Generalist aboveground biomass equations for Mexican forest communities

Jose De Jesus Navar, CIIDIR-IPN Unidad Durango, jnavar@ipn.mx (Presenter)

Tree, plot and regional aboveground biomass, M, assessments remain a key challenge for the successful implementation of carbon off set projects in world forest communities due to the large uncertainty. Potential ways to overcome this problem are: (i) to develop as many local tree-specific aboveground biomass equations as required; (ii) to calculate a mean allometric equation across on and off site equations; (iii) to develop generalist equations using all biomass information available, and (iv) to develop and apply theoretical and semi-empirical models. This study aims to apply theoretical and semi-empirical equations as well as to develop generalist equations for Mexican tropical dry, temperate and semi-arid forest communities, where several sources of information are already available. I employed data collected from eighteen, twenty-three and forty-four M equations with 312, 1539, and 1230 biomass datasets for fitting and developing generalist equations; and with 44, 117, and 440 M datasets for validating models for tropical dry, temperate and semi-arid forest communities, respectively. Theoretical, semi-empirical and empirical generalist models fitted this data source using wood specific gravity, pw, diameter at breast height, D, basal diameter, Db, top height, H, and form factor, C, av, ah, values as exogenous variables. The empirically generalist computer-based equations fitted slightly better M data than semi-empirical or theoretical applied models. Wood specific gravity data values taken from internet sources could have explained deviations between theoretical, semi-empirical models and aboveground raw biomass data. The preliminary recommended total aboveground biomass equations are: M = exp(-1.8655+ 0.6746*Ln(pw) + 2.1581*Ln(D) + 0.1345*Ln(H)); M = exp(-3.27 + 2.747*Ln(D) + 0.675*(pw) + 0.36*Ln(C)); and M = (-4.49 + pw*av*(Db2*H)0.781); for tropical dry, temperate and semi-arid forest communities, respectively. Two semi-empirical and two fully theoretical models deserve further attention once wood specific gravity, bole volume, and shape factor data is collected in the field for each harvested tree with the aim to improve total aboveground biomass assessments with more physically-based models.

Presentation Type:  Poster

Session:  Science in Support of Decision Making   (Wed 10:00 AM)

Associated Project(s): 

• Related Activity

Poster Location ID: 299