The bark is widely applied in West Africa, in decoction or macerated in palm wine, to treat dysentery and diarrhea. In Senegal, the roots are used for the same purposes and are further used to treat stomach complaints, including constipation and colic, to prevent spontaneous abortion, to treat sterility, and as a diuretic to treat venereal diseases (Arevalo et al., 2020).  An infusion of the leaves is taken to treat diabetes and amenorrhea. In Sierra Leone, the leaves, mixed with kola nuts are eaten to treat gonorrhea. In Guinea Bissau, the fruit is used to prepare a remedy for dropsy. The latex is applied to snakebites. The stem bark and leaves are also widely used to treat fever, especially malaria. They are boiled and added to a bath, or taken orally.

In Côte d’Ivoire, a decoction of the bark is used as an enema or in baths to treat skin affections. The leaf sap is sprinkled on wounds as a haemostatic. The leaves, mashed with those of Myrianthus arboreus P. Beauv and fruits of Capsicum pepper in water, are applied as an enema against kidney pain. The latex has been used as arrow poison or fish poison (Arevalo et al., 2020). The 5-8 cm wide band of lighter-colored sapwood readily distinguishes the reddish-brown heartwood. The grain is narrowly interlocked, giving a stripe figure; the sheen is medium; there is no particular aroma or flavor; the wood is marked by dark scar tissue streaks; and it has a mild greasy feel (Arevalo et al., 2020). In Ghana, H. floribunda is primarily utilized for carving stools for kings, queen mothers, fetish priests, and other prominent members of society, and it is widely regarded as the best white wood available for these uses. N. papaverifera is also commonly employed in the manufacture of furniture and for other structural uses.

Commercial interest in H. floribunda and N. papaverifera wood for other technical uses has increased in recent years (eg, construction, window frames, and sculpture). In 2019, Ghana exported a total volume of 1898.57 m³ of N. papaverifera for €379.876.48 (3,343,913.02 cedis) and finished curved products and sculptures of H. floribunda species for €976,430.88 (8,592,591.74 cedis) respectively (TEDB 2019). However, information on the physical and mechanical properties of these timbers' branch wood, which is required to improve their applications as a supplement to their stem wood, is scarce in the literature.

Branch wood is a valuable wood resource with a wide range of applications; it accounts for 25-32% of total wood volume and is a secondary resource with high-value applications such as chaise lounges, wall and floor mosaics, garden arbors, dining stools, beds, garment racks, curtain rods, and a variety of other applications that have yet to be fully explored (Dawkins and Philip, 2020). Overexploitation of most 'traditional' market species has resulted in some being endangered (such as Milicia excelsa, Entandrophragma cylindricum, Khaya ivorensis, and others) due to increased market demand, both locally and globally. Manufacturers and producers have no choice but to pay attention to the branch wood of established and lesser-known species that were previously ignored if they want to stay in business as traditional timber prices rise and quality and quantity decline (Dadzie et al., 2018).

The physical and mechanical qualities of H. floribunda and N. papaverifera branch wood from Ghana's semi-deciduous forest zone are the subject of this research. This could provide stakeholders in the wood products manufacturing industry with more valuable information. The research could also promote the use of forest tree branch wood as a substitute for the tree's stem wood, supporting sustainable forestry and ensuring that future generations will have forest trees that meet their needs. Based on the outcomes of this study, manufacturers and producers will be able to decide which parts of the tree can be used in the future to substitute commonly used timber species.

Education RS232 digital electronic balance (with precision 0.001g) to obtain the initial mass (W₁). The samples were then soaked in water for 24 h to obtain the swollen volume (V₁) which was determined by the immersion method. According to Archimedes’ principle, the increase in the mass of water displaced by the submerged wood sample is numerically equal to the volume of water displaced. Afterward, the wood samples were oven-dried at 103 ± 2°C with intermittent weighing until constant mass, oven-dry mass (W₀) was attained (ASTM D 2395). The test was done under an ambient temperature condition of 20°C. The test duration was within 24 h. The basic density (BD) of the samples was then calculated from the formulae:

BD = W₀ / V_s                                                                                   (1)

Where W₀ = Oven-dried mass; V_s = Swollen volume.

The green moisture content (GMC) of the samples was then calculated from formulae:

Where W₁ = Initial mass; W₀ = Oven-dried mass 

The shrinkage and swelling values (radial and tangential) were calculated using standard methodology after measuring the dimensions of the specimens under green and oven-dry conditions (DIN 52184, 2005). The 3-point loading (that is, central loading) system on an 'Instron' Universal Testing Machine was used to perform static bending tests for the determination of modulus of elasticity (MOE) and modulus of rupture (MOR) (BS 373(1957)  requirements). According to BS 373 (1957) requirements, axial compression strength, shear strength parallel to the grain, and Janka hardness in the axial and transverse directions was measured. Heartwood and sapwood were well distinguished in N. papaverifera species; however, heartwood and sapwood were not clearly distinguished in H. floribunda species (Figure 1).

Data analyses

Using descriptive statistics, the data were numerically summarized. The findings of the various parameters determined are represented by the mean and standard deviation. The Single Factor Turkey Multiple Comparison Test was used to determine the statistical significance of each pair of means, as well as variance in quantitative physical and mechanical characteristics. To assess whether  the  two  treatment  pairs  were  significantly  different,  the Tukey HSD post-hoc tests were utilized.

The physical and mechanical properties of H. floribunda and N. papaverifera branch wood, as well as stem wood properties and available literature values, are presented in Table 2. It should be emphasized that the literature figures are unknown whether they apply to heartwood or sapwood. As a result, they can only make a relative comparison to the results of this study. H. floribunda 467.53 kg/m³ and N. papaverifera 720.80 kg/m³ had comparable density values (oven-dry), and H. floribunda shrinkage (radial 2.0%, tangential 3.8%) and N. papaverifera shrinkage (radial 1.8%, tangential 3.2%) were likewise equivalent to their stem wood qualities and literature values.

H. floribunda had an average MOE of 8213.83 N/mm² and N. papaverifera had an average MOE of 12902.80 N/mm², which is comparable to literature values. The average MOR value of N. papaverifera branch wood (122.28 2.18 N/mm²) compares favorably to most heavy construction species such as wawabima (127 N/mm²), essa  (104  N/mm²),  dahoma   (109 N/mm²),  and  Albizia (102 N/mm²) (Dadzie et al., 2018). The mean values (80.15 1.10 N/ mm²) obtained for H. floribunda branch wood were lower than those obtained for these heavy construction species but were comparable to some medium-class wood species such as ofram (Terminalia superba), iroko (Chlorophora spp), and emeri (Terminalia ivorensis), which can be used for medium to light constructional works.

H. floribunda branch wood had a compression strength of 36.93 N/mm² and N. papaverifera had a compression value of 53.14 N/mm². These values are comparable to Antwi's (2018) stem wood values. According to the ASTM D 143-83 standard (2008), practically all specimens showed an overall compression failure of the "shearing kind." The compressive strengths of N. papaverifera (53.14 N/mm²) and H. floribunda (36.93 N/mm²) have been classed as medium according to Olorunisola (2017) categorization.

Shear strength values obtained for N. papaverifera branch wood (16.54 0.60 N/mm²) compare favorably to those obtained for stem wood and most heavy construction species such as odum (Milicia exelsa) 14.10 N/mm², denya (Cyclidiscus gabunensis) 11.10 N/mm², dahoma (Piptadeniastrum africanum) 17.60 N/mm², asanfena  (Aningeria   altis)   (Desch   and   Dinwoodie, 2016). However, as compared to N. papaverifera trees, the shear strength values for H. floribunda branch wood (11.87 0.12 N/mm²) were lower but remained comparable to most known species appropriate for structural and non-structural uses.

Finally, the Janka hardness found to be 4.33 ± 0.14 N/mm² and 8.92 ± 0.21 N/mm² in the radial direction and 6.21 ± 0.43 N/mm² and 10.29 ± 0.37 N/mm² in the tangential direction for H. floribunda and N. papaverifera branch wood were comparable to the literature values reported by Antwi (2018) and Dadzie et al. (2018). The resistance of N. papaverifera to indentation was relatively high for branch portions and medium for H. floribunda.

N. papaverifera and H. floribunda branch wood were equivalent to its stem wood and other species. The shrinkage and swelling qualities of its stem wood and other species were comparable. In both species, the modulus of elasticity values of branch wood compares favorably to stem wood. Most heavy construction species, such as wawabima, essa, dahoma, and Albizia, have a lower modulus of rupture mean values than N. papaverifera. H. floribunda, on the other hand, has lower mean values than these heavy construction species, but it can still be used for light building. H. floribunda and N. papaverifera stem and branch shear resistance showed no significant differences, and the values obtained for N. papaverifera trees compare favorably to most heavy construction species such as odum (Milicia exelsa), denya (Cyclidiscus gabunensis), dahoma (Piptadeniastrum africanum), asanfena (Aningeria altissima), and H. floribunda (Terminalia ivorensis). The branch section of N. papaverifera had a high resistance to indentation, while H. floribunda had a medium resistance.

N. papaverifera branch wood is suitable for exterior and interior usage, even when untreated, due to its exceptional strength in resisting failure. For external usage, however, H. floribunda must be treated. The species (stem and branch wood) investigated have a high potential for industrial usage, and their qualities would be suited for a variety of wood-related applications.

The authors have not declared any conflict of interests.

The research project received no funding. Mr. Haruna and Mrs. Brigette Brentuo of Ghana's Forestry Research Institute provided technical help to the authors.