Rubber trees (Hevea brasiliensis (Willd.) Muell.Arg.) are cultivated for latex production, but they also produce timber for industry, and logging residues can be used for power generation. In this study, we determined the biomass of above- and below-ground tree compartments (leaves, branches <3 cm in diameter, branches 3–5 cm in diameter, stumps and roots) of 20-, 25-, and 30-year-old rubber tree plantations in Songkhla province, southern Thailand, at the clear-cutting stage. We also studied the nutrient content and heating value of the compartments. The total dry mass (including leaves, branches, stems and stumps and roots) of the mature rubber wood stands was 157–289 Mg ha⁻¹. The residual harvestable dry mass without leaves (39–68 Mg ha⁻¹, branches <5 cm in diameter, stumps and roots) comprised 25% of the total dry mass. Nutrient concentrations were highest in the leaves, followed by small branches. In most cases, the stems and larger branches had similar concentrations. One ton of rubber tree biomass (leaves and stumps and roots included) contained an average of 2.4 kg N, 0.2 kg P, 3.4 kg K, and 4.8 kg Ca. Depending on the biomass of the stands, the rubber trees had 380–700 kg, 36–64 kg, 530–980 kg, and 750–1360 kg of bound N, P, K, and Ca per hectare, respectively. The effective heating value of the stumps and roots was the lowest (17.65 MJ kg⁻¹). Stems and branches were similar (18.37–18.58 MJ kg⁻¹), and leaves were the highest (20.34 MJ kg⁻¹). The unharvested residual biomass in southern Thailand is a potential fuel source for power generation.

Forest roads provide access to logging sites and enable transportation of timber from forest to mills. Efficient forest management and forest industry are impossible without a proper forest road network. The bearing capacity of forest roads varies significantly by weather conditions and seasons since they are generally made of poor materials and the constructed layers may be mixed with subgrade. A bearing capacity assessment is valuable information when trafficability is uncertain and rutting is obvious. In this study, bearing capacity measurements were carried out using the light falling weight deflectometer (LFWD), the dynamic cone penetrometer (DCP) and the conventional falling weight deflectometer (FWD). The aim was to compare their measurement results in relation to road characteristics and moisture conditions. Data were collected from 35 test road sections in four consecutive springs and during one summer. The test road sections had measurement points both on the wheel path and the centre line. The data show logical correlations between measured quantities, and the study presents reliable regression models between measuring devices. The results indicate that light portable tools, the DCP and the LFWD, can in most cases be used instead of the expensive falling weight deflectometer on forest roads.

Occupational safety is generally known to be low in forestry work. A similar situation may be found in Southeast Asian countries, where health and safety aspects are not commonly taken care of so rigorously. However, there is also a lack of primary data which could be suitable for evaluating such issues. The auditing reports of FCS certification are a source of useful information to evaluate and analyze health and safety concerns in forestry work. This paper addressed the coverage of available information, classified the risk factors uniformly from different certifying body criteria, compared occurrence of risk factors in groups and checked for dependencies in data. The key findings are that the main issues were those related to the organizations’ failures to protect the workers and to the lack of awareness of safety. In turn, these may explain the high incidence of forestry-related work accidents in Southeast Asia.

The aim of this study was to determine the effect of leaching of heavy metals (Cr, As, Cd, Cu, Ni, Pb, Zn, Co, Mo) and earth-alkaline metal, barium (Ba), on the percolation and ditch water quality from the forest roads that contained ash in the road structures. Water quality was studied in the immediate vicinity below the ash layers as well as deeper in the road structure. Water quality was also determined in the drainage water in ditches that crossed the forest roads. A mixture of wood and peat based fly ash was used in the road structures. The treatments were: 1) no ash, 2) a 15 cm layer of ash/gravel mixture, 3) a 20 cm layer of ash/gravel mixture, 4) a 25 cm layer of ash, and 5) a 50 cm layer of ash. Large variation in the concentrations of Cr, As, Cu, Ni, Pb, Mo and Ba in the percolation water, even within the same treatment, caused difficulties to generalize the results. The concentrations of Cr, As, Ni, Pb, Mo and Ba in water samples were high in some treatment plot lysimeters containing ash compared to the control (no ash). On the other hand, many lysimeters had low and similar concentrations in water samples in the treatment plots containing ash compared to concentrations in the control plots. The ash in the roads did not affect the concentrations in the ditches. The leaching is uneven and seems to take place only from some parts of the ash layer. Risk for leaching is minimal if such parts are not widely spread.

Precise information on the origin of timber can be obtained by using an identifier system, which can help in preventing illegal logging, managing timber supply chains and increasing value adding. Radio frequency identification (RFID) is increasingly used in log-tracking systems. The RFID tags currently available on the market are not directly suitable for forestry applications, however, unless the tags are protected by a housing. Harsh working environments mean that tag housings must be robust in order to keep their valuable information safe throughout a logging operation. The aim of this study was to provide a testing method for use as a decision-making tool by RFID users. The study used five tests to evaluate the applicability of eight kinds of tag housing for forestry applications. The tests considered climatic aspects, mechanical stress, readability and survival in the field. The method was found to work well with tested tag housings, revealing their strengths and weaknesses. Using the testing method, a procedure is recommended to determine the most appropriate tag housing.