Preliminary estimates of biomass growth in the Tamaulipan thornscrub in north-eastern Mexico

The objective of this research was to estimate the biomass growth of 10 typ ical species of the Tamaulipan thornscrub in north-eastern Mexico. In total , eight biomass growth models of three parameters were tested. Parameter fi tting was conducted by least square techniques in non-linear regression. Th e best model for each shrub species generated growth and increment of above -ground dry biomass. The results showed that the Logistic and Weibull model s consistently fitted better the observed biomass growth for 60% of the stu died shrub species. Models predict that Diospyros texana, Acacia berlandier i and Cordia boissieri have the largest growth rates of standing biomass in contrast to Helietta parvifolia, Acacia rigidula and Pithecellobium pallen s. At the spatial scale, the Tamaulipan thornscrub produces a peak periodic biomass increment of 4.11 Mg ha(-1) year(-1). However, this biome currentl y produces a periodic biomass increment of 1.67 Mg ha(-1) year(-1). This re port highlights the need to establish permanents sampling plots to observe and better model biomass growth at the stand level. (C) 2001 Academic Press .