Predicting future yields normally requires an estimate of site quality.  A commonly used measure is site index (SI). SI is often incorrectly quantified operationally due to the ambiguity associated with selecting “site” trees.  Plus, error in the measurement of height itself occurs.  This study quantifies the impacts on the number and timing of thinnings, and the final harvest ages, as well as financial returns when incorrectly determining SI.  Three values of SI (base age 25 years) were examined using two older generation loblolly pine plantation growth and yield simulation models from the Western Gulf, USA; 16.76 m, 21.34 m, and 25.91 m.  Firstly, a particular SI was assumed to be the “true” value, growth and yield estimates were obtained, and financial assessments were conducted.  The same process was then conducted again, but assuming that the SI was incorrectly determined by varying positively and negatively the SI by up to 1.22 m from the assumed “true” value. For these older generation plantations, incorrectly determining SI did impact the age of the first thinning by as much as 5 years.  In some cases, errors of +/- 1.22 m in SI estimation had little impact on the estimated timing of the first thinning.  Errors in SI of up to +/- 1.22 m had little impact on the number of thinnings across economic rotation ages. For both unthinned and twice-thinned stands, final harvest (clearcut) ages differed by as much as 4 years for SI errors up to +/- 1.22 m.  These errors led to differences in Land Expectation Value (LEV) up to $406.50 ha-1.  Across the three SI (16.76, 21.34, and 25.91 m), differences in LEV ranged from $237.49 to $406.50 ha-1.  These differences in LEV could be enough to incorrectly not conduct, or incorrectly conduct, a silvicultural operation such as an herbicide treatment or a fertilization treatment across a rotation, among other treatments.

The paper presents the study on the condition and structural stability of European beech (Fagus sylvatica L.) stands after the 2014 ice storm disturbance. The research was conducted in three pure beech stands on the Rtanj mountain in eastern Serbia. The stand condition after the ice storm was analyzed using changes in taxation elements. The assessment of tree damage was done according to the ICP Forests methodology, while the structural stability of the stands and individual trees was analyzed using the slenderness coefficient. The obtained results indicate very heterogeneous responses of beech stands to the negative impact of the ice storm. Heterogeneity is not only expressed between stands but also within individual stands. The stands after the ice storm are characterized by significantly reduced values of production indicators, but also by satisfactory stability, considering that the trees from the understory suffered the most. Statistically significant differences in the stability of trees of different dimensions expressed through the slenderness coefficient were determined. Consequently, the stands have maintained an appropriate level of stability thanks to the survival and resistance of the dominant trees that are the bearers of functions in these stands (trees with dbh > 40 cm). This indicates the great potential of silvicultural treatments that can increase the stability and resistance of stands in areas with a high risk of such phenomena. In addition, repressive action in the form of salvage logging has a very important role with the aim of ensuring the continuity of stands after damage has occurred.

The study assessed the carbon sequestration of Tectona grandis Linn. F. in five age series (11-15 years old), at the University of Ilorin, north-central Nigeria. Data were collected using a stratified sampling technique and twenty square plots of 25 m × 25 m were laid. A non-destructive method was used to determine the biomass of the trees. Tree enumerations were carried out for diameters at the base, top, middle, diameter at breast height (DBH), and height. Soil samples at two different depths (0-15 cm and 15-30 cm) were collected and analyzed to obtain soil organic carbon. The results were summarized using descriptive statistics, while the relationship between tree growth variables and carbon stock was assessed using correlation and regression analysis. The results showed that tree carbon stocks were 230.05 t ha-1, 362.35 t ha-1, 277.48 t ha-1, 216.40 t ha-1, and 126.20 t ha-1 for 11 years old (2012), 12 years old (2011), 13 years old (2010), 14 years old (2009) and 15 years old (2008) age series, respectively. The soil organic carbon stocks were 1.1025 t ha-1, 0.6253 t ha-1, 1.2019 t ha-1, 1.4070 t ha-1 and 0.7615 t ha-1 for 11 years old (2012), 12 years old (2011), 13 years old (2010), 14 years old (2009) and 15 years old (2008) age series, respectively. The study also revealed that the 14-year-old (2009) age series had the highest carbon stock, and the total carbon stock estimate was 151,850.84 t. The potential cash value of the carbon stock was also estimated at $91,894.40 t C ha-1 and the total PCV was $56,606,951.50. Correlation analysis showed a strong positive correlation between most of the growth variables and carbon stock. The regression equation (Y = -596.48 + 27.16 THT + 1238.34 DBH, Adj R2 = 82.7%) showed that DBH and height of trees are suitable for evaluating the carbon stock in the study area.

This study combines research on soil physical and chemical properties as affected by four Eucalyptus species in Ruhande arboretum. The soil samples for research properties were taken from 0-20 cm depth using auger and one undisturbed core from each sampling unit was taken for the analysis of soil bulk density. Soil bulk density and moisture did not differ significantly between all treatments. Sand proportions differed significantly only between E. tereticornis and E. maidenii whereas silt and clay were non-significant. The soil under Eucalyptus was sandy, with sand proportion ranging from 66.4-71%. Bulk density increased with increasing sand whereas moisture content showed a reverse trend. The soil samples for studying chemical properties were taken as described in Nsabimana et al. 2008. All chemical parameters except base saturation differed significantly between treatments. Soil pH was strongly acidic but rich in total nitrogen and organic carbon which was attributed to higher litter production, its relatively faster rate of decomposition, and greater amount of residues produced by the eucalypts. Carbon/nitrogen ratio, CEC, and BS were high under all treatments while the available phosphorus was lower which was attributed to the low pH. Future studies should test if the species similarly affect the soil or not and confirm if the species increase soil nutrients. Benchmarked study sites should be used to enable differences in the species effects on the site if any.

Lowland pedunculate oak forests in the alluvium of the river Sava are of a great economic and ecological importance. Their growth and development features, and their survival, as well, mostly depend on soil moisture and available water. The paper deals with the influence of groundwater level on pedunculate oak forests condition in flooded area of Donji Srem. During four-year long research, the average (reference) groundwater level was determined, and extremes, the wettest and the driest year, were determined based on climate factors such as temperature and rainfalls. Deviation of the average from the reference groundwater level in the vegetation period during some years indicates possibility of risk zones presence. These zones are defined according to geostatistical analysis – ArcGIS, Kriging model and they are very significant for forestry practice, because they can predict some drought events and warn forestry experts to react in time in order to prevent big damages. Bearing in mind that investigated area is flooded, and that groundwater level is close to the soil surface, these anaerobic site conditions are obviously more suitable for another hygrophilous species than for pedunculate oak.

Zinc deficiencies are rare in pine seedlings with less than five documented cases in bareroot nurseries. One temporary deficiency occurred after soil was land-leveled (i.e., topsoil removed) and another occurred on a peat soil after more than 2,200 kg of agricultural lime was applied before sowing. Farmers also observe zinc deficiencies on (1) over-limed areas and (2) where Zn-demanding crops are grown on areas where topsoil was removed during land leveling. Since ZnSO4 is a naturally occurring pesticide, sometimes height growth increases are due to pest control. In pathogen-rich soils, pine growth may be improved more by the fungicidal effect than by a growth benefit from added sulphur and zinc. As a result, a pseudo-deficient response is possible when growth of non-deficient seedlings increases after treatment with large amounts of ZnSO4 or ZnCl2. In some trials, claims of a Zn deficiency have been made without supporting evidence from foliar tests or from tests using pathogen-free soil. Although fertilization with Zn increased seedling growth at pine nurseries in New Zealand, India, Russia, and Wisconsin, only at the Sweetwater Nursery in New Zealand did foliar tests prove a Zn deficiency.