# Characterization of Congolese Woody Biomass and Its Potential as a Bioenergy Source
## 1 Introduction  
There is an increasing need to identify renewable energy resources in the form of materials, chemicals, fuels, and energy. Biomass is considered the most abundant andaccessible renewable energy resource in most developing countries, contributing about 14% of the world's energy supply [1;2]. Woody biomass is particularly attractive for biofuel production because it does not create a \"food versus fuel\" conflict, unlike starch and vegetable oil-based feedstocks, which often divert agricultural land for fuel production [3]. Additionally, woody crops can be grown in agroforestry systems alongside food crops. These non-edible plant residues are also known as next-generation biofuel feedstocks or lignocellulosic biomass. \"Lignocellulosic\" refers to raw materials containing cellulose, hemicellulose, and lignin in varying compositions. On average, lignocellulosic makes up about 70% of plant cell walls and about half of the plant matter produced by photosynthesis, making it the most abundant renewable organic resource [4]. The annual global production of lignocellulosic biomass from terrestrial plants is about 17-20 \(\times\) 10\({}^{10}\) tonnes [5]. The Republic of Congo is largely covered by forest (80% of the national territory), representing 10% of all dense tropical rainforests [6]. This makes it a globally important carbon stock and a priority for biodiversity conservation. Lignocellulosic biomass includes agricultural and forestry residues and can be used as an energy feedstock. It can be converted into biofuels through three main routes: thermochemical, mechanical extraction, and biochemical processes. Estimates of biomass potential are usually obtained by measuring aboveground biomass (AGB) using an allometric equation, which translates measurements such as diameter at breast height (DBH) and total height into volume and wood biomass [7]. Biomass characterization is crucial for evaluating suitable feedstocks for bioenergy production. Common tools used include ultimate analysis to determine the proportions of carbon, hydrogen, nitrogen, sulfur, and oxygen; proximate analysis to determine moisture content, volatile matter, fixed carbon, and ash content [2]; and X-ray fluorescence (XRF) spectroscopy to determine metal and mineral contents. thermogravimetric analysis (TGA) is used to predict the thermal behavior of biomass during pyrolysis or combustion by determining the mass loss of the feedstock as a function of temperature under controlled heating rates and atmospheric conditions [8]. The physicochemical properties of lignocellulosic biomass have been extensively studied. [PERSON] et al. [9] reviewed properties such as particle size, grindability, density, flowability, moisture sorption, thermal properties, proximate analysis properties, elemental composition, energy content, chemical composition, and analytical characterization methods. They found that understanding these properties is key to designing effective thermochemical or biochemical processing methods, as they significantly influence process conversion performance. [PERSON] et al. [10] determined the chemical composition of lignocellulosic biomass in Abies religigosa wood across an altitudinal gradient using Van Soest gravimetric analysis and Fourier Transform Infrared (FTIR) spectroscopy. Their results showed cellulose content of 54.81 \(\pm\) 2.20%, hemicellulose of 12.37 \(\pm\) 1.33%, and insoluble lignin of 24.68 \(\pm\) 1.16%. [PERSON] et al. [11] studied forest biomass from chestnut coppice, maritime pine, poplar, and willow short rotation and found that biomass from maritime pine had a higher energetic value than poplar and willow clones and chestnut coppice, but also higher nitrogen and sulfur content. [PERSON], [PERSON] et al. [12] characterized biomass from wood chips of oak, birch, pine, and spruce to determine gasification and combustion properties. They concluded that moisture, calorific value, volatile content, and ash residue are the most important factors influencing these properties.