Moso bamboo forest (Phyllostachys heterocycla [Carr.] Mitford cv. Pubescens) is an important forest type in subtropical China and comprises an important pool in the global carbon cycle. Understanding the effects of the stand management, such as understory removal, on soil respiration (RS) will help to provide a more accurate estimation of carbon cycling and predict future climate change. The study aimed to compare RS and net ecosystem production (NEP) in two Moso bamboo forests managed by the application of herbicide (AH) and conventional hand-weeded (HW) treatment, and further examine their root carbon use efficiency (RCUE). Trenching and litter removal were used to partition the source components of RS and one-year field measurement was conducted. Maximum-minimum approach was used to estimate fine root production. NEP was determined by the balance between NPP of vegetation and heterotrophic respiration (RH) of soil. RCUE was calculated using an indirect method. In both stands, soil temperature and soil moisture at 5 cm depth were the main driving forces to the seasonality of RS. Annual RS was 31.6 t CO2 ha-1 for the stand AH and 33.9 t CO2 ha-1 for the stand HW, while net ecosystem production (NEP) were 21.9 and 21.1 t CO2 ha-1, respectively, indicating that the both Moso bamboo stands acted as carbon sinks in the scenarios of current climate change. The RCUE was 30.6% for the stand AH, which was significantly lower than that for the stand HW (58.8%). This result indicates that different stand management practices can alter RCUE and the assumed constant universal carbon use efficiency (CUE) of 50% is not appropriate in Moso bamboo forests. This study highlight the importance of partition the source components of RS and accurate estimation of RCUE in modelling carbon cycling in Moso bamboo forests.

This study was conducted to evaluate the variability of the chemical properties of the soil of an oak forest affected by defoliation and the corresponding microbial abundance. Soil samples were collected from a control zone (zone 1) without outbreaks of defoliating insects and from a sample zone (zone 2) where the trees were affected by Lymantria dispar L. defoliation. The research was conducted to determine the changed conditions for soil microorganisms produced as a consequence of defoliation. The results indicated, by means of analysis of variance (two-way ANOVA, P = 0.05), statistically significant differences (P < 0.0001) with respect to soil hydrolytic acidity, pH, ammonium nitrogen, heterotrophic bacteria, nitrogen fixing bacteria from genus Azotobacter and fungi. The data revealed a low number of heterotrophic bacteria and low pH values in samples taken from the area affected by defoliation. Soils under stands of defoliated trees showed higher values with respect to soil acidity, ammonium nitrogen, fungi and nitrogen fixing bacteria Azotobacter. Moreover, the soil moisture, nitrate nitrogen, organic matter content, organic carbon, the number of heterotrophic bacteria and the number of bacteria from genus Azotobacter exhibited statistically significant seasonal differences between the two zones studied. The correlations between the tested parameters showed that soil parameters such as moisture content, soil acidity, pH, organic matter content, organic carbon, total nitrogen and nitrate nitrogen are important factors influencing the soil populations of aerobic mesophilic heterotrophic bacteria, fungi and nitrogen fixing bacteria in the studied forest ecosystem.

Cultivation of energy crops is concerned with estimation of the total lignified biomass (dendromass) production, which is based on the plantation density and individual plant dendromass. The main objective of this study was to investigate the allometry of aboveground leafless biomass of juvenile black poplar hybrids (Populus deltoides x P. nigra ), traditionally used for timber and cellulose production, and to derive generic allometric models for dendromass prediction, relevant to energy crop cultivation in Bulgaria. The study material comprised a variety of growth sites, tree ages and clones, specific to poplar plantings in Bulgaria. We used three principal quantitative predictors: diameter at breast height, total tree height and mean stand (stock) height. The models were not differentiated by clone, because the black poplar hybrids tested were not equally represented in the data, and the inclusion of tree age as a predictor variable seemed unreliable, because of the significant, up to 3 years, variation, which was possible within the narrow age range investigated. We defined the mean stand (stock) height as a composite quantitative variable, which reflected the interaction between the time since planting (age), site quality and the intrinsic growth potential. Stepwise and backward multiple regression analyses were applied to these quantitative variables and their products and sets of adequacy and goodnessof-fit criteria were used to derive individual biomass models for stem and branches. Then we developed compatible additive systems of models for stem, branch and total lignified biomass in log-transformed form. Finally, the prediction data were back-transformed, applying correction for bias, and were cross-validated. Three systems of generic equations were derived to enable flexible model implementation. Equation system M1 proposes a stem biomass model based on tree and stand heights and stem diameter, and a model for branches including mean stand height and breast height diameter; this model displayed the best goodness-of-fit characteristics. Model system M2 uses only the tree height and diameter and therefore is most relevant to dendromass determination in single trees or harvested saplings, while model M3 allows fast and sufficiently accurate biomass estimation of standing  poplar stock, because it employs the average stand height and the individual tree diameters. All models are applicable to predict lignified aboveground biomass of juvenile Populus deltoides x P. nigra trees of diameter up to 21 cm and total height up to 16 m.

The aim of this paper was to validate factors affecting the in-stand landscape quality and how important each factor was in determining scenic beauty of natural secondary forests. The study was limited to 23 stand-level cases of natural secondary forests in Shen Zhen city in southern China. Typical samples of photographs and public estimations were applied to evaluate scenic beauty inside the natural secondary forests. The major factors were then selected by multiple linear-regression analysis and a model between scenic beauty estimation (SBE) values and in-stand landscape features was established. Rise in crown density, fall in plant litter, glow in color of trunk, fall in arbor richness, and rise in visible distance increased scenic beauty values of in-stand landscape. These five factors significantly explained the differences in scenic beauty, and together accounted for 45% of total variance in SBEs. Personal factors (e.g. gender, age and education) did not significantly affect the ratings of landscape photos, although variations of landscape quality were affected by some personal factors. Results of this study will assist policymakers, silviculturists and planners in landscape design and management of natural secondary forests in Shenzhen city. People can improve the scenic beauty values by pruning branches and clearing plant litter, which subsequently improve the forest health and contribute to forest recreation.

A simulation system, based on pre-existing models, was used to investigate and visualize the solution space for optimizing forest management planning. The simulation system used existing forestry profits estimation models to test the outcomes of different crop rotations by previous studies. The simulation enabled us to predict forestry profits and labor requirements under different forestry management plans, and to examine the consequences for harvesting strategies. A part of the Kyushu region was selected as the study site, because the basic sub-models for predicting timber production, labor requirements and forestry profits were developed in the area. This study has investigated and visualized the solution space optimized for forest economics using various combinations of short and long rotation silvicultural practices implemented at a local scale. Based on the simulations, optimization of the plans was formulated under the forestry scale of compartment and total level. Visualizing the 3-dimensional optimized solution space by using a simulation system is useful for decision-makers involved with local forest management planning. The differences of forestry profits, labor requirements and timber volume depending on the intensity of silvicultural practices were analyzed. The simulation system is also useful for sustainable forest management under the Japanese forestry planning system.

Biomass rail transport is a useful alternative to unimodal truck transport for medium or long transport distances, if only a short road pre-haulage is required. Up to now primary forest fuels (PFF) are rarely transported on the rail network in Austria and rail terminals able to tranship notable volumes are not established yet. The objective of this study is to investigate the potentials of existing transhipment infrastructure for introducing and operating PFF terminals. Such PFF terminals enable a regular PFF supply to bioenergy plants and additionally provide opportunities for buffer storage and production processes like comminution. Three existing railway sidings in South, Central and Western Austria were chosen to serve as a multimodal transhipment hub with a road pre-haulage and a rail main-haulage for this case study. The logistic potential of these terminals was investigated, modelling the specific PFF supply chains, by means of a discrete event simulation. Simulation results provide daily and annual transhipment capacities and revealed bottlenecks in the terminal layout under different supply scenarios.