BioEnergy Research

, Volume 1, Issue 3, pp 229–238

Assessment of Canopy Structure, Light Interception, and Light-use Efficiency of First Year Regrowth of Shrub Willow (Salix sp.)

Authors

  • Pradeep J. Tharakan
    • International Resources Group
    • Dept. of Forest and Natural Resources ManagementState University of New York, College of Environmental Science and Forestry (SUNY-ESF)
    • Dept. of Forest and Natural Resources ManagementSUNY-ESF
  • Christopher A. Nowak
    • Dept. of Forest and Natural Resources ManagementState University of New York, College of Environmental Science and Forestry (SUNY-ESF)
  • Godfrey J. Ofezu
    • Dept. of Forest and Natural Resources ManagementState University of New York, College of Environmental Science and Forestry (SUNY-ESF)
Article

DOI: 10.1007/s12155-008-9023-9

Cite this article as:
Tharakan, P.J., Volk, T.A., Nowak, C.A. et al. Bioenerg. Res. (2008) 1: 229. doi:10.1007/s12155-008-9023-9

Abstract

According to the light-use efficiency model, differential biomass production among willow varieties may be attributed either to differences in the amount of light intercepted, the efficiency with which the intercepted light is converted to aboveground biomass, or both. In this study, variation in aboveground biomass production (AGBP) was analyzed in relation to fraction of incoming radiation intercepted (IPARF) and light-use efficiency (LUE) for five willow varieties. The plants were grown in a short-rotation woody crop (SRWC) system and were in their first year of regrowth on a 5 year old root system. The study was conducted during a two-month period (June 15th–August 15th, 2001) when growing conditions were deemed most favorable. The objectives were: (1) to assess the relative importance of IPARF in explaining variation in AGBP, and (2) to identify the key drivers of variation in LUE from a suite of measured leaf and canopy-level traits. Aboveground biomass production varied nearly three-fold among genotypes (3.55–10.02 Mg ha−1), while LUE spanned a two-fold range (1.21–2.52 g MJ−1). At peak leaf area index (LAI), IPARF ranged from 66%–92%. Nonetheless, both IPARF and LUE contributed to AGBP. An additive model combining photosynthesis on leaf area basis (Aarea), leaf mass per unit area (LMA), and light extinction coefficient (k) produced the most compelling predictors of LUE. In a post-coppice willow crop, the ability to maximize IPARF and LUE early in the growing season is advantageous for maximizing biomass production.

Keywords

Aboveground biomassCanopy structureLight interceptionLight-use efficiencyWillow (Salix sp.)

Abbreviation

Aarea

Light-saturated photosynthesis per unit leaf area μmol m−2 s−1

AGBP

Aboveground biomass production Mg ha−1

Amass

Light-saturated photosynthesis per unit leaf mass nmol g−1 s−1

Ic

Leaf compensation irradiance

IPARF

Fraction of incoming photosynthetically active radiation intercepted

IPART

Total incoming photosynthetically active radiation intercepted MJ m−2

IRGA

Infrared gas analyzer

k

Light extinction coefficient for Beer’s law

LAI

Leaf area index

LMA

Leaf mass per unit area g m−2

LUE

Light-use efficiency g MJ−1

Narea

Leaf nitrogen concentration expressed on a per unit area g m−2

Nmass

Leaf nitrogen concentration expressed on a per unit mass g kg−1

NOAA

National Oceanic and Atmospheric Administration

PAR

Photosynthetically active radiation μmol m−2 s−1

PARA

Incident photosynthetically active radiation on top of the canopy μmol m−2 s−1

PARB

Photosynthetically active radiation below the canopy μmol m−2 s−1

PFD

Photon flux density μE m−2 s−1

SRWC

Short-rotation woody crop

SUNY-ESF

State University of New York, College of Environmental Science and Forestry

Copyright information

© Springer Science+Business Media, LLC. 2008