Above-ground biomass production and allometric relations of Eucalyptus globulus Labill. coppice plantations along a chronosequence in the central highlands of Ethiopia.

Abstract Eucalyptus plantations are extensively managed for wood production in the central highlands of Ethiopia. Nevertheless, little is known about their biomass (dry matter) production, partitioning and dynamics over time. Data from 10 different Eucalyptus globulus stands, with a plantation age ranging from 11 to 60 years and with a coppice-shoot age ranging from 1 to 9 years were collected and analyzed. Above-ground tree biomass of 7–10 sampled trees per stand was determined destructively. Dry weights of tree components ( W c ; leaves, twigs, branches, stembark, and stemwood) and total above-ground biomass ( W a ) were estimated as a function of diameter above stump ( D ), tree height ( H ) and a combination of these. The best fits were obtained, using combinations of D and H . When only one explanatory variable was used, D performed better than H . Total above-ground biomass was linearly related to coppice-shoot age. In contrast a negative relation was observed between the above-ground biomass production and total plantation age (number of cutting cycles). Total above-ground biomass increased from 11 t ha −1 at a stand age of 1 year to 153 t ha −1 at 9 years. The highest dry weight was allocated to stemwood and decreased in the following order: stemwood > leaves > stembark > twigs > branches. The equations developed in this study to estimate biomass components can be applied to other Eucalyptus plantations under the assumption that the populations being studied are similar with regard to density and tree size to those for which the relationships were developed.

[1]  H. C. Dawkins,et al.  Plantation Forestry in the Tropics. , 1985 .

[2]  A. Das,et al.  Above-ground biomass and nutrient contents in an age series of Khasi Pine (Pinus kesiya) , 1987 .

[3]  A. Schönau,et al.  Preliminary Biomass Studies in Young Eucalypts , 1982 .

[4]  J. Laclau,et al.  Dynamics of biomass and nutrient accumulation in a clonal plantation of Eucalyptus in Congo , 2000 .

[5]  T. Verwijst,et al.  The influence of allometric variation, vertical biomass distribution and sampling procedure on biomass estimates in commercial short-rotation forests , 1995 .

[6]  Margarida Tomé,et al.  Effect of tree, stand, and site variables on the allometry of Eucalyptus globulus tree biomass , 2007 .

[7]  M. Cannell,et al.  Attributes of trees as crop plants , 1985 .

[8]  J. P. Kimmins,et al.  Biomass estimation errors associated with the use of published regression equations of paper birch and trembling aspen , 2002 .

[9]  T. Grove,et al.  Biomass production by trees and understorey shrubs in an age-series of Eucalyptus diversicolor F. Muell. stands , 1985 .

[10]  Nutrition of Eucalypts , 1996 .

[11]  M. Lemenih.  Effects of land use changes on soil quality and native flora degradation and restoration in the highlands of Ethiopia , 2004 .

[12]  Marcia J. Lambert,et al.  Additive biomass equations for native eucalypt forest trees of temperate Australia , 2004, Trees.

[13]  Ralph E.H. Sims,et al.  Tree biomass equations for short rotation eucalypts grown in New Zealand , 1997 .

[14]  J. Turner.  Organic matter accumulation in a series of Eucalyptus grandis plantations , 1986 .

[15]  A. Keeves.  SOME EVIDENCE OF LOSS OF PRODUCTIVITY WITH SUCCESSIVE ROTATIONS OF PINUS RADIATA IN THE SOUTH-EAST OF SOUTH AUSTRALIA , 1966 .

[16]  P. Mohr.  The Geology of Ethiopia , 1961 .

[17]  Lawrence P. Abrahamson,et al.  Development and validation of aboveground biomass estimations for four Salix clones in central New York. , 2007 .

[18]  Theo Verwijst,et al.  Biomass estimation procedures in short rotation forestry , 1999 .

[19]  J. D. Ovington,et al.  Organic matter changes in an age series of Pinus radiata plantations [in Australia. , 1970 .