MSc

An experiment to evaluate the fuelwood value, and physical and
mechanical properties of selected agroforestry tree species was conducted at the
College of Forestry, Vellanikkara. The study involved determination of the
fuelwood value of 48 species/materials and assessment of the physical and
mechanical properties of three promising multipurpose trees having local
importance, viz., Acacia auriculiformis, Acacia mangium and Grevillea robusta.
Variations abound in the calorific values of agroforestry species and
their tissue-types. Ash content, specific gravity, chemical composition and
moisture content of tissues are primary factors affecting calorific value; while
species and tissue-types, may exert a secondary control. Ash content and moisture
content had a negative correlation with calorific value, whereas specific gravity
exerted a positive influence. Based on the range in calorific values and fuelwood
value indices obtained, different species and tissue-types could be broadly divided
into three categories: high, medium and low. Calorific value of different tissue
fractions decreased in the order: heartwood> sapwood > bark.
Mean ash percentage of tissue-types followed the order: bark> sapwood
> heartwood. Variations of ash content along bole height followed the order:
branchwood > top > bottom > middle. Mean specific gravity of tissue-types
followed the order: heartwood> sapwood > bark. For sample positions it followed
the sequence: bottom> middle> top> branchwood. Wood moisture content
increased from bottom to top along tree height and for tissue-types, it followed the

order: bark < heartwood < sapwood. Coconut shell recorded the highest fuel value
index (FVI) which was approximately 25 times greater than the highest value for
tree species (Casuarina equisetifolia).
Physical and mechanical properties of Acacia auriculiformis was
significantly supenor to that of Acacia mangium and Grevillea robusta. The
physical and mechanical properties were affected by both species and sample
positions. Wood specific gravity increased from inner to outer sample positions
along radial direction except for Grevillea robusta, which followed the order: outer
< inner < middle. Moisture content decreased from inner to outer sample positions
in Acacia mangium; while Grevillea robusta exhibited a divergent trend.
Variations in shrinkage along radial direction followed the same trend as that of
moisture content but was inconsistent with that of specific gravity. Most of the
strength properties followed a trend similar to that of specific gravity. On a final
note, specific gravity, work to limit of proportionality in static bending, work to
maximum load in static bending, compressive stress at limit of proportionality in
parallel to grain, compressive stress at limit of proportionality in perpendicular to
grain and end-hardness of Acacia auriculiformis were greater than the values
reported for teak. The physical and mechanical properties of Acacia mangium and
Grevillea robusta except for shrinkage were less than that of teak.