A fast phenotype approach of 3D point clouds of Pinus massoniana seedlings

The phenotyping of Pinus massoniana seedlings is essential for breeding, vegetation protection, resource investigation, and so on. Few reports regarding estimating phenotypic parameters accurately in the seeding stage of Pinus massoniana plants using 3D point clouds exist. In this study, seedlings with heights of approximately 15-30 cm were taken as the research object, and an improved approach was proposed to automatically calculate five key parameters. The key procedure of our proposed method includes point cloud preprocessing, stem and leaf segmentation, and morphological trait extraction steps. In the skeletonization step, the cloud points were sliced in vertical and horizontal directions, gray value clustering was performed, the centroid of the slice was regarded as the skeleton point, and the alternative skeleton point of the main stem was determined by the DAG single source shortest path algorithm. Then, the skeleton points of the canopy in the alternative skeleton point were removed, and the skeleton point of the main stem was obtained. Last, the main stem skeleton point after linear interpolation was restored, while stem and leaf segmentation was achieved. Because of the leaf morphological characteristics of Pinus massoniana, its leaves are large and dense. Even using a high-precision industrial digital readout, it is impossible to obtain a 3D model of Pinus massoniana leaves. In this study, an improved algorithm based on density and projection is proposed to estimate the relevant parameters of Pinus massoniana leaves. Finally, five important phenotypic parameters, namely plant height, stem diameter, main stem length, regional leaf length, and total leaf number, are obtained from the skeleton and the point cloud after separation and reconstruction. The experimental results showed that there was a high correlation between the actual value from manual measurement and the predicted value from the algorithm output. The accuracies of the main stem diameter, main stem length, and leaf length were 93.5%, 95.7%, and 83.8%, respectively, which meet the requirements of real applications

Genetic and Morphological Variation in Tropical and Temperate Plant Species

Plants provide the foundation for the structure and function, as well as interactions, among organisms in both tropical and temperate zone habitats. To date, many investigations have revealed patterns and mechanisms generating plant diversity at various scales and from diverse ecological perspectives. However, in the era of climate change, anthropogenic disturbance, and rapid urbanization, new insights are needed to understand how plant species in these forest habitats are changing and adapting. Investigations of plants in both little-disturbed, more natural environments, as well as in urban areas in which crucial green infrastructure is ever more important for sustaining complex human societies are needed. This Special Issue of Forests will focus on plant variation from the perspectives of morphology, genetics, and function, especially plant interactions with biotic and abiotic factors. Research articles may address any aspect of plant evolution and community phylogenetics (explorations of patterns and mechanisms from diverse organismal levels, e.g., molecular, population, species, community, landscape, and ecosystem), plant functional traits (e.g., nutrient traits of leaf, stem, root; reproductive traits of flower, fruit, seed), and/or responses of plant species to changing environments (e.g., water, atmosphere, soil, human activities). Studies providing quantitative evaluation or description of interactions of plants with animals and microbes, both in natural and urban environments, including terrestrial and aquatic systems, are also welcome

Pruning Chinese trees : an experimental and modelling approach

Pruning of trees, in which some branches are removed from the lower crown of a tree, has been extensively used in China in silvicultural management for many purposes. With an experimental and modelling approach, the effects of pruning on tree growth and on the harvest of plant material were studied. In Chapter 2 the aboveground biomass production and harvest of plant material of five subtropical Chinese tree species as affected by annual pruning were analysed. The biomass production of trees decreased following pruning, and the reduction in biomass production was correlated with pruning intensity. The results indicated that, for the investigated five subtropical tree species, the annual pruning regime could not provide enough time for a tree to fully recover its growth, which consequently prevented the sustainable gain of high harvests of plant materials. In Chapter 3, the aboveground biomass allocation and leaf dynamics of four tree species following pruning were investigated. Pruned trees allocated proportionally more of their aboveground biomass to leaves and less to wood, irrespective of species and pruning seasons. This allocation pattern was positively correlated with pruning intensity. The increased proportional allocation of aboveground biomass to leaves following pruning would benefit pruned trees to alleviate the negative pruning effects and recover from the pruning damage. Chapter 4 focuses on the leaf emergence and shoot production of trees after pruning. Pruning had no effect on the leaf density and shoot production. Pruning facilitated the shoot production on the bare stem parts beneath the remaining crown. In Chapter 5 the leaf efficiency of two Ficus tree species as affected by pruning is reported. The leaf efficiency of both species was increased after pruning. In Chapters 6, a tree growth model was constructed. In Chapter 7, this tree model was applied to simulate the effects of pruning on branch harvest, taking pruning intensity, pruning season, pruning frequency, and tree size at which pruning starts into consideration. To sum up, the effects of pruning on tree growth depended on many factors including pruning season, pruning intensity, pruning interval, tree species, and tree size. Heavy and repeated pruning with short intervals reduced tree growth always. This negative effect, however, can be mitigated to some extent by the increased biomass partitioning to leaves and the increased leaf productivity in the pruned tree

Remote sensing technology applications in forestry and REDD+

Advances in close-range and remote sensing technologies are driving innovations in forest resource assessments and monitoring on varying scales. Data acquired with airborne and spaceborne platforms provide high(er) spatial resolution, more frequent coverage, and more spectral information. Recent developments in ground-based sensors have advanced 3D measurements, low-cost permanent systems, and community-based monitoring of forests. The UNFCCC REDD+ mechanism has advanced the remote sensing community and the development of forest geospatial products that can be used by countries for the international reporting and national forest monitoring. However, an urgent need remains to better understand the options and limitations of remote and close-range sensing techniques in the field of forest degradation and forest change. Therefore, we invite scientists working on remote sensing technologies, close-range sensing, and field data to contribute to this Special Issue. Topics of interest include: (1) novel remote sensing applications that can meet the needs of forest resource information and REDD+ MRV, (2) case studies of applying remote sensing data for REDD+ MRV, (3) timeseries algorithms and methodologies for forest resource assessment on different spatial scales varying from the tree to the national level, and (4) novel close-range sensing applications that can support sustainable forestry and REDD+ MRV. We particularly welcome submissions on data fusion

Applications of Remote Sensing Data in Mapping of Forest Growing Stock and Biomass

This Special Issue (SI), entitled "Applications of Remote Sensing Data in Mapping of Forest Growing Stock and Biomass”, resulted from 13 peer-reviewed papers dedicated to Forestry and Biomass mapping, characterization and accounting. The papers' authors presented improvements in Remote Sensing processing techniques on satellite images, drone-acquired images and LiDAR images, both aerial and terrestrial. Regarding the images’ classification models, all authors presented supervised methods, such as Random Forest, complemented by GIS routines and biophysical variables measured on the field, which were properly georeferenced. The achieved results enable the statement that remote imagery could be successfully used as a data source for regression analysis and formulation and, in this way, used in forestry actions such as canopy structure analysis and mapping, or to estimate biomass. This collection of papers, presented in the form of a book, brings together 13 articles covering various forest issues and issues in forest biomass calculation, constituting an important work manual for those who use mixed GIS and RS techniques

The influence of forest-forming tree species on diversity and spatial distribution of algae in forest litter

The forest litter plays a significant role in forest ecosystems. The composition of the litter biota comprises micro- and mesofauna, and a great diversity of microorganisms, including unrecognized algae (eukaryotic representatives and Cyanoprokaryota). The aim of this work was to study the diversity of algae in the different types of forest litters and to clarify the relationship between the algae composition and the forest-forming tree species. Our results show that the pine forest litter is the most appropriate habitat for the development of green and yellow-green algae and that this litter type limits the variety of blue-green ones. The admixture of deciduous leaf litter to pine litter caused an increase in the species richness of blue-green algae and diatoms. The algae were unevenly distributed across the sub-horizons of pine litter. The highest species richness of algae was identified in the enzymatic sub-horizon of litter. The peculiarity of the composition of leaf litter algae was a significant variety of green, yellow-green and blue-green algae. The spatial organization of algae communities in the leaf litter was characterized by equal distribution of algae species in the litter-subhorizon

Systematics, diversification, and functional diversity of Russulaceae (Russulales)

The family Russulaceae is an iconic family of mushroom-forming Basidiomycetes both because of their importance as edible mushrooms in many parts of the world and their species richness in both temperate and tropical forested biomes. While much mycological research has been focused on this group, recent systematic and ecological research has failed to develop a comprehensive or cohesive organization by which to understand the evolutionary relationships, patterns of diversification, or functional importance of the group. Recently, interest in ectomycorrhizal fungi (EmF), of which Russulaceae is a key lineage, has greatly increased due to the recognition of the importance of EmF in carbon sequestration in the face of global climate change. By specifically taking a lineage-based approach to the study of Russulaceae, this work is an attempt to elucidate the biological importance of this group as a model for understanding important biological patterns in EmF. To this end, this dissertation work seeks to address five key questions: 1) What are the major systematic relationships in the Russula, Russulaceae, and their placement within Russulales? 2) What are the biogeographic and host patterns in Russula? 3) What factors have contributed to the high diversification of Russula? 4) What are the functional differences between major groups within Russulaceae? 5) To what extent have members of Russulaceae retained the ability to decompose soil organic matter? To address these main questions, my research has combined the collection and study of sporocarps with molecular phylogenetics and contemporary evolutionary analytics. These efforts have led to the first multi-gene phylogeny of the genus Russula with a clade-based classification system proposed. By applying ancestral area reconstruction methodologies and diversification analyses using state speciation-extinction (SSE) models, I have inferred a temperate origin associated with angiosperms for Russula. I have provided support for a higher net diversification rate in temperate species of Russula that is not a result of migration. Here I present a molecular systematic revision of the Roseinae clade and provide support for at least 5 new species. Finally, in a comparative genomic analysis I show that Russulaceae are widely diverse in gene content, indicating diverse functional roles

Genetics and Genomics of Forest Trees

Forest tree genetics and genomics are advancing at an accelerated rate, thanks to recent developments in high-throughput, next-generation sequencing capabilities, and novel biostatistical tools. Population and landscape genetics and genomics have seen the rise of new approaches implemented in large-scale studies that employ the use of genome-wide sampling. Such studies have started to discern the dynamics of neutral and adaptive variation in nature and the processes that underlie spatially explicit patterns of genetic and genomic variation in nature. The continuous development of genetic maps in forest trees and the expansion of QTL and association mapping approaches contribute to the unravelling of the genotype-phenotype relationship and lead to marker-assisted and genome-wide selection. However, major challenges lie ahead. Recent literature suggests that species demography and genetic diversity have been affected both by climatic oscillations and anthropogenically induced stresses in a way calls into question the possibility of future adaptation. Moreover, the pace of contemporary environmental change presents a great challenge to forest tree populations and their ability to adapt, taking into consideration their life history characteristics. Several questions emerge that include, but are not limited to, the interpretation of forest tree genome surveillance and their structural/functional properties, the adaptive and neutral processes that have shaped forest tree genomes, the analysis of phenotypic traits relevant to adaptation (especially adaptation under contemporary climate change), the link between epigenetics/epigenomics and phenotype/genotype, and the use of genetics/genomics as well as genetic monitoring to advance conservation priorities

Experimental micromechanical characterisation of wood cell walls

International audienceThe properties of wood and wood based materials are strongly dependent on the properties of its fibres; i.e. the cell wall properties. The ability to characterize these in order to increase our understanding of structure-property relationships is thus highly important. This article gives a brief overview of the state of the art in experimental techniques to characterize the mechanical properties of wood at both the level of the single cell and that of the cell-wall. Challenges, opportunities, drawbacks and limitations of single fibre tensile tests and nanoindentation are discussed with respect to the wood material properties

Ammonium regulates the development of pine roots through hormonal crosstalk and differential expression of transcription factors in the apex

Ammonium is a prominent source of inorganic nitrogen for plant nutrition, but excessive amounts can be toxic for many species. However, most conifers are tolerant to ammonium, a relevant physiological feature of this ancient evolutionary lineage. For a better understanding of the molecular basis of this trait, ammonium‐induced changes in the transcriptome of maritime pine (Pinus pinaster Ait.) root apex have been determined by laser capture microdissection and RNA sequencing. Ammonium promoted changes in the transcriptional profiles of multiple transcription factors, such as SHORT‐ROOT, and phytohormone‐related transcripts, such as ACO, involved in the development of the root meristem. Nano‐PALDI‐MSI and transcriptomic analyses showed that the distributions of IAA and CKs were altered in the root apex in response to ammonium nutrition. Taken together, the data suggest that this early response is involved in the increased lateral root branching and principal root growth, which characterize the long‐term response to ammonium supply in pine. All these results suggest that ammonium induces changes in the root system architecture through the IAA‐CK‐ET phytohormone crosstalk and transcriptional regulation.This study was funded by Spanish Ministerio de Ciencia e Innovación, grant numbers BIO2015‐73512‐JIN MINECO/AEI/FEDER, UE; RTI2018‐094041‐B‐I00 and EQC2018‐004346‐P. Funding for open access charge: Universidad de Málaga/CBUA. FO was supported by grants from the Universidad de Málaga (Programa Operativo de Empleo Juvenil vía SNJG, UMAJI11, FEDER, FSE, Junta de Andalucía) and BIO‐114, Junta de Andalucí