Facilitation is a positive interaction demonstrated to be one of the important factors shaping the regeneration niche of trees, mostly under stressful conditions which is currently studied in the frame of complex ecological networks. The protection provided by benefactor plants for tree seedlings playing the role of beneficiaries is documented mainly in arid and semi-arid habitats or in situations where herbivores’ pressure constitutes the main stressful factor for tree regeneration. One of the iconic Transylvanian landscapes is the wood-pasture, also one of the oldest agro-forestry systems to which recent forest expansion in abandoned agricultural fields or pastures is added. The proposed work represents a preliminary investigation on the association between benefactor plants, mostly spiny shrubs (Rosa canina, Crataegus monogyna, Prunus spinosa as the most frequently encountered benefactors) and tree seedlings (Quercus spp., Tilia spp., Carpinus betulus, Fraxinus angustifolia, Pyrus pyraster as most frequently encountered beneficiaries), in four different locations from North-Western and Western Romania, wood-pastures, abandoned pastures and abandoned agricultural fields under the consideration that the main stressful factor is represented by livestock grazing. Bipartite, qualitative merged network was generated depicting the interaction between beneficiaries and benefactors. Commonly used metrics were calculated: connectivity, nestedness, modularity, betweenness centrality and centralization compared to similar facilitation networks presented in the literature. Facilitation network is characterized by high nestedness (N=0.896), lack of modularity, relatively high connectance (C=0.233), features encountered in mutualistic networks also. Betweenness centrality scores highlighted the keystone benefactor and beneficiary species, while betweenness centralization score (0.192) indicates the fact that there are several species sharing the dominant position in terms of interactions. The analysis of measurement data (seedlings’ and benefactor plants’ heights, distance from focal seedlings to nearest benefactor species and orientation) showed that there is common pattern in orientation (most of the benefactor species oriented toward South or South West) also in dimensional variability (MANOVA results).

Despite the importance of forests and trees, Senegal is facing to the loss of forests and the decline of tree diversity and density. This study focuses on Moringa oleifera Lam., Acacia mellifera (Vahl) Benth. and Zizyphus mauritiana Lam. which constitute a significant source of food and economic value for the populations of Casamance. In addition to a germination test, a follow-up of seedlings on different substrates was carried out in the nursery, in order to determine the effect of substrates on some growth parameters (number of leaves, height, diameter and biomass).The substrates used were three potting mixtures of forest soil of Faidherbia albida (FSFA), Elaeis guineensis (FSEG) and Anacardium occidentale (FSAO) and sand with the following proportion: 1/3 sand + 2/3 forest soil). Based on species, the germination rate was higher for A. mellifera (84%) followed by M.oleifera (55%) and Z. mauritiana (50%). The germination rate was more important in FSFA and FSEG than in FSAO. For growth parameters, there was a significant effect (P<0.05) of substrate type on height, diameter, number of leaves and root biomass. In term of growth parameters, the seedling performed better in FSFA and FSEG than in FSAO. The species effect was also significant (P<0.05) with higher root biomass and diameter found in M. oleifera and height and number of leaves in A. mellifera. The most important total biomass was found in FSFA followed by FSEG. Comparing the fraction of biomass according to the part of the seedling, the stem and branch had the higher fraction of biomass for A. mellifera (43%) and M. oleifera (38%) and the leaves for Z. mauritiana (46%).However, thetype of substrate can affect seedling development and growth parameters and the better results were recorded in FSFA and FSEG substrates.

Arbuscular mycorrhizal fungi (AMF) play a significant role for mine tailing rehabilitation due to their sensitivity towards a range of soil pollutants. This beneficial biological agent can enhance plant tolerance to heavy metal contamination. This study screened indigenous AMF associated with growing indigenous ferns and grasses in the mine tailings for potential use in rehabilitating a 3-decade abandoned mined out area in Mogpog, Marinduque. Pterocarpus indicus Willd. (narra) was used as the host plant to establish mycorrhizal fungi association. Among the treatments, indigenous AMF associated with Ferns 1, 2 and 5 generally improved the height and shoot diameter of the narra seedlings and the effect was comparable with commercially available AMF inoculants, MYKOVAM® and MYKORICH®. The dry weight of the roots and nodules was consistently improved by indigenous AMF from Fern2 and Grass1, which had comparable effect with MYKOVAM® and MYKORICH®. Overall, the total seedling dry matter of narra seedlings was significantly stimulated by AMF, irrespective of isolates’ origin. The mycorrhizal root infection by AMF and number of spores in the soil were all high as compared with the uninoculated control counterpart. Lastly, AMF inoculation induced Cu retention in the roots of the seedlings. Thus the results imply that, the mined out indigenous AMF are potential agents to rehabilitate the abandoned mine tailings in the Philippines.

Preserving forest legacy was an important objective throughout Romanian history and so is today. Artificial forest regeneration (including both reforestation and afforestation) was widely used to ensure the forest continuity, following forest harvesting, or to create new forests on non-forest lands. As Romania has undergone various political changes that affected the socio-economic environment, these changes also left significant marks on forest cover dynamics. In this paper, we chronologically present the historical initiatives to preserve and increase forest cover in Romania, the current practices, available funding and future perspectives on artificial forest regeneration. Increasing forest cover from the current level of 27% to, and beyond European average of 33% seems an ambitious target for Romania. However, that may be achievable if the sources of funding for afforestation would diversify and increase, the available funds would be more effectively accessed, national forestry regulations would be less bureaucratic and the guidelines on artificial forest regeneration would be up to date and less restrictive. The whole framework of forestation should be revised to comply with recent social, economic and environmental realities, and modern criteria and indicators for sustainable forest management should be explicitly included. The new goals should also be tailored to the changes regarding the property type, climate related trends and new requirements of the forest certification systems.

The historical development of afforestations in Bulgaria was investigated. Some of the more important decisions and events which determine the correct state policy in the field of afforestations are pointed out. The most significant achievements are in: erosion control, incl. water tank protection from silting up; increasing the tree volume and forest growth; protection of agriculture via forest protection belts; landscape improving. The social importance for more employment and improvement of means of livelihood is mentioned. Proved reasons for decreasing the afforested areas since 1980s are given. The main mistakes and problems are mentioned as well as the changes in the afforestation policy and future challenges.

The experiments were led to study the effect of pretreatments and their duration on germination behavior of three Acacia species A. cyanophylla Lindl., A. farnesiana L. and A. decurrens Willd. by analyzing three parameters (GP: germination percentage; MGT: germination mean time (days) and GRI: germination rate index) for various times of incubation (5, 10 and 15 days) in Petri dishes. Pre-sowing treatment included immersion in concentrated sulphuric acid for 60, 90 and 120 minutes. The sowing in distilled water (Control) had no positive effect on the germination induction. Generally, the seed pretreatments were very useful to improve germination. Time of immersion significantly (P < 0.0001) affected GP, MGT and GRI in all species. Increasing the duration of sulphuric acid immersion (from 60 to 120 min) improved the germination percentages for A. cyanophylla and A. farnesiana seeds to (98% and 99%), respectively. However, increasing this duration had a negative effect on A. decurrens seed germination, reducing the final germination percentage from 97% at 60 minutes of immersion to 43% at 120 minutes.

In the past, the entire region of Poland was overgrown by forests. Due to economic changes, the forest cover was reduced to 40% in the 18th century and 21% after the Second World War. After the war, Polish foresters undertook considerable efforts to increase the forest cover to 30.8% by 2015. Polish forests are characterized by the dominance of oligo- and mesotrophic coniferous species (68.7%). This include the pioneer species, Scots pine. It covers approximately 60% of the area. The species composition of Polish forests determined the dominance of artificial regenerations. However, the currently prevailing direction of forest culture is natural regeneration. This tendency is related to “greening” of the forest management, the priority of PERSONAL durability over productivity and culture of multifunctional forests. A natural or seminatural direction of forest culture is being promoted. Renewal of the species such as fir, beech, oak, or spruce from the last stages of succession have always taken place in a natural manner, whereas the statistics are generated by the dominant species preferring open areas during renewal. Currently, the scale of natural regenerations of the pine is increasing. It is increasingly common to value the favorable economic aspect of natural renewal of the species, and the experience of practitioners supported by scientific research increase the likelihood for success. In Poland, the majority of methods of regeneration proceedings (forest cutting) and the law are directed at obtaining and promoting natural renewal. Independent of the concept of natural renewal promotion, the location of Poland in the intermediate climate zone, between the influence of oceanic and continental climates, resulted in the formation of valuable tree stands with high flexibility and tolerance to growth conditions. They are divided into seed stands, excluded stands, and timberlands. Thus, Poland is in possession of a great base for seed collection. At the beginning of 1990s, a rapid need for container seedlings occurred due to numerous disasters (wind-broken trees, gradations). Currently, in Poland, 17 field nurseries are in operation producing 1–10 million seedlings. In 1992, Poland received a loan from the World Bank to conduct afforestations and the “National Program for Increasing the Forest Cover” was started. The main objective of the plan is to increase the forest cover to 30% in 2020 and 33% in 2050. Within the program, it is planned to include vegetation of the natural succession in the area of approximately 80,000 ha. 

Two pH experiments were conducted at a sandy, bareroot loblolly pine (Pinus taeda L.) nursery in Texas. A sulfur trial (0, 813, 1626, 2439 kg ha^-1 of elemental sulfur) was installed to determine if lowering soil pH would result in nutrient toxicity symptoms and affect seedling morphology. Although soil acidity in the sulfur study ranged from pH 3.9 to pH 5.0, none of the treatments resulted in micronutrient toxicity and none affected height growth, root-collar diameter, root mass, shoot mass or the root-mass ratio (root dry mass/total dry mass). Acidifying soil with sulfur increased leaching of calcium, potassium, magnesium, manganese and zinc but there was no effect on seedling morphology. The objective of the liming trial (0, 813, 1626, 3252 kg ha^-1 of dolomitic lime) was to determine if increasing alkalinity would result in an iron deficiency and reduce seedling growth. As expected, applying lime increased the calcium and magnesium levels but had no effect on soil levels of iron, phosphorus, potassium, sulfur, zinc and sodium. However, the root-mass ratio was reduced by applications of dolomitic lime (pH ranged from 5.3 to 6.0). Differences in soil properties (i.e. plot location) had a greater effect on seedling morphology than lime applications. Foliage levels of manganese and boron were reduced by the highest rate of lime and sulfur, respectively.

Oriental beech established in the Hyrcanian forests, is a valuable tree whose habitats are constantly exposed to destructive factors which change the nutritional status of soil and leaves. Analysis of foliar elements is a commonly used method for studying tree nutrient status that indicates site's quality. Foliar analysis of beech (Fagus orientalis Lipsky) was carried out in Kojour (Mazandaran) in order to assess the nutritional balance of trees in a damaged forest site (a direct result of livestock grazing and anthropogenic perturbations). Sunny leaves of dominant trees were taken in August and foliar concentration of macroelements, N, P, Ca, K and Mg were measured. The diagnosis and recommendation integrated system (DRIS) analysis was applied for evaluating the nutritional state. The results showed deficiency with K and P in disturbed stands. Nutrient Balance Index (NBI) indicated imbalance in nutrient status. These results suggest the usefulness of DRIS for foliar tissue analysis as an indicator of nutritional status and elemental stress in natural forests.

Direct seeding has been considered a forest restoration option for centuries. Over the past half century, the use of this practice has declined in developed countries as forest regeneration programs have advanced with the production of quality seedlings that can successfully establish restoration sites. Direct seeding is being reconsidered as a restoration option as the potential size of the worldwide forest restoration program has grown because of massive deforestation in third-world nations and due to global climate change. This review examines direct seeding from a number of perspectives. First, merits of using this practice in restoration programs are defined. Major merits of this option are that it can be done quickly, over hard to reach and large disturbed areas, and at a relatively low cost. Second, current research findings from restoration programs are discussed. The major finding is that seedling establishment rates are low (i.e. typically around 20% of seeds planted) due to site conditions, seed predation and vegetation competition, and field performance (i.e. survival and growth) is lower than planted seedlings. Third, operational practices for the application in restoration programs are reviewed. To successfully conduct direct seeding programs practitioners need to consider seedbed receptivity, seed distribution and seeding rate. Fourth, potential new practices are presented. Some of these new practices attempt to create a more effective means to disperse seed across the site, minimize seed predation or create a more favorable microsite environment. This review provides a synthesis of what is known about direct seeding, thereby allowing practitioners to make a rational decision of whether to apply this practice towards their forest restoration program.