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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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Review

15 pages, 5781 KiB  
Review
Recent Applications of Smart Technologies for Monitoring the Sustainability of Forest Operations
by Rachele Venanzi, Francesco Latterini, Vincenzo Civitarese and Rodolfo Picchio
Forests 2023, 14(7), 1503; https://doi.org/10.3390/f14071503 - 23 Jul 2023
Cited by 17 | Viewed by 5182
Abstract
Precision forestry is a useful technique to help forest stakeholders with proper sustainable forest management. Modern sensors and technologies, with special reference to the sustainability of forest operations, can be applied on a variety of levels, including the monitoring of forest activities regarding [...] Read more.
Precision forestry is a useful technique to help forest stakeholders with proper sustainable forest management. Modern sensors and technologies, with special reference to the sustainability of forest operations, can be applied on a variety of levels, including the monitoring of forest activities regarding the three pillars (economy, environment, and society). In this review, we summarised the current level of knowledge regarding the use of precision forestry techniques for monitoring forest operations. We concentrated on recent data from the last five years (2019–2023). We demonstrated how an Industry 4.0 strategy for remote and proximal monitoring of working performance can be effective when using CAN-bus and StanForD data collected by modern forest machines. The same information can be effectively used to create maps of soil trafficability and to evaluate the patterns of skid tracks or strip roads built as a result of forest intervention. Similar information can be gathered in the case of small-scale forestry by using GNSS-RF (Global Navigation Satellite Systems—Radio Frequency) or even monitoring systems based on smartwatches or smartphones. LiDAR and Structure for Motion (SfM) photogrammetry are both useful tools for tracking soil rutting and disturbances caused by the passage of forest machinery. SfM offers denser point clouds and a more approachable method, whereas laser scanning can be considerably faster but needs a more experienced operator and better data-processing skills. Finally, in terms of the social component of sustainability, the use of location sharing technologies is strongly advised, based for instance on GNSS—RF to monitor the security of forest workers as they operate. Full article
(This article belongs to the Special Issue Forest Mechanization and Harvesting—Trends and Perspectives)
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13 pages, 1698 KiB  
Review
The Utilization of European Beech Wood (Fagus sylvatica L.) in Europe
by Maximilian Pramreiter and Michael Grabner
Forests 2023, 14(7), 1419; https://doi.org/10.3390/f14071419 - 11 Jul 2023
Cited by 21 | Viewed by 4685
Abstract
European beech is one of the dominating wood species in central Europe and the most abundant hardwood species in Austrian, German and Swiss forests. Today, it is predominantly used for the provision of energy and in the furniture industry. With the increasing demand [...] Read more.
European beech is one of the dominating wood species in central Europe and the most abundant hardwood species in Austrian, German and Swiss forests. Today, it is predominantly used for the provision of energy and in the furniture industry. With the increasing demand on forests to provide sustainable raw materials for energy as well as products, the importance of lesser-used wood species like European beech has continuously increased over the last decade. The application in load-bearing products has gained significant interest. In order to connect the current and historical state of knowledge about this wood species, this review provides an overview of the past and present utilization of European beech wood. On the basis of the historical literature, technical approvals and standards of established products, it aims to summarize the extensive state of the art of this wood species and provide an overview of recent scientific publications in the field of wood material science. Based on the reviewed literature, current research efforts deal with different engineered wood products like glued laminated timber, cross-laminated timber and laminated veneer lumber. Furthermore, strength grading, adhesive technology as well as improving dimensional stability is of particular interest. Full article
(This article belongs to the Special Issue Synergies and Trade-Offs between Nature Conservation and Climate Mitigation in European Beech Forests)
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14 pages, 2227 KiB  
Review
An Overview of Oak Species in Pakistan: Past, Present, and Future Research Perspectives
by Noor Muhammad, María Ángeles Castillejo, Maria-Dolores Rey and Jesús V. Jorrín-Novo
Forests 2023, 14(4), 777; https://doi.org/10.3390/f14040777 - 10 Apr 2023
Cited by 6 | Viewed by 9562
Abstract
Quercus spp. have formed broad-leaved evergreen forests in the Hindu Kush and Himalayan regions of Pakistan. Seven species of the genus Quercus (Q. baloot Griff., Q. dilatata Royle., Q. glauca Thunb., Q. incana Roxb., Q. robur Linn., Q. semecarpifolia Smith., and Q. [...] Read more.
Quercus spp. have formed broad-leaved evergreen forests in the Hindu Kush and Himalayan regions of Pakistan. Seven species of the genus Quercus (Q. baloot Griff., Q. dilatata Royle., Q. glauca Thunb., Q. incana Roxb., Q. robur Linn., Q. semecarpifolia Smith., and Q. leucotrichophora A. Camus.) have been identified. These species have received little attention compared with other economically valuable plant species in Pakistan, which has been mainly linked to traditional medicine and the identification of phytonutrients to evaluate their bioactivities and toxicological effects. Quercus spp. are promising for commercial applications, so government policy should encourage their management and conservation. However, they are currently threatened by severe human activities and climate change. The goal of this review is to highlight the relevance of these forgotten species, describing overall aspects related to their distribution, morphology, traditional uses, phytochemical constituents, and threats. To date, no proper and comprehensive molecular studies on the populations of these species found in Pakistan have been conducted, which is a critical gap as molecular studies are essential for conservation and management strategies. Finally, we discuss future directions in molecular approaches for Quercus that follow the strategies that are being used for other species of the genus Quercus that are not found in Pakistan. Full article
(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)
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23 pages, 3095 KiB  
Review
Carbon Sequestration Potential of Commercial Agroforestry Systems in Indo-Gangetic Plains of India: Poplar and Eucalyptus-Based Agroforestry Systems
by Sangram Bhanudas Chavan, Ravinder Singh Dhillon, Chhavi Sirohi, Appanderanda Ramani Uthappa, Dinesh Jinger, Hanuman Singh Jatav, Akash Ravindra Chichaghare, Vijaysinha Kakade, Venkatesh Paramesh, Sushil Kumari, Dinesh Kumar Yadav, Tatiana Minkina and Vishnu D. Rajput
Forests 2023, 14(3), 559; https://doi.org/10.3390/f14030559 - 12 Mar 2023
Cited by 27 | Viewed by 12576
Abstract
Climate change, land degradation, and desertification lead to the loss of carbon present in the soil and plants. The carbon dioxide (CO2) concentration in the atmosphere has reached 412 ppm. This is a rise of 47% since the start of the [...] Read more.
Climate change, land degradation, and desertification lead to the loss of carbon present in the soil and plants. The carbon dioxide (CO2) concentration in the atmosphere has reached 412 ppm. This is a rise of 47% since the start of the industrial period, when the concentration was close to 280 ppm. Therefore, the sequestration of carbon from the atmosphere to earth is the need of the hour. Many scientists have suggested agroforestry as a potent instrument for climate change mitigation as well as to fetch lucrative benefits. The Indian government is also promulgating tree-based systems for increasing tree cover up to 33% of the total geographical area to mitigate climate change. Therefore, the expansion of the commercial agroforestry system of fast-growing tree species producing higher biomass could be a sustainable and ecologically benign technique to sequester carbon, increase green cover, and improve the financial status of farmers. This review highlights the commercial agroforestry systems, biomass and carbon sequestration potential, and case studies of poplar and eucalyptus. The species such as poplar (Populus deltoides), nilgiri (Eucalyptus spp.), subabul (Leucaena leucocephala), tree of heaven (Ailanthus excelsa), willow (Salix spp.), malabar neem (Melia dubia), cadamba (Neolamarckia cadamba), and white teak (Gmelina arborea) are the suitable tree species for carbon sequestration under agroforestry. Among these species, poplar and eucalyptus are major agroforestry tree species that have been adopted by millions of farmers in India since the 1990s. Indo-Gangetic plains are considered the birthplace of commercial or industrial agroforestry, as poplar and eucalyptus are widely planted. This review reports that poplar and eucalyptus have the potential to sequester carbon stock of 212.7 Mg C ha−1 and 237.2 Mg C ha−1, respectively. Further, the net carbon sequestration rate in poplar and eucalyptus was 10.3 and 12.7 Mg C ha−1 yr−1, respectively. In conclusion, the commercial agroforestry system was very successful in the Indo-Gangetic regions of the country but needs further expansion with suitable compatible crops in different parts of the country. Full article
(This article belongs to the Special Issue Pollution, Heavy Metal, and Emerging Threats in Forest Soil)
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15 pages, 772 KiB  
Review
A Review of Research on Forest Ecosystem Quality Assessment and Prediction Methods
by Ke Guo, Bing Wang and Xiang Niu
Forests 2023, 14(2), 317; https://doi.org/10.3390/f14020317 - 6 Feb 2023
Cited by 11 | Viewed by 8289
Abstract
The accurate assessment and prediction of forest ecosystem quality is an important basis for evaluating the effectiveness of regional ecological protection and restoration, establishing a positive feedback mechanism for forest quality improvement and restoration policies, and promoting the construction of an ecological civilization [...] Read more.
The accurate assessment and prediction of forest ecosystem quality is an important basis for evaluating the effectiveness of regional ecological protection and restoration, establishing a positive feedback mechanism for forest quality improvement and restoration policies, and promoting the construction of an ecological civilization in China. Based on the existing studies at home and abroad, this paper mainly analyzes and summarizes the connotation of forest ecosystem quality, assessment index systems, assessment and prediction methods, and outlooks on the existing problems of imperfect forest ecological quality assessment index systems, preliminary assessment and prediction capabilities, and unknown dynamic responses of forest ecological quality to climate change, etc. Efforts should be made to develop a scientific and standardized assessment index system, produce high-quality forest ecological data products, develop localization of assessment model parameters, and explore forest quality–climate change response mechanisms to provide references for in-depth research to realize the transformation of forest ecosystem quality assessments from historical and status quo assessments to future predictions, and to support the construction of a national ecological civilization. Full article
(This article belongs to the Special Issue Forests Research in Beijing Forestry University: Commemorating the University’s 70th Anniversary)
28 pages, 7986 KiB  
Review
Adhesive-and Metal-Free Assembly Techniques for Prefabricated Multi-Layer Engineered Wood Products: A Review on Wooden Connectors
by Lei Han, Andreja Kutnar, Jakub Sandak, Iztok Šušteršič and Dick Sandberg
Forests 2023, 14(2), 311; https://doi.org/10.3390/f14020311 - 5 Feb 2023
Cited by 21 | Viewed by 9140
Abstract
Engineered wood products (EWPs) are being increasingly used as construction materials. EWPs are currently being made using synthetic adhesives or metal fasteners, which lead to poor recyclability and reusability. Therefore, this review paper focused on emerging adhesive- and metal-free assembling techniques including wood [...] Read more.
Engineered wood products (EWPs) are being increasingly used as construction materials. EWPs are currently being made using synthetic adhesives or metal fasteners, which lead to poor recyclability and reusability. Therefore, this review paper focused on emerging adhesive- and metal-free assembling techniques including wood dowels, rotary-dowel welding, wooden nails, and dovetail joining as alternative ways of making prefabricated EWPs. This will contribute towards green construction and optimising the building process to minimise its negative impact on the environment and its inhabitants, while maximising the positive aspects of the finished structure. The respective advantages and shortcomings will be compared with those of equivalent EWPs. In general, the dowel-laminated timber (DLT) provides sufficient load-bearing capacity and even better ductility than EWPs of equivalent size, but its relatively low stiffness under a bending load limits its application as a structural element. Optimised manufacturing parameters such as dowel species, dowel spacing, dowel diameter, dowel insertion angle, dowel shape, etc. could be studied to improve the stiffness. The improved mechanical properties and tight fitting due to set-recovery of densified wood support its use as sustainable alternatives to hardwood dowels in DLT to overcome problems such as the loosening of connections over time and dimensional instability. The rotary welding technology could also enhance the strength and long-term performance of dowel-type joints, but its poor water resistance needs further investigation. The main obstacles to implementing DLT products in the market are missing technical information and design guidelines based on national codes. Full article
(This article belongs to the Special Issue Frontiers in Modification of Wood and Wood-Based Composites)
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22 pages, 5336 KiB  
Review
Distinct Responses of European Beech (Fagus sylvatica L.) to Drought Intensity and Length—A Review of the Impacts of the 2003 and 2018–2019 Drought Events in Central Europe
by Shah Rukh, Tanja G. M. Sanders, Inken Krüger, Tobias Schad and Andreas Bolte
Forests 2023, 14(2), 248; https://doi.org/10.3390/f14020248 - 28 Jan 2023
Cited by 41 | Viewed by 7103
Abstract
A combined severe heatwave and drought, starting in 2018 and lasting for several months, restarted the discussion on the resistance of European beech to climatic changes, with severe growth reductions, early leaf senescence, leaf browning, and diebacks reported across Central Europe. These responses [...] Read more.
A combined severe heatwave and drought, starting in 2018 and lasting for several months, restarted the discussion on the resistance of European beech to climatic changes, with severe growth reductions, early leaf senescence, leaf browning, and diebacks reported across Central Europe. These responses may result in long-term impacts such as reduced vitality of beech, especially under potential future drought periods. While the 2003 drought caused severe crown damage and defoliation and a loss in vitality, resulting in insect and fungal infestations and subsequent dieback, the drought in 2018 was even more severe in terms of geographical scale, duration, and intensity with reports of complete diebacks and severe mortality across Central Europe. These impacts were exacerbated in some regions by the consecutive drought in 2019 and secondary attacks from pathogens, as well as a further loss in vitality. Such enhanced drought exposure of beech trees could push them beyond their hydraulic safety margins. Moreover, growth legacy effects due to past droughts may lead to lower recovery over time, potentially leading to subsequent tree death. In order to better predict the future of beech growth and vitality in Central Europe, both short- and long-term legacy effects of defoliation and their influence on post-drought growth should be explored, and adaptive forest management strategies evaluated. Moreover, synergistic or additive interactions of legacy effects with drought, as well as with biotic disturbances, require further investigation. Long-term forest monitoring data facilitates investigations of drought responses of beech. Full article
(This article belongs to the Section Forest Ecology and Management)
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30 pages, 3691 KiB  
Review
Water in Wood: A Review of Current Understanding and Knowledge Gaps
by Emil Engelund Thybring, Maria Fredriksson, Samuel L. Zelinka and Samuel V. Glass
Forests 2022, 13(12), 2051; https://doi.org/10.3390/f13122051 - 2 Dec 2022
Cited by 61 | Viewed by 15624
Abstract
Wood-water interactions are central to the utilization of wood in our society since water affects many important characteristics of wood. This topic has been investigated for more than a century, but new knowledge continues to be generated as a result of improved experimental [...] Read more.
Wood-water interactions are central to the utilization of wood in our society since water affects many important characteristics of wood. This topic has been investigated for more than a century, but new knowledge continues to be generated as a result of improved experimental and computational methods. This review summarizes our current understanding of the fundamentals of water in wood and highlights significant knowledge gaps. Thus, the focus is not only on what is currently known but equally important, what is yet unknown. The review covers locations of water in wood; phase changes and equilibrium states of water in wood; thermodynamics of sorption; terminology including cell wall water (bound water), capillary water (free water), fiber saturation point, and maximum cell wall moisture content; shrinkage and swelling; sorption hysteresis; transport of water in wood; and kinetics of water vapor sorption in the cell wall. Full article
(This article belongs to the Special Issue Reviews on Structure and Physical and Mechanical Properties of Wood)
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Graphical abstract

21 pages, 1741 KiB  
Review
Toward the Genetic Improvement of Drought Tolerance in Conifers: An Integrated Approach
by Paolo Baldi and Nicola La Porta
Forests 2022, 13(12), 2016; https://doi.org/10.3390/f13122016 - 29 Nov 2022
Cited by 17 | Viewed by 4733
Abstract
The constant rise in the global temperature and unpredictable shifts in precipitation patterns are two of the main effects of climate change. Therefore, there is an increasing amount of interest in the identification of tree species, provenances and genotypes capable of withstanding more [...] Read more.
The constant rise in the global temperature and unpredictable shifts in precipitation patterns are two of the main effects of climate change. Therefore, there is an increasing amount of interest in the identification of tree species, provenances and genotypes capable of withstanding more arid conditions and tolerating drought stress. In the present review, we focus our attention on generally more susceptible conifers and describe the different strategies that plants adopt to respond to drought stress. We describe the main approaches taken in studies of conifer adaptations to low water availability, the advantages and limitations of each, and the main results obtained with each of these approaches in the recent years. Then we discuss how the increasing amount of morphological, physiological and genetic data may find practical applications in forest management, and in particular in next-generation breeding programs. Finally, we provide some recommendations for future research. In particular, we suggest extending future studies to a broader selection of species and genera, increasing the number of studies on adult plants, in particular those on gene expression, and distinguishing between the different types of drought stress that a tree can withstand during its life cycle. The integration of data coming from different disciplines and approaches will be a key factor to increasing our knowledge about a trait as complex as drought resistance. Full article
(This article belongs to the Special Issue Tree Genetics: Molecular and Functional Characterization of Genes)
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25 pages, 2759 KiB  
Review
Twelve Years into Genomic Selection in Forest Trees: Climbing the Slope of Enlightenment of Marker Assisted Tree Breeding
by Dario Grattapaglia
Forests 2022, 13(10), 1554; https://doi.org/10.3390/f13101554 - 23 Sep 2022
Cited by 42 | Viewed by 8939
Abstract
Twelve years have passed since the early outlooks of applying genomic selection (GS) to forest tree breeding, initially based on deterministic simulations, soon followed by empirical reports. Given its solid projections for causing a paradigm shift in tree breeding practice in the years [...] Read more.
Twelve years have passed since the early outlooks of applying genomic selection (GS) to forest tree breeding, initially based on deterministic simulations, soon followed by empirical reports. Given its solid projections for causing a paradigm shift in tree breeding practice in the years to come, GS went from a hot, somewhat hyped, topic to a fast-moving area of applied research and operational implementation worldwide. The hype cycle curve of emerging technologies introduced by Gartner Inc. in 1995, models the path a technology takes in terms of expectations of its value through time. Starting with a sudden and excessively positive “peak of inflated expectations” at its introduction, a technology that survives the “valley of disappointment” moves into maturity to climb the “slope of enlightenment”, to eventually reach the “plateau of productivity”. Following the pioneering steps of GS in animal breeding, we have surpassed the initial phases of the Gartner hype cycle and we are now climbing the slope of enlightenment towards a wide application of GS in forest tree breeding. By merging modern high-throughput DNA typing, time-proven quantitative genetics and mixed-model analysis, GS moved the focus away from the questionable concept of dissecting a complex, polygenic trait in its individual components for breeding advancement. Instead of trying to find the needle in a haystack, i.e., the “magic” gene in the complex and fluid genome, GS more efficiently and humbly “buys the whole haystack” of genomic effects to predict complex phenotypes, similarly to an exchange-traded fund that more efficiently “buys the whole market”. Tens of studies have now been published in forest trees showing that GS matches or surpasses the performance of phenotypic selection for growth and wood properties traits, enhancing the rate of genetic gain per unit time by increasing selection intensity, radically reducing generation interval and improving the accuracy of breeding values. Breeder-friendly and cost-effective SNP (single nucleotide polymorphism) genotyping platforms are now available for all mainstream plantation forest trees, but methods based on low-pass whole genome sequencing with imputation might further reduce genotyping costs. In this perspective, I provide answers to why GS will soon become the most efficient and effective way to carry out advanced tree breeding, and outline a simple pilot demonstration project that tree breeders can propose in their organization. While the fundamental properties of GS in tree breeding are now solidly established, strategic, logistics and financial aspects for the optimized adoption of GS are now the focus of attentions towards the plateau of productivity in the cycle, when this new breeding method will become fully established into routine tree improvement. Full article
(This article belongs to the Special Issue Using Genomic Information in Forest Tree Breeding, Restoration, and Conservation: Separating Hype from Reality)
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Graphical abstract

46 pages, 4818 KiB  
Review
Review of Wood Modification and Wood Functionalization Technologies
by Samuel L. Zelinka, Michael Altgen, Lukas Emmerich, Nathanael Guigo, Tobias Keplinger, Maija Kymäläinen, Emil E. Thybring and Lisbeth G. Thygesen
Forests 2022, 13(7), 1004; https://doi.org/10.3390/f13071004 - 26 Jun 2022
Cited by 105 | Viewed by 15811
Abstract
Wood modifications are becoming popular as a way to enhance the performance of wood, either to make it more durable, improve the performance of wood, or give it new functionality as a multifunctional or smart material. While wood modifications have been examined since [...] Read more.
Wood modifications are becoming popular as a way to enhance the performance of wood, either to make it more durable, improve the performance of wood, or give it new functionality as a multifunctional or smart material. While wood modifications have been examined since the early 1900s, the topic has become a dominant area of study in wood science over the past decade. This review summarizes recent advances and provides future perspective on a selection of wood modifications, i.e., the methods that are currently commercialized (acetylation, furfurylation, and thermal modification), a rediscovered ancient practice (charring), a family of polymerization modifications that have so far made it to the pilot scale, and examples of novel wood-based functional materials explored at laboratory scale. Full article
(This article belongs to the Special Issue Reviews on Structure and Physical and Mechanical Properties of Wood)
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31 pages, 4562 KiB  
Review
Recent Advances in Forest Insect Pests and Diseases Monitoring Using UAV-Based Data: A Systematic Review
by André Duarte, Nuno Borralho, Pedro Cabral and Mário Caetano
Forests 2022, 13(6), 911; https://doi.org/10.3390/f13060911 - 10 Jun 2022
Cited by 80 | Viewed by 9380
Abstract
Unmanned aerial vehicles (UAVs) are platforms that have been increasingly used over the last decade to collect data for forest insect pest and disease (FIPD) monitoring. These machines provide flexibility, cost efficiency, and a high temporal and spatial resolution of remotely sensed data. [...] Read more.
Unmanned aerial vehicles (UAVs) are platforms that have been increasingly used over the last decade to collect data for forest insect pest and disease (FIPD) monitoring. These machines provide flexibility, cost efficiency, and a high temporal and spatial resolution of remotely sensed data. The purpose of this review is to summarize recent contributions and to identify knowledge gaps in UAV remote sensing for FIPD monitoring. A systematic review was performed using the preferred reporting items for systematic reviews and meta-analysis (PRISMA) protocol. We reviewed the full text of 49 studies published between 2015 and 2021. The parameters examined were the taxonomic characteristics, the type of UAV and sensor, data collection and pre-processing, processing and analytical methods, and software used. We found that the number of papers on this topic has increased in recent years, with most being studies located in China and Europe. The main FIPDs studied were pine wilt disease (PWD) and bark beetles (BB) using UAV multirotor architectures. Among the sensor types, multispectral and red–green–blue (RGB) bands were preferred for the monitoring tasks. Regarding the analytical methods, random forest (RF) and deep learning (DL) classifiers were the most frequently applied in UAV imagery processing. This paper discusses the advantages and limitations associated with the use of UAVs and the processing methods for FIPDs, and research gaps and challenges are presented. Full article
(This article belongs to the Special Issue Advanced Applications of UAV Remote Sensing in Forest Structure)
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15 pages, 834 KiB  
Review
Cultivation Potential and Uses of Paulownia Wood: A Review
by Marcin Jakubowski
Forests 2022, 13(5), 668; https://doi.org/10.3390/f13050668 - 26 Apr 2022
Cited by 38 | Viewed by 15111
Abstract
This review aimed to determine the current state of research on the growth conditions and use pertaining to paulownia wood, mainly in European countries where paulownia has been introduced only relatively recently. Several studies carried out on Paulownia hybrids have shown significant differences [...] Read more.
This review aimed to determine the current state of research on the growth conditions and use pertaining to paulownia wood, mainly in European countries where paulownia has been introduced only relatively recently. Several studies carried out on Paulownia hybrids have shown significant differences in the growth dynamics of individual clones in their response to local environmental and climatic conditions. For example, dry biomass production yields in the second year of cultivation range from 1.5 t ha−1 to as much as 14 t ha−1. This diversity has manifested itself not only in growth characteristics but also in the properties of the wood and the possibilities for its use. Despite having clear similarities to the genus Paulownia, the cultivation of species and hybrids under different conditions has produced varying results. The best growing conditions for this wood (that make economic sense) are in the Middle East and Southern Europe. These regions have accumulated the most experience because of the earlier establishment of the crop. Today, paulownia cultivation is dominated by hybrids with selected traits that are propagated mainly in vitro. The most commonly planted hybrids include the clones in vitro 112, Cotevisa 2 and Shan Tong. The growth results and production capacity in central European countries are lower compared to Southern Europe. Experiments on paulownia cultivation are still relatively young, mainly consisting of replicating the cultivation of hybrids developed in Asia or Southern Europe. However, agronomic procedures are being developed and reactions to local climatic conditions are being studied. It is likely that, in the next few years, the profitability of growing paulownia in these regions will become apparent. Full article
(This article belongs to the Special Issue Wood as Biomechanical Structure)
27 pages, 1005 KiB  
Review
The Potential of Low-Cost 3D Imaging Technologies for Forestry Applications: Setting a Research Agenda for Low-Cost Remote Sensing Inventory Tasks
by James McGlade, Luke Wallace, Karin Reinke and Simon Jones
Forests 2022, 13(2), 204; https://doi.org/10.3390/f13020204 - 28 Jan 2022
Cited by 18 | Viewed by 5801
Abstract
Limitations with benchmark light detection and ranging (LiDAR) technologies in forestry have prompted the exploration of handheld or wearable low-cost 3D sensors (<2000 USD). These sensors are now being integrated into consumer devices, such as the Apple iPad Pro 2020. This study was [...] Read more.
Limitations with benchmark light detection and ranging (LiDAR) technologies in forestry have prompted the exploration of handheld or wearable low-cost 3D sensors (<2000 USD). These sensors are now being integrated into consumer devices, such as the Apple iPad Pro 2020. This study was aimed at determining future research recommendations to promote the adoption of terrestrial low-cost technologies within forest measurement tasks. We reviewed the current literature surrounding the application of low-cost 3D remote sensing (RS) technologies. We also surveyed forestry professionals to determine what inventory metrics were considered important and/or difficult to capture using conventional methods. The current research focus regarding inventory metrics captured by low-cost sensors aligns with the metrics identified as important by survey respondents. Based on the literature review and survey, a suite of research directions are proposed to democratise the access to and development of low-cost 3D for forestry: (1) the development of methods for integrating standalone colour and depth (RGB-D) sensors into handheld or wearable devices; (2) the development of a sensor-agnostic method for determining the optimal capture procedures with low-cost RS technologies in forestry settings; (3) the development of simultaneous localisation and mapping (SLAM) algorithms designed for forestry environments; and (4) the exploration of plot-scale forestry captures that utilise low-cost devices at both terrestrial and airborne scales. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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15 pages, 1303 KiB  
Review
Impacts of Climate Change on Blue Carbon Stocks and Fluxes in Mangrove Forests
by Daniel Michael Alongi
Forests 2022, 13(2), 149; https://doi.org/10.3390/f13020149 - 19 Jan 2022
Cited by 70 | Viewed by 11680
Abstract
Mangroves store blue carbon (693 Mg CORG ha−1) disproportionate to their small area, mainly (74%) in deep soil horizons. Global stock estimates for mangroves (5.23–8.63 Pg CORG) are equivalent to 15–24% of those in the tropical coastal ocean. [...] Read more.
Mangroves store blue carbon (693 Mg CORG ha−1) disproportionate to their small area, mainly (74%) in deep soil horizons. Global stock estimates for mangroves (5.23–8.63 Pg CORG) are equivalent to 15–24% of those in the tropical coastal ocean. Carbon burial in mangrove soils averages 184 g CORG m−2 a−1 with global estimates (9.6–15.8 Tg CORG a−1) reflecting their importance in carbon sequestration. Extreme weather events result in carbon stock losses and declines in carbon cycling and export. Increased frequency and ferocity of storms result in increasingly negative responses with increasing strength. Increasing temperatures result in increases in carbon stocks and cycling up to a critical threshold, while positive/negative responses will likely result from increases/decreases in rainfall. Forest responses to sea-level rise (SLR) and rising CO2 are species- and site-specific and complex due to interactive effects with other drivers (e.g., temperature, salinity). The SLR critical threshold is ≈ 6 mm a−1 indicating survival only under very low-low CO2 emissions scenarios. Under low coastal squeeze, landward migration could result in sequestration and CO2 losses of 1.5 and −1.1 Pg C with net stock gains and losses (−0.3 to +0.5 Pg C) and CO2 losses (−3.4 Pg) under high coastal squeeze. Full article
(This article belongs to the Special Issue Carbon and Water Cycles in Coastal Forests under Climate Change and Variability)
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18 pages, 2388 KiB  
Review
Structural Stability of Urban Trees Using Visual and Instrumental Techniques: A Review
by Camila S. F. Linhares, Raquel Gonçalves, Luis M. Martins and Sofia Knapic
Forests 2021, 12(12), 1752; https://doi.org/10.3390/f12121752 - 11 Dec 2021
Cited by 19 | Viewed by 5811
Abstract
This review focuses on tree health assessment in urban forest, specifically on the methodologies commonly used to detect levels, dimensions, and location of wood deterioration. The acknowledged benefits to the urban forestry area from the application of assessment techniques are also addressed. A [...] Read more.
This review focuses on tree health assessment in urban forest, specifically on the methodologies commonly used to detect levels, dimensions, and location of wood deterioration. The acknowledged benefits to the urban forestry area from the application of assessment techniques are also addressed. A summary is presented of the different methodologies, such as visual analyses, acoustic tomography, and digital wood inspection drill, with the underlined importance of the biodeterioration of wood by fungi and termites. Full article
(This article belongs to the Section Wood Science and Forest Products)
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30 pages, 2619 KiB  
Review
Forest and Wellbeing: Bridging Medical and Forest Research for Effective Forest-Based Initiatives
by Ilaria Doimo, Mauro Masiero and Paola Gatto
Forests 2020, 11(8), 791; https://doi.org/10.3390/f11080791 - 22 Jul 2020
Cited by 84 | Viewed by 12547
Abstract
Research Highlights: This review gives an overview of existing literature on the emerging topic of human wellbeing-forest contact nexus and provides a preliminary framework linking forests to wellbeing by highlighting key variables affecting this relationship. Background and Objectives: Existing literature reveals the psychological, [...] Read more.
Research Highlights: This review gives an overview of existing literature on the emerging topic of human wellbeing-forest contact nexus and provides a preliminary framework linking forests to wellbeing by highlighting key variables affecting this relationship. Background and Objectives: Existing literature reveals the psychological, physiological and social wellbeing benefits of contact with forest ecosystems; however, the role of forests in this relationship remains largely unexplored. The objectives of this review are twofold: (i) to provide an overview of the contributions of forest experiences to human wellbeing and the related interplay with forest ecosystems and (ii) to identify knowledge gaps to inform future research and systematize information available for forest managers and planners to support the development of effective forest-based initiatives. Materials and Methods: A scoping review was performed with a five-phase method integrating a systematic approach on Scopus, Web of Science and PubMed databases and snowball search. Studies were analyzed using a descriptive-analytical method. Results: Overall, 93 papers were included in the review. These are mainly from health-related sciences providing limited information for forest managers, planners and practitioners. Four main underlying variables of the forest-wellbeing relationship are identified: interaction, forest features, sensorial dimension of the forest and individual traits and reactions. Conclusions: Forest-based initiatives provide good opportunities for supporting public health and time spent in contact with forests seems to have a “health-bonus”. Whether and to what extent forest management can contribute to this is still poorly investigated. There is the need to better study causal relationships between specific forest features, type of interactions, frequency and “dose” of experiences, individual reactions and needs and wellbeing effects to maximize benefits from forest-based initiatives. Full article
(This article belongs to the Special Issue The Designing and Marketing of Regulating and Cultural Forest Ecosystem Services: Successes, Failures, Lessons Learnt and Future Perspectives)
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38 pages, 3813 KiB  
Review
Global Geographic Distribution and Host Range of Fusarium circinatum, the Causal Agent of Pine Pitch Canker
by Rein Drenkhan, Beccy Ganley, Jorge Martín-García, Petr Vahalík, Kalev Adamson, Katarína Adamčíková, Rodrigo Ahumada, Lior Blank, Helena Bragança, Paolo Capretti, Michelle Cleary, Carolina Cornejo, Kateryna Davydenko, Julio J. Diez, Hatice Tuğba Doğmuş Lehtijärvi, Miloň Dvořák, Rasmus Enderle, Gerda Fourie, Margarita Georgieva, Luisa Ghelardini, Jarkko Hantula, Renaud Ioos, Eugenia Iturritxa, Loukas Kanetis, Natalia N. Karpun, András Koltay, Elena Landeras, Svetlana Markovskaja, Nebai Mesanza, Ivan Milenković, Dmitry L. Musolin, Konstantinos Nikolaou, Justyna A. Nowakowska, Nikica Ogris, Funda Oskay, Tomasz Oszako, Irena Papazova-Anakieva, Marius Paraschiv, Matias Pasquali, Francesco Pecori, Trond Rafoss, Kristina Raitelaitytė, Rosa Raposo, Cecile Robin, Carlos A. Rodas, Alberto Santini, Antonio V. Sanz-Ros, Andrey V. Selikhovkin, Alejandro Solla, Mirkka Soukainen, Nikoleta Soulioti, Emma T. Steenkamp, Panaghiotis Tsopelas, Aleksandar Vemić, Anna Maria Vettraino, Michael J. Wingfield, Stephen Woodward, Cristina Zamora-Ballesteros and Martin S. Mullettadd Show full author list remove Hide full author list
Forests 2020, 11(7), 724; https://doi.org/10.3390/f11070724 - 1 Jul 2020
Cited by 61 | Viewed by 11788
Abstract
Fusarium circinatum, the causal agent of pine pitch canker (PPC), is currently one of the most important threats of Pinus spp. globally. This pathogen is known in many pine-growing regions, including natural and planted forests, and can affect all life stages of [...] Read more.
Fusarium circinatum, the causal agent of pine pitch canker (PPC), is currently one of the most important threats of Pinus spp. globally. This pathogen is known in many pine-growing regions, including natural and planted forests, and can affect all life stages of trees, from emerging seedlings to mature trees. Despite the importance of PPC, the global distribution of F. circinatum is poorly documented, and this problem is also true of the hosts within countries that are affected. The aim of this study was to review the global distribution of F. circinatum, with a particular focus on Europe. We considered (1) the current and historical pathogen records, both positive and negative, based on confirmed reports from Europe and globally; (2) the genetic diversity and population structure of the pathogen; (3) the current distribution of PPC in Europe, comparing published models of predicted disease distribution; and (4) host susceptibility by reviewing literature and generating a comprehensive list of known hosts for the fungus. These data were collated from 41 countries and used to compile a specially constructed geo-database. A review of 6297 observation records showed that F. circinatum and the symptoms it causes on conifers occurred in 14 countries, including four in Europe, and is absent in 28 countries. Field observations and experimental data from 138 host species revealed 106 susceptible host species including 85 Pinus species, 6 non-pine tree species and 15 grass and herb species. Our data confirm that susceptibility to F. circinatum varies between different host species, tree ages and environmental characteristics. Knowledge on the geographic distribution, host range and the relative susceptibility of different hosts is essential for disease management, mitigation and containment strategies. The findings reported in this review will support countries that are currently free of F. circinatum in implementing effective procedures and restrictions and prevent further spread of the pathogen. Full article
(This article belongs to the Special Issue Biological and Bio-Based Management of Forest Pests and Pathogens)
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24 pages, 3073 KiB  
Review
Co-Creating Conceptual and Working Frameworks for Implementing Forest and Landscape Restoration Based on Core Principles
by Robin L. Chazdon, Victoria Gutierrez, Pedro H. S. Brancalion, Lars Laestadius and Manuel R. Guariguata
Forests 2020, 11(6), 706; https://doi.org/10.3390/f11060706 - 24 Jun 2020
Cited by 44 | Viewed by 10612
Abstract
Existing guidelines and best-practices documents do not satisfy, at present, the need for guiding implementation of Forest and Landscape Restoration (FLR) based on core principles. Given the wide range of FLR practices and the varied spectrum of actors involved, a single working framework [...] Read more.
Existing guidelines and best-practices documents do not satisfy, at present, the need for guiding implementation of Forest and Landscape Restoration (FLR) based on core principles. Given the wide range of FLR practices and the varied spectrum of actors involved, a single working framework is unlikely to be effective, but tailored working frameworks can be co-created based on a common conceptual framework (i.e., a common core set of principles and a generalized set of criteria and indicators). We present background regarding FLR concepts, definitions, and principles, and discuss the challenges that confront effective and long-term implementation of FLR. We enumerate the many benefits that a transformative criteria and indicators framework can bring to actors and different sectors involved in restoration when such framework is anchored in the FLR principles. We justify the need to co-develop and apply specifically tailored working frameworks to help ensure that FLR interventions bring social, economic, and environmental benefits to multiple stakeholders within landscapes and adjust to changing conditions over time. Several examples of working FLR frameworks are presented to illustrate the goals and needs of communities, donors and investors, and government agencies. Transparency, feedback, communication, assessment, and adaptive management are important components of all working frameworks. Finally, we describe existing FLR guidelines and what we can learn from them. Working frameworks can be developed and used by different actors who seek to initiate an FLR process and to align restoration actions at different scales and levels. Full article
(This article belongs to the Special Issue Forest and Landscape Restoration—Making it Happen)
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12 pages, 2168 KiB  
Review
A Review of Non-Chemical Weed Control Practices in Christmas Tree Production
by Debalina Saha, Bert M. Cregg and Manjot Kaur Sidhu
Forests 2020, 11(5), 554; https://doi.org/10.3390/f11050554 - 14 May 2020
Cited by 10 | Viewed by 4647
Abstract
Weeds interfere with Christmas tree growth at any time and at any stage of production. Growers mostly rely on mechanical mowing and applications of herbicides for weed control in their fields. However, herbicides can be phytotoxic to non-target plants, can cause environment-related issues, [...] Read more.
Weeds interfere with Christmas tree growth at any time and at any stage of production. Growers mostly rely on mechanical mowing and applications of herbicides for weed control in their fields. However, herbicides can be phytotoxic to non-target plants, can cause environment-related issues, and their repeated application can even cause herbicide-resistant weeds. The main objective of this manuscript is to provide a review of non-chemical weed control strategies in Christmas tree production and identify areas where current practices could potentially be improved or in which further research is required. Preventing the introduction of weed seeds requires controlling weeds along farm roads, maintaining clean equipment, and eliminating new weeds before they start seeding. Mowing helps to reduce the number of seeds produced by the weeds and can significantly reduce competition with trees. Shropshire sheep are well suited for grazing Christmas tree plantations as they prefer grazing on grasses and weeds rather than on coniferous trees. Weeds can also be controlled around Christmas trees by mulching. Organic mulch can improve soil moisture, maintain soil temperatures, enhance root establishment and transplant survival, and improve plant establishment and overall growth. Incorporating cover crops into Christmas tree plantations may improve tree growth, quality, and soil fertility and can supplement conventional nitrogen fertilizers. However, if cover crops are not properly managed, they can be highly competitive with the trees. Flaming can cause suppression of many annual weed species but is less effective on larger weeds and needs to be applied with caution. Several insects have been used as biological agents to control selective weed species. However, further research is required to focus on several potential biological agents, different types and depths of mulches, on cover crops types and their competition with different species of Christmas trees and their effects on seedling survival and growth. Full article
(This article belongs to the Section Forest Ecology and Management)
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24 pages, 1865 KiB  
Review
Stand Structural Characteristics Are the Most Practical Biodiversity Indicators for Forest Management Planning in Europe
by Marija Ćosović, Miguel N. Bugalho, Dominik Thom and José G. Borges
Forests 2020, 11(3), 343; https://doi.org/10.3390/f11030343 - 19 Mar 2020
Cited by 50 | Viewed by 10567
Abstract
Including biodiversity assessments in forest management planning is becoming increasingly important due to the importance of biodiversity for forest ecosystem resilience provision and sustainable functioning. Here we investigated the potential to include biodiversity indicators into forest management planning in Europe. In particular, we [...] Read more.
Including biodiversity assessments in forest management planning is becoming increasingly important due to the importance of biodiversity for forest ecosystem resilience provision and sustainable functioning. Here we investigated the potential to include biodiversity indicators into forest management planning in Europe. In particular, we aimed to (i) identify biodiversity indicators and data collection methods for biodiversity assessments at the stand and landscape levels, and (ii) evaluate the practicality of those indicators for forest management planning. We performed a literature review in which we screened 188 research studies published between 1990 and 2020. We selected 94 studies that fulfilled the inclusion criteria and examined in more detail. We considered three aspects of biodiversity: structure, composition, and function, and four forest management categories: unmanaged, managed, plantation, and silvopastoral. We used three criteria to evaluate the practicality of forest biodiversity indicators: cost-effectiveness, ease of application, and time-effectiveness. We identified differences in the practicality of biodiversity indicators for their incorporation into management plans. Stand-level indicators are more practical than landscape-level indicators. Moreover, structural biodiversity indicators (e.g., large trees, canopy openness, and old forest stands) are more useful in management plans than compositional indicators, as these are easily observable by non-professionals and can be obtained by forest inventories. Compositional indicators such are vascular plants, fungi, bryophyte, lichens, and invertebrate species are hard to identify by non-professionals and thus are impractical. Functional indicators (e.g., nutrient cycling) are not sufficiently addressed in the literature. Using recently updated existing databases (e.g., national forest inventories and bird atlases) is very time and cost-efficient. Remote sensing and other technology (e.g., smartphone applications) are promising for efficient data collection in the future. However, more research is needed to make these tools more accurate and applicable to a variety of ecological conditions and scales. Until then, forest stand structural variables derived from inventories can help improve management plans to prepare European forests towards an uncertain future. Full article
(This article belongs to the Special Issue Forest Structural Characteristics and Their Relationship with Ecosystem Services and Functions)
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14 pages, 7108 KiB  
Review
Metrics of Growth Habit Derived from the 3D Tree Point Cloud Used for Species Determination—A New Approach in Botanical Taxonomy Tested on Dragon Tree Group Example
by Petr Vahalík, Karel Drápela, Andrea Procházková, Zdeněk Patočka, Marie Balková, Martin Šenfeldr, Klára Lengálová, Hana Kalivodová, Lucie Vaníčková, Lenka Ehrenbergerová, Samuel Lvončík and Petr Maděra
Forests 2020, 11(3), 272; https://doi.org/10.3390/f11030272 - 28 Feb 2020
Cited by 6 | Viewed by 2969
Abstract
Detailed, three-dimensional modeling of trees is a new approach in botanical taxonomy. Representations of individual trees are a prerequisite for accurate assessments of tree growth and morphological metronomy. This study tests the abilities of 3D modeling of trees to determine the various metrics [...] Read more.
Detailed, three-dimensional modeling of trees is a new approach in botanical taxonomy. Representations of individual trees are a prerequisite for accurate assessments of tree growth and morphological metronomy. This study tests the abilities of 3D modeling of trees to determine the various metrics of growth habit and compare morphological differences. The study included four species of the genus Dracaena: D. draco, D. cinnabari, D. ombet, and D. serrulata. Forty-nine 3D tree point clouds were created, and their morphological metrics were derived and compared. Our results indicate the possible application of 3D tree point clouds to dendrological taxonomy. Basic metrics of growth habit and coefficients derived from the 3D point clouds developed in the present study enable the statistical evaluation of differences among dragon tree species. Full article
(This article belongs to the Special Issue Dragon Trees - Tertiary Relicts in Current Reality)
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34 pages, 3222 KiB  
Review
What We Know and What We Do Not Know about Dragon Trees?
by Petr Maděra, Alan Forrest, Pavel Hanáček, Petr Vahalík, Roman Gebauer, Roman Plichta, Radek Jupa, Julian Jansen Van Rensburg, Miranda Morris, Nadezhda Nadezhdina, Lucie Vaníčková, Joanna Jura-Morawiec, Justyna Wiland-Szymańska, Hana Kalivodová, Klára Lengálová, Martin Rejžek and Hana Habrová
Forests 2020, 11(2), 236; https://doi.org/10.3390/f11020236 - 21 Feb 2020
Cited by 42 | Viewed by 13266
Abstract
This article is a broad review focused on dragon trees—one of the most famous groups of trees in the world, well known from ancient times. These tertiary relicts are severely endangered in most of the area where they grow. The characteristic features of [...] Read more.
This article is a broad review focused on dragon trees—one of the most famous groups of trees in the world, well known from ancient times. These tertiary relicts are severely endangered in most of the area where they grow. The characteristic features of the dragon tree group are described and the species belonging to this group are listed. This review gathers together current knowledge regarding the taxonomy, evolution, anatomy and morphology, physiology, and ontogeny of arborescent dragon tree species. Attention is also paid to the composition, harvesting, medicinal, and ethnobotanical use of the resin (dragons’ blood). An evaluation of population structure, distribution, ecology, threats, and nature conservation forms the final part of the review. In the conclusions we recommend further avenues of research that will be needed to effectively protect all dragon tree species. Full article
(This article belongs to the Special Issue Dragon Trees - Tertiary Relicts in Current Reality)
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22 pages, 2241 KiB  
Review
Functional Role of Extrafloral Nectar in Boreal Forest Ecosystems under Climate Change
by Jarmo K. Holopainen, James D. Blande and Jouni Sorvari
Forests 2020, 11(1), 67; https://doi.org/10.3390/f11010067 - 6 Jan 2020
Cited by 6 | Viewed by 7967
Abstract
Carbohydrate-rich extrafloral nectar (EFN) is produced in nectaries on the leaves, stipules, and stems of plants and provides a significant energy source for ants and other plant mutualists outside of the flowering period. Our review of literature on EFN indicates that only a [...] Read more.
Carbohydrate-rich extrafloral nectar (EFN) is produced in nectaries on the leaves, stipules, and stems of plants and provides a significant energy source for ants and other plant mutualists outside of the flowering period. Our review of literature on EFN indicates that only a few forest plant species in cool boreal environments bear EFN-producing nectaries and that EFN production in many boreal and subarctic plant species is poorly studied. Boreal forest, the world’s largest land biome, is dominated by coniferous trees, which, like most gymnosperms, do not produce EFN. Notably, common deciduous tree species that can be dominant in boreal forest stands, such as Betula and Alnus species, do not produce EFN, while Prunus and Populus species are the most important EFN-producing tree species. EFN together with aphid honeydew is known to play a main role in shaping ant communities. Ants are considered to be keystone species in mixed and conifer-dominated boreal and mountain forests because they transfer a significant amount of carbon from the canopy to the soil. Our review suggests that in boreal forests aphid honeydew is a more important carbohydrate source for ants than in many warmer ecosystems and that EFN-bearing plant species might not have a competitive advantage against herbivores. However, this hypothesis needs to be tested in the future. Warming of northern ecosystems under climate change might drastically promote the invasion of many EFN-producing plants and the associated insect species that consume EFN as their major carbohydrate source. This may result in substantial changes in the diet preferences of ant communities, the preventative roles of ants against insect pest outbreaks, and the ecosystem services they provide. However, wood ants have adapted to using tree sap that leaks from bark cracks in spring, which may mitigate the effects of improved EFN availability. Full article
(This article belongs to the Section Forest Ecology and Management)
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12 pages, 717 KiB  
Review
Forest Climax Phenomenon: An Invariance of Scale
by Raimundas Petrokas
Forests 2020, 11(1), 56; https://doi.org/10.3390/f11010056 - 2 Jan 2020
Cited by 8 | Viewed by 4376
Abstract
We can think of forests as multiscale multispecies networks, constantly evolving toward a climax or potential natural community—the successional process-pattern of natural regeneration that exhibits sensitivity to initial conditions. This is why I look into forest succession in light of the Red Queen [...] Read more.
We can think of forests as multiscale multispecies networks, constantly evolving toward a climax or potential natural community—the successional process-pattern of natural regeneration that exhibits sensitivity to initial conditions. This is why I look into forest succession in light of the Red Queen hypothesis and focus on the key aspects of ecological self-organisation: dynamical criticality, evolvability and intransitivity. The idea of the review is that forest climax should be associated with habitat dynamics driven by a large continuum of ecologically equivalent time scales, so that the same ecological conclusions could be drawn statistically from any scale. A synthesis of the literature is undertaken in order to (1) present the framework for assessing habitat dynamics and (2) present the types of successional trajectories based on tree regeneration mode in forest gaps. In general, there are four types of successional trajectories within the process-pattern of forest regeneration that exhibits sensitivity to initial conditions: advance reproduction specialists, advance reproduction generalists, early reproduction generalists and early reproduction specialists. A successional trajectory is an expression of a fractal connectivity among certain patterns of natural regeneration in the multiscale multispecies networks of landscape habitats. Theoretically, the organically derived measures of pattern diversity, integrity and complexity, determined by the rates of recruitment, growth and mortality of forest tree species, are the means to test the efficacy of specific interventions to avert the disturbance-related decline in forest regeneration. That is of relevance to the emerging field of biocomplexity research. Full article
(This article belongs to the Special Issue Protection and Management of Species, Habitats, Ecosystems and Landscapes)
31 pages, 3565 KiB  
Review
Treeline Research—From the Roots of the Past to Present Time. A Review
by Friedrich-Karl Holtmeier and Gabriele Broll
Forests 2020, 11(1), 38; https://doi.org/10.3390/f11010038 - 26 Dec 2019
Cited by 51 | Viewed by 7908
Abstract
Elevational and polar treelines have been studied for more than two centuries. The aim of the present article is to highlight in retrospect the scope of treeline research, scientific approaches and hypotheses on treeline causation, its spatial structures and temporal change. Systematic treeline [...] Read more.
Elevational and polar treelines have been studied for more than two centuries. The aim of the present article is to highlight in retrospect the scope of treeline research, scientific approaches and hypotheses on treeline causation, its spatial structures and temporal change. Systematic treeline research dates back to the end of the 19th century. The abundance of global, regional, and local studies has provided a complex picture of the great variety and heterogeneity of both altitudinal and polar treelines. Modern treeline research started in the 1930s, with experimental field and laboratory studies on the trees’ physiological response to the treeline environment. During the following decades, researchers’ interest increasingly focused on the altitudinal and polar treeline dynamics to climate warming since the Little Ice Age. Since the 1970s interest in treeline dynamics again increased and has considerably intensified from the 1990s to today. At the same time, remote sensing techniques and GIS application have essentially supported previous analyses of treeline spatial patterns and temporal variation. Simultaneously, the modelling of treeline has been rapidly increasing, often related to the current treeline shift and and its implications for biodiversity, and the ecosystem function and services of high-elevation forests. It appears, that many seemingly ‘new ideas’ already originated many decades ago and just confirm what has been known for a long time. Suggestions for further research are outlined. Full article
(This article belongs to the Special Issue Alpine and Polar Treelines in a Changing Environment)
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19 pages, 2787 KiB  
Review
Tropical Dry Forest Diversity, Climatic Response, and Resilience in a Changing Climate
by Kayla Stan and Arturo Sanchez-Azofeifa
Forests 2019, 10(5), 443; https://doi.org/10.3390/f10050443 - 23 May 2019
Cited by 77 | Viewed by 14681
Abstract
Central and South America tropical dry forest (TDF) is a water-limited biome with a high number of endemic species and numerous ecosystem services which has experienced a boom in research in the last decade. Although the number of case studies across these seasonal, [...] Read more.
Central and South America tropical dry forest (TDF) is a water-limited biome with a high number of endemic species and numerous ecosystem services which has experienced a boom in research in the last decade. Although the number of case studies across these seasonal, water-limited, tropical forests has increased, there has not been a comprehensive review to assess the physiological variability of this biome across the continent and assess how these forests respond to climatic variables. Additionally, understanding forest change and resilience under climatic variability, currently and in the future, is essential for assessing the future extent and health of forests in the future. Therefore, the objective of this paper is to provide a literature review on the variability of TDF diversity and structure across a latitudinal gradient and to assess how these components respond to differences in climatic variables across this geographic area. We first assess the current state of understanding of the structure, biomass, phenological cycles, and successional stages across the latitudinal gradient. We subsequently review the response of these five areas to differences in precipitation, temperature, and extreme weather events, such as droughts and hurricanes. We find that there is a range of adaptability to precipitation, with many areas exhibiting drought tolerance except under the most extreme circumstances, while being susceptible to damage from increased extreme precipitation events. Finally, we use this climatic response to provide a commentary on the projected resilience of TDFs under climatic changes, finding a likelihood of resilience under drying scenarios, although model projections do not agree on the magnitude or direction of precipitation change. This review of quantitative studies will provide more concrete details on the current diversity that encompasses the TDF, the natural climatic ranges under which this ecosystem can survive and thrive, and can help inform future forest management practices under climate change scenarios. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Other

46 pages, 5413 KiB  
Systematic Review
Nature-Based Tourism in National and Natural Parks in Europe: A Systematic Review
by Delia S. Donici and Diana E. Dumitras
Forests 2024, 15(4), 588; https://doi.org/10.3390/f15040588 - 24 Mar 2024
Cited by 7 | Viewed by 4867
Abstract
Considered among the fastest-growing industries in the world, tourism brings immense benefits but also creates certain challenges. Conservation of natural resources is a stringent necessity, without which the extraordinary ecosystems’ attributes that create the premises for nature-based tourism would reduce, alter, and subsequently [...] Read more.
Considered among the fastest-growing industries in the world, tourism brings immense benefits but also creates certain challenges. Conservation of natural resources is a stringent necessity, without which the extraordinary ecosystems’ attributes that create the premises for nature-based tourism would reduce, alter, and subsequently disappear. The aim of the present review is twofold: gaining a general understanding of what nature-based tourism is and providing a systematic literature review of articles on nature-based tourism in European national and natural parks, with emphasis on their applicability. The articles included in the present review were selected based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The review accounts for research conducted between 2000 and 2021 and is divided into two sections: articles aimed at understanding tourists’ behaviour and articles that are focused on other stakeholders or have the local communities in the foreground. While many studies are aimed at understanding tourists’ behaviour as a means of improving parks’ management, participatory strategies including local communities are often indicated as beneficial. The results of this paper can facilitate future research in the field and provide valuable knowledge to policymakers and any interested parties. Full article
(This article belongs to the Special Issue Changes in the Value of Forest Resources: Impacts of Human Activities)
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16 pages, 2994 KiB  
Perspective
Linking Forest Flammability and Plant Vulnerability to Drought
by Rachael H. Nolan, Chris J. Blackman, Víctor Resco de Dios, Brendan Choat, Belinda E. Medlyn, Ximeng Li, Ross A. Bradstock and Matthias M. Boer
Forests 2020, 11(7), 779; https://doi.org/10.3390/f11070779 - 20 Jul 2020
Cited by 91 | Viewed by 10795
Abstract
Globally, fire regimes are being altered by changing climatic conditions. New fire regimes have the potential to drive species extinctions and cause ecosystem state changes, with a range of consequences for ecosystem services. Despite the co-occurrence of forest fires with drought, current approaches [...] Read more.
Globally, fire regimes are being altered by changing climatic conditions. New fire regimes have the potential to drive species extinctions and cause ecosystem state changes, with a range of consequences for ecosystem services. Despite the co-occurrence of forest fires with drought, current approaches to modelling flammability largely overlook the large body of research into plant vulnerability to drought. Here, we outline the mechanisms through which plant responses to drought may affect forest flammability, specifically fuel moisture and the ratio of dead to live fuels. We present a framework for modelling live fuel moisture content (moisture content of foliage and twigs) from soil water content and plant traits, including rooting patterns and leaf traits such as the turgor loss point, osmotic potential, elasticity and leaf mass per area. We also present evidence that physiological drought stress may contribute to previously observed fuel moisture thresholds in south-eastern Australia. Of particular relevance is leaf cavitation and subsequent shedding, which transforms live fuels into dead fuels, which are drier, and thus easier to ignite. We suggest that capitalising on drought research to inform wildfire research presents a major opportunity to develop new insights into wildfires, and new predictive models of seasonal fuel dynamics. Full article
(This article belongs to the Special Issue Forest Fire Risk Prediction)
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16 pages, 1389 KiB  
Perspective
Vitex agnus-castus L.: Main Features and Nutraceutical Perspectives
by Eliana B. Souto, Alessandra Durazzo, Amirhossein Nazhand, Massimo Lucarini, Massimo Zaccardelli, Selma B. Souto, Amelia M. Silva, Patricia Severino, Ettore Novellino and Antonello Santini
Forests 2020, 11(7), 761; https://doi.org/10.3390/f11070761 - 16 Jul 2020
Cited by 16 | Viewed by 16877
Abstract
Medicinal plants are used worldwide due to their lower risk of side effects and eco-friendly, cost-effective production when compared to chemical drugs, encouraging researchers to further exploit the therapeutic potential of the former. One of the most popular medicinal plants is Vitex agnus-castus [...] Read more.
Medicinal plants are used worldwide due to their lower risk of side effects and eco-friendly, cost-effective production when compared to chemical drugs, encouraging researchers to further exploit the therapeutic potential of the former. One of the most popular medicinal plants is Vitex agnus-castus L., grown in tropical and sub-tropical regions, to which different health benefits have already been attributed. In this perspective article, the in vitro and in vivo therapeutic properties of V. agnus-castus L. have been analyzed and reviewed with a special focus on its health-promoting effects and potential nutraceutical applications. Full article
(This article belongs to the Special Issue Forest, Foods and Nutrition)
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8 pages, 1532 KiB  
Conference Report
Manila Declaration on Forest and Landscape Restoration: Making It Happen
by Robin L. Chazdon, John Herbohn, Sharif A. Mukul, Nestor Gregorio, Liz Ota, Rhett D. Harrison, Patrick B. Durst, Rafael B. Chaves, Arturo Pasa, James G. Hallett, J. David Neidel, Cathy Watson and Victoria Gutierrez
Forests 2020, 11(6), 685; https://doi.org/10.3390/f11060685 - 18 Jun 2020
Cited by 25 | Viewed by 7607
Abstract
Globally, Forest and Landscape Restoration (FLR) is gaining widespread recognition from governments and policymakers for its potential to restore key ecosystem services and to improve human wellbeing. We organized an international conference on FLR, titled—Forest and Landscape Restoration: Making it Happen, between 25–27 [...] Read more.
Globally, Forest and Landscape Restoration (FLR) is gaining widespread recognition from governments and policymakers for its potential to restore key ecosystem services and to improve human wellbeing. We organized an international conference on FLR, titled—Forest and Landscape Restoration: Making it Happen, between 25–27 February 2019 in Manila, the Philippines with 139 participants from 22 countries. The Forest and Landscape Restoration Standards (FLoRES) task force also met prior to the conference, which included a field visit to a pilot community-based forest reforestation site in Biliran Island, the Philippines. Based on the three-day conference, case study presentations, and FLoRES task force meeting, we prepared the Manila Declaration on Forest and Landscape Restoration to highlight the need to support quality of FLR efforts and outcomes in the tropics. Here we provide a synthesis of the main messages of the conference, with key outcomes including the Manila Declaration on Forest and Landscape Restoration, and ways forward to make quality FLR happen on the ground. Full article
(This article belongs to the Special Issue Forest and Landscape Restoration—Making it Happen)
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21 pages, 1301 KiB  
Perspective
Hawthorn (Crataegus spp.): An Updated Overview on Its Beneficial Properties
by Amirhossein Nazhand, Massimo Lucarini, Alessandra Durazzo, Massimo Zaccardelli, Santo Cristarella, Selma B. Souto, Amélia M. Silva, Patrícia Severino, Eliana B. Souto and Antonello Santini
Forests 2020, 11(5), 564; https://doi.org/10.3390/f11050564 - 18 May 2020
Cited by 80 | Viewed by 20061
Abstract
Medicinal plants, many of which are wild, have recently been under the spotlight worldwide due to growing requests for natural and sustainable eco-compatible remedies for pathological conditions with beneficial health effects that are able to support/supplement a daily diet or to support and/or [...] Read more.
Medicinal plants, many of which are wild, have recently been under the spotlight worldwide due to growing requests for natural and sustainable eco-compatible remedies for pathological conditions with beneficial health effects that are able to support/supplement a daily diet or to support and/or replace conventional pharmacological therapy. The main requests for these products are: safety, minimum adverse unwanted effects, better efficacy, greater bioavailability, and lower cost when compared with synthetic medications available on the market. One of these popular herbs is hawthorn (Crataegus spp.), belonging to the Rosaceae family, with about 280 species present in Europe, North Africa, West Asia, and North America. Various parts of this herb, including the berries, flowers, and leaves, are rich in nutrients and beneficial bioactive compounds. Its chemical composition has been reported to have many health benefits, including medicinal and nutraceutical properties. Accordingly, the present review gives a snapshot of the in vitro and in vivo therapeutic potential of this herb on human health. Full article
(This article belongs to the Special Issue Forest, Foods and Nutrition)
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10 pages, 986 KiB  
Brief Report
A Four-Year, Seven-State Reforestation Trial with Eastern Hemlocks (Tsuga canadensis) Resistant to Hemlock Woolly Adelgid (Adelges tsugae)
by Ian G. Kinahan, Gabrielle Grandstaff, Alana Russell, Chad M. Rigsby, Richard A. Casagrande and Evan L. Preisser
Forests 2020, 11(3), 312; https://doi.org/10.3390/f11030312 - 12 Mar 2020
Cited by 6 | Viewed by 5918
Abstract
We conducted over a decade of research into individual eastern hemlock (Tsuga canadensis; hemlock) trees that are potentially resistant to hemlock woolly adelgid (Adelges tsugae; HWA), an invasive xylem-feeding insect that is capable of rapidly killing even mature trees. [...] Read more.
We conducted over a decade of research into individual eastern hemlock (Tsuga canadensis; hemlock) trees that are potentially resistant to hemlock woolly adelgid (Adelges tsugae; HWA), an invasive xylem-feeding insect that is capable of rapidly killing even mature trees. Following clonal propagation of these individuals, in 2015 we planted size- and age-matched HWA-resistant and HWA-susceptible hemlocks in HWA-infested forest plots in seven states. In 2019, we re-surveyed the plots; 96% of HWA-resistant hemlocks survived compared to 48% of susceptible trees. The surviving HWA-resistant trees were also taller, produced more lateral growth, retained more foliage, and supported lower densities of the elongate hemlock scale Fiorinia externa, another invasive hemlock pest, than the surviving HWA-susceptible trees. Our results suggest that HWA management may benefit from additional research exploring the identification, characterization, and use of HWA-resistant eastern hemlocks in future reforestation efforts. Full article
(This article belongs to the Section Forest Ecology and Management)
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17 pages, 2600 KiB  
Concept Paper
From Dendrochronology to Allometry
by Franco Biondi
Forests 2020, 11(2), 146; https://doi.org/10.3390/f11020146 - 27 Jan 2020
Cited by 11 | Viewed by 8411
Abstract
The contribution of tree-ring analysis to other fields of scientific inquiry with overlapping interests, such as forestry and plant population biology, is often hampered by the different parameters and methods that are used for measuring growth. Here I present relatively simple graphical, numerical, [...] Read more.
The contribution of tree-ring analysis to other fields of scientific inquiry with overlapping interests, such as forestry and plant population biology, is often hampered by the different parameters and methods that are used for measuring growth. Here I present relatively simple graphical, numerical, and mathematical considerations aimed at bridging these fields, highlighting the value of crossdating. Lack of temporal control prevents accurate identification of factors that drive wood formation, thus crossdating becomes crucial for any type of tree growth study at inter-annual and longer time scales. In particular, exactly dated tree rings, and their measurements, are crucial contributors to the testing and betterment of allometric relationships. Full article
(This article belongs to the Section Forest Ecology and Management)
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