The ecological importance of scattered tree species such as elms (the European white elm, the wych elm and the field elm) is widely recognized in Europe. The European white elm, along with other elm ...species, is important as part of the traditional landscape and as a tree with multiple uses. In Germany, a total of more than 825 white elm populations numbering approximately 138,000 trees have been inventoried. Most of the largest populations are closely associated with the main rivers and concentrated mainly in the northeast of the country. However, to date there has been a lack of knowledge on the genetic structure and diversity of European white elm populations in Bavaria (southern Germany). The aim of this study was to assess genetic structure and diversity and to select putative seed stands and gene conservation units (GCU) for European white elm. Nuclear microsatellite loci (nSSR) were first selected for successful elm species discrimination. Next, in order to represent the distribution range of European white elms in Bavaria, 18 populations were selected and sampled for genetic analysis with 12 variable nSSR loci. AMOVA revealed that genetic variation is mainly distributed within populations (89%), while only 11% occurred between them (
F
ST
= 0.11). Bayesian clustering indicated the highest probability for the presence of four genetic clusters (Delta
K
= 19.954 at K4) within the dataset. However, spatial genetic structure indicates a close link to the two main river basins in Bavaria (Main River basin and the Danube River basin). Thus, our results fill existing gaps in sustainable use and conservation of rare and scattered tree species by providing insights into genetic variation and genetic structure of the species and allow us to better plan genetic conservation measures and to select GCU and seed stands in Bavaria. We, therefore, suggest that in the future all putative seed stands or gene conservation units should be assessed based on several aspects, one of them being the level of genetic diversity, before final selection and use as a source of forest reproductive material (FRM).
Genetic conservation is key to maintaining forests for the future; however, these face several threats. Mexico is an example of the degradation of forest genetic resources during the past three ...decades due to its deforestation rates. This country is considered a center of pine diversity but its genetic conservation efforts are not enough. To define genetic conservation units (GCUs) and propose measures for the conservation and sustainable use of 18 Mexican pine species, we analyzed the distribution of the species at the national level and in germplasm transfer zones, and evaluated the species with a set of minimum requirements for conservation and indicators from the EUFORGEN program. We determined that 13 to 15 genetic zones harbored the target species, in which Pinus teocote, Pinus cembroides, Pinus devoniana, Pinus maximinoi, Pinus douglasiana, and Pinus leiophylla were the most widely distributed. We defined 173 areas for establishing GCUs for the total of the species studied; 50% of them were selected from areas with genetic information, 5% were selected from seed stands, and 45% from natural forests. We detected that most of the forest reproductive material used is collected from seed stands, and the use of seeds from breeding trials is scarce.
Eucalyptus urophylla is important for the establishment of commercial forest plantations in Mexico. Genetic improvement programs are currently being implemented to increase timber productivity. The ...objectives of this study were to evaluate the adaptability and growth stability of 26 clonal lines of E. urophylla in Acrisol and Fluvisol soils and to identify the most suitable genotypes for each soil type. Tree survival, diameter at breast height, and total height were measured annually for six years. These variables were used to estimate individual volume, volume per hectare, and mean annual (MAIv) and current annual (CAIv) volume increment. Survival ranged from 14 to 100% in the Acrisol soil and from 0 to 89% in the Fluvisol soil. Volume per hectare ranged from 65.3 to 488.7 m3, MAIv from 11.1 to 83.1 m3 ha−1 year−1, and CAIv from 2.4 to 134.7 m3 ha−1 year−1. Individual heritability (Hi2) was moderate (0.29–0.49) while the mean heritability of the cloned lines was high (0.73–0.90), indicating that growth is subject to high genetic control. Diameter, height, and volume presented no genotype × environment interaction effects, demonstrating stability in the growth of the clonal lines in both soil types.
With the birth of classical genetics, forest genetic breeding has laid a foundation in the formation of the basic theories of population genetics, quantitative genetics, cytogenetics, and molecular ...genetics. Driven by the rapid growth of social demand for wood and other forest products, modern genetics, biotechnology, biostatistics, crop and animal husbandry breeding theories, and technical achievements have been continuously introduced for innovation, thus forming a close combination of genetic basic research and breeding practice. Forest tree breeding research in the world has a history of more than 200 years. By the middle of the 20th century, the forest tree genetic breeding system was gradually formed. After entering the 21st century, the in-depth development stage of molecular design breeding was opened. With the continuous improvement of traditional genetic breeding methods, emerging modern bioengineering technology has also continuously promoted the development of forest genetic breeding. This study mainly summarizes the research history of forest tree genetics and breeding, as well as discusses the application of modern bioengineering technology represented by genome selection and gene editing in forest tree breeding, so as to provide better reference for forest tree breeding research.
The most recent climate change scenarios show that Southern and Eastern Europe will be affected by a significant increase in temperature and drought frequency by the end of the 21st century. Romania ...has already recorded very high temperatures and long periods of drought over recent decades, the most affected regions being the south, west and east of the country. Considering that successful forest management requires suitable species and high-quality reproductive material for reforestation, the aim of this study was to evaluate and compare the growth and drought response of Douglas fir (Pseudotsuga menziessi var. menziesii) and Norway spruce (Picea abies) in two stands installed at the end of the 19th century in western Romania. The growth traits, wood characteristics and drought parameters (resistance, recovery, resilience and relative resilience) of Douglas fir and Norway spruce trees have been analyzed and compared. The climate–growth relationship was determined using growth response functions over the period 1938–2017. Additionally, to simulate the potential impact of climate change on Douglas fir in this region, the RCP4.5 scenario was used over two periods: 2041–2070 and 2071–2100. The results reveal that Douglas fir has an exceptional growth capacity, overcoming the Norway spruce since the early ages in both site conditions. The highest growth performances were seen in the low-productivity site. From analyzing the responses to drought events, considerable differences were found between species. The results highlight the high resistance and relative resilience to extreme droughts of Douglas fir compared to Norway spruce. However, autumn–winter temperatures play an important role in the adaptation of Douglas fir to site conditions in Romania. The use of appropriate provenances of Douglas fir in mixed stands with native broadleaved species may be an option for climatically exposed sites, thus increasing the value of these stands.
Building forests for the future MacKenzie, A. Robert; Ullah, Sami; Foyer, Christine H.
Food and energy security,
March/April 2024, 2024-03-00, 20240301, 2024-03-01, Letnik:
13, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Many governments have set ambitious targets for tree planting and increased woodland cover as a key part of actions to reach net‐zero carbon emissions by 2050. However, many uncertainties remain ...concerning how and where to expand tree cover, what species to plant, and how best to manage new plantations. Much contemporary forestry has been based on even‐aged monocultures, largely because of perceived advantages for timber production. However, in order to play a key role in climate change mitigation future forests will have to achieve timber production (and wider ecosystem service provision) alongside resilience to biotic and abiotic challenge. It is therefore crucial that appropriate informed decisions are made with regard to the structure, composition, and planning of future forests, in order to provide sustainable solutions that provide environmental, economic, and health benefits to society. Genetically diverse, mixed, and irregular forests, with their higher biodiversity and niche complementarity, are promising new forest configurations for regulating the water cycle, storing carbon, and delivering other goods and services. In the following discussion, we have used UK information to illustrate the benefits of mixed woodland versus monocultures and highlighted current issues related to government initiatives and policies for current and future forests. However, similar issues and problems are encountered globally.
Purpose of Review
Recognizing that in the context of global change, tree genetic diversity represents a crucial resource for future forest adaptation, we review and highlight the major forest ...genetics research achievements of the past decades in biodiversity-rich countries of the Mediterranean region. For this, we conducted a bibliometric analysis of the scientific literature spanning the past thirty years (1991–2020). Putting together the representative regionwide expertise of our co-authorship, we propose research perspectives for the next decade.
Recent Findings
Forest genetics research in Mediterranean countries is organized into three different scientific domains of unequal importance. The domain “Population diversity and Differentiation” related to over 62% of all publications of the period, the domain “Environmental conditions, growth and stress response” to almost 23%, and the domain “Phylogeography” to almost 15%. Citation rate was trending the opposite way, indicating a strong and sustained interest in phylogeography and a rising interest for genetics research related to climate change and drought resistance. The share of publications from Asia and Africa to the total within the Mediterranean increased significantly during the 30-year period analyzed, reaching just below 30% during the last decade.
Summary
Describing poorly known species and populations, including marginal populations, using the full potential of genomic methods, testing adaptation in common gardens, and modeling adaptive capacity to build reliable scenarios for forest management remain strategic research priorities. Delineating areas of high and low genetic diversity, for conservation and restoration, respectively, is needed. Joining forces between forest management and forest research, sharing data, experience, and knowledge within and among countries will have to progress significantly, e.g., to assess the potential of Mediterranean genetic resources as assisted migration material worldwide.
Introductory quote:
Let us collect with care the facts we can observe, let us consult experience wherever we can, and when this experience is inaccessible to us, let us assemble all the inductions which observation of facts analogous to those which escape us can furnish and let us assert nothing categorically; in this way, we shall be able little by little to discover the causes of a multitude of natural phenomena, and, perhaps, even of phenomena which seem the most incomprehensible... J.B. de Lamarck (Philosophie zoologique, 1809), cited by O. L
anglet (1971).
Forest genetic resources are the aggregate of genofonds of native and cultivar populations of forest woody plants, valuable really or potential for specific territory (A brief dictionary… 2014). ...Forest genetic resources are studied in practice in most cases on example of forest-forming woody plants. It is necessary to consider of study of these resources in two positions: taxonomic and geographic. Forest forming coniferous species are studied best of all from the taxonomic point of view taking into account biodiversity. Genetic polymorphism is studied most in detail with such species as Pinus sylvestris, Pinus sibirica, Larix sibirica, Larix sukaczevii, Picea obovata, Abies sibirica. Populations of Larix gmelinii, Larix cajanderi, Picea ajanensis are studied considerable worse. Materials about genetic polymorphism of forest forming foliage species – representative of genera Betula and Populus are absent. Caryological polymorphism is studied sufficiently well in all Siberian conifer species. It should be noted especially attached to examination of this problem, that individuals with B-chromosome were discovered first by gymnosperms as an example Picea obovata. Discovery in Siberia of triploid asp deserve special attention. Geographic variability is shown most broadly in the investigations of Pinus sylvestris, Pinus sibirica, Larix sibirica. These investigations were conducted both in natural populations and in provenance trials. Such investigations of another conifer and foliage species either are shown by separate fragments or are absent at all Geographic variability is shown in a large measure in the operative forest seed sources regionalization. Numerous investigations directed to the analysis of morphological variability are conducted by all forest forming species in the first place by conifers. Questions of hereditary determination of either signs remain in this problem. Similar questions concern the variability of other signs: phonological peculiarities, resin productivity etc. It can be noted from the geographic point of view. General typical peculiarity for all species: best study of forest genetic resources in the south regions and worse study in the north regions. This fact concerns all species with the exception of Larix cajanderi, which does not grow in the south regions of Siberia. Noted regularity is explained simply of more difficult availability of forests in the north Siberian regions. Certainly the north forests are characterized as a general rule by bad productivity, but they have great ecological importance. Besides that, north forests are represented in most cases by autochthonous stands that raise value of their genetic resources. It is necessary to note too that investigations of species of woody plants near the north edge of their range (by south range edge, too) are an important component of the adaptive breeding of their species. It is necessary to take into account by analysis of Siberian forest genetic resources specifics of different types of woody plants populations: isolated insular populations outside the main areas, hybrid populations in the zones of natural intraspecific hybridization etc.
Pachira aquatica Aubl. is an important fruit-ornamental tree of Sinú valley at risk of genetic erosion. The objective was to estimate correlations between fruit characteristics, seeds, and path ...analyses for fresh fruit weight, for the purpose of genetic improvement. The treatments corresponded to 10 trees; 10 random fruits of each tree were taken. Analysis of variance were performed for fixed effects models, correlations and path analysis among the variables: fresh fruit weight, fruit length, fruit peel weight, number of seed per fruit, weight of seed per fruit and weight and volume and density of a seed. Statistical differences between trees were presented for all the characteristics, except for volume of one seed. Genetic correlations were greater in magnitude (32.8%) and statistical significance than phenotypic ones (29.7%). Seed weight showed high genetic correlation with seven characteristics (rG>0.53). The fresh fruit weight showed significant and direct genetic correlations with five variables, with correlation coefficients between 0.65* and 1.00**. The indirect effects explained the level of association between fruit length, seed/fruit weight, and percentage of seed/fruit with fresh fruit weight. The weight of peel/fruit exhibited greater direct and indirect effects on the fresh fruit weight in the two path analysis. It is possible to increase the weight of seed/fruit, weight and volume of a seed indirectly through the selection of trees with higher fresh fruit weight and/or peel/fruit weight, to improve yield and physiological quality of the seed.
Climate change is predicted to increase forest fires in boreal forests, which can threaten the sustainability of forest genetic resources. Wildfires can potentially impact genetic diversity and ...population structure in forest trees by creating population bottlenecks, and influencing demography, effective population size (Ne) and various evolutionary processes. We have investigated this critical issue in a widely-distributed, transcontinental, ecologically and economically important and fire-intolerant boreal conifer, white spruce (Picea glauca (Moench) Voss). We tested the hypothesis that in a predominantly outcrossing species with long distance gene flow, such as white spruce, located in primary undisturbed forests, normal forest fires do not adversely affect genetic diversity and population structure. We used 10 nuclear genic and genomic microsatellite loci to examine genetic diversity and population structure of post-fire pristine old-growth (PF-OG) and adjacent post-fire naturally regenerated young (PF-YR) stands. The genetic diversity, inbreeding and genetic differentiation levels, Bayesian population structure, Ne and latent genetic potential were statistically similar between the PF-OG and PF-YR populations. None of the microsatellites showed any signature of selection. Our study demonstrates that normal wild forest fires do not adversely affect genetic diversity, differentiation, and population genetic structure in white spruce. The results should have wide significance for sustainable forest management.
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