Provenance variation in wood characteristics of Pinus caribaea Morelet and P. oocarpa Scheide
Densitometric, volumetric and paper-making traits of provenances of Pinus caribaea Morelet, P. oocarpa Schiede and P. patula SchiedeariclDeppe ssp. tecunumanii (Eguiluz and Perry) Styles were evaluated. Provenance mean values of densitometric density (DEN) and within tree density variation (VAR) were significantly different (p<0.05) at seven of the fourteen P.caribaea and at one of the seven of P. oocarpa and P. patula ssp. tecunumanii trials. Provenance mean valuesor volume under bark (VUB)and dry matter index (DMI) were significantly (p<0.05) different at all of the P. caribaea and at five of the P. oocarpa and P. patula ssp. tecunumanii trials. The inland provenances of P. caribaea were generally Higher for DEN and VAR than the coastal provenances, he Camelias, Mountain Pine Ridge, Rafael and Yucul provenances of P. patula ssp. tecunumanii were superior to P. oocarpa provenances for VUB and DMI in all of these trials and were superior to P. caribaea at two sites where the species were growing under similar conditions. Evaluation of densitometric races revealed large differences between species, provenances and sites for the width and density of latewood; this could explain much of the variation in VAR between these sources. The analysis of variance was used to assess genotype by environment interaction of DEN and VAR from eleven provenances of P. caribaea var. hondurensis Barrett and Golfari at eleven sites and from five provenances of P. oocarpa and four provenances of P. patula ssp. tecunumanii at sfx sites. Sites and provenances were significantly different for DEN and VAR in both series of trials out the site by provenance term was not statistically significant in either. Indications were that P. caribaea would be expected to have lower values of DEN and VAR at higher altitude. Provenances of P. oocarpa and P. patula ssp. tecunumanii were lower for VAR at sites of lower latitude but there were no individual site factors which could be correlated with DEN in these provenances. The comparison of full-scale pulping with micropulping of small wood samples from felled trees of six pine species in the Eastern Transvaal, South Africa, revealed positive and significant correlations for the pulp yield and paper strength traits. The correlation of tear index and VAR in these trees was positive and significant. Evaluation and analyses of a number of pine species and provenances by micropulping of cores from standing trees revealed significant differences for certain of the paper strength traits. The Caftas provenance of P. oocarpa was unusual in having high values for both tear index and burst index when grown in Zululand. Similar conclusions were reached for provenances of P. patula ssp. tecunumanii grown in the Eastern Transvaal. The conclusions of this thesis were: 1. Site climatic factors did not affect DEN and VAR of the different species and provenances in the same way; 2. The VAR term varied as a result of site, species and provenance; 3. There was no genotype by environment interaction for DEN«*rJ VAR; 4. The correlation of VAR with pulp and paper-making traits indicated that trees with high VAR were superior for tear index to trees with low VAR; 5. Micropulping of small wood samples could be used to assess the paper-making traits of individual trees.