Nigeria, a country in West Africa, sits on the Atlantic coast with a land area of approximately 90 million hectares and a population of more than 140 million people. The southern part of the country falls within the tropical rainforest which has now been largely depleted and is in dire need of reforestation. About 10 percent of the land area was constituted into forest reserves for purposes of conservation but this has suffered perturbations over the years to the extent that what remains of the constituted forest reserves currently is less than 4 percent of the country land area. As at today about 382,000 ha have been reforested with indigenous and exotic species representing about 4 percent of the remaining forest estate. Regrettably, funding of the Forestry sector in Nigeria has been critically low, rendering reforestation programme near impossible, especially in the last two decades. To revive the forestry sector government at all levels must re-strategize and involve the local communities as co-managers of the forest estates in order to create mutual dependence and interaction in resource conservation.

Planted forests are an important source of various services (economic, environmental, and social) with increasing portion in the total world’s forest area. Genetic diversity is fundamental for success and sustainability of planted forests. Facing the concern of the reduction of genetic diversity in planted forests, this study offers a review of evidence on comparisons between the levels of genetic diversity in forests established by different regeneration methods. A total of 34 papers comparing genetic diversity in natural forests versus various regeneration methods of 24 tree species examined by the range of markers are reviewed. In most cases, there are no significant differences in genetic diversity between natural and planted forests, followed by an almost equal number of cases with decreased and increased level of genetic diversity. The loss of rare alleles, but also new alleles are reported in planted forests. Although the origin of planting material in the most cases are unknown, the size of parental population is determinant for the level of genetic diversity in the new forest, with the provenancing and seed collection strategy as the most important management practices in planting projects.

Meeting forest restoration challenges relies on successful establishment of plant materials (e.g., seeds, cuttings, rooted cuttings, or seedlings, etc.; hereafter simply “seedlings”). The Target Plant Concept (TPC) provides a flexible framework that nursery managers and their clients can use to improve the survival and growth of these seedlings. The key tenets of the TPC are that (1) more emphasis is placed on how seedlings perform on the outplanting site rather than on nursery performance, (2) a partnership exists between the nursery manager and the client to determine the target plant based on site characteristics, and (3) that information gleaned from post-planting monitoring is used to improve subsequent plant materials. Through the nursery manager–client partnership, answers to a matrix of interrelated questions define a target plant to meet the reforestation or forest restoration objectives. These questions focus on project objectives; site characteristics, limiting factors, and possible mitigation efforts; species and genetic criteria; stocktype; outplanting tools and techniques; and outplanting window. We provide examples from the southeastern United States, Hawai‛i, and Lebanon on how the TPC process has improved performance of seedlings deployed for reforestation and forest restoration.

Increased summer drought and wildfires as a consequence of continuing climate change are expected to lead to disturbance of Mediterranean ecosystems. Seedlings recruitment is sensitive to both stresses and, therefore, any adaptation and restoration strategy devised to protect these forests should take into account a careful study on their effects on seedling development. As a substantial fraction of net primary productivity of forested ecosystems is channelled in the belowground compartments, the knowledge of how roots behave under stressful conditions becomes of primary importance to select the right management strategy to be implemented. This work tries to enlighten the events occurring in the fine root portion of the root system in young seedlings of three co-existing oak species (Quercus ilex, Quercus trojana and Quercus virgiliana) under controlled conditions. We have made a comparative analysis of the effect of these two stresses, alone or in combination, with the aim to evaluate the tolerance level of these seedlings and, therefore, to obtain an indication of their recruitment potential in the field. The parameters investigated were biomass and a number of morphological traits. Data obtained suggest that a decrease in diameter could be part of a tolerance strategy in all three oaks tested together with a reduction of root length. In addition, tolerance to water shortage could require a reduction of carbon allocated belowground, in particular in the very fine roots, which leads to an overall reduction of the root system dimension. Q. trojana seedlings seem to be the fastest in resuming growth after stress interruption but a good recovery was also found for the remaining two oak species. Although our study provides interesting information regarding a possible tolerance strategy taking place in the fine root compartment when seedlings of these three oak species undergo water stress and fire treatment, more information is needed before any suggestion can be made as to which species would be best suited to make these forests more resistant to global changes.

Most of the Iberian Peninsula has a Mediterranean climate, which strongly determines the objectives, strategies and techniques of forest restoration. This communication addresses a main forest restoration challenge for Mediterranean-climate woodlands in Spain: the transformation of old monospecific pine plantations to more diverse, resistant and resilient forest systems. I also present how afforestation methods and some ideas on plant quality have evolved in the last 80 years. Productivity of Mediterranean forests is low, which discourages private owners to invest in woodland management. Therefore, woodland management strongly relies on public funds. Large-scale afforestation in the 20th century has created huge areas of monospecific pine plantations, which have been under thinned and are very simple structurally with almost no understory. The stands are very prone to fires, diseases and drought dieback. However, old pine plantations can facilitate the establishment of late successional trees and shrubs when properly thinned. Therefore, pine plantations are an opportunity for restoring several types of oak-dominated forests at a large scale and resources should invested to preserve and gradually transform these plantations into mixed forests. Funds should be invested in thinning progressively rather than to plant new areas. In many plantations close to oak forests remnants, thinning is the only management required. However, many pine plantations are far from seed sources and enrichment plantations together with thinning are needed. Extensive enrichment plantations are expensive. Therefore, an option is to develop a network of small islets strategically placed inside pine plantations and properly managed as seed foci to foster pine plantation colonization. This option is cheaper than conventional extensive low-density enrichment plantations but research is needed to assess its effectiveness for pine plantation transformation.

Plantations offer a high potential to respond to the increasing pressure on forests to deliver social, economic, and environmental services. Exotic tree species have a long history of use in plantation forestry, mostly because of their improved productivity compared with that of native species. Because of their impacts on land management and the environment, questions arise regarding the compatibility of exotic tree plantations with sustainable forest management (SFM), the overarching paradigm driving forest legislations in Canada. Our objectives were thus to i) briefly review the historical and current use of exotic tree species in Canada, ii) identify the social, economic and environmental issues related to the use of exotic tree species in Canadian forestry, based on sustainable forest management criteria, and iii) identify perspectives related to the use of exotic tree species in the sustainable management of Canadian forests. Results show that six out of ten Canadian provinces do not have specific legislations to control the use of exotic tree species for reforestation within their borders. The use of exotic tree species is mainly controlled through third-party certification agencies. Exotic tree species represent a small proportion of the planted seedlings in Canada and Norway spruce is the most common one. The use of exotic tree species is compatible with sustainable forest management criteria used in Canada, but forest managers must take into account several issues related to their use and maintain a social license to be entitled to plant them. Issues are highly dependent upon scale. The zoning of management intensity could provide environmental, economic and social benefits, but costs/benefits analyses should be carried out. The concept of naturalness could also be useful to integrate plantations of exotic species in jurisdiction where SFM strategies are based on ecosystem management principles. Monitoring of hybridization and invasiveness of exotic species must be included in landscape analyses to forestall loss of resilience leading to compromised structural and functional ecosystem states. The use of exotics species is recognized as a tool to sequester carbon and facilitate adaptation of forests to global changes, but it is necessary to carefully identified contexts where assisted migration is justified and disentangle planned novel ecosystems coherent with global changes generated by assisted migration from those emerging from invasive species forming undesired states.

Over the past five decades, researchers in the southern United States have been working with nursery managers to develop ways to reduce the cost of producing seedlings. In this regard, the Southern Forest Nursery Management Cooperative (at Auburn University in Alabama) has helped reduce hand-weeding costs and losses due to nematodes and disease. As a result, nursery managers are able to legally use a variety of registered herbicides and fungicides for use in pine and hardwood seedbeds.  Other changes over the last three decades include a reduction in the number of nurseries growing seedlings, a reduction in the number of seedlings outplanted per ha, an increase in the number of container nurseries, an increase in the average production per nursery, an increase in production by the private sector, growing two or more crops after fumigation, the development of synthetic soil stabilizers, applying polyacrylamide gels to roots and the use of seedling bags and boxes for shipping seedlings.

The concern for environmental protection has existed since the time of first human civilization. As society develops, the chain of changes during the natural flow of processes in ecosystems has been supplemented by a new link - pollutants. They have an effect on all other members of the ecosystem (changes may be visible immediately or harder to spot), which leads to an extremely complex relationship with nature. The values of some parameters of pollutants reached an alarmingly high level. The tendency to reduce the risk of air, soil, water, plant, and animal pollution to a tolerable limit, which would salvage the environment and most importantly human health, became a global problem. Heavy metals as pollutants have been an interest of researchers for their conduct, especially in forest ecosystems, which has been expressed in the previous year's more than ever. With its numerous toxic effects, heavy metals are endangering the existence of plant species that live in already contaminated environments. This is all an argument regarding the fight of modern society that the emission of polluted materials gets reduced in order to avoid multiple negative effects, which can endanger the existence of living organisms in general, as an argument for the continuation of numerous researches that are conducted in this area. The monitoring of heavy metals is of significant importance because their toxicity and accumulations are vital for the ecosystem. Polluted soils can be reduced and they can restore their function using physical, chemical, and biological techniques. Physical and chemical methods are very expensive and cause mainly irreversible changes, thus destroying biological variety. The biological recovery of contaminated soil represents an efficient method of reducing health risks for both mankind and the ecosystem.  For this purpose, biological indicators are used. Numerous researches have led to improvements of the initial idea about using plants as a remediation of the environment and the removal of different contaminants from contaminated medias into promising technologies of environmental protection under the title "Phytoremediation". This technology consists of the reduction of concentrations of polluted materials in polluted soils, water, or air. Plants have the ability to store, degrade, or eliminate metals, pesticides, solutions, explosives, and crude oils. Its derivatives and various other contaminants form mediums that contain them. This paper especially considers methods of the possibility of the usage and application of plants in restoring soil contaminated by heavy metals as well as other pollutants.

The three major functions of a potting medium for plant production is to provide support, to retain water and nutrients, and to allow oxygen diffusion to the roots. A potting medium should meet the requirements of practical plant production such as: to be available and ready at all times, easy to handle, lightweight and to produce uniform plant growth. Constituents such as natural soil, peat, sand, perlite and vermiculite are commonly used as substrates for container plant production. Nevertheless, these materials might be fully or partially replaced by various organic or inorganic wastes, thus achieving environmental and economic benefits. This study presents a synthesis of results extracted from many trials on waste materials as potting media substitutes for the seedlings production of the following native plant species: Pinus halepensis, Quercus ilex, Quercus macropleis and Ceratonia siliqua. The studied waste materials were either organic or inorganic components including: spoils of peridotite, raw rice hulls, coconut fiber and kenaf (the ground stem of the plant H. cannabinus L). The experimental potting media tested were: peat:perlite (3:1), a common medium used for seedling production, peat:spoils of peridotite (3:1), peat:rice hulls (3:1), peat:rice hulls (1:1), peat:coconut fiber (1:1), kenaf (100%) and kenaf:peat:rice hulls (3:1:1). The main physical (water retention characteristics, bulk density, particle density, total porosity) and chemical (N, K, Ca, Mg, soluble P, exchangeable cations, pH and loss on ignition) properties of each potting medium were measured. For each plant species the following seedling quality parameters were assessed: morphological characteristics (shoot height, root collar diameter), shoot and root biomass, Dickson’s quality index and shoot and root nutrient concentrations. Then seedlings were planted in the field and their survival and growth was monitored. The feasibility of replacing peat or perlite with various waste materials as well as their effect on seedling quality and field performance are discussed.