Tree Productivity Enhanced with Conversion from Forest to Urban Land Covers

PLoS One. 2015 Aug 24;10(8):e0136237. doi: 10.1371/journal.pone.0136237. eCollection 2015.

Abstract

Urban areas are expanding, changing the structure and productivity of landscapes. While some urban areas have been shown to hold substantial biomass, the productivity of these systems is largely unknown. We assessed how conversion from forest to urban land uses affected both biomass structure and productivity across eastern Massachusetts. We found that urban land uses held less than half the biomass of adjacent forest expanses with a plot level mean biomass density of 33.5 ± 8.0 Mg C ha(-1). As the intensity of urban development increased, the canopy cover, stem density, and biomass decreased. Analysis of Quercus rubra tree cores showed that tree-level basal area increment nearly doubled following development, increasing from 17.1 ± 3.0 to 35.8 ± 4.7 cm(2) yr(-1). Scaling the observed stem densities and growth rates within developed areas suggests an aboveground biomass growth rate of 1.8 ± 0.4 Mg C ha(-1) yr(-1), a growth rate comparable to nearby, intact forests. The contrasting high growth rates and lower biomass pools within urban areas suggest a highly dynamic ecosystem with rapid turnover. As global urban extent continues to grow, cities consider climate mitigation options, and as the verification of net greenhouse gas emissions emerges as critical for policy, quantifying the role of urban vegetation in regional-to-global carbon budgets will become ever more important.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Carbon / metabolism
  • Ecosystem*
  • Environmental Monitoring
  • Forests*
  • Humans
  • Massachusetts
  • Trees / growth & development*
  • Urban Renewal*

Substances

  • Carbon

Grant support

For this study, Lucy Hutyra received funding from the National Science Foundation NSF CAREER award (DEB-1149471, http://www.nsf.gov/funding/pgm_summ.jsp?pims_id=503214) and a NASA Interdisciplinary Science grant (NNX12AM82G). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.