Antonio Guindeo

Sorption and thermodynamic properties of juvenile Pinus sylvestris L. wood after 103 years of submersion

Abstract The hygroscopicity and thermodynamic properties of juvenile Pinus sylvestris L. wood taken from the submerged piles of a bridge built in 1903 over the Jiloca River, in Spain, were compared with the corresponding values of juvenile wood of the same species from recently cut trees. The 35°C and 50°C isotherms were plotted and subsequently fitted using the Guggenheim-Anderson-Boer-Dent method, and the isosteric heat of sorption was obtained through the integration method of the Clausius-Clapeyron equation. The isotherms were compared by means of the hysteresis coefficients. Infrared spectra were recorded to study the chemical modifications, and the crystal structure of the cellulose was studied by X-ray diffractograms. The submersion in water resulted in hemicellulose degradation and a decrease in the crystallinity index and the crystallite length, accompanied by a corresponding increase in the proportion of amorphous zones. Owing to this, the equilibrium moisture contents of the water logged wood are higher than in the recent wood, both in adsorption and in desorption. In terms of the thermodynamic properties, the bond energy is higher in the recent wood than in the water logged wood.

The Wood of Pinus Canariensis and Its Resinous Heartwood

Pinus canariensis (Canary Island Pine or Piteh Pine) forms natural forests on the islands of Tenerife and La Palma. The heartwood has an extraordinarily high resin eontent, and this paper provides an anatomical deseription of the wood as well as an interpretation of the faetors relating to this resinifieation

Comparative Anatomy of the Wood of Abies Pinsapo and Its two Moroccan Varieties

This study describes the structure of the wood of Abies pinsapo from samples taken from its three natural distribution areas in the Iberian Peninsula (Sierra de Grazalema, Sierra de las Nieves and Sierra Bermeja) and compares them with the varieties from the north of Africa, Abies pinsapo var. marocana from the Talassemtane mountains and A. pinsapo var. tazaotana from the Tazaout mountains. All the samples were collected in their regions of provenance. To put the results into perspective, a comparison was also made with the wood of Abies alba and A. numidica. The wood of the Iberian A. pinsapo and of its two varieties from the Rif mountains in Morocco is anatomically similar, and there are no qualitative differences that enable the wood to be differentiated except for the presence of resin deposits in the tracheids adjacent to the rays in the samples from Grazalema. Quantitatively, for tracheid diameter and tracheid length there are statistically significantly differences (p<0.05) between those of Spanish provenance and the Moroccan varieties, but for tracheid pit diameter, largest diameter of cross-field pits and tall ray frequency the samples from Sierra Bermeja have more in common with the African samples.