Species diversity and litter dynamics in secondary mixed deciduous forest, Thung Salaeng Lung National Park, Northern, Thailand

This study present species composition and potential of litter on carbon and nitrogen return in secondary mixed deciduous forest after shifting cultivation. The dominant species of trees were Haldina cordifolia, Albizia odoratissima and Lagerstroemia duperreana. The Important Value Index (IVI) values of trees were 132.91, 17.78 and 14.22, respectively. The pattern for the decomposition coefficients (k) was highest in the wet period (May–September) and lowest in the dry period (October–April). The carbon and nitrogen return patterns increased in the dry period (October– April) and decreased in the wet period (May–September). Carbon and nitrogen loss in the decomposing litter continually decreased during the decomposition process from the initial levels, with a final relatively rapid release in the wet period. Results from this study was understanding of community composition, litterfall production and litter decomposition for understanding potential of secondary mixed deciduous forest for balancing carbon for mitigating greenhouse gas effect in the local area

Impacts of Small-Scale Mechanized Logging Equipment on Soil Compaction in Forests

The present study focuses on assessing the effects of different numbers of skidders on soil compaction. To assess the skidding effects, four-wheeled small-scale logging equipment attached to an ATV (Automated Transfer Vehicle) was used. Skidding operations were carried out on undistributed forest corridor (20 × 3 m).To measure soil compaction, 11 measurement lines were used, spaced at 2-m intervals. A total of 33 measurement points were used to measure soil compaction. Soil compaction values were measured for different soil depths with 5 cm intervals in the 0–40 cm range as MpA. The results were evaluated for the skidding zone and the wheel zone. Prior to skidding, soil compactions at 0 cm (top soil) is almost 2.5–3 times lower than those at the other depths. The p values indicate that the numbers of passes and the compaction values belong to nonidentical groups. The Bonferroni method was used to determine whether the compaction values are similar. The Dunn test results demonstrate that there were statistically significant differences between the mean values of the number of passes up to the 60th pass. However, there are no statistically significant differences between the means of the compaction values occurring between 60 and 80 and 100 and 120 passes. Generally, soil compaction is expressed as an increase in the soil bulk density. Soil bulk density and soil porosity are negatively correlated. It was found that for each of the zones, soil compaction values between the depths of 15 cm and 40 cm are approximately 4 times higher than at the 0 cm soil depth. Soil compaction values increased 3 times at the depths of between 0 cm and 5 cm. The average soil compactions values in the skidding zone are approximately 1.5 times higher than those at the wheel zones at the depth greater than 5 cm. The use of different skid trails will decrease soil compaction of the forest stand, provide uniformity of soil compactions in forest stand. © 2020, Sociedad Chilena de la Ciencia del Suelo