Forestry

Woody plant resources continue to disappear in anthropogenic landscapes in Uganda. To slow down further loss of these resources requires the collaboration of farmers in tree planting in agroforestry systems. Tree planting interventions with the collaboration of farmers require a good understanding of tree management practices as well as trees that best satisfy farmers’ needs. We carried out this research to determine (1) the most preferred tree species and reasons why they are preferred, (2) the species conservation statuses, and (3) existing tree management practices and challenges to tree planting. Fourteen priority species valued because they yield edible fruits and timber have been prioritised in this study. Farmers are interested in managing trees but are constrained by many factors, key among which is scarcity of land and financial capital to manage tree planting. Trees are managed in crop fields and around the homestead. From farmers’ reports, the highly valued species are in...

This paper reports on the results on an ongoing study into the mechanisms by which chemical modification, thermal modification, and cell wall impregnation with monomers with subsequent polymerization impart decay protection to wood. Results from two preliminary studies, where wood was modified with a variety of anhydride reagents of different molecular weight were presented at an earlier meeting of this action. This paper presents the results of a recent study of the changes of the cell wall volume due to acetylation determined using a helium pycnometer. In addition, the results of two previous studies of the cell wall accessibility of anhydride modified wood are given and discussed. The role of cell wall moisture content and cell wall micropore blocking are considered as possible decay protection mechanisms in anhydride modified wood.

SUFFIAN M, ORMONDROYD GA & HALE MD. 2010. Comparisons of particleboard produced from Acacia hybrid and a UK commercial particleboard furnish from recycled wood. A series of particleboards were produced from small diameter logs of Acacia hybrid and a UK commercial furnish (recycled wood). Physical and mechanical properties of the boards were then determined. It was hypothesised that the particleboard produced from Acacia hybrid would have acceptable mechanical and physical properties for the European market. Both particleboards surpassed the European standard requirements for general purpose boards (Type P1). Boards produced using Acacia hybrid exceeded the standard requirements for load bearing boards (Type P4). Thickness swelling and water absorption values were about half of those achieved by boards manufactured from the commercial furnish after being immersed in water for 2 and 24 hours. Similar trends could be seen when boards were immersed in water for nearly 70 hours and expos...

The reduced equilibrium moisture content (EMCR) and moisture exclusion efficiency (MEE) of acetylated rattan was studied in relation with age and time of acetylation. Rattans aged 10 and 13 years grown under rubber trees were reacted with acetic anhydride for 0.25 to 30 hours. Results showed that the lowest EMCR and the highest MEE were obtained after 10 hours reaction or at the levelling-off per cent weight gain for both rattan ages. The EMCR values at the levelling-off per cent weight gain were lower in acetylated older rattan than the younger rattan. The low EMCR was highly correlated with the bulking coefficient.

Ink disease caused by Phytophthora cambivora is a major disease of sweet chestnut (Castanea sativa). In two C. sativa stands in central Italy, one (Montesanti) that is infected with P. cambivora and the trees showing symptoms of ink disease and another healthy stand ( ...

In the woodworking industry image analysis is routinely used for quality control and for matching and classification during various processes. An extension of these automated systems for the prediction of physical properties of thermally-modified wood (TMW) is enticing, because to date there is no a generalized procedure for the quality assurance of this material. The purpose of this work was to investigate the relationship between property changes in TMW and heated-induced colour changes. A description of the effect of the temperature and time of treatment on colour variables and its relationship between these and colour changes in Klason lignin is also given.