The organic carbon stock (SOC) (t/ha) was calculated in different approaches in order to enhance the differences among methods and their utility regarding specific studies. Using data obtained in Romania (2000-2012) from 4,500 profiles and 9,523 soil horizons, the organic carbon stock was calculated for the main forest soils (18 types) using three different methods: 1) on pedogenetical horizons, by soil bulk density and depth class/horizon thickness; 2) by soil type and standard depths; 3) using regression equations between the quantity of organic C and harvesting depths. Even though the same data were used, the differences between the values of C stock obtained from the three methods were relatively high. The first method led to an overvaluation of the C stock. The differences between methods 1 and 2 were high (and reached 33% for andosol), while the differences between methods 2 and 3 were smaller (a maximum of 23% for rendzic leptosol). The differences between methods 2 and 3 were significantly lower especially for andosol, arenosol and vertisol. A thorough analysis of all three methods concluded that the best method to evaluate the organic C stock was to distribute the obtained values on the following standard depths: 0 - 10 cm; 10 - 20 cm; 20 - 40 cm; > 40 cm. For each soil type, a correlation between the quantity of organic C and the sample harvesting depth was also established. These correlations were significant for all types of soil; however, lower correlation coefficients were registered for rendzic leptosol, haplic podzol and fluvisol.

Forest soils belong to the major carbon sinks on Earth because of their high organic matter content. Forest soils from Europe store approximately 1.5 times more carbon than trees (EC/UN-ECE 2003). As dystric cambisol (2,292,385 ha) and eutric cambisol (869,909 ha) are the most widespread forest soils in Romania, we studied 5958 dystric cambisol pedogenetic horizons and 6784 eutric cambisol pedogenetic horizons. A series of correlations was made between soil organic matter and elevation, but also with tree age and stand production class. The differences between stratified soil organic matter in terms of slope aspect categories were tested, and multiple linear regression was used to determine the influences of some relief (elevation) and stand (age) characteristics on the soil organic matter content. Overall, the soil organic matter content increased with increasing elevation. Based on all 12,742 soil samples over a period of 33 years, the soil organic matter content is influenced by elevation and tree age, especially on shaded and partially shaded slope aspects.

Cities are affected by the impact of rapid urbanization on changes to soil properties. The aim of this study was to assess the physical and chemical properties of the soil of urban and peri-urban forests and to define which soil property is more significant for these two types of forests. The research took place in urban and peri-urban forests in the metropolitan area of Brasov, Romania. Among the properties determined were: particle size distribution, reaction, soil organic matter content, and the base saturation degree. As supplementary data, for plots from urban forests, the heavy metal content was determined. The results revealed that soils from urban forests had an alkaline reaction and the ones from peri-urban forests had a moderately acid reaction. The soil from the peri-urban plots was sandier and the other ones were more clayey. Testing the differences between the forests led to significant differences in the case of seven properties of which we mentioned pH and sand and clay content. Using PCA, the most significant and important soil properties for urban forests were the sum of basic exchangeable cations, cation exchange capacity, soil organic matter, and silt and clay contents. This study is more relevant in light of the EU Soil Strategy, which sets out a framework and concrete measures to protect and restore soils.

The climate has changed significantly over the past few decades around the globe. To make meaningful comparisons between changes occurring over time in the tree world, comprehensive databases on the most important species and their evolution must be created. It is essential to consider latitude, longitude, altitude and local relief when analyzing data. Given the extensive distribution of oak, hornbeam and ash, a sequence analysis was conducted to definitively examine the characteristics of these species in West Plain, West Hills, Apuseni Mountains and Transylvania's Tableland. The data for all the regions comprised a total of 708511 ha, which were subjected to rigorous analysis to determine characteristics such as yield class, volume, increment, structure and participation percentage. The data was analyzed using the most appropriate modern statistical programs, including correlation matrices, ANOVA, principal component analysis, matrix data analysis and the cluster method. In relation to the altitudinal variation, oak is present at average altitudes of 200–250 m in West Plain, 400–500 m in West Hills and Transylvania's Tableland, and 900–950 m in Apuseni Mountains. Hornbeam has a similar spreading with oak, but records its presence in slightly higher altitudes of West Hills (400–700 m) and lower in Apuseni Mountains (700–750 m). Volume is also an important indicator, as it is susceptible to climate change. Oak has the highest age-volume, over 95 years, while ash and hornbeam have it less than 90 years. The results are crucial for understanding the ecological requirements of oak, hornbeam and ash, as well as for effectively managing these forests.

The organic carbon stock (SOC) (t/ha) was calculated in different approaches in order to enhance the differences among methods and their utility regarding specific studies. Using data obtained in Romania (2000-2012) from 4,500 profiles and 9,523 soil horizons, the organic carbon stock was calculated for the main forest soils (18 types) using three different methods: 1) on pedogenetical horizons, by soil bulk density and depth class/horizon thickness; 2) by soil type and standard depths; 3) using regression equations between the quantity of organic C and harvesting depths. Even though the same data were used, the differences between the values of C stock obtained from the three methods were relatively high. The first method led to an overvaluation of the C stock. The differences between methods 1 and 2 were high (and reached 33% for andosol), while the differences between methods 2 and 3 were smaller (a maximum of 23% for rendzic leptosol). The differences between methods 2 and 3 were significantly lower especially for andosol, arenosol and vertisol. A thorough analysis of all three methods concluded that the best method to evaluate the organic C stock was to distribute the obtained values on the following standard depths: 0 - 10 cm; 10 - 20 cm; 20 - 40 cm; > 40 cm. For each soil type, a correlation between the quantity of organic C and the sample harvesting depth was also established. These correlations were significant for all types of soil; however, lower correlation coefficients were registered for rendzic leptosol, haplic podzol and fluvisol.