Potential CAPPS Loblolly Pine
Plots - Volume MAI

• Waycross Wet Site - 435 ft3/ac/yr - age 10
• Waycross Dry Site - 369 ft3/ac/yr - age 10
• Tifton - 333 ft3/ac/yr - age 9
• Eatonton - 320 ft3/ac/yr - age 9
• Athens - 305 ft3/ac/yr - age 8

These values have continued to increase through
age 15 with maximum productivity in the coastal
plain of approximately 5 cords/ac/year (500 cubic
feet/ac/year) obviously more intensive
management leads to more production should hold
for slash pine as well.
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Slash Pine Growth Potential Intensive
Culture/Density Study

• This is a new study that will provide information
  about intensively managed loblolly and slash pine
  plantations for the next 20 years or more
• 17 installations in the LCP of Georgia Florida
  installed 1995/96
• 24 installations in the piedmont/UCP of South
  Carolina, Georgia, Alabama 1998/99

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Slash Pine Growth Potential Intensive
Culture/Density Study

• Initial Planting Densities - 300, 600, 900, 1200,
  1500 and 1800 tpa for loblolly and 300, 900 and
  1500 tpa for slash at 9 locations
• Operational intensive management - one year HWC
  plus time of planting fertilization
• Super intensive management - complete vegetation
  control, fertilize as often as necessary based on
  soils and foliage tests

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Slash Pine Growth Potential Intensive
Culture/Density Study

• Study is very young we have just gotten 6 year
  measurements on the coastal plain slash
  installations
• Trees are showing very high growth rates
• On the intensive loblolly installations age 6
  height is averaging 30 to 32 feet (5 feet/year)
  with approximately 90 to 110 square feet of basal
  area in densities of 600 and 900 tpa
• On the intensive slash installations age 6 height
  is averaging 25 feet (4 feet/year) with
  approximately 100 square feet of basal area for
  the 900 tpa density

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Slash Pine Growth Potential Intensive
Culture/Density Study 300 TPA - Slash Age 6
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Slash Pine Growth Potential Intensive
Culture/Density Study 900 TPA - Slash Age 6
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Slash Pine Growth Potential Intensive
Culture/Density Study 1500 TPA - Slash Age 6
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Slash Pine Growth Potential Future
Management/Research

• We must continue to evaluate impact of cultural
  treatments and their interaction on slash pine
  development across a wide range of soils in the
  southeastern U.S. this will help develop better
  site specific management prescriptions

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Slash Pine Growth Potential Future
Management/Research

• We must evaluate the wood quality of the fast
  grown stands to better understand how cultural
  treatments impact potential end uses for our raw
  material
• We must evaluate the impact that our cultural
  treatments have on other resources (water,
  wildlife, even insects and lower organisms) so
  that we have sound data with which we can
  interact intelligently with various green
  organizations

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Slash Pine Growth Potential - Conclusioins

• Biological potential of slash and loblolly pine
  exceeds 500 ft3/ac/yr
• In the southern U.S. much of this potential has
  been masked by our management (or lack of
  management)
• It is possible to produce more than 300 ft3/ac/yr
  on many sites throughout the South (more than 450
  ft3/ac/yr on a smaller number of sites) with both
  of these species
• Dont plant slash because you believe it is a
  more productive species than loblolly

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Questions/Comments?