The scarcity of timber to supply the wood-based industries is one of the prevailing problems worldwide. Tree plantations are the remaining solutions to subdue the shortage of raw materials, at the same time sequester atmospheric CO 2 in its biomass to reduce global warming. Planting Big-leaf mahogany (Swietenia macrophylla King) contributes valuable economic inputs to small tree farmers in the Philippines. However, the occurrence of lumber defects during processing due to growth stresses reduces the potential value of timber. This study aimed to examine the differences of surface growth stresses and wood properties of an 8-year-old BL mahogany from six landrace provenances in two progeny trial sites, Butuan and Cagayan de Oro in the Philippines. The longitudinal released strains of the surface growth stress (SRS) were not significantly different among six landrace provenances and between two trial sites. The SRS were not significantly related to diameter at breast height (DBH) in both trial sites. The high level of negative SRS was observed in some tested trees with small diameter in both trial sites, which was attributed to the tension wood formation in an irregular-shaped stem. The xylem density (XD), average microfibril angle in the secondary cell wall (MFA), vessel element length (VL) and vessel element width (VW) had no significant differences among six landrace provenances. In terms of trial sites, Butuan trial site gave high lateral growth DBH, high XD, longer fiber length (FL) with a narrow fiber width (FW) and smaller MFA as compared to the Cagayan de Oro trial site. It was observed that an 8-year-old BL mahogany plantation with small-diameter trees exhibited high SRS, low XD, small FL, wide FW and large MFA, which are passively considered as properties of juvenile wood.

This paper presents the mechanical properties, veneer recovery including the cost benefits, of 3-, 5-, and 7-yr-old falcata [Falcataria moluccana (Miq.) Barneby & J. W. Grimes] for veneer production. Mechanical properties covered modulus of rupture (MOR), stress at the proportional limit, and modulus of elasticity (MOE) in static bending; compression paralleland perpendicular-to-grain; shear; and hardness and toughness. The study was conducted to evaluate the effects of age on these properties and the cost-benefits of converting the species at different ages, and to recommend the optimum age and price for the utilization of the species for veneer production. The experimental materials consisted of six plus-size trees each per age from superior seeds of known origin in Caraga, Philippines. Standard procedures for testing the strength properties of timber (ASTM D143-14) were followed. Veneering was conducted using a spindleless lathe with a fixed setting for each designated veneer thickness output. Gross veneer recovery was 52% for both 3- and 5-yr-olds and 55% for the 7-yr-old. Net recovery, on the other hand, was 46% for the 3- and 5-yr-olds while 49% for the 7-yr-old. Utilizing falcata trees as young as 3-yr-old can generate positive cash flows for veneering plants, making it a worthwhile investment. However, from the perspective of falcata farmers and plantation owners, selling at 3-yr-old would be unfavorable considering the low selling price.

The anatomical properties – namely, fiber length, fiber diameter, lumen diameter, cell wall thickness, vessel length, and width – of young (3-, 5-, and 7-yr-old) Falcataria molucanna (Miq.) Barneby & J. W. Grimes from Caraga Region, Philippines were evaluated to determine the variations among ages between and among trees, tree height, and their derived values as well, henceforth as a basis in recommending the potential of the species for various enduses. Three trees per age of known seed origin were collected and used as materials. FPRDI standard procedures for determining anatomical properties were followed. Data were analyzed using three-factorial in complete randomized design (CRD) and Tukey’s honestly significant difference (HSD) test was used to determine significant differences among treatment means. Except for cell wall thickness, the variations in anatomical properties among age and tree were highly significant but not significant among height levels. Fiber diameter and lumen diameter increased as the trees aged. The cell wall was very thin with mean values of 0.0033 mm (3-yr-old), 0.0032 mm (5-yr-old), and 0.0031 mm (7-yr-old). Vessel length and width decreased from 3- to 5-yr-old and increased at 7-yr-old. Fiber length’s mean values increased from near pith (NP), middle (M), to near bark (NB) at all three ages and height levels except in the 3-yr middle (1.1665, 1.2032, and 1.1541 mm) and 7-yr butt (1.1541, 1.2326, and 1.2009 mm). Other anatomical properties at three ages showed no consistent trend of variations from NP to NB. The potential uses of younger falcata based on their anatomical properties were for pulp and paper, veneer, and light construction applications where strength and durability are not important.

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Young (3-, 5-, and 7-yr-old) falcata [Falcataria moluccana (Miq.) Barneby & J W. Grimes] trees were evaluated for their suitability to be processed into veneer and plywood. Three sample trees per age level were harvested from industrial tree plantations in Agusan del Norte and Surigao del Sur, Mindanao, Philippines. A straight portion of each tree from the bottom up to 4.5 m long was cut and divided into three billets at 1.5 m each. These were assigned to be peeled into 0.85-, 2.20-, and 2.80-mm veneer thicknesses. Veneering was done in a spindleless lathe using established lathe settings for falcata billets. Veneer quality per thickness and age level was evaluated based on the frequency and depth of lathe checks (LC). Results showed that LC occurred more frequently in the 2.20-mm-thick veneer, but these were shallower than the 2.80- mm, which had less frequent but deeper LC. On the other hand, age was found to significantly affect the formation of deeper LC in the 3-year-old 0.85-mm thick veneer; thus, it should only be used as a core veneer. The bond strength quality test showed that, regardless of age, falcata plywood passed the glue bond requirement of PNS ISO 12466-2:2016.