The Effect of Prior Land Use on Biomass Growth Rates in the Black Rock Forest

1
The Effect of Prior Land Use on Biomass Growth
Rates in the Black Rock Forest

• Michelle LaRocco
• Advisor Dr. Dallas Abbott, LDEO
• Mentor Dr. William Schuster, Black Rock Forest

Barnard College, Department of Environmental
Science March 4, 2004
2
Introduction

• Large portions of East coast cleared for
  agriculture or lumber
• Maximum clearing between 1850-1900
• Recovery of cleared land takes from 50-200 years
• In the past 100 years significant forest regrowth
  has occurred
• Regrowth of forests could be a significant sink
  for CO2

3
The Study

• Determine the biomass growth rates of trees in
  the Black Rock Forest
• Compare plots of varying former land use former
  agricultural land, former wood lots
• Rates in former agricultural land may be lower
  than other use areas due to depletion of
  nutrients

4
Black Rock Forest History

• Originally settled in 1684
• Underwent several shifts in usage subsistence
  farming, commercial agriculture, dairying, lumber
  cutting
• Black Rock Forest Preserve established in 1928
  Currently 3785 acres

5
Methods

• Three species of trees used red maple, red oak,
  white oak
• Diameter-at-breast-height measured for each tree
  (1.3 m)
• Tree ring core sampled to determine the age of
  the tree MeasureJ2X
• Annual growth rate determined for each tree and
  average growth rate for species in plots

6
Site Description The Barton Farm

• Dominant species maple, oak,
• Other species beech, birch
• Former agricultural site surrounded by low stone
  walls
• Few visible rocks on the ground
• No stone walls near wood lot site
• Many rocks at surface and rocky outcrops

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Maps of Sites

Stone walls
Swamp Trail
Agricultural Site
Pond
Outcrop
Wood Lot Site
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Diameter of Sampled Trees in Former Agricultural
Land and Former Wood Lot
9
Age of Trees in Agro/woodlot land
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Average annual trunk growth of trees
11
Why is this the case??

• Farmers generally chose the best lands for fields
• Greater number of trees at non agricultural land
  site may result in lower average growth per tree
• Would the slope of the land have impacted the
  result?

12
Conclusions

• The non-intensive farming may not have caused a
  large enough impact on the soil for an effect to
  be measurable in the biomass.
• The soil may have had sufficient time for
  recovery.