Short running title: The cost of restoring forest carbon stocks
Abstract: Knowing which restoration approach provides the best
returns on investment for accumulating carbon is essential to foster
restoration planning, financing, and implementation. We assessed the
recovery of carbon stocks, implementation and land opportunity costs of
forests established by natural regeneration and high-diversity native
tree plantations. Our study was based on chronosequences (10-60 yr) of
12 naturally regenerating forests, 13 restoration plantations, and 5
reference forests located in Brazil’s Atlantic Forest. Restoration
plantations accumulated approximately 50% more above-ground carbon than
regenerating forests throughout the chronosequence. When controlling for
soil clay content, soil carbon stocks were higher in reference than in
restored forests, but they were comparable between plantations and
regenerating forests. After 60 years of stand development, recovery of
total carbon stocks in both restoration management types reached only
half of the average stocks of reference forests. Total
cost-effectiveness for carbon accumulation, including both
implementation and land opportunity costs, was on average 60% higher
for regenerating forests than for plantations (15.1
kgC.US$-1 and 9.4 kgC.US$-1,
respectively). Both restoration management types had cost-effectiveness
for carbon accumulation markedly lower than the price of carbon credits
considered, so some voluntary forest carbon markets are not adequately
priced to support restoration derived offsets. Although tree plantations
initially had higher rates of carbon storage than regenerating forests,
their higher implementation and land opportunity costs make them less
cost-effective for carbon farming. Our results further suggest that
carbon markets alone have a limited potential to up-scale restoration
efforts in Brazil’s Atlantic Forest.
Keywords: carbon sequestration; passive restoration; natural
regeneration; restoration plantations; soil carbon; tree planting