BIOMASS EQUATIONS FOR EVENAGED STANDS OF CARIBBEAN PINE (<em>PINUS</em> <em>CARIBAEA</em>) PLANTED AS AN EXOTIC IN NIGERIA

Abstract

Allometric regression equations for biomass prediction were developed for trees of Caribbean pine from stands aged 14 years at three sites in the subhumid savanna region of Nigeria. Individual tree component weights (bole, branches, needles, roots and total aboveground) were regressed against DBH (stem diameter at breast height, 1.3 m) using 12 sample trees from each site. When statistical comparisons showed no significant differences (P<0.05) in regression models among sites, combined equations based on pooled data of 36 trees were developed. In every case the combined equations which had higher slopes than the individual site equations either underestimated or overestimated tree biomass depending on the site. The combined equations were thus considered inappropriate and the site specific equations were used to calculate the dry weight instead. Total tree biomass and net primary production varied with site but in all the sites, approximately 82% of tree biomass was in the aerial part and 18% in the roots. The bole, needles and branches constituted about 59, 13 and 10% of whole tree biomass respectively.The results showed that because of site quality there were differences in rates and magnitude of dry matter production.