Studies on population genetics are the key to designing effective in situ management plans for tree species, in particular, those subjected to pressure from anthropogenic processes, such as forest fragmentation and logging. To investigate genetic diversity, inbreeding and intrapopulation spatial genetic structure (SGS) in a fragmented population of the insect-pollinated tropical tree, Esenbeckia leiocarpa, we developed specific microsatellite markers for this species and mapped and sampled 100 individuals in a forest plot. Two issues were addressed in particular: (i) the level of genetic diversity, inbreeding and effective population size, (ii) whether intrapopulation spatial genetic structure exists. Among the 14 loci developed, we only used the three that presented polymorphism to estimate the genetic parameters. Genetic diversity was low, whereby the average number of alleles per locus (A) was 3.3 and observed (H0) and expected heterozygosities (He) were 0.336 and 0.298, respectively. The average fixation index was significantly higher than zero (F = 0.112), suggesting inbreeding. Significant SGS was found up to 7 m and between 31 to 38 m, indicating that trees growing within these distances may be related. Estimates of the effective population size indicated that the 100 sampled trees correspond to 14 individuals that are neither related nor inbred. Our results suggest that the microsatellite markers developed in this study are suitable for studies on genetic
diversity and structure, mating systems, gene flow and SGS in this species.

The photosynthetic characteristics of Abies holophylla seedlings from six provenances under four artificial light intensities in a greenhouse (full light, 75.08%, 55.42%, and 30.38% of full light) were studied to explore the underlying genetic differences in foliar photosynthesis. Varying light intensities significantly affected the foliar photosynthetic parameters of A. holophylla seedlings from six provenances. As the light intensity dropped, the foliar CO2 assimilation capacity of A. holophylla seedlings sharply decreased, and the foliar light utilization capacity significantly increased. Analysis of genetic variation showed highly significant differences in terms of CO2 assimilation capacity, light utilization capacity, and respiration depletion of A. holophylla seedlings among different provenances under different light intensities. The variations were mainly controlled by the genetic factors of the provenance itself. The obtained results revealed that different sensitivities of A. holophylla seedlings from different provenances in response to changed light intensities elicited significant differences in foliar photosynthesis among different provenances. The relationships between sensitivities and annual temperature difference, mean temperature in January, and mean annual evaporation of provenance were found to be the most closely related, which indicated that temperature range and effective precipitation of provenance were the main factors that affected photosynthetic plasticity of A. holophylla seedlings. 

Natural establishment of forests in the Brazilian Pampa biome should occur due to soil, hydrology and climate conditions, although no significant forest expansion over grassland has been noticed, precluded mainly by human interference and lack of environmental management. In this study, we used niche-modeling distribution of the tree species Schinus molle L. based on climatic variables to access the vegetation dynamics of the Brazilian Pampa and to develop strategies that assure the conservation of this biome, concerning both grassland and forest formations. Here we show that a large area of the Brazilian Pampa is suitable for expansion of S. molle populations, supporting the forest expansion over grassland as a natural process in this biome. We propose that the current absence of tree species expansion over the grassland in these areas is a result of the resilience of the grassland and of human interferences through expansion of agriculture, ranching and forestry with exotic species. Therefore, conservationist actions should focus on establishing preservation unities that include forest populations and grassland, while environmental management should be applied just in farming areas with historical human interference. Such actions will respect the ecological dynamics of the Pampa and value the forest formations in this grassland-dominated environment.

The long-term effects of gap creation and liming on tree regeneration and understory competition were examined in a mature European beech (Fagus sylvatica) stand on a nutrient-poor site. In 1989, trees were felled to create four 30 m wide circular gaps, and 3 t ha-1 fine dolomite was applied to two of these gaps and the surrounding area, whereas the remaining two gaps and most parts of the stand remained untreated. In 2010, the stand density was 153 trees x ha-1 and the basal area was 29.51 m2 x ha-1. Testing a factorial combination of two levels of canopy cover (gap and stand) and two levels of lime application (limed and unlimed), the results of the case study partly support our initial hypothesis that the combined or single effects of liming and canopy removal on understory plant communities last for more than 20 years. Some effects disappeared slowly over time, while others did not. Understory vegetation of the unlimed gaps and the
limed and unlimed stands was rapidly dominated by beech regeneration, whereas limed gaps were dominated by fireweed (Epilobium angustifolium), bramble (Rubus fruticosus agg.) and raspberry (Rubus ideaus) for around 14 years. There, the density of the beech regeneration was reduced by competitive ground vegetation species. Plant species richness (n/100 m²) was still significantly different after 23 years, with an average 10 species per 100 m² in the limed stand area, 5 species in the unlimed stand area, 25 species in the limed gaps, and only 5 species in the unlimed gaps. Only the combination of liming and canopy removal enhanced the species richness in the long run. On our study site, this combination of liming and canopy opening had a long lasting influence on the ground vegetation in terms of retarding the beech regeneration and enhancing species’ richness.

Grid-based inventories of 1,924 deciduous forests plots in Germany and 4,775 in Romania were used to investigate tree species composition as affected by browsing and grazing under different forest management (rotation forestry, selectively cut forest, protected forest). At regional scale, the loss of tree species in the dominant layer was between 52 to 67% in Germany and of 10 to 30% in Romania, with largest effects in protected nature reserves in Germany. At plot level, only 50% (Germany) to 54% (Romania) of canopy species were found in the regeneration layer with a height of 1.5 m. Browsing was influenced by the proportion of Fagus in the regenerating trees in Germany, and by stand density, basal area, and management in both regions. Structural equation modeling explained 11 to 26% of the variance in species loss based on the fresh loss of the terminal bud in the winter prior to the inventory work (one season browsing). Browsing (and grazing in Romania) is shown to be a significant cause of species loss across both countries and all management types. Potential cascading effects on other organisms of deciduous forest ecosystems are discussed. We conclude that the present hunting practices that support overabundant ungulate populations constitute a major threat to the biodiversity of deciduous forests in Germany and Romania and to other places with similar ungulate management, and that changes my only be possible by modernizing the legal framework of hunting.

The availability of long-term land datasets is fundamental to ensure consistent and accurate national greenhouse gas inventories for land use and land use changes. Estimation of Romania’s CO2 removals and emissions over 1970-2010 was assessed comparatively by using National Statistics (as reference dataset), Corine Land Cover data, as well as four additional datasets produced from the reference dataset and assuming some forest data changes according to other available partial datasets (NFI,LUCAS or expert judgment). A spreadsheet, implementing a model of UNFCCC national greenhouse gas inventory, allowed estimation of both net CO2 removals and emissions and gross CO2 fluxes from all carbon pools, for all land subcategories over 1970-2010. The model was run for each dataset. The reference dataset resulted in an average annual gross flux of CO2, twice as large as the corresponding annual net removals of 13 TgCO2, while annual estimates were more than double in post-1990 compared to pre - 1990. Uncertainty of net annual CO2 removals by reference dataset was estimated around 31 %, slightly lower than for gross estimate, and just around 55% when based on CLC dataset. Overall, the contribution of 12 broad land sub-categories to CO2 inventory was similar in the national net and gross estimates, for both pre- and post-1990 periods. Land under conversion represented 9% of the country’s area in pre- and only 2% in post-1990, corresponding to an annual average of 28% of gross and 6% of net annual CO2 estimates. Among the choices of datasets tested, the reference dataset provided the most conservative estimates of the CO2 inventory. Other datasets generally overestimated annual LULUCF sink and its main contributor forestland, as well as the emissions or removals from land conversion. Compared to pre-1990, when annual sink was rather low, land abandonment and moderating management in the post-1990 period has led to an increase of C stock in all pools, showing the relevance of political changes on land’s CO2 emissions/removals. Inconsistency within available land datasets impairs more accurate estimation of national GHG inventory. The development of an improved land use assessment system around National Forest Inventory is therefore suggested as a solution to implement consistent land definitions and to accurately estimate their areas in time.

Processor tower yarders (PTY) represent the current state of yarding technology being extensively used in mountainous conditions such as those from Central Europe where they were also developed and used for the first time. In proper technical conditions which are mostly related to forest road infrastructure such equipment may be introduced by technology transfer in other countries such as Romania where they could replace actual less-efficient forest equipment used in steep terrains. The aim of this study was to evaluate the efficiency of such equipment in conditions of thinning operations by adapting a time study to the general concepts and by using data collection techniques to suit the operational conditions imposed by such equipment. In conditions of a mean tree volume of 0.21 m3 × tree-1, the results of our study indicate net production rates as high as 12.72 m3 × h-1 when processing trees on landing, which could be also improved up to 17.52 m3 × h-1 if the PTY have been be adequately installed on the forest road. Another key aspect which could improve the efficiency of such equipment performing landing operations is the number of planned and realized wood assortments since the time expenditure was affected by their number. Given the reduced impact on forest soils as well as the increased efficiency of tower yarders, our study concludes that there would be a lot of potential in actually using them in the Romanian forests located in steep terrain, if proper transportation infrastructure would exist.