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Forests, Volume 13, Issue 6 (June 2022) – 150 articles

Cover Story (view full-size image): The photo shows a plantation of half-sibs Abies alba Mill. (plot No. 1, subcompartment 416Ad), one of the rarest coniferous species in Białowieża Forest. This is the only object (included in the information system of forest genetic resources conserved in Europe) in which the seed progeny of the autochthonous silver fir population most advanced to the northeast, located in the Tysovik tract, was collected. This species is typical of the mountainous regions of central and southern Europe. But in our case, we are dealing with a generation of a population adapted to lowland conditions. The state of plants that have already entered the fruiting phase does not incite any concern at the present time. View this paper
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Article
Changes in the Abundance of Monoterpenes from Breathable Air of a Mediterranean Conifer Forest: When Is the Best Time for a Human Healthy Leisure Activity?
Forests 2022, 13(6), 965; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060965 - 20 Jun 2022
Viewed by 436
Abstract
The exposure to monoterpenes emitted by plants to the air might provide human health benefits during forest-based leisure activities. However, forests, especially Mediterranean ones, lack studies to relate forest production and the emission of monoterpenes, considering potential human forest exposure. Thus, the aim [...] Read more.
The exposure to monoterpenes emitted by plants to the air might provide human health benefits during forest-based leisure activities. However, forests, especially Mediterranean ones, lack studies to relate forest production and the emission of monoterpenes, considering potential human forest exposure. Thus, the aim of this study was to analyze the variation in the abundance of monoterpenes in the human breathable air under the canopy of a Mediterranean conifer forest, evaluating the influence of different factors. For this purpose, from March to November 2018, we monitored the abundance of monoterpenes in the air at nose height, leaf development, air temperature and soil water potential in a mountain Mediterranean forest of Pinus pinaster located in Sierra de Albarracín (Teruel, Spain). We detected six monoterpenes, with α-pinene, β-pinene and limonene being the three most abundant. Temperature was the main environmental factor driving the abundance of monoterpenes in air, with a maxima of abundance found during summer. Leaf development in spring decreased the abundance, while after a drought period, the abundance increased. Thus, people enjoying forest-based activities in Mediterranean conifer areas would be more exposed to air monoterpenes when the temperature increases during the period after leaf development, as long as the trees are not severely water-stressed. If that is the case, the abundance of monoterpenes in the air would increase after the drought period. Full article
(This article belongs to the Special Issue Forest Recreation and Landscape Protection)
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Review
Oak Decline Syndrome in Korean Forests: History, Biology, and Prospects for Korean Oak Wilt
Forests 2022, 13(6), 964; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060964 - 20 Jun 2022
Viewed by 383
Abstract
Oak decline syndrome has been observed in South Korea and Japan and variously referred to as Korean oak wilt (KOW) and Japanese oak wilt (JOW). We reviewed aspects of the historical occurrence of KOW, disease cycle, and its potential causes. KOW has been [...] Read more.
Oak decline syndrome has been observed in South Korea and Japan and variously referred to as Korean oak wilt (KOW) and Japanese oak wilt (JOW). We reviewed aspects of the historical occurrence of KOW, disease cycle, and its potential causes. KOW has been seen principally in Mongolian oak (Quercus mongolica Fisch. ex Ledeb.). The first occurrence of KOW was in 2004 in Seongnam, South Korea. KOW is associated with the fungus Raffaelea quercus-mongolicae, which is vectored by the ambrosia beetle Platypus koryoensis. In addition, it has been suggested that yeasts have evolved a symbiotic relationship with the vector without antagonism for the pathogenic fungus. The number of trees in Korea killed by KOW increased to about 331,000 in 2011, but then decreased to about 157,000 in 2019. We hypothesized that trees infected by R. quercus-mongolicae accumulate phenolic compounds in the sapwood and the vector (P. koryoensis) beetles then avoid these trees. Therefore, the number of hosts available for the beetle after a KOW outbreak decrease due to accumulation of phenolic compounds in the wood, although most oak trees survive outbreaks. Therefore, P. koryoensis beetles move longer distances after outbreaks to find susceptible host trees. Novel occurrence of KOW in Korea may be due to either (1) an increase in tree age (size) in Korean oak stands, for which the beetle has a known preference or (2) climate change, which may be increasing the number of weakened or stressed trees, for which P. koryoensis also shows a preference. Full article
(This article belongs to the Special Issue Management of Forest Pests and Diseases)
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Article
Forest Fire Detection of FY-3D Using Genetic Algorithm and Brightness Temperature Change
Forests 2022, 13(6), 963; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060963 - 20 Jun 2022
Viewed by 394
Abstract
As one of China’s new generation polar-orbiting meteorological satellites, FengYun-3D (FY-3D) provides critical data for forest fire detection. Most of the existing related methods identify fire points by comparing the spatial features and setting thresholds empirically. However, they ignore temporal features that are [...] Read more.
As one of China’s new generation polar-orbiting meteorological satellites, FengYun-3D (FY-3D) provides critical data for forest fire detection. Most of the existing related methods identify fire points by comparing the spatial features and setting thresholds empirically. However, they ignore temporal features that are associated with forest fires. Besides, they are difficult to generalize to multiple areas with different environmental characteristics. A novel method based on FY-3D combining the genetic algorithm and brightness temperature change detection is proposed in this work to improve these problems. After analyzing the spatial features of the FY-3D data, it adaptively detects potential fire points based on these features using the genetic algorithm, then filters the points with contextual information. To address the false alarms resulting from the confusing spectral characteristics between fire pixels and conventional hotspots, temporal information is introduced and the “MIR change rate” based on the multitemporal brightness temperature change is further proposed. In order to evaluate the performance of the proposed algorithm, several fire events occurring in different areas are used for testing. The Moderate-Resolution Imaging Spectroradiometer (MODIS) Thermal Anomalies/Fire products (MYD14) is chosen as the validation data to assess the accuracy of the proposed algorithm. A comparison of results demonstrates that the algorithm can identify fire points effectively and obtain a higher accuracy than the previous FY-3D algorithm. Full article
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Article
Chemical Compositions of Walnut (Juglans Spp.) Oil: Combined Effects of Genetic and Climatic Factors
Forests 2022, 13(6), 962; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060962 - 20 Jun 2022
Viewed by 360
Abstract
Walnut oil is a high-value oil product. Investigation of the variation and the main climatic factors affecting the oil’s chemical composition is vital for breeding and oil quality improvement. Therefore, the fatty acid, micronutrients, and secondary metabolites compositions and contents in walnut oil [...] Read more.
Walnut oil is a high-value oil product. Investigation of the variation and the main climatic factors affecting the oil’s chemical composition is vital for breeding and oil quality improvement. Therefore, the fatty acid, micronutrients, and secondary metabolites compositions and contents in walnut oil were determined in three species: Juglans regia L. (common walnut), J. sigillata Dode (iron walnut), and their hybrids (Juglans sigillata Dode × J. regia L.), which were cultivated aat different sites. The major fatty acids were linoleic (51.39–63.12%), oleic (18.40–33.56%), and linolenic acid (6.52–11.69%). High variation in the contents of fatty acids, micronutrients, and secondary metabolites was found between both species and sites. Interestingly, myristic, margaric, and margaroleic acid were only detected in the hybrids’ walnut oil, yet α-tocopherol was only detected in common and iron walnut oil. Climatic factors significantly affected the composition and content of fatty acid, whereas δ-tocopherol was mostly dependent on the genetic factors. The average relative humidity explained the most variation in the fatty acids, micronutrients, and secondary metabolites, which showed a significant positive and negative effect on the monounsaturated fatty acids and polyunsaturated fatty acids, respectively. These findings contribute to the provision of better guidance in matching sites with walnut trees, and improvement of the nutritional value of walnut oil. Full article
(This article belongs to the Special Issue Strategies for Tree Improvement under Stress Conditions)
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Article
Auxiliary Seed Treatment Is Necessary to Increase Recruitment of a Critically Endangered Species, Abies beshanzuensis (Pinaceae)
Forests 2022, 13(6), 961; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060961 - 19 Jun 2022
Viewed by 429
Abstract
Disordered germination is widely observed in plant species with extremely small populations (PSESPs) in China. Abies beshanzuensis M. H. Wu, a PSESP (with only three extant adults in Zhejiang Province, China) that also has poor seed germination in the field, belongs to the [...] Read more.
Disordered germination is widely observed in plant species with extremely small populations (PSESPs) in China. Abies beshanzuensis M. H. Wu, a PSESP (with only three extant adults in Zhejiang Province, China) that also has poor seed germination in the field, belongs to the Pinaceae family. Pinaceae generally tend toward symbiosis with ectomycorrhizal (ECM) fungi to alleviate climate change-induced stresses. Therefore, exploring how to improve seed germination of A. beshanzuensis and whether it is an ECM species will contribute to increasing recruitment for conducting further conservation research. In this study, four temperature regimes (10/15 °C, 15/20 °C, 20/25 °C, and 25/30 °C) were selected to explore the response of seed germination to rising temperature. Based on the microscopic features of fine roots, together with molecular techniques, the mycorrhizal type of this species was identified. The seed germination of A. beshanzuensis was increased from 1–2% to around 4.5% by 14-day cold stratification and under 20/25 °C fluctuating temperature conditions. Our findings indicated that A. beshanzuensis may be endangered as a result of insufficient seedling recruitment due to poor germination under the current climate. A. beshanzuensis was confirmed as an ECM fungi-associated tree species. This study highlights the necessity of incorporating auxiliary seed treatment into population recovery programs of A. beshanzuensis, thereby better conserving the species under ongoing environmental changes. Full article
(This article belongs to the Special Issue Topicalities in Forest Ecology of Seeds)
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Article
Psychophysiological Impacts of Traffic Sounds in Urban Green Spaces
Forests 2022, 13(6), 960; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060960 - 19 Jun 2022
Viewed by 431
Abstract
The goal of this study is to investigate the psychophysiological effects of traffic sounds in urban green spaces. In a laboratory experiment, psychological and physiological responses to four traffic sounds were measured, including road, conventional train, high-speed train, and tram. The findings demonstrated [...] Read more.
The goal of this study is to investigate the psychophysiological effects of traffic sounds in urban green spaces. In a laboratory experiment, psychological and physiological responses to four traffic sounds were measured, including road, conventional train, high-speed train, and tram. The findings demonstrated that traffic sounds had significant detrimental psychological and physiological effects. In terms of psychological responses, the peak sound level outperformed the equivalent sound level in determining the psychological impact of traffic sounds. The physiological effects of traffic sounds were shown to be significantly influenced by sound type and sound level. The physiological response to the high-speed train sound differed significantly from the other three traffic sounds. The physiological effects of road traffic sounds were found to be unrelated to the sound level. On the contrary, as for the railway sounds, the change in sound level was observed to have a significant impact on the participants’ physiological indicators. Full article
(This article belongs to the Special Issue Soundscape in Urban Forests)
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Article
Phenotypic Variation in Seed Morphochemical and Seedling Traits in Four Chinese Provenances of Xanthoceras sorbifolium
Forests 2022, 13(6), 959; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060959 - 19 Jun 2022
Viewed by 408
Abstract
Variability in seed and seedling traits of Xanthoceras sorbifolium Bunge was evaluated at the population level. Seed samples were collected from four provenances in China and examined for variations in morphometric traits, chemical components, and seedling growth in the nursery stage. There were [...] Read more.
Variability in seed and seedling traits of Xanthoceras sorbifolium Bunge was evaluated at the population level. Seed samples were collected from four provenances in China and examined for variations in morphometric traits, chemical components, and seedling growth in the nursery stage. There were significant differences in the seed length, width, dry weight, 1000-seed weight, oil concentration, Mg and Cu concentrations, root biomass, and root–stem biomass ratio. The largest seed in terms of size and weight was from Ongniud Banner, Inner Mongolia (OB), but these seeds also had the lowest seed oil concentration. At the end of the first growing season in the nursery, seedlings stopped growing one month earlier in height than in diameter. The provenance difference in height was significant at the first 2 months after sowing but disappeared later. Genotypic variance (Vg) was found to be higher than corresponding environmental (Ve) variance for seed length, seed width, seed dry weight, 1000-seed weight, diameter, and root biomass, indicating that these parameters were strongly inherited and there was ample scope for improvement. Moreover, correlations between seed and seedling traits and climatic and geographical factors were assessed. Some significant intercharacter correlations were found, such as between seed length, width and seed weight, between oil concentration and seed size, and between seedling height, diameter, and root biomass. Combining the seed- and seedling-related parameters, our results indicated that Mulei, Xinjiang (ML) may be used as an ideal material for a further improvement program. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Article
Changes in Soil Microbial Community and Carbon Flux Regime across a Subtropical Montane Peatland-to-Forest Successional Series in Taiwan
Forests 2022, 13(6), 958; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060958 - 19 Jun 2022
Viewed by 430
Abstract
Subtropical montane peatland is among several rare ecosystems that continue to receive insufficient scientific exploration. We analyzed the vegetation types and soil bacterial composition, as well as surface carbon dioxide and methane fluxes along a successional peatland-to-upland-forest series in one such ecosystem in [...] Read more.
Subtropical montane peatland is among several rare ecosystems that continue to receive insufficient scientific exploration. We analyzed the vegetation types and soil bacterial composition, as well as surface carbon dioxide and methane fluxes along a successional peatland-to-upland-forest series in one such ecosystem in Taiwan. The Yuanyang Lake (YYL) study site is characterized by low temperature, high precipitation, prevailing fog, and acidic soil, which are typical conditions for the surrounding dominant Chamaecyparis obtusa var. formosana forest. Bacterial communities were dominated by Acidobacteriota and Proteobacteria. Along the bog-to-forest gradient, Proteobacteria decreased and Acidobacteriota increased while CO2 fluxes increased and CH4 fluxes decreased. Principal coordinate analysis allowed separating samples into four clusters, which correspond to samples from the bog, marsh, forest, and forest outside of the watershed. The majority of bacterial genera were found in all plots, suggesting that these communities can easily switch to other types. Variation among samples from the same vegetation type suggests influence of habitat heterogeneity on bacterial community composition. Variations of soil water content and season caused the variations of carbon fluxes. While CO2 flux decreased exponentially with increasing soil water content, the CH4 fluxes exhibited an exponential increase together with soil water content. Because YYL is in a process of gradual terrestrialization, especially under the warming climate, we expect changes in microbial composition and the greenhouse gas budget at the landscape scale within the next decades. Full article
(This article belongs to the Special Issue Microbial Cycling of Trace Greenhouse Gases in Forest Soils)
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Article
Distribution Pattern of Woody Plants in a Mountain Forest Ecosystem Influenced by Topography and Monsoons
Forests 2022, 13(6), 957; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060957 - 19 Jun 2022
Viewed by 373
Abstract
Many areas are affected by the monsoon because of different sea and land positions. At the same time, the blocking effect of a mountain range forms different habitats on both sides of the mountain range. However, the distribution mechanism of woody plants is [...] Read more.
Many areas are affected by the monsoon because of different sea and land positions. At the same time, the blocking effect of a mountain range forms different habitats on both sides of the mountain range. However, the distribution mechanism of woody plants is unclear in mountain forest ecosystems influenced by topography and monsoons. In this study, 10 plots, each with an area of 1 hm2 (100 m × 100 m), were randomly established on the south and north aspects of a mountain forest. We examined community structure differences and distribution preferences of woody plants on both sides of the mountain. Our findings were as follows: (1) The characteristics of woody plant assemblages differed among various aspects. (2) Network analysis showed that specialization index was 0.186 and modularity index was 0.235, and the torus translation test showed that a total of 45 species were detected to be associated with at least one of the habitats (45/106, 42.45%). (3) The community stability of the south aspect was higher than that of the north aspect. Our findings suggest that the distribution of woody plants among different aspects was specialized and not random in alpine forest ecosystems. This study contributes to a clear understanding of the distribution mechanism of woody plants in mountain forest ecosystems influenced by topography and monsoons. Full article
(This article belongs to the Section Forest Ecology and Management)
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Article
Wood Anatomical Traits Respond to Climate but More Individualistically as Compared to Radial Growth: Analyze Trees, Not Means
Forests 2022, 13(6), 956; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060956 - 18 Jun 2022
Viewed by 534
Abstract
Wood encodes environmental information that can be recovered through the study of tree-ring width and wood anatomical variables such as lumen area or cell-wall thickness. Anatomical variables often provide a stronger hydroclimate signal than tree-ring width, but they show a low tree-to-tree coherence. [...] Read more.
Wood encodes environmental information that can be recovered through the study of tree-ring width and wood anatomical variables such as lumen area or cell-wall thickness. Anatomical variables often provide a stronger hydroclimate signal than tree-ring width, but they show a low tree-to-tree coherence. We investigate the sources of variation in tree-ring width, lumen area, and cell-wall thickness in three pine species inhabiting sites with contrasting climate conditions: Pinus lumholtzii in wet-summer northern Mexico, and Pinus halepensis and Pinus sylvestris in dry-summer north-eastern Spain. We quantified the amount of variance of these three variables explained by spring and summer water balance and how it varied among trees. Wood anatomical variables accounted for a larger inter-individual variability than tree-ring width data. Anatomical traits responded to hydroclimate more individualistically than tree-ring width. This individualistic response represents an important issue in long-term studies on wood anatomical characteristics. We emphasized the degree of variation among individuals of the same population, which has far-reaching implications for understanding tree species’ responses to climate change. Dendroclimatic and wood anatomical studies should focus on trees rather than on the mean population series. Full article
(This article belongs to the Special Issue Radial-Growth and Wood Anatomical Responses to Climate Change)
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Article
Discovery and Biology of Spathius verustus Chao (Hymenoptera: Braconidae), a Potential Biological Agent on Two Monochamus Vectors of the Pinewood Nematode
Forests 2022, 13(6), 955; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060955 - 18 Jun 2022
Viewed by 554
Abstract
Pine wilt disease in Korea can be managed by reducing vector density through chemical application. To reduce the side effects from pesticides, effective natural enemies must be identified and used to reduce the vectors’ natural density. Sentinel logs were used to investigate a [...] Read more.
Pine wilt disease in Korea can be managed by reducing vector density through chemical application. To reduce the side effects from pesticides, effective natural enemies must be identified and used to reduce the vectors’ natural density. Sentinel logs were used to investigate a parasitoid wasp parasitic to Monochamus alternatus and Monochamus saltuarius, the vectors of Bursaphelenchus xylophilus, which causes this disease. During 2016–2017, the parasitoid wasps distributed in the Pinus densiflora and Pinus koraiensis forests were surveyed using sentinel logs at six different areas. An ectoparasitoid wasp Spathius verustus Chao of M. alternatus and M. saltuarius was identified. We showed for the first time that S. verustus was parasitic to M. alternatus in South Korea and to M. saltuarius worldwide. The parasitism rates were affected by region and session but not by the sentinel log height in the tree and the distances between the trap and forest edge locations. Studies also showed that S. verustus appeared to prefer M. alternatus to M. saltuarius as a host. This study unveiled the ecological details of S. verustus. Further research on various environmental factors such as regional differences, host density differences, and the degree of damage from the pine wilt disease is required to understand the effects of environmental or ecological factors on parasitism rates. Full article
(This article belongs to the Special Issue Management of Forest Pests and Diseases)
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Article
Forest Dependence of Rural Communities in the Republic of Moldova
Forests 2022, 13(6), 954; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060954 - 18 Jun 2022
Viewed by 513
Abstract
The high dependency on forest resources and the fact that forests play an important role in the lives of people in poorer rural areas are well known forest characteristics. This depicts a deep connection between people and nature. For the rural communities, forest [...] Read more.
The high dependency on forest resources and the fact that forests play an important role in the lives of people in poorer rural areas are well known forest characteristics. This depicts a deep connection between people and nature. For the rural communities, forest ecosystems display another important role, namely in alleviating poverty through stable provisions of vital functions and livelihoods. The present study aims to identify what influences the current level of the local communities of the Republic of Moldova’s dependence on forests, who still face poverty-related challenges, and how ecosystem services provided by forests are perceived by the rural population. After six years since the last forest dependency research, this time the level of dependence is investigated using the same methodology, but through improved socio-economic conditions. Although the consumption of non-timber forest products decreased, the pressure on forest resources remained at the same level due to the high dependence of communities on firewood. The highest dependency was found in low-income households, manifested by their necessity to spend an average share of 18.8% from their total income on firewood due to their restricted access to forest resources. Since most Moldovans rely more heavily on subsistence-oriented forest products such as fuelwood, forest management sustainability efforts might not be achieved as long as the need for wood products exceeds the supply, and neither will the living conditions of the poor be improved. Solutions should be sought based on cross-sectoral and long-term approaches by involving all stakeholders, and not neglecting local communities. Full article
(This article belongs to the Special Issue The Dynamic Interaction between People and Forest Ecosystems)
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Article
Over-Expression of Larch DAL1 Accelerates Life-Cycle Progression in Arabidopsis
Forests 2022, 13(6), 953; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060953 - 17 Jun 2022
Viewed by 554
Abstract
Homologs of Larix kaempferiDEFICIENS-AGAMOUS-LIKE 1 (LaDAL1) promote flowering in Arabidopsis. However, their functional role in the whole life-cycle is limited. Here, we analyzed the phenotypes and transcriptomes of Arabidopsis plants over-expressing LaDAL1. With respect to the defined life-cycle [...] Read more.
Homologs of Larix kaempferiDEFICIENS-AGAMOUS-LIKE 1 (LaDAL1) promote flowering in Arabidopsis. However, their functional role in the whole life-cycle is limited. Here, we analyzed the phenotypes and transcriptomes of Arabidopsis plants over-expressing LaDAL1. With respect to the defined life-cycle stage of Arabidopsis based on the meristem state, the results showed that LaDAL1 promoted seed germination, bolting, flower initiation, and global proliferative arrest, indicating that LaDAL1 accelerates the meristem reactivation, the transitions of vegetative meristem to inflorescence and flower meristem, and meristem arrest. As a marker gene of meristem, TERMINAL FLOWER 1 was down-regulated after LaDAL1 over-expression. These results reveal that LaDAL1 accelerates the life-cycle progression in Arabidopsis by promoting the transition of meristem fate, providing more and novel functional information about the conifer age-related gene DAL1. Full article
(This article belongs to the Special Issue Tree Genetics: Molecular and Functional Characterization of Genes)
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Article
Identification and Functional Evaluation of Three Polyubiquitin Promoters from Hevea brasiliensis
Forests 2022, 13(6), 952; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060952 - 17 Jun 2022
Viewed by 445
Abstract
Hevea brasiliensis is an economically important tree species that provides the only commercial source of natural rubber. The replacement of the CaMV35S promoter by endogenous polyubiquitin promoters may be a viable way to improve the genetic transformation of this species. However, no endogenous [...] Read more.
Hevea brasiliensis is an economically important tree species that provides the only commercial source of natural rubber. The replacement of the CaMV35S promoter by endogenous polyubiquitin promoters may be a viable way to improve the genetic transformation of this species. However, no endogenous polyubiquitin promoters in Hevea have been reported yet. Here, we identified three Hevea polyubiquitin genes HbUBI10.1, HbUBI10.2 and HbUBI10.3, which encode ubiquitin monomers having nearly identical amino acid sequences to that of AtUBQ10. The genomic fragments upstream of these HbUBI genes, including the signature leading introns, were amplified as putative HbUBI promoters. In silico analysis showed that a number of cis-acting elements which are conserved within strong constitutive polyubiquitin promoters were presented in these HbUBI promoters. Transcriptomic data revealed that HbUBI10.1 and HbUBI10.2 had a constitutive expression in Hevea plants. Semi-quantitative RT-PCR showed that these three HbUBI genes were expressed higher than the GUS gene driven by CaMV35S in transgenic Hevea leaves. All three HbUBI promoters exhibited the capability to direct GFP expression in both transient and stable transformation assays, although they produced lower protoplast transformation efficiencies than the CaMV35S promoter. These HbUBI promoters will expand the availability of promoters for driving the transgene expression in Hevea genetic engineering. Full article
(This article belongs to the Special Issue Tree Genetics: Molecular and Functional Characterization of Genes)
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Article
Foliar Water Uptake Capacity in Six Mangrove Species
Forests 2022, 13(6), 951; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060951 - 17 Jun 2022
Viewed by 449
Abstract
Foliar water uptake (FWU) is a mechanism that enables plants to acquire water from the atmosphere through their leaves. As mangroves live in a saline sediment water environment, the mechanism of FWU might be of vital importance to acquire freshwater and grow. The [...] Read more.
Foliar water uptake (FWU) is a mechanism that enables plants to acquire water from the atmosphere through their leaves. As mangroves live in a saline sediment water environment, the mechanism of FWU might be of vital importance to acquire freshwater and grow. The goal of this study was to assess the FWU capacity of six different mangrove species belonging to four genera using a series of submersion experiments in which the leaf mass increase was measured and expressed per unit leaf area. The foliar water uptake capacity differed between species with the highest and lowest average water uptake in Avicennia marina (Forssk.) Vierh. (1.52 ± 0.48 mg H2O cm−2) and Bruguiera gymnorhiza (L.) Lam. (0.13 ± 0.06 mg H2O cm−2), respectively. Salt-excreting species showed a higher FWU capacity than non-excreting species. Moreover, A. marina, a salt-excreting species, showed a distinct leaf anatomical trait, i.e., trichomes, which were not observed in the other species and might be involved in the water absorption process. The storage of leaves in moist Ziplock bags prior to measurement caused leaf water uptake to already occur during transport to the field station, which proportionately increased the leaf water potential (A. marina: −0.31 ± 0.13 MPa and B. gymnorhiza: −2.70 ± 0.27 MPa). This increase should be considered when performing best practice leaf water potential measurements but did not affect the quantification of FWU capacity because of the water potential gradient between a leaf and the surrounding water during submersion. Our results highlight the differences that exist in FWU capacity between species residing in the same area and growing under the same environmental conditions. This comparative study therefore enhances our understanding of mangrove species’ functioning. Full article
(This article belongs to the Special Issue Advances in Mangrove Ecology)
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Article
Validation of the Habitat Quality Index of Tetraclinis articulata Forests and Its Application in Cost-Effectiveness Analysis of Restoration Projects
Forests 2022, 13(6), 950; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060950 - 17 Jun 2022
Viewed by 379
Abstract
The latest reports from the European Commission warn of the need to improve the conservation status of its forest habitats. Native populations of priority habitat 9570 (Tetraclinis articulata forests) in continental Europe are located in the southeast of the Iberian Peninsula. The [...] Read more.
The latest reports from the European Commission warn of the need to improve the conservation status of its forest habitats. Native populations of priority habitat 9570 (Tetraclinis articulata forests) in continental Europe are located in the southeast of the Iberian Peninsula. The LIFE-TETRACLINIS-EUROPE project aimed to improve habitat conservation conditions. As part of the results of this project, a habitat quality index was proposed with the intention of evaluating both its conservation conditions and its evolution after the implemented action measures. The variables used in this index were selected with the aim of achieving high representativeness of the quality of the habitat while at the same time being easily integrated into monitoring programs. In this paper, we intend to verify the suitability of the variables chosen for this index, its sensitivity to discriminate different conservation levels, and its possible inclusion in forest management programs through a cost-effectiveness analysis. Full article
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Article
Change Analysis of Urban Tree Canopy in Miami-Dade County
Forests 2022, 13(6), 949; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060949 - 17 Jun 2022
Viewed by 431
Abstract
This study mapped and analyzed urban tree canopy change between 2014 and 2019 within the Urban Development Boundary of Miami-Dade County, Florida. The goal was to identify local areas of tree canopy gain or loss over this 5-year period. The comparison is based [...] Read more.
This study mapped and analyzed urban tree canopy change between 2014 and 2019 within the Urban Development Boundary of Miami-Dade County, Florida. The goal was to identify local areas of tree canopy gain or loss over this 5-year period. The comparison is based on land cover maps delineated from WorldView-2 satellite data applying a random forest classification algorithm, in combination with publicly available vector data of infrastructure (roads, railroads) and land use maps (water, cropland). Existing urban tree canopy (EUTC) was computed for census block groups and municipalities to compare tree canopy cover loss or gain to support strategic planning of equitable urban reforestation. For the entire study area, the percentage of EUTC did not change significantly between 2014 (19.9 ± 1.2%) and 2019 (20.1 ± 1.5%). However, some municipalities experienced changes in EUTC by over 10%. Comparison of Landsat-8 Thermal Infrared satellite imagery between both periods identified land cover change patterns that were associated with an increase or decrease in surface temperature. A significantly negative relationship between percentage of African American population and tree canopy in 2014 turned statistically insignificant in 2019, whereas the negative relationship with percentage of Hispanic population further strengthened in 2019 compared to 2014. Full article
(This article belongs to the Section Urban Forestry)
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Article
Audio-Visual Preferences for the Exercise-Oriented Population in Urban Forest Parks in China
Forests 2022, 13(6), 948; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060948 - 17 Jun 2022
Viewed by 338
Abstract
The purpose of this study is to explore the audio-visual preferences of exercisers in urban forest parks in China and to make practical suggestions for park landscape design. Taking Beigushan Forest Park in Lianyungang City, Jiangsu Province as a case, based on field [...] Read more.
The purpose of this study is to explore the audio-visual preferences of exercisers in urban forest parks in China and to make practical suggestions for park landscape design. Taking Beigushan Forest Park in Lianyungang City, Jiangsu Province as a case, based on field research and questionnaire survey, this study analyzed the audio-visual preference characteristics of exercisers in the park, revealed the correlation between audio-visual preference and exercisers’ behaviors and individual characteristics, and explored the influence of audio-visual preferences on exercise feelings by establishing a structural equation model. It was found that (1) the forest and its avenue landscape and birdsong are most preferred by exercisers; (2) the audio-visual preferences of people with different exercise forms differ, for example, people who slowly walk, run, and briskly walk have stronger preferences for natural soundscape and visual landscape, while people who use fitness equipment have stronger inclusiveness for human activity sound and prefer public facility-based landscapes. In addition, some individual characteristics such as exercise intensity and exercise frequency significantly affect exercisers’ audio-visual preferences; (3) visual landscape preferences have a greater direct impact on exercise feelings, with natural waterscape having the greatest direct impact, but overall soundscape preferences do not have a high degree of direct impact on exercise feelings, with natural sound still having a strong positive impact. These findings provide a more quantitative basis for the landscape design of urban forest parks from the perspective of exercise behavior. Full article
(This article belongs to the Special Issue Soundscape in Urban Forests)
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Article
Magnetic Treatment Improves the Seedling Growth, Nitrogen Metabolism, and Mineral Nutrient Contents in Populus × euramericana ‘Neva’ under Cadmium Stress
Forests 2022, 13(6), 947; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060947 - 17 Jun 2022
Viewed by 399
Abstract
This pot experiment was carried out to investigate the mechanism underlying nutrient metabolism and seedling growth responses to magnetic treatment following exposure to cadmium (Cd) stress. A magnetic device of 300 Gs was applied during Cd(NO3)2 solution treatment at 0 [...] Read more.
This pot experiment was carried out to investigate the mechanism underlying nutrient metabolism and seedling growth responses to magnetic treatment following exposure to cadmium (Cd) stress. A magnetic device of 300 Gs was applied during Cd(NO3)2 solution treatment at 0 and 100 mM·L−1. One-year-old seedlings of Populus × euramericana ‘Neva’ were treated with different Cd(NO3)2 solutions in the presence or absence of magnetic treatment for 30 days. Seedling growth and physiological–biochemical indexes were measured under Cd stress. The contents of ammonium (NH4+–N), nitrate (NO3–N), and total nitrogen (TN) in leaves, as well as NH4+–N and TN in roots, were increased by magnetic treatment combined with Cd stress, although the NO3–N content was decreased. The activities of nitrate reductase (NR), nitrite reductase (NiR), glutathione reductase (GR), and glutamate synthase (GOGAT) in leaves and the activities of NR, glutamine synthetase (GS), and GOGAT in roots were stimulated by magnetic treatment; conversely, the NiR activity in roots was inhibited by magnetic effects. Magnetic treatment improved the synthesis of cysteine (Cys) and glutamine (Gln) in leaves and reduced the contents of glutamic acid (Glu) and glycine (Gly), while the contents of Cys, Glu, Gln, and Gly were increased in roots. The contents of Ca, Mg, Fe, Mn, Zn, and Cu in leaves were increased by magnetic treatment under Cd stress, whereas the content of K was reduced. In roots, the contents of K, Ca, and Fe were increased by magnetic treatment under Cd stress, but the contents of Na, Mg, Mn, Zn, and Cu were decreased. Magnetization could regulate the uptake of mineral nutrients by roots and translocation from the roots to the aboveground parts by affecting root morphology. Magnetic treatment could also improve nitrogen assimilation and the synthesis of free amino acids by stimulating the activities of key enzymes. Full article
(This article belongs to the Special Issue Advances in Forest Tree Seedling Cultivation Technology)
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Article
SNP Detection in Pinus pinaster Transcriptome and Association with Resistance to Pinewood Nematode
Forests 2022, 13(6), 946; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060946 - 17 Jun 2022
Viewed by 411
Abstract
Pinewood nematode (PWN, Bursaphelenchus xylophilus) is the causal agent of pine wilt disease (PWD), which severely affects Pinus pinaster stands in southwestern Europe. Despite the high susceptibility of P. pinaster, individuals of selected half-sib families have shown genetic variability in survival [...] Read more.
Pinewood nematode (PWN, Bursaphelenchus xylophilus) is the causal agent of pine wilt disease (PWD), which severely affects Pinus pinaster stands in southwestern Europe. Despite the high susceptibility of P. pinaster, individuals of selected half-sib families have shown genetic variability in survival after PWN inoculation, indicating that breeding for resistance can be a valuable strategy to control PWD. In this work, RNA-seq data from susceptible and resistant plants inoculated with PWN were used for SNP discovery and analysis. A total of 186,506 SNPs were identified, of which 31 were highly differentiated between resistant and susceptible plants, including SNPs in genes involved in cell wall lignification, a process previously linked to PWN resistance. Fifteen of these SNPs were selected for validation through Sanger sequencing and 14 were validated. To evaluate SNP-phenotype associations, 40 half-sib plants were genotyped for six validated SNPs. Associations with phenotype after PWN inoculation were found for two SNPs in two different genes (MEE12 and PCMP-E91), as well as two haplotypes of HIPP41, although significance was not maintained following Bonferroni correction. SNPs here detected may be useful for the development of molecular markers for PWD resistance and should be further investigated in future association studies. Full article
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Article
Use of Harvester Data to Estimate the Amount of Merchantable Non-Utilized Woody Material Remaining after Mechanized Cut-to-Length Forest Operations
Forests 2022, 13(6), 945; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060945 - 17 Jun 2022
Viewed by 400
Abstract
An agreement between the provincial government of Québec, Canada and the forest industry executing forest management activities on public lands has been established regarding non-utilized woody material (NUWM) left on the cutting area. Problems linked to this agreement are compounded by labor shortages, [...] Read more.
An agreement between the provincial government of Québec, Canada and the forest industry executing forest management activities on public lands has been established regarding non-utilized woody material (NUWM) left on the cutting area. Problems linked to this agreement are compounded by labor shortages, which have an impact on the precision of the mandatory inventories. The objectives of this study were to: (1) reconstruct and estimate the merchantable NUWM volume beyond the last processed log of balsam fir and white spruce with the use of harvester on-board computer (OBC) data, (2) design a software tool to estimate and spatialize merchantable NUWM, and (3) perform an explorative comparison between the OBC method and conventional field inventory. In total, five sites were harvested to develop the volume algorithms. Each site was harvested by a single-grip harvester operating a different OBC system (OPTI4G, Log Mate 500, and Log Mate 510). Results suggest that, with Varjo’s model and linear regression, estimation of NUWM volume using OBC data is possible. The spatialization tool positioned NUWM within the harvest area for StanForD and StanForD 2010. The explorative comparison highlighted a possible cost reduction of approx. 36.8 $/ha and an increase of precision for the OBC method. Full article
(This article belongs to the Special Issue Forest Harvesting, Operations and Management)
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Article
China’s Forest Eco-Bank Project: An Analysis Based on the Actor-Network Theory
Forests 2022, 13(6), 944; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060944 - 16 Jun 2022
Viewed by 447
Abstract
The high degree of fragmentation and unsustainable exploitation patterns of forest resources have become prominent obstacles to the realisation of the economic and social value of China’s forest resources. China’s forest eco-bank (FEB) project was set up to achieve centralised utilisation of diffuse [...] Read more.
The high degree of fragmentation and unsustainable exploitation patterns of forest resources have become prominent obstacles to the realisation of the economic and social value of China’s forest resources. China’s forest eco-bank (FEB) project was set up to achieve centralised utilisation of diffuse forest resources in an underdeveloped area. Analysing FEB projects is of great significance to countries with abundant forest resources aiming to benefit from the economic and ecological functions of such resources and achieve sustainable economic and social development. This study uses the actor-network theory framework to analyse cooperation among various actors in the implementation process of the FEB project in China. Our results indicate the following. First, the government was the principal actor playing a vital role in motivating the other parties and driving the project forward. Second, the diffuse nature of China’s forest resources is a major obstacle to their utilisation. The centralised integration of forest resources is a prerequisite for their effective utilisation. Finally, it is necessary to improve the balance of interests of the various actors to promote a more stable actor network and attract more actors to participate in the FEB project. Full article
(This article belongs to the Section Forest Economics, Policy, and Social Science)
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Article
Verification of a Deep Learning-Based Tree Species Identification Model Using Images of Broadleaf and Coniferous Tree Leaves
Forests 2022, 13(6), 943; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060943 - 16 Jun 2022
Viewed by 369
Abstract
The objective of this study was to verify the accuracy of tree species identification using deep learning with leaf images of broadleaf and coniferous trees in outdoor photographs. For each of 12 broadleaf and eight coniferous tree species, we acquired 300 photographs of [...] Read more.
The objective of this study was to verify the accuracy of tree species identification using deep learning with leaf images of broadleaf and coniferous trees in outdoor photographs. For each of 12 broadleaf and eight coniferous tree species, we acquired 300 photographs of leaves and used those to produce 72,000 256 × 256-pixel images. We used Caffe as the deep learning framework and AlexNet and GoogLeNet as the deep learning algorithms. We constructed four learning models that combined two learning patterns: one for individual classification of 20 species and the other for two-group classification (broadleaf vs. coniferous trees), with and without data augmentation, respectively. The performance of the proposed model was evaluated according to the MCC and F-score. Both classification models exhibited very high accuracy for all learning patterns; the highest MCC was 0.997 for GoogLeNet with data augmentation. The classification accuracy was higher for broadleaf trees when the model was trained using broadleaf only; for coniferous trees, the classification accuracy was higher when the model was trained using both tree types simultaneously than when it was trained using coniferous trees only. Full article
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Brief Report
Regularly Planted Rather Than Natural Understory of Norway Spruce (Picea abies H. Karst.) Contributes to the Individual Stability of Canopy Silver Birch (Betula pendula Roth.)
Forests 2022, 13(6), 942; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060942 - 16 Jun 2022
Viewed by 360
Abstract
Forest plantations, particularly high-density planted stands, are considered to be more prone to wind damage compared to naturally regenerated stands. The wind resistance (mechanical stability) of plantations can, however, be improved by close-to-natural management, for example, combining pioneer and shade-tolerant species. Presumably, the [...] Read more.
Forest plantations, particularly high-density planted stands, are considered to be more prone to wind damage compared to naturally regenerated stands. The wind resistance (mechanical stability) of plantations can, however, be improved by close-to-natural management, for example, combining pioneer and shade-tolerant species. Presumably, the stability of such stands would be enhanced by the reduced competition of canopy trees and stronger root contacts provided by understory trees, which depend on spatial distribution. In the hemiboreal forest zone, silver birch (Betula pendula Roth.) and Norway spruce (Picea abies (L.) H.Karst.) form such a combination naturally. In this study, the static tree-pulling tests were performed to estimate the mechanical stability of canopy silver birch growing with random Norway spruce understory in naturally regenerated (post-clear-cut) and regularly planted bi-species mixed stands. The regular mixing of the high-density bi-species stand significantly improved the loading resistance of canopy silver birch compared to the naturally regenerated stands of similar composition and age. Such an effect might be related to the stratification of the canopy space between pioneer birch and shade-tolerant spruce, which improved the individual stability of the canopy trees. Further, a regular rooting network of the planted stands likely contributed to the stability by reducing weak spots. Accordingly, the wind resistance of trees in regularly planted bi-species stands might be improved, avoiding additional management. Full article
(This article belongs to the Section Forest Ecology and Management)
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Editorial
Forests for a Better Future: Sustainability, Innovation and Interdisciplinarity
Forests 2022, 13(6), 941; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060941 - 16 Jun 2022
Viewed by 412
Abstract
Forests offer a solution to climate change through carbon storage and providing ecosystem services and sustainable products [...] Full article
Article
Protein Markers for the Identification of Cork Oak Plants Infected with Phytophthora cinnamomi by Applying an (α, β)-k-Feature Set Approach
Forests 2022, 13(6), 940; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060940 - 15 Jun 2022
Viewed by 501
Abstract
Cork oak decline in Mediterranean forests is a complex phenomenon, observed with remarkable frequency in the southern part of the Iberian Peninsula, causing the weakening and death of these woody plants. The defoliation of the canopy, the presence of dry peripheral branches, and [...] Read more.
Cork oak decline in Mediterranean forests is a complex phenomenon, observed with remarkable frequency in the southern part of the Iberian Peninsula, causing the weakening and death of these woody plants. The defoliation of the canopy, the presence of dry peripheral branches, and exudations on the trunk are visible symptoms used for the prognosis of decline, complemented by the presence of Phytophthora cinnamomi identified in the rhizosphere of the trees and adjacent soils. Recently, a large proteomic dataset obtained from the leaves of cork oak plants inoculated and non-inoculated with P. cinnamomi has become available. We explored it to search for an optimal set of proteins, markers of the biological pattern of interaction with the oomycete. Thus, using published data from the cork oak leaf proteome, we mathematically modelled the problem as an α, β-k-Feature Set Problem to select molecular markers. A set of proteins (features) that represent dominant effects on the host metabolism resulting from pathogen action on roots was found. These results contribute to an early diagnosis of biochemical changes occurring in cork oak associated with P. cinnamomi infection. We hypothesize that these markers may be decisive in identifying trees that go into decline due to interactions with the pathogen, assisting the management of cork oak forest ecosystems. Full article
(This article belongs to the Special Issue Fungal–Plant Interactions: Latest Advances and Prospects)
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Review
Windstorm Impacts on Forest-Related Socio-Ecological Systems: An Analysis from a Socio-Economic and Institutional Perspective
Forests 2022, 13(6), 939; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060939 - 15 Jun 2022
Viewed by 412
Abstract
Windstorms are considered among the most impacting natural events for European forests and related Socio-Ecological Systems (SES). Given that their intensity and frequency are increasing, an in-depth understanding of their impacts is crucial to mitigate risks and potential negative effects. However, so far, [...] Read more.
Windstorms are considered among the most impacting natural events for European forests and related Socio-Ecological Systems (SES). Given that their intensity and frequency are increasing, an in-depth understanding of their impacts is crucial to mitigate risks and potential negative effects. However, so far, scientific research on windstorm impacts has mainly focused on environmental dimensions, while socio-economic and institutional ones are rarely taken into consideration. Our analysis aims at enriching the current scientific knowledge on windstorm impacts on forest SES by providing an overview of the state-of-the-art academic investigations on windstorm impacts on socio-economic and institutional dimensions. Overall, 46 papers were reviewed to identify the most recurrent post-windstorm dynamics and drivers that influence resilience and adaptation of socio-economic, institutional and related governance dimensions of European forest SES. Results show that the current scientific knowledge on socio-economic impacts of windstorms mainly concentrates on forest-related stakeholders and sectors, paying little attention to the broader social, cultural and institutional drivers that contribute to forest SES resilience. Further, cascade effects linking environmental, social and institutional dimensions are poorly analyzed. This restricted focus could lead to an incomplete understanding of the dynamics shaping socio-economic adaptability to windstorms, affecting long-term and sustainable recovery from extreme natural events. To correctly frame effective, intersectoral and coordinated recovery strategies gaining a deeper understanding of human–environment interactions is needed, as well as acknowledging the positive influence of causal relationships in improving forest-related SES resilience. Full article
(This article belongs to the Section Forest Economics, Policy, and Social Science)
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Article
Germination and Growth Characteristics of Quercus myrsinifolia Blume Seedlings According to Seed Coat Removal, Type of Potting Soil and Irrigation Cycle
Forests 2022, 13(6), 938; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060938 - 15 Jun 2022
Viewed by 420
Abstract
The importance of evergreen oak species is increasing due to changes in the ecosystem caused by climate change and environmental changes such as fine dust and carbon dioxide. The Quercus myrsinifolia Blume seeds showed a recalcitrant seed property, where the germination rate decreased [...] Read more.
The importance of evergreen oak species is increasing due to changes in the ecosystem caused by climate change and environmental changes such as fine dust and carbon dioxide. The Quercus myrsinifolia Blume seeds showed a recalcitrant seed property, where the germination rate decreased when the moisture content was decreased. For seedling propagation of evergreen oak, the effect of oak seed coat (pericarp and testa) removal on germination and seedling growth as well as the effect of potting soil and irrigation cycle on seedling quality were investigated. The germination rate and germination characteristics of Q. myrsinifolia evergreen oak seeds showed significant differences depending on the storage period and the presence or absence of seed coat. Seed coat removal significantly increased germination rate compared to intact seeds, accelerated mean germination time, and increased germination rate and germination value. There was no significant difference in germination rate according to the storage period. The growth of Q. myrsinifolia seedlings was much better in the seeds with the seed coat removed than the intact seeds. The root collar diameter of seedlings germinated from intact seeds was 2.44 mm, and the root collar diameter of seedlings from which the seed coat was removed was 3.38 mm. As a result of the growth characteristics according to the potting soil, 1- and 3-year-old Q. myrsinifolia seedlings showed excellent root growth in commercial potting soil and sand mixed potting soil. Consequently, seedling quality index was 0.124–0.257 according to irrigation and 0.149–0.262 according to potting soil. From observing the root growth of the seedlings according to the irrigation treatment, in the case of 3-year-old seedlings, the total root length was 432 cm when irrigated every 3 days, and the growth was the best. The above results are expected to contribute significantly to the mass propagation of Q. myrsinifolia, which is important for warming and urban greening. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Article
Does the Age of Pinus sylvestris Mother Trees Influence Reproductive Capacity and Offspring Seedling Survival?
Forests 2022, 13(6), 937; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060937 - 15 Jun 2022
Viewed by 374
Abstract
We assess how the age of Pinus sylvestris mother trees influences seed size, seed viability, germination capacity and later offspring seedling survival under greenhouse conditions. Thirty trees ranging from 30 to 219 years old were selected in the north facing slopes in the [...] Read more.
We assess how the age of Pinus sylvestris mother trees influences seed size, seed viability, germination capacity and later offspring seedling survival under greenhouse conditions. Thirty trees ranging from 30 to 219 years old were selected in the north facing slopes in the Sierra de Guadarrama, where we could find the oldest Pinus sylvestris trees in central Spain. Forty cones per tree were harvested to study cone and seed characteristics (size and weight), seed viability and germination capacity related to the mother tree age. In addition, 25 germinated seeds per tree were grown in a greenhouse to assess offspring seedling survival during a death trial, where watering was stopped. Significant differences between trees in cone and seed morphological traits were observed. The age of the mother tree had a significant effect on cone size, seed size, and seed weight, but there was no effect on seed germination capacity and seed viability. Seedling survival was mainly affected by the decrease in water availability. However, a significant effect of the tree age was found once soil moisture had reached 0%. Our results show the ability of overmature Pinus sylvestris trees to maintain a relatively high reproductive capacity that assures its persistence. Full article
(This article belongs to the Special Issue Topicalities in Forest Ecology of Seeds)
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Article
Growth Response of Nine Tree Species to Water Supply in Planting Soils Representative for Urban Street Tree Sites
Forests 2022, 13(6), 936; https://0-doi-org.brum.beds.ac.uk/10.3390/f13060936 - 15 Jun 2022
Viewed by 419
Abstract
In urban environments, newly planted street trees suffer from poor site conditions and limited water availability. It is challenging to provide site conditions that allow the trees to thrive in the long term, particularly under climate change. Knowledge about the hydrological properties of [...] Read more.
In urban environments, newly planted street trees suffer from poor site conditions and limited water availability. It is challenging to provide site conditions that allow the trees to thrive in the long term, particularly under climate change. Knowledge about the hydrological properties of artificial urban planting soils related to the response of tree species-specific growth is crucial, but still lacking. Therefore, we established a three-year experimental field setup to investigate the response of nine tree species (135 individuals) to two common urban planting soils and a loamy silt reference. We determined and measured soil hydrological parameters and monitored tree growth. Our results revealed low plant available water capacities (6% and 10% v/v) and hydraulic conductivity restrictions with the drying of the sandy-textured urban planting soils. Therefore, tree species that are investing in fine root growth to extract water from dry soils might be more successful than trees that are lowering their water potential. Tree growth was overall evidently lower in the urban planting soils compared with the reference and differed between and within the species. We showed that using unfavorable planting soils causes severe, species-specific growth deficits reflecting limited above-ground carbon uptake as a consequence of low water availability. Full article
(This article belongs to the Special Issue Urban Tree Design and Urban Microclimate)
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