This paper reviews the development of the Chinese wood products development in the last 10 years, besides offering an overview about its forestry and specific export and import markets for the commodities, encompassing sawn wood and wood-based components. In the last decades, China’s forestry and wood industry encountered an accelerated development. This progress resulted in China’s emergence as the largest player not only in the global wooden raw materials, but also in the wood products market, and has become the largest exporter of value-added wood products. Since 2000, China has introduced modern industrial equipment for the forest products manufacturing and consolidated its trade marketing. It is likewise the largest importer of unprocessed or semi-processed soft-, hard- and tropical wood species. Moreover, China itself developed over the past 10 years into the largest importer of logs worldwide, a position traditionally held by the USA. Its imports are decreasing nowadays due to increasing restrictions imposed on wood exports by other countries. The national consumption of wood-based panel products in China increased steadily due to the higher purchasing power that determined a quick development of the furniture, flooring and construction industry. China is the largest producer of medium density fiberboard/high density fiberboard, plywood and particleboard, as well as container floors and wooden pallets; furthermore, one of the world’s largest user and especially important producer of pellets. China has been the leading exporter of wooden furniture since 2004, overtaking the traditional European exporters.

Walnut and hazelnut shells are agricultural by-products, available in high quantities during the harvest season. The potential of using these two agricultural residues as raw materials in particleboard production has been evaluated in this study. Different panels with either walnut or hazelnut shells in combination with melamine-urea formaldehyde or polyurethane at the same level of 1000 kg/m³ density were produced in a laboratory hot press and mechanical properties (modulus of elasticity, bending strength, and Brinell hardness) and physical properties (thickness swelling and water absorption) were determined, together with formaldehyde content. Although Brinell hardness was 35% to 65% higher for the nutshell-based panels, bending strength and modulus of elasticity were 40% to 50% lower for the melamine-urea formaldehyde bonded nutshells compared to spruce particleboards, but was 65% higher in the case of using polyurethane. Water absorption and thickness swelling could be reduced significantly for the nutshell-based boards compared to the spruce boards (the values recorded ranged between 58% to 87% lower as for the particleboards). Using polyurethane as an adhesive has benefits for water uptake and thickness swelling and also for bending strength and modulus of elasticity. The free formaldehyde content of the lignocellulosic-based panels was included in the E0 category (≤2.5 mg/100 g) for both walnut and hazelnut shell raw materials and the use of polyurethane improved these values to super E0 category (≤1.5 mg/100 g).

The objective of this study was to investigate the sound absorption coefficient of bark-based insulation panels made of softwood barks Spruce (Picea abies (L.) H. Karst.) and Larch (Larix decidua Mill.) by means of impedance tube, with a frequency range between 125 and 4000 Hz. The highest efficiency of sound absorption was recorded for spruce bark-based insulation boards bonded with urea-formaldehyde resin, at a level of 1000 and 2000 Hz. The potential of noise reduction of larch bark-based panels glued with tannin-based adhesive covers the same frequency interval. The experimental results show that softwood bark, an underrated material, can substitute expensive materials that involve more grey energy in sound insulation applications. Compared with wood-based composites, the engineered spruce bark (with coarse-grained and fine-grained particles) can absorb the sound even better than MDF, particleboard or OSB. Therefore, the sound absorption coefficient values strengthen the application of insulation panels based on tree bark as structural elements for the noise reduction in residential buildings, and concurrently they open the new ways for a deeper research in this field.

Tree bark is a by-product of the timber industry available in large amounts, considering that approximately 10% of the volume of a tree stem is bark. Bark is used primarily for low-value applications such as heat generation or as mulch. To the best of our knowledge, this study is the first one that scrutinises thermal insulation panels made from spruce bark fibres with different densities and fibre lengths manufactured in a wet process. The insulation boards with densities between 160 and 300 kg/m³ were self-bonded. Internal bond, thermal conductivity, and dimensional stability (thickness swelling and water absorption), together with formaldehyde content, were analysed. The thermal properties of the boards were directly correlated with the density and reached about 0.044 W/m*K, while the internal bond was rather influenced by the fibre length and was relatively low (on average 0.07 N/mm²). The water absorption was high (from 55% to 380%), while the thickness swelling remained moderate (up to 23%). The results of this study have shown that widely available bark residues can be successfully utilised as an innovative raw material for efficient eco-friendly thermal insulation products.

Ecofriendly wood-based materials are required by consumers at present. Decorative panels are part of a large group of wood-composite materials, and their environmental properties must not be neglected. More environmentally friendly decorative panels can be achieved by various methods. This paper describes a method of production from larch bark. Tree bark, as a byproduct of the wood industry, is one of the research topics that have gained interest in the last decade, especially for its applications in biobased lignocomposites, with regard to the shrinkage of wood resources. In the present work, the formaldehyde content of decorative boards based on larch bark (0.6 g/cm³) was analyzed when bonded with five different types of adhesive systems: urea-formaldehyde, polyvinyl acetate, the mixture of 70% urea-formaldehyde + 30% polyvinyl acetate, polyurethane, and tannin-based adhesive. A self-agglomerated board was also analyzed. The formaldehyde content of the larch-bark samples was determined with the perforator method (EN 120:2011), and findings showed that all tested samples reached the E1 classification (≤8 mg/100 oven dry). Moreover, 75% of the values of the corrected formaldehyde content were included in the super-E0 class (≤1.5 mg/100 oven dry). In the case of boards bonded with tannin-based adhesive, this natural polymer acted as a formaldehyde scavenger.

Tree bark is a byproduct of the timber industry which accrues in large amounts, because approximately 10% of the volume a log is bark. Bark is used primarily for low-value applications such as fuel or as a soil covering material in agriculture. Within the present study, thermal insulation panels made from larch, pine, spruce, fir and oak tree bark with different resins (urea formaldehyde, melamine formaldehyde, Quebracho, Mimosa) as a binder are discussed. Also, the properties of panels made from larch bark mixed with industrial popcorn are investigated. The physical-mechanical properties of the panels, which are dependent on panel density, bark species, resin type, resin content and particle size, are analyzed. The bark species has a minor effect on the mechanical characteristics of the panels, while the compression ratio is important for the panel strength, and hence, barks with lower bulk density are preferable. Under laboratory conditions, panels made with green tannin resins proved to have adequate properties for practical use. The addition of popcorn is a means to lower the panel density, but the water absorption of such panels is comparably high. The bark type has a minor effect on the thermal conductivity of the panels; rather, this parameter is predominantly affected by the panel density.