Forests

13 pages, 16834 KiB

Open AccessArticle

Profiling of Widely Targeted Metabolomics for the Identification of Secondary Metabolites in Heartwood and Sapwood of the Red-Heart Chinese Fir (Cunninghamia Lanceolata)

by Sen Cao, Zijie Zhang, Yuhan Sun, Yun Li and Huiquan Zheng

Forests 2020, 11(8), 897; https://doi.org/10.3390/f11080897 - 18 Aug 2020

Cited by 13 | Viewed by 3325

Abstract

The chemical composition of secondary metabolites is important for the quality control of wood products. In this study, the widely targeted metabolomics approach was used to analyze the metabolic profiles of heartwood and sapwood in the red-heart Chinese fir (Cunninghamia lanceolata), [...] Read more.

The chemical composition of secondary metabolites is important for the quality control of wood products. In this study, the widely targeted metabolomics approach was used to analyze the metabolic profiles of heartwood and sapwood in the red-heart Chinese fir (Cunninghamia lanceolata), with an ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry system. A total of 224 secondary metabolites were detected in the heartwood and sapwood, and of these, flavonoids and phenolic acids accounted for 36% and 26% of the components, respectively. The main pathways appeared to be differentially activated, including those for the biosynthesis of phenylpropanoids and flavonoids. Moreover, we observed highly significant accumulation of naringenin chalcone, dihydrokaempferol, pinocembrin, hesperetin, and other important secondary metabolites in the flavonoid biosynthesis pathway. Our results provide insight into the flavonoid pathway associated with wood color formation in Chinese fir that will be useful for further breeding programs. Full article

(This article belongs to the Special Issue Genetics and Improvement of Forest Trees)

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26 pages, 8252 KiB

Open AccessArticle

Comparison and Analysis of Radial and Tangential Bending of Softwood and Hardwood at Static and Dynamic Loading

by Vlastimil Borůvka, David Novák and Přemysl Šedivka

Forests 2020, 11(8), 896; https://doi.org/10.3390/f11080896 - 18 Aug 2020

Cited by 17 | Viewed by 3740

Abstract

This paper should primarily lead to a targeted expansion of the database dealing with bending characteristics, and thus help to understand the static and dynamic bending strength depending on the direction of external forces. Wood is very often used in the structural elements [...] Read more.

This paper should primarily lead to a targeted expansion of the database dealing with bending characteristics, and thus help to understand the static and dynamic bending strength depending on the direction of external forces. Wood is very often used in the structural elements of buildings and wood products (e.g., furniture), in which there is both a static load, and in many cases a dynamic load, whilst the direction of loading is usually not considered. Specifically, the paper focuses on determining the bending strength and impact strength of seven economically-important wood species in the Czech Republic. The research includes not only the above-mentioned strength characteristics, but also the elastic characteristics, i.e., the static modulus of elasticity, and the dynamic modules of elasticity determined using the ultrasound and resonance methods. The procedure was methodologically in accordance with the valid harmonized standards or the usual methodological regulations. The most significant finding can be considered that the largest difference of the mean values of impact strength in the radial direction to the tangential direction was recorded for spruce wood, namely 50.3%. Slightly smaller differences were observed for larch wood, i.e., 41.2%. Minor differences of around 20% were recorded for beech, ash and oak wood. A difference with the opposite trend was recorded for birch wood rather than for the above-mentioned woods, namely −9.5%. Linden wood showed almost no difference (−0.8%). With regard to static bending strength, it was found that the largest difference (radial/tangential) was recorded for oak wood, i.e., 7.9%, while smaller differences were found for linden wood amounting to 6.6% and birch 4.7%. For spruce, larch, beech and ash wood, these differences are negligible. Another finding is that the dynamic modules of elasticity are greatly overestimated compared to static modules of elasticity. In the case of the examined wood of coniferous trees, these differences were up to a maximum of 20%. For wood of wood species with a diffuse-porous structure of wood, the differences were more pronounced, i.e., the range of 36% to 68%, and for wood species with a ring-porous structure in the range of 21% to 43%. Full article

(This article belongs to the Section Wood Science and Forest Products)

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23 pages, 3848 KiB

Open AccessArticle

Decline of European Beech in Austria: Involvement of Phytophthora spp. and Contributing Biotic and Abiotic Factors

by Tamara Corcobado, Thomas L. Cech, Martin Brandstetter, Andreas Daxer, Christine Hüttler, Tomáš Kudláček, Marília Horta Jung and Thomas Jung

Forests 2020, 11(8), 895; https://doi.org/10.3390/f11080895 - 18 Aug 2020

Cited by 35 | Viewed by 4947

Abstract

A severe decline and dieback of European beech (Fagus sylvatica L.) stands have been observed in Austria in recent decades. From 2008 to 2010, the distribution and diversity of Phytophthora species and pathogenic fungi and pests were surveyed in 34 beech forest [...] Read more.

A severe decline and dieback of European beech (Fagus sylvatica L.) stands have been observed in Austria in recent decades. From 2008 to 2010, the distribution and diversity of Phytophthora species and pathogenic fungi and pests were surveyed in 34 beech forest stands in Lower Austria, and analyses performed to assess the relationships between Phytophthora presence and various parameters, i.e. root condition, crown damage, ectomycorrhizal abundance and site conditions. In total, 6464 trees were surveyed, and Phytophthora-associated collar rot and aerial bark cankers were detected on 133 trees (2.1%) in 25 stands (73.5%). Isolations tests were performed from 103 trees in 27 stands and seven Phytophthora species were isolated from bleeding bark cankers and/or from the rhizosphere soil of 49 trees (47.6%) in 25 stands (92.6%). The most common species were P. ×cambivora (16 stands) followed by P. plurivora (eight stands) and P. cactorum (four stands), while P. gonapodyides, P. syringae, P. psychrophila and P. tubulina were each found in only one stand. Geological substrate had a significant effect on the distribution of P. ×cambivora and P. plurivora while P. cactorum showed no site preferences. In addition, 21 fungal species were identified on beech bark, of which 19 and five species were associated with collar rot and aerial bark cankers, respectively. Four tested fine root parameters showed differences between declining and non-declining beech trees in both Phytophthora-infested and Phytophthora-free stands. In both stand categories, ectomycorrhizal frequency of fine root tips was significantly higher in non-declining than in declining trees. This study confirmed the involvement of Phytophthora species in European beech decline and underlines the need of more research on the root condition of beech stands and other biotic and abiotic factors interacting with Phytophthora infections or causing beech decline in absence of Phytophthora. Full article

(This article belongs to the Special Issue Phytophthora Infestations in Forest Ecosystems)

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20 pages, 4235 KiB

Open AccessArticle

Leaf Habit and Stem Hydraulic Traits Determine Functional Segregation of Multiple Oak Species along a Water Availability Gradient

by Maribel Arenas-Navarro, Felipe García-Oliva, Teresa Terrazas, Andrés Torres-Miranda and Ken Oyama

Forests 2020, 11(8), 894; https://doi.org/10.3390/f11080894 - 18 Aug 2020

Cited by 13 | Viewed by 3707

Abstract

Oaks are a dominant woody plant genus in the northern hemisphere that occupy a wide range of habitats and are ecologically diverse. We implemented a functional trait approach that included nine functional traits related to leaves and stems in order to explain the [...] Read more.

Oaks are a dominant woody plant genus in the northern hemisphere that occupy a wide range of habitats and are ecologically diverse. We implemented a functional trait approach that included nine functional traits related to leaves and stems in order to explain the species coexistence of 21 oak species along a water availability gradient in a temperate forest in Mexico. This particular forest is characterized as a biodiversity hotspot, with many oak species including some endemics. Our main aim was to investigate whether the different oak species had specific trait associations that allow them to coexist along an environmental gradient at regional scale. First, we explored trait covariation and determined the main functional dimensions in which oaks were segregated. Second, we explored how environmental variation has selected for restricted functional dimensions that shape oak distributions along the gradient, regardless of their leaf life span or phylogeny (section level). Third, we quantified the niche overlap between the oak functional spaces at different levels. The analyzed species showed three functional dimensions of trait variation: a primary axis related to the leaf economic spectrum, which corresponds to the segregation of the species according to leaf habit; a second axis that reflects the stem hydraulic properties and corresponds to species segregation followed by phylogenetic segregation, reflecting some degree of trait conservatism, and a third axis, represented mainly by leaf area and plant height, that corresponds to species segregation. Finally, our findings indicated that the functional space measured with leaf traits and stem traits such as hydraulic capacity was integrally linked to niche differentiation. This linkage suggests that the earliest mechanism of species segregation was related to habitat suitability and that the stem hydraulic trade-off reflects differences between phylogenetic sections; these traits may promote coexistence between distantly related oak species. Full article

(This article belongs to the Special Issue The Physiology of Tree Response to Drought)

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12 pages, 2694 KiB

Open AccessArticle

Preparation of Wood-Based Panel Composites with Poplar Veneer as the Surface Layer Modified by In-Situ Polymerization of Active Monomers

by Xiaoyan Yu, Dandan Xu, Yan Sun, Yuran Geng, Jilong Fan, Xiaohan Dai, Zaixin He, Xiaoying Dong, Yufeng Dong and Yongfeng Li

Forests 2020, 11(8), 893; https://doi.org/10.3390/f11080893 - 18 Aug 2020

Cited by 19 | Viewed by 3139

Abstract

Wood-based panels covered by melamine-impregnated paper are widely used in floors and furniture, due to its good surface texture, hardness, wear resistance, and waterproof function. However, there are still some problems, such as formaldehyde release from the impregnated resin, non-wood touch, and complex [...] Read more.

Wood-based panels covered by melamine-impregnated paper are widely used in floors and furniture, due to its good surface texture, hardness, wear resistance, and waterproof function. However, there are still some problems, such as formaldehyde release from the impregnated resin, non-wood touch, and complex preparation processes. Therefore, this study designed glycidyl methacrylate (GMA) and ethyleneglycol dimethacrylate (EGDMA), combined with maleic anhydride (MAN) as a reactive catalyst, to build an active monomers system. It was first impregnated into poplar veneers, and then in-situ polymerized within the veneer using a hot pressing process, which realized the gluing of the veneer onto the wood-based panel substrate, synchronously. Such treatment aims to obtain wood-based panel composites decorated by the modified veneer, with real solid wood touch feeling, satisfied surface properties, and environment friendly glue bonding. The results indicated that the optimized reaction ratio of the active monomers (GMA:EGDMA) was 2:1 (molar ratio), and the maleic anhydride addition accounted for 6 wt.% of the total monomers. Under the optimized hot pressing condition, the modified veneer closely bonded to the wood-based panel substrate without obvious interfacial gaps. The hardness, abrasion resistance, modulus of rupture, and water resistance of the composites were significantly improved. Such results indicate that the treatment realized the perfect merging of solid wood touch feeling, environment friendly feature, and excellent properties of the composite. It was highly expected to replace the traditional melamine-impregnated paper to decorate wood-based panels, and could be potentially applied as surface decorating materials in wide areas of desktop, floor, cupboard, wardrobe, and so on. Full article

(This article belongs to the Special Issue Wood Modification: Physical Properties and Biological Efficacy)

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12 pages, 2209 KiB

Open AccessArticle

Potential Pollution Sources from Agricultural Activities on Tropical Forested Floodplain Wetlands Revealed by Soil eDNA

by Maria Fernanda Adame and Ruth Reef

Forests 2020, 11(8), 892; https://doi.org/10.3390/f11080892 - 17 Aug 2020

Cited by 11 | Viewed by 3774

Abstract

Tropical floodplain wetlands are found in low-lying areas that are periodically inundated. During wet periods, these wetlands can receive large amounts of suspended and dissolved material from the catchment, including many potential pollutants. In this study, we use traditional isotope tracers (δ¹⁵ [...] Read more.

Tropical floodplain wetlands are found in low-lying areas that are periodically inundated. During wet periods, these wetlands can receive large amounts of suspended and dissolved material from the catchment, including many potential pollutants. In this study, we use traditional isotope tracers (δ¹⁵N and δ¹³C) along with soil eDNA to investigate the sources of transported materials and potential contaminants in seven forested floodplain wetlands in tropical Australia. We hypothesised that eDNA and isotope tracers in the soil would reflect the land use of the catchment. Our goal was to test whether eDNA could be used as a potential tool to identify and monitor pollutants in floodplain wetlands. The sampling sites were located within catchments that have a mosaic of land types, from well-conserved rainforests to intensive agricultural land uses, such as grazing, sugar cane, wood production, and horticulture. The soil eDNA was comprised of a mix of plant species consistent with the land use of the catchments. Most of the eDNA pool was derived from native trees, accounting for 46.2 ± 6.5% of the total; while cultivated species associated with agricultural activities contributed to 1–24% of the total. From the cultivated species, highest contributions (>5%) were from Sorghum sp. used for grazing, banana (Musa ornata), melons (Cucumis melo), and Pinus radiata and Juniperus sp. grown for wood production. Interestingly, tropical wetlands on sites 15 km offshore had soil eDNA from agricultural activities of the mainland, highlighting the connectivity of these wetlands, probably during extensive floods. Overall, soil eDNA, more than isotopic tracers, showed promising results for tracing and monitoring potential pollutants in tropical floodplain wetlands that are highly connected and susceptible to environmental degradation. Full article

(This article belongs to the Special Issue Structure, Function, and Dynamics of Tropical Floodplain Forests)

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16 pages, 4384 KiB

Open AccessArticle

Predicting Suitable Habitats of Camptotheca acuminata Considering Both Climatic and Soil Variables

by Lei Feng, Jiejie Sun, Yuanbao Shi, Guibin Wang and Tongli Wang

Forests 2020, 11(8), 891; https://doi.org/10.3390/f11080891 - 17 Aug 2020

Cited by 28 | Viewed by 3535

Abstract

Camptotheca acuminata is considered a natural medicinal plant with antitumor activity. The assessment of climate change impact on its suitable habitats is important for cultivation and conservation. In this study, we applied a novel approach to build ecological niche models with both climate [...] Read more.

Camptotheca acuminata is considered a natural medicinal plant with antitumor activity. The assessment of climate change impact on its suitable habitats is important for cultivation and conservation. In this study, we applied a novel approach to build ecological niche models with both climate and soil variables while the confounding effects between the variables in the two categories were avoided. We found that the degree-days below zero and mean annual precipitation were the most important climatic factors, while the basic soil saturation, soil gravel volume percentage, and clay content were the main soil factors, determining the suitable habitats of C. acuminata. We found that suitable habitats of this species would moderately increase in future climates under both the RCP4.5 and RCP8.5 climate change scenarios for the 2020s, 2050s, and 2080s. However, substantial shifts among levels of habitat suitability were projected. The dual high-suitable habitats would expand, which would be favorable for commercial plantations. Our findings contribute to a better understanding of the impact of climate change on this species and provide a scientific basis for the cultivation and conservation purposes. Full article

(This article belongs to the Special Issue Genetic Resources and Adaptive Management of Conifers in a Changing World)

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11 pages, 3251 KiB

Open AccessArticle

The Effect of Contact-Drying on Physical Properties of European Beech (Fagus sylvatica L.)

by Ivan Klement, Peter Vilkovský and Tatiana Vilkovská

Forests 2020, 11(8), 890; https://doi.org/10.3390/f11080890 - 16 Aug 2020

Cited by 3 | Viewed by 2694

Abstract

Beech wood is mainly used for furniture, plywood, decorative veneer manufacturing or packaging. Timber or lumber is traditionally dried in kilns by processes often taking several weeks. This research deals with more rapid process called contact-drying process. Drying was performed using the heating [...] Read more.

Beech wood is mainly used for furniture, plywood, decorative veneer manufacturing or packaging. Timber or lumber is traditionally dried in kilns by processes often taking several weeks. This research deals with more rapid process called contact-drying process. Drying was performed using the heating plates with a temperature of 160 °C and pressures of 1.0 MPa, 1.4 MPa and 1.8 MPa. The results were compared to conventional warm-air drying. The warm-air drying mode was divided into two phases, with and without free water and bound water in the dried wood. The density of the samples increased remarkably during the contact-drying. The effect of the pressure of the heating plates was substantial. The difference in the average density between the pressure of 1.0 MPa and 1.8 MPa was more than 22 kg·m⁻³. The pressure of the heating plates affected the process and the resulting change in the sample thickness. The change in the sample thickness was more considerable in the case of the tangential samples. The thickness did not increase significantly after air conditioning. During contact-drying, the hygroscopicity and absorptivity of wood reduced on average by 21.24% and 25%, respectively, compared to warm-air drying. Full article

(This article belongs to the Special Issue Wood Structure and Properties)

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11 pages, 3558 KiB

Open AccessArticle

Survival of Quercus alba (White Oak) Advance Reproduction in Small Group and Single Tree Openings

by Martin A. Spetich

Forests 2020, 11(8), 889; https://doi.org/10.3390/f11080889 - 15 Aug 2020

Cited by 3 | Viewed by 2291

Abstract

Survival probabilities of white oak (Quercus alba) in small circular group and single tree openings ranging in size from 0.001 to 0.175 ha twelve years after opening creation are presented. At the beginning of the study, 3948 advance reproduction white oak [...] Read more.

Survival probabilities of white oak (Quercus alba) in small circular group and single tree openings ranging in size from 0.001 to 0.175 ha twelve years after opening creation are presented. At the beginning of the study, 3948 advance reproduction white oak trees were measured and tagged to determine survival of each tagged seedling at the end of the study. Logistic regression indicated that variables important in predicting advance reproduction survival included initial seedling basal diameter, aspect, slope, canopy opening size, opening border tree height and treatment for control of understory competition. Survival probability ranged from 10% to 90% depending on the combination of and disposition of variables. For these small openings, the greatest probability of survival of advance reproduction resulted when advance reproduction initial basal diameters were ≥1 cm, when the height of trees bordering the openings were relatively short, with understory chemical competition control, in the largest canopy openings, on 6% slopes, and on southwest and northwest aspects. These criteria can help managers select sites and treatment options for group opening creation that provide optimal conditions for advance reproduction survival. Full article

(This article belongs to the Special Issue Natural Regeneration in Mixed Hardwood Forests)

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29 pages, 6335 KiB

Open AccessArticle

Long-Term Effects of Fuels Treatments, Overstory Structure, and Wildfire on Tree Regeneration in Dry Forests of Central Washington

by Allison K. Rossman, Jonathan D. Bakker, David W. Peterson and Charles B. Halpern

Forests 2020, 11(8), 888; https://doi.org/10.3390/f11080888 - 15 Aug 2020

Cited by 2 | Viewed by 2431

Abstract

The long-term effectiveness of dry-forest fuels treatments (restoration thinning and prescribed burning) depends, in part, on the pace at which trees regenerate and recruit into the overstory. Knowledge of the factors that shape post-treatment regeneration and growth is limited by the short timeframes [...] Read more.

The long-term effectiveness of dry-forest fuels treatments (restoration thinning and prescribed burning) depends, in part, on the pace at which trees regenerate and recruit into the overstory. Knowledge of the factors that shape post-treatment regeneration and growth is limited by the short timeframes and simple disturbance histories of past research. Here, we present results of a 15-year fuels-reduction experiment in central Washington, including responses to planned and unplanned disturbances. We explore the changing patterns of Douglas-fir regeneration in 72 permanent plots (0.1 ha) varying in overstory abundance (a function of density and basal area) and disturbance history—the latter including thinning, prescribed burning, and/or wildfire. Plots were measured before treatment (2000/2001), soon afterwards (2004/2005), and more than a decade later (2015). Thinning combined with burning enhanced sapling recruitment (ingrowth) into the overstory, although rates of ingrowth were consistently low and greatly exceeded by mortality. Relationships between seedling frequency (proportion of quadrats within a plot) and overstory abundance shifted from weakly negative before treatment to positive after thinning, to neutral in the longer term. However, these relationships were overshadowed by more recent, higher-severity prescribed fire and wildfire that stimulated seedling establishment while killing advanced regeneration and overstory trees. Our results highlight the dependence of regeneration responses on the history of, and time since, fuels treatment and subsequent disturbance. Managers must be aware of this spatial and temporal complexity and plan for future disturbances that are inevitable but unpredictable in timing and severity. Full article

(This article belongs to the Special Issue Impacts of Wildfire and Forest Management Activities on Forest Understory Plant Communities)

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19 pages, 1824 KiB

Open AccessArticle

Is Soil Contributing to Climate Change Mitigation during Woody Encroachment? A Case Study on the Italian Alps

by Ernesto Fino, Emanuele Blasi, Lucia Perugini, Guido Pellis, Riccardo Valentini and Tommaso Chiti

Forests 2020, 11(8), 887; https://doi.org/10.3390/f11080887 - 15 Aug 2020

Cited by 5 | Viewed by 3038

Abstract

Background and Objectives: Over the last few decades, the European mountain environment has been characterized by the progressive abandonment of agro-pastoral activities and consequent forest expansion due to secondary succession. While woody encroachment is commonly considered as a climate change mitigation measure, studies [...] Read more.

Background and Objectives: Over the last few decades, the European mountain environment has been characterized by the progressive abandonment of agro-pastoral activities and consequent forest expansion due to secondary succession. While woody encroachment is commonly considered as a climate change mitigation measure, studies suggest a still uncertain role of the soil organic carbon (SOC) pool in contributing to climate change mitigation during this process. Therefore, the objective of the study is to investigate the possible SOC variations occurring as a consequence of the secondary succession process at the provincial level in an Alpine area in Italy. Materials and Methods: A chronosequence approach was applied to identify, in five different study areas of the Belluno province, the land use/land cover change over four different stages of natural succession, from managed grazing land to secondary forest developed on abandoned grazing land. In each chronosequence stage, soil samples were collected down to the bedrock (0–60 cm depth) to determine the changes in the SOC stock due to the woody encroachment process. Results: In all areas, small or no significant (p < 0.05) SOC stock changes were observed during the secondary succession in the upper 30 cm of mineral soil, while significant changes were evident in the 30–60 cm compartment, with the SOC stock significantly decreasing from 30% to 60% in the final stage of the succession. This fact indicates the great importance of considering also the subsoil when dealing with land use/land cover change dynamics. Conclusions: The recorded trend in SOC has been proved to be the opposite in other Italian regions, so our results indicate the importance of local observation and data collection to correctly evaluate the soil contribution to climate change mitigation during woody encroachment. Full article

(This article belongs to the Section Forest Ecology and Management)

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Graphical abstract

13 pages, 3855 KiB

Open AccessArticle

Compression Properties and Its Prediction of Wood-Based Sandwich Panels with a Novel Taiji Honeycomb Core

by Jingxin Hao, Xinfeng Wu, Gloria Oporto-Velasquez, Jingxin Wang and Gregory Dahle

Forests 2020, 11(8), 886; https://doi.org/10.3390/f11080886 - 15 Aug 2020

Cited by 5 | Viewed by 3546

Abstract

The transverse compression property is one of most important aspects of the mechanical performance of a sandwich structure with a soft core. An experiment, analytical method and three digital strain measurement systems were applied to investigate the compression behavior and the failure mechanism [...] Read more.

The transverse compression property is one of most important aspects of the mechanical performance of a sandwich structure with a soft core. An experiment, analytical method and three digital strain measurement systems were applied to investigate the compression behavior and the failure mechanism for a wood-based sandwich structure with a novel Taiji honeycomb core. The results show that the structure of the Taiji honeycomb can improve dramatically on compression strength and modulus of composite compared to that of a traditional hexagonal one. There was no obvious deflection in the transverse direction detected by the three digital images before the buckling of the honeycomb occurred. An analytical equation between the key structure parameters and properties of the composite were applied to predict its threshold stresses and modulus. The properties of the core determine the strength of the entire structure, but the compression strength decreases slightly with an elevated core thickness, and its effect on the compression modulus can be neglected. Both the surface sheets and loading speed have little impact on the compression strength and modulus, respectively. Full article

(This article belongs to the Section Wood Science and Forest Products)

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15 pages, 4384 KiB

Open AccessArticle

Domesticating Commercially Important Native Tree Species in the Philippines: Early Growth Performance Level

by Rustum Aguilos, Conrado Marquez, Henry Adornado and Maricar Aguilos

Forests 2020, 11(8), 885; https://doi.org/10.3390/f11080885 - 14 Aug 2020

Cited by 10 | Viewed by 12008

Abstract

Selection of native tree species for commercial purposes is a continuing challenge and an opportunity in tropical silviculture. Because of this, we explored domesticating 33 native species in the Philippines that were tested for survival rate, total height, and diameter-at-ground-level (dgl) increments. The [...] Read more.

Selection of native tree species for commercial purposes is a continuing challenge and an opportunity in tropical silviculture. Because of this, we explored domesticating 33 native species in the Philippines that were tested for survival rate, total height, and diameter-at-ground-level (dgl) increments. The first five years (2014–2018) of assessment showed that 13 species (40%) of the 33 native species reached a survival rate of more than 80%. Grouped as ‘slow’-, ‘medium’- and ‘fast’-growing field trial species, a 709 cm average total height at five years was attained by the fast-growing cluster where Bagalunga (Melia dubia L.) and Kupang (Parkia javanica (D.C.) Merr.) were among the fastest-growing species. Slow-growing trees like Tindalo (Afzelia rhomboidei (Blanco)) and Kamagong (Diospyros blancoi (Willd)) were among the slowest-growing with an average height of 193.8 cm. Dipterocarps like Yakal (Shorea stylosa (Foxw.)), Tanguile (Shorea polysperma (Blanco)) and Mayapis (Shorea squamata (Blanco) Merr.) had the lowest diameter at ground level (dgl) increments (average 25.9 mm) while diametric expansion of fast-growing species spanned up to 93.5 mm. Overall, height and dgl increments were almost five times the original measurement five years after planting. A sudden surge in the rate of change in total height (83%) and dgl (72%) occurred a year after planting, yet a sudden decline occurred in the fifth year with only 21% for height and 23% for diameter growth suggesting the first 3–4 years as the crucial stage in seedling development. Survival rate is better correlated with the changes in dgl increment (R² = 0.19, p < 0.05) than the height growth (R² = 0.12, p < 0.05). Increasing rainfall and optimum air temperature significantly correlated with height and diameter growth while any increase in recorded wind speed slightly reduced the growth of the species. Our findings are initial steps towards developing appropriate silvicultural and management interventions when planning for the massive plantation development of domesticated Philippine native trees in the future. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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10 pages, 2086 KiB

Open AccessArticle

Complete Chloroplast Genome of Japanese Larch (Larix kaempferi): Insights into Intraspecific Variation with an Isolated Northern Limit Population

by Shufen Chen, Wataru Ishizuka, Toshihiko Hara and Susumu Goto

Forests 2020, 11(8), 884; https://doi.org/10.3390/f11080884 - 14 Aug 2020

Cited by 12 | Viewed by 3000

Abstract

Research Highlights: The complete chloroplast genome for eight individuals of Japanese larch, including from the isolated population at the northern limit of the range (Manokami larch), revealed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed in [...] Read more.

Research Highlights: The complete chloroplast genome for eight individuals of Japanese larch, including from the isolated population at the northern limit of the range (Manokami larch), revealed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed in Japanese larch. We detected intraspecific variation for possible candidate cpDNA markers in Japanese larch. Background and Objectives: The natural distribution of Japanese larch is limited to the mountainous range in the central part of Honshu Island, Japan, with an isolated northern limit population (Manokami larch). In this study, we determined the phylogenetic position of Manokami larch within Japanese larch, characterized the chloroplast genome of Japanese larch, detected intraspecific variation, and determined candidate cpDNA markers. Materials and Methods: The complete genome sequence was determined for eight individuals, including Manokami larch, in this study. The genetic position of the northern limit population was evaluated using phylogenetic analysis. The chloroplast genome of Japanese larch was characterized by comparison with eight individuals. Furthermore, intraspecific variations were extracted to find candidate cpDNA markers. Results: The phylogenetic tree showed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed, based on the complete chloroplast genome, with a bootstrap value of 100%. The value of nucleotide diversity (π) was calculated at 0.00004, based on SNP sites for Japanese larch, suggesting that sequences had low variation. However, we found three hyper-polymorphic regions within the cpDNA. Finally, we detected 31 intraspecific variations, including 19 single nucleotide polymorphisms, 8 simple sequence repeats, and 4 insertions or deletions. Conclusions: Using a distant genotype in a northern limit population (Manokami larch), we detected sufficient intraspecific variation for the possible candidates of cpDNA markers in Japanese larch. Full article

(This article belongs to the Special Issue Genetics and Improvement of Forest Trees)

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13 pages, 2059 KiB

Open AccessArticle

Diplodia fraxini and Diplodia subglobosa: The Main Species Associated with Cankers and Dieback of Fraxinus excelsior in North-Eastern Italy

by Benedetto T. Linaldeddu, Francesco Bottecchia, Carlo Bregant, Lucia Maddau and Lucio Montecchio

Forests 2020, 11(8), 883; https://doi.org/10.3390/f11080883 - 14 Aug 2020

Cited by 22 | Viewed by 4148

Abstract

In Italy, after the first report in Friuli-Venezia Giulia along the border with Slovenia in 2009, ash dieback has successively been reported in Veneto, Tuscany and Trentino-Alto Adige. Given its alarming expansion in European ash formations along the sub-montane belt of north-eastern Italy [...] Read more.

In Italy, after the first report in Friuli-Venezia Giulia along the border with Slovenia in 2009, ash dieback has successively been reported in Veneto, Tuscany and Trentino-Alto Adige. Given its alarming expansion in European ash formations along the sub-montane belt of north-eastern Italy and the limited information about the associated fungal microorganisms; since 2017, a study has been conducted in order to isolate and characterize the fungal species involved in the aetiology of the disease. The surveys were conducted in six ash–maple forests distributed along the Veneto and Friuli-Venezia Giulia pre-Alpine regions (Italy). In each site, the health status of ash trees was assessed and a sample (shoot or branch) with the typical symptoms of the disease was taken from ten trees to isolate the associated pathogens. The fungal colonies developed were identified using morphological features and DNA sequences. The 60 samples processed yielded a total of 109 fungal isolates belonging to 9 families including: Botryosphaeriaceae (62 isolates), Diaporthaceae (18), Nectriaceae (10), Didymellaceae (9), Helotiaceae (5), Diatrypaceae (2), Didymosphaeriaceae (1), Phaeosphaeriaceae (1) and Valsaceae (1). In particular, three species—Diplodia subglobosa, Diplodia fraxini and Diaporthe eres—were isolated with high frequency, while Hymenoscyphus fraxineus was isolated from only five plants distributed in four sites. The pathogenicity tests, conducted on 3-year-old seedlings, detached branches (3–4 cm diameter), and leaves of Fraxinus excelsior, showed that Diplodia fraxini is the most virulent species and the only one able to reproduce the symptoms observed in nature. Overall, the results obtained emphasize that several fungal pathogens are involved in the aetiology of the disease, many of which belong to the Botryosphaeriaceae family. Full article

(This article belongs to the Special Issue Tree Care in 2020, the International Year of Plant Health)

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15 pages, 2716 KiB

Open AccessArticle

Litter Decomposition and Nutrient Dynamics in Fire-Affected Larch Forests in the Russian Far East

by Semyon Bryanin, Anjelica Kondratova and Evgeniya Abramova

Forests 2020, 11(8), 882; https://doi.org/10.3390/f11080882 - 13 Aug 2020

Cited by 10 | Viewed by 3043

Abstract

Russian boreal forests hold a considerable carbon (C) stock and are subjected to frequent surface fires that unbalance C storage and ecosystem function. Although postfire ecological changes aboveground are well understood, biological C flows (e.g., decomposition in the postfire period) remain unclear. We [...] Read more.

Russian boreal forests hold a considerable carbon (C) stock and are subjected to frequent surface fires that unbalance C storage and ecosystem function. Although postfire ecological changes aboveground are well understood, biological C flows (e.g., decomposition in the postfire period) remain unclear. We present the results of a long-term field litterbag experiment on needle litter decomposition in typical Larix gmelinii boreal forests in the Russian Far East. For 3 years, we measured mass loss, C and nitrogen (N) concentrations, lignin and manganese dynamics, respiration intensity and enzyme activity in decaying needles, and environmental conditions (temperature and litter moisture). The decomposition rate at 850 days was 0.435 and 0.213 yr⁻¹ in a control forest and in a forest 15 years after a surface fire, respectively. Early stages of needle decay did not differ among sites, whereas decomposition slowed in later stages in burned forest relative to the control (p < 0.01). This was supported by hampered respiration, slow lignin accumulation in decaying needles, and low peroxidase activity in burned forest. We found no direct N release, and decaying litter immobilization was more pronounced in the control forest. In the later stages, we revealed restrained mass loss and associated C release from larch litter in burned forest. Slow and delayed N release may alter organic matter accumulation, the N cycle, and regeneration of the fire-disturbed larch ecosystem. Our investigations highlight hampered C flow from aboveground litter to soil humus even decades after surface fire in a larch ecosystem. Given the climate-induced increase of fire activity, C retained in the litter layer represents a pool that is more vulnerable to the next fire event. Full article

(This article belongs to the Section Forest Ecology and Management)

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20 pages, 3745 KiB

Open AccessReview

Structural Vulnerability Assessment of Heritage Timber Buildings: A Methodological Proposal

by Amirhosein Shabani, Mahdi Kioumarsi, Vagelis Plevris and Haris Stamatopoulos

Forests 2020, 11(8), 881; https://doi.org/10.3390/f11080881 - 13 Aug 2020

Cited by 32 | Viewed by 6215

Abstract

The conservation of heritage structures is pivotal not only due to their cultural or historical importance for nations, but also for understanding their construction techniques as a lesson that can be applied to contemporary structures. Timber is considered to be the oldest organic [...] Read more.

The conservation of heritage structures is pivotal not only due to their cultural or historical importance for nations, but also for understanding their construction techniques as a lesson that can be applied to contemporary structures. Timber is considered to be the oldest organic construction material and is more vulnerable to environmental threats than nonorganic materials such as masonry bricks. In order to assess the structural vulnerability of heritage timber structures subjected to different types of risk, knowledge about their structural systems and configurations, the nature and properties of the materials, and the behavior of the structure when subjected to different risks, is essential for analysts. In order to facilitate the procedure, different assessment methods have been divided into the categories in situ and ex situ, which are applicable for vulnerability assessments at the element and full-scale level of a case study. An existing methodology for structural vulnerability assessments and conservation of heritage timber buildings is reviewed and a new methodology is proposed. Full article

(This article belongs to the Special Issue Timber and Construction Structure)

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29 pages, 6602 KiB

Open AccessArticle

Species Ecological Envelopes under Climate Change Scenarios: A Case Study for the Main Two Wood-Production Forest Species in Portugal

by Cristina Alegria, Natália Roque, Teresa Albuquerque, Saki Gerassis, Paulo Fernandez and Maria Margarida Ribeiro

Forests 2020, 11(8), 880; https://doi.org/10.3390/f11080880 - 12 Aug 2020

Cited by 8 | Viewed by 3881

Abstract

Species ecological envelope maps were obtained for the two main Portuguese wood-production species (Eucalyptus globulus Labill. and Pinus pinaster Aiton) and projected future climate change scenarios. A machine learning approach was used to understand the most influential environmental variables that may explain [...] Read more.

Species ecological envelope maps were obtained for the two main Portuguese wood-production species (Eucalyptus globulus Labill. and Pinus pinaster Aiton) and projected future climate change scenarios. A machine learning approach was used to understand the most influential environmental variables that may explain current species distribution and productivity. Background and Objectives: The aims of the study were: (1) to map species potential suitability areas using ecological envelopes in the present and to project them in the future under climate change scenarios; (2) to map species current distributions; (3) to map species current productivity; and (4) to explore the most influential environmental variables on species current distribution and productivity. Materials and Methods: Climate, elevation data, and soil data sets were used to obtain present and future species ecological envelopes under two climate change scenarios. The official land cover maps were used to map species distributions. Forest inventory data were used to map the species productivity by geostatistical techniques. A Bayesian machine learning approach, supported by species distributions and productivity data, was used to explore the most influential environmental variables on species distribution and productivity and to validate species ecological envelopes. Results: The species ecological envelope methodology was found to be robust. Species’ ecological envelopes showed a high potential for both species’ afforestation. In the future, a decrease in the country’s area potentiality was forecasted for both species. The distribution of maritime pine was found to be mainly determined by precipitation-related variables, but the elevation and temperature-related variables were very important to differentiate species productivity. For eucalypts, species distribution was mainly explained by temperature-related variables, as well as the species productivity. Conclusions: These findings are key to support recommendations for future afforestation and will bring value to policy-makers and environmental authorities in policy formulation under climate change scenarios. Full article

(This article belongs to the Section Wood Science and Forest Products)

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17 pages, 1581 KiB

Open AccessArticle

Structural Carbon Allocation and Wood Growth Reflect Climate Variation in Stands of Hybrid White Spruce in Central Interior British Columbia, Canada

by Anastasia Ivanusic, Lisa J. Wood and Kathy Lewis

Forests 2020, 11(8), 879; https://doi.org/10.3390/f11080879 - 12 Aug 2020

Cited by 1 | Viewed by 2480

Abstract

Research Highlights: This research presents a novel approach for comparing structural carbon allocation to tree growth and to climate in a dendrochronological analysis. Increasing temperatures reduced the carbon proportion of wood in some cases. Background and Objectives: Our goal was to estimate [...] Read more.

Research Highlights: This research presents a novel approach for comparing structural carbon allocation to tree growth and to climate in a dendrochronological analysis. Increasing temperatures reduced the carbon proportion of wood in some cases. Background and Objectives: Our goal was to estimate the structural carbon content of wood within hybrid white spruce (Picea glauca (Moench) × engelmannii (Parry) grown in British Columbia, Canada, and compare the percent carbon content to wood properties and climate conditions of the region. Specific objectives included: (i) the determination of average incremental percent carbon, ring widths (RW), earlywood (EW) and latewood (LW) widths, cell wall thickness, and density over time; (ii) the determination of differences between percent carbon in individual forest stands and between regions; and (iii) the evaluation of the relationships between percent carbon and climate variation over time. Methods: Trees were sampled from twelve sites in northern British Columbia. Wood cores were analyzed with standard dendrochronology techniques and SilviScan analysis. Percent structural carbon was determined using acetone extraction and elemental analysis for 5 year increments. Individual chronologies of wood properties and percent carbon, and chronologies grouped by region were compared by difference of means. Temperature and precipitation values from the regions were compared to the carbon chronologies using correlation, regression, and visual interpretation. Results: Significant differences were found between the percent structural carbon of wood in individual natural and planted stands; none in regional aggregates. Some significant relationships were found between percent carbon, RW, EW, LW, and the cell wall thickness and density values. Percent carbon accumulation in planted stands and natural stands was found in some cases to correlate with increasing temperatures. Natural stand percent carbon values truncated to the last 30 years of growth was shown as more sensitive to climate variation compared to the entire time series. Conclusions: Differences between the stands in terms of structural carbon proportion vary by site-specific climate characteristics in areas of central interior British Columbia. Wood properties can be good indicators of variation in sequestered carbon in some stands. Carbon accumulation was reduced with increasing temperatures; however, warmer late-season conditions appear to enhance growth and carbon accumulation. Full article

(This article belongs to the Special Issue Growth and Allocation of Woody Biomass in Forest Trees Based on Environmental Conditions)

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13 pages, 3397 KiB

Open AccessArticle

The Brinell Method for Determining Hardness of Wood Flooring Materials

by Maciej Sydor, Grzegorz Pinkowski and Anna Jasińska

Forests 2020, 11(8), 878; https://doi.org/10.3390/f11080878 - 12 Aug 2020

Cited by 14 | Viewed by 4644

Abstract

We hypothesize that the ability to recovery the depth of the indentation increases with increasing the hardness of the flooring material. The research was carried out for ten lignocellulosic flooring materials: merbau, oak, maple, red oak, laminated HDF (high-density fiberboard), innovative plywood, beech, [...] Read more.

We hypothesize that the ability to recovery the depth of the indentation increases with increasing the hardness of the flooring material. The research was carried out for ten lignocellulosic flooring materials: merbau, oak, maple, red oak, laminated HDF (high-density fiberboard), innovative plywood, beech, pine, peasantry, iroko. The hardness was examined using the Brinell method, and additionally, the elastic indentation of the indenter was measured during the hardness test. On this basis, the permanent (plastic) and temporary (elastic) component of total deformation was determined. Different ability to recovery was found. The harder materials were the higher percentage of elastic indentation in total indentation depth. Moreover, it was found that the measurement of the indentation diameter in wood materials is characterized by high uncertainty and measurements based on the depth of the indentation are more unambiguous and of greater practical importance, especially when testing hard lignocellulosic flooring materials. Full article

(This article belongs to the Special Issue Performance of Wood and Wood-Based Materials)

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8 pages, 715 KiB

Open AccessArticle

Verifying the Utility of Black Locust (Robinia pseudoacacia L.) in the Reclamation of a Lignite Combustion Waste Disposal Site in Central European Conditions

by Bartłomiej Woś, Marek Pająk, Wojciech Krzaklewski and Marcin Pietrzykowski

Forests 2020, 11(8), 877; https://doi.org/10.3390/f11080877 - 12 Aug 2020

Cited by 9 | Viewed by 2161

Abstract

N-fixing tree species, such as black locust, have achieved very promising results in the reclamation of technosols, especially those at combustion waste disposal sites, which have extremely poor nutrients and adverse physicochemical parameters. This paper presents an assessment of the survival rates, growth [...] Read more.

N-fixing tree species, such as black locust, have achieved very promising results in the reclamation of technosols, especially those at combustion waste disposal sites, which have extremely poor nutrients and adverse physicochemical parameters. This paper presents an assessment of the survival rates, growth parameters, and quality and vitality of and nutrient supply (NPK) to black locust (Robinia pseudoacacia L.) specimens that were experimentally planted on a lignite combustion waste disposal site. The black locust seedlings were introduced directly into the combustion waste using two variants of NPK (7% N, 5.5% P₂O₅, and 9% K₂O) fertilisation, at doses of 250 and 500 kg ha⁻¹, and in control plots with no mineral fertilisation. No significant impacts of the applied mineral fertilisation were found on the soil properties, growth parameters, or nutrient supplies to the trees. Black locust introduced to the landfill after three years of revegetation was characterised by a very high survival rate of 95%–100%, as well as good growth parameters (height and diameter at the root collar). Nutrient supply was determined on the basis of the chemical composition of the leaves, which indicated an adequate supply of nitrogen, similar to levels found under natural conditions. In the case of K and P, the supply levels were lower than optimal when compared with data from the literature. However, at this initial stage of tree development on the combustion waste disposal site, nutrient supply is similar on all variants and is not a critical factor for successful black locust introduction. We suggest using growth parameters, survival, and vitality of trees as decisive factors for the reclamation of combustion waste landfill sites strategy. All these factors confirmed the usefulness of black locust to the reclamation of combustion waste disposal sites. Full article

(This article belongs to the Special Issue Forest Ecosystem Restoration on Postindustrial Sites)

22 pages, 771 KiB

Open AccessArticle

Qualitative Exploration of Perception and Use of Cultural Ecosystem Services from Tree-Based Urban Green Space in the City of Zagreb (Croatia)

by Silvija Krajter Ostoić, Ana Marija Marin, Martina Kičić and Dijana Vuletić

Forests 2020, 11(8), 876; https://doi.org/10.3390/f11080876 - 11 Aug 2020

Cited by 18 | Viewed by 4992

Abstract

Background and Objectives: Cultural ecosystem services of urban green spaces are increasingly important and often recognized as such by people living in urban areas. Qualitative studies on perception of cultural ecosystem services from urban green spaces are still rare. Previous studies addressed only [...] Read more.

Background and Objectives: Cultural ecosystem services of urban green spaces are increasingly important and often recognized as such by people living in urban areas. Qualitative studies on perception of cultural ecosystem services from urban green spaces are still rare. Previous studies addressed only certain types of urban green space and often only some services. There is a lack of understanding how people perceive cultural ecosystem services from different types of tree-based urban green spaces. Hence, the purpose of the study was to explore whether and how people perceive and use cultural ecosystem services of different types of tree-based urban green spaces. Materials and Methods: Focus groups were conducted with citizens in each city district. Interviews were recorded, transcribed and transcripts analyzed in MAXQDA software. We used bottom up code-category-theme approach to analyze the data without predefined set of codes or categories. Results: Place attachment, aesthetic and recreational services were more recognized than educational and cultural identity services. For place attachment, most important single attributes were positive memories, and good maintenance, while most important categories were facilities, existence of emotional ties, possibility of experiences, recreational use and access. Presence of specific tree species and presence of trees in general were most important attributes for aesthetic services, while possibility of experiences and trees were the most important categories. Conclusions: People perceived various cultural ecosystem services from tree-based urban green space, even though some services more than others. Recreation may be the underlying goal of our participants when interacting with tree-based urban nature. Forests, parks were recognized as those providing multiple cultural ecosystem services. However, other types of green spaces were also recognized as bearers of these services, albeit with less services and attributes attached. It supports the importance of careful planning of urban green spaces in terms of providing a variety of green space types. The study provides basis for later quantification of cultural ecosystem services (CES) from tree-based urban green space. Full article

(This article belongs to the Special Issue Assessing, Valuing and Mapping Ecosystem Services)

20 pages, 1952 KiB

Open AccessArticle

Ethnomycological Knowledge of Three Ethnic Groups in Ethiopia

by Gizachew Zeleke, Tatek Dejene, Wubalem Tadesse, Dolores Agúndez and Pablo Martín-Pinto

Forests 2020, 11(8), 875; https://doi.org/10.3390/f11080875 - 11 Aug 2020

Cited by 11 | Viewed by 3748

Abstract

Ethnomycological information was gathered by conducting semi-structured interviews with members of the Amhara, Agew, and Sidama ethnic groups in Ethiopia. A total of 300 individuals were involved in this study. Forest excursions were also undertaken to investigate the habitat and to identify useful [...] Read more.

Ethnomycological information was gathered by conducting semi-structured interviews with members of the Amhara, Agew, and Sidama ethnic groups in Ethiopia. A total of 300 individuals were involved in this study. Forest excursions were also undertaken to investigate the habitat and to identify useful wild mushroom species present in the study areas. A total of 24 useful wild mushroom species were identified. Among the three ethnic groups, the Sidama have the most extensive ethnomycological knowledge and over seven vernacular names for useful fungal species were recorded for this group. Collecting mushrooms is common practice among the Sidama and usually carried out by women and children during the main rainy season from June to September. Useful mushrooms are collected in natural forests, plantation forests, grazing areas, home gardens, and swampy areas. In terms of medicinal uses, Lycoperdon perlatum Pers. and Calvatia rubroflava (Cragin) Lloyd. are well-known treatments for wounds and skin disease. Harvest storage of wild mushroom species is unknown. Respondents in the Amhara and Agew ethnic groups were similar in terms of their use and knowledge of mushrooms. Both ethnic groups reported that although wild mushroom species were consumed by their grandparents, they do not eat mushrooms themselves, which could eventually represent a loss of mycological knowledge in these two ethnic groups. Such inconsistency between ethnic groups in terms of their knowledge may also be linked to the social valuation of mushroom resources, which could easily be mitigated by raising awareness. Thus, the baseline information obtained in this study could be useful for further investigations and documentation, and to promote ethnomycological benefits to different ethnic groups in countries with similar settings. Full article

(This article belongs to the Special Issue Forest, Foods and Nutrition)

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17 pages, 1271 KiB

Open AccessArticle

Allometric Equations for Volume, Biomass, and Carbon in Commercial Stems Harvested in a Managed Forest in the Southwestern Amazon: A Case Study

by Flora Magdaline Benitez Romero, Laércio Antônio Gonçalves Jacovine, Sabina Cerruto Ribeiro, Carlos Moreira Miquelino Eleto Torres, Liniker Fernandes da Silva, Ricardo de Oliveira Gaspar, Samuel José Silva Soares da Rocha, Christina Lynn Staudhammer and Philip Martin Fearnside

Forests 2020, 11(8), 874; https://doi.org/10.3390/f11080874 - 11 Aug 2020

Cited by 27 | Viewed by 6539

Abstract

Forests in the southwestern Amazon are rich, diverse, and dense. The region is of high ecological importance, is crucial for conservation and management of natural resources, and contains substantial carbon and biodiversity stocks. Nevertheless, few studies have developed allometric equations for this part [...] Read more.

Forests in the southwestern Amazon are rich, diverse, and dense. The region is of high ecological importance, is crucial for conservation and management of natural resources, and contains substantial carbon and biodiversity stocks. Nevertheless, few studies have developed allometric equations for this part of the Amazon, which differs ecologically from the parts of Amazonia where most allometric studies have been done. To fill this gap, we developed allometric equations to estimate the volume, biomass, and carbon in commercial trees with diameter at breast height (DBH) ≥ 50 cm in an area under forest management in the southeastern portion of Brazil’s state of Acre. We applied the Smalian formula to data collected from 223 felled trees in 20 species, and compared multiple linear and nonlinear models. The models used diameter (DBH) measured at 1.30 m height (d), length of the commercial stem (l), basic wood density (p), and carbon content (t), as independent variables. For each dependent variable (volume, biomass, or carbon) we compared models using multiple measures of goodness-of-fit, as well as graphically analyzing residuals. The best fit for estimating aboveground volume of individual stems using diameter (d) and length (l) as variables was obtained with the Spurr model (1952; logarithmic) (root mean square error (RMSE) = 1.637, R² = 0.833, mean absolute deviation (MAD) = 1.059). The best-fit equation for biomass, considering d, l, and p as the explanatory variables, was the Loetsch et al. (1973; logarithmic) model (RMSE = 1.047, R² = 0.855, MAD = 0.609). The best fit equation for carbon was the Loetsch et al. (1973; modified) model, using the explanatory variables d, l, p, and t (RMSE = 0.530, R² = 0.85, MAD = 0.304). Existing allometric equations applied to our study trees performed poorly. We showed that the use of linear and nonlinear allometric equations for volume, biomass, and carbon can reduce the errors and improve the estimation of these metrics for the harvested stems of commercial species in the southwestern Amazon. Full article

(This article belongs to the Section Forest Ecology and Management)

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11 pages, 1606 KiB

Open AccessArticle

Identification of a Natural Hybrid between Castanopsis sclerophylla and Castanopsis tibetana (Fagaceae) Based on Chloroplast and Nuclear DNA Sequences

by Xiaorong Zeng, Risheng Chen, Yunxin Bian, Xinsheng Qin, Zhuoxin Zhang and Ye Sun

Forests 2020, 11(8), 873; https://doi.org/10.3390/f11080873 - 11 Aug 2020

Cited by 3 | Viewed by 2568

Abstract

Castanopsis × kuchugouzhui Huang et Y. T. Chang was recorded in Flora Reipublicae Popularis Sinicae (FRPS) as a hybrid species on Yuelushan mountain, but it is treated as a hybrid between Castanopsis sclerophylla (Lindl.) Schott. and Castanopsis tibetana Hance in Flora of China. [...] Read more.

Castanopsis × kuchugouzhui Huang et Y. T. Chang was recorded in Flora Reipublicae Popularis Sinicae (FRPS) as a hybrid species on Yuelushan mountain, but it is treated as a hybrid between Castanopsis sclerophylla (Lindl.) Schott. and Castanopsis tibetana Hance in Flora of China. After a thorough investigation on Yuelushan mountain, we found a population of C. sclerophylla and one individual of C. × kuchugouzhui, but no living individual of C. tibetana. We collected C. × kuchugouzhui, and we sampled 42 individuals of C. sclerophylla from Yuelushan and Xiushui and 43 individuals of C. tibetana from Liangyeshan and Xiushui. We used chloroplast DNA sequences and 29 nuclear microsatellite markers to investigate if C. × kuchugouzhui is a natural hybrid between C. sclerophylla and C. tibetana. The chloroplast haplotype analysis showed that C. × kuchugouzhui shared haplotype H2 with C. sclerophylla on Yuelushan. The STRUCTURE analysis identified two distinct genetic pools that corresponded well to C. sclerophylla and C. tibetana, revealing the genetic admixture of C. × kuchugouzhui. Furthermore, the NewHybrids analysis suggested that C. × kuchugouzhui is an F2 hybrid between C. sclerophylla and C. tibetana. Our results confirm that C. × kuchugouzhui recorded in FRPS is a rare hybrid between C. sclerophylla and C. tibetana. Full article

(This article belongs to the Special Issue Genetic and Phenotypic Variation in Tree Crops Biodiversity)

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15 pages, 1906 KiB

Open AccessArticle

The Impact of Visits to Dryland Forests on Environmental Outlook: Results from a National Survey

by Alon Tal and Miriam Billig

Forests 2020, 11(8), 872; https://doi.org/10.3390/f11080872 - 10 Aug 2020

Cited by 1 | Viewed by 3733

Abstract

The effect of visits to the country’s forests on environmental perspectives and commitments was assessed in a national survey of the Israeli public. As a highly urbanized country, visits to the country’s dryland forests constitute an important national pastime across ethnic lines. We [...] Read more.

The effect of visits to the country’s forests on environmental perspectives and commitments was assessed in a national survey of the Israeli public. As a highly urbanized country, visits to the country’s dryland forests constitute an important national pastime across ethnic lines. We evaluated the impact that forest visitation had on the attitudes and perspectives of the visitors. A strong correlation was found between the frequency of visits to forests by individuals and a range of pro-environmental and pro-conservation sentiments. Of particular interest was the response of Israel’s Arab citizens. Not only do Israeli Arabs visit forests more frequently, but they also support environmental policy positions more avidly than do Jewish citizens. The article argues that increasing accessibility to forests and natural sites by expanding public transportation lines should constitute an important component in conservation strategies. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

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15 pages, 1939 KiB

Open AccessArticle

Site Classification of Eucalyptus urophylla × Eucalyptus grandis Plantations in China

by Haifei Lu, Jianmin Xu, Guangyou Li and Wangshu Liu

Forests 2020, 11(8), 871; https://doi.org/10.3390/f11080871 - 10 Aug 2020

Cited by 17 | Viewed by 4217

Abstract

Background and Objectives: It is important to match species needs with site conditions for sustainable forestry. In Eucalyptus urophylla × Eucalyptus grandis plantations in southern Yunnan, China, species-site mismatches have led to inappropriate expansion and management, which has degraded forests and decreased [...] Read more.

Background and Objectives: It is important to match species needs with site conditions for sustainable forestry. In Eucalyptus urophylla × Eucalyptus grandis plantations in southern Yunnan, China, species-site mismatches have led to inappropriate expansion and management, which has degraded forests and decreased efficiency in plantation production. Further research is needed to understand the relationship between tree growth and site productivity. We empirically explored site features and classified site types within these plantations in southern Yunnan. Our objective was to develop a theoretical basis for improving site selection for afforestation, and to establish intensive management in that region. Materials and Methods: 130 standard plots were set up in 1−15-year-old eucalyptus plantations in Pu’er and Lincang. We used quantification theory to examine the relationship between dominant tree growth traits and site factors. Hierarchical cluster analysis and canonical correlation analysis were applied to classify sites and evaluate the growth potential of E. urophylla × E. grandis plantations, respectively. Results: The multiple correlation coefficient between eight site factors (altitude, slope, slope position, aspect, soil depth, texture, bulk density, and litter thickness) and the quantitative growth of the dominant tree was 0.834 (p < 0.05). Slope position, altitude, and soil depth were the main factors contributing to the variation in stand growth. Plantation growth was best on lower slopes at relatively low altitude, where thick and weathered red soil layers existed. Conversely, the poorest plantations were located on upper slopes at higher altitude, with a thin semi-weathered purple soil layer. The soil factors total nitrogen (N) and potassium (K), trace boron (B), copper (Cu), and zinc (Zn) content, available phosphorous (P), and organic matter content in the soil influenced plantation growth. Conclusions. The addition of N, P, and K fertilizer as well as trace elements such as B, Cu, and Zn can promote the productivity of these plantations. Full article

(This article belongs to the Section Forest Ecology and Management)

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17 pages, 1487 KiB

Open AccessArticle

Growth and Nutrient Acclimation of Evergreen Oak Seedlings Infected with Boletus reticulatus in Infertile Colluvial Soil in Warm Temperate Monsoon Asia: Evaluation of Early Growth

by Masazumi Kayama

Forests 2020, 11(8), 870; https://doi.org/10.3390/f11080870 - 10 Aug 2020

Cited by 2 | Viewed by 2393

Abstract

Soil erosion after harvesting of forest plantations can create infertile colluvial soil, therefore, seedlings used for site reforestation should be equipped against nutrient-poor edaphic conditions. The oak genus is a suitable candidate for such reforestation efforts. Oak is an ectomycorrhizal (ECM) tree genus [...] Read more.

Soil erosion after harvesting of forest plantations can create infertile colluvial soil, therefore, seedlings used for site reforestation should be equipped against nutrient-poor edaphic conditions. The oak genus is a suitable candidate for such reforestation efforts. Oak is an ectomycorrhizal (ECM) tree genus known to grow under infertile environments. In this study, the initial stage of tree growth in three species of oak seedlings inoculated with a spore suspension of ECM fungus was monitored to evaluate the acceleration of seedling growth and nutrient uptake. I selected Quercus acuta Thunb., Quercus glauca Thunb., and Quercus salicina Blume, as these are common, evergreen, broad-leaved woody species commonly found in Southwestern Japan. The seedlings were inoculated with Boletus reticulatus and planted in infertile colluvial soils collected from a site that had undergone soil erosion. I also compared the ecophysiological characteristics of the potted seedlings planted in colluvial soil and normal forest soil. After six months of cultivation, Q. glauca with the ECM showed the highest growth rate in the fertile forest soil and had leaves with a higher nutrient content. In contrast, root dry mass increased slightly in Q. acuta and Q. salicina planted in colluvial soil. In all species, the seedling’s ECM colonization rate in colluvial soil was lower than that in forest soil, yet the increase in nutrient uptake in the former was not obvious. The contents of K and Ca in the roots of Q. acuta and Q. salicina increased with B. reticulatus infection. I concluded that the inoculation with a B. reticulatus spore suspension effectively accelerated the growths in all three Quercus species. Q. glauca favored a fertile environment, and Q. acuta and Q. salicina suitably acclimated to both soil types. Thus, these species were selected as potential future candidates for reforestation in such eroded sites. Full article

(This article belongs to the Special Issue Ecophysiology of Forest Succession under Changing Environment)

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16 pages, 5941 KiB

Open AccessArticle

Introduction of Fractal-Based Tree Digitalization and Accurate In-Canopy Radiation Transfer Modelling to the Microclimate Model ENVI-met

by Helge Simon, Tim Sinsel and Michael Bruse

Forests 2020, 11(8), 869; https://doi.org/10.3390/f11080869 - 10 Aug 2020

Cited by 25 | Viewed by 4494

Abstract

While complex urban morphologies including different materials, wall structures, etc., are rather adequately represented in microclimate models, replication of actual plant geometry is—so far—rather crudely handled. However, plant geometry greatly differs within species and locations while strongly determining a plant’s microclimate performance. To [...] Read more.

While complex urban morphologies including different materials, wall structures, etc., are rather adequately represented in microclimate models, replication of actual plant geometry is—so far—rather crudely handled. However, plant geometry greatly differs within species and locations while strongly determining a plant’s microclimate performance. To improve the plants representation in numerical models, a new method to describe plant skeletons using the so-called Lindenmayer-System has been implemented in the microclimate model ENVI-met. The new model allows describing much more realistic plants including the position and alignment of leaf clusters, a hierarchical description of the branching system and the calculation of the plant’s biomechanics. Additionally, a new canopy radiation transfer module is introduced that allows not only the simulation of diffuse radiation extinction but also secondary sources of diffuse radiation due to scattering of direct radiation within plant canopies. Intercomparisons between model runs with and without the advancements showed large differences for various plant parameters due to the introduction of the Lindenmayer-System and the advanced radiation scheme. The combination of the two developments represents a sophisticated approach to accurately digitize plants, model radiative transfer in crown canopies, and thus achieve more realistic microclimate results. Full article

(This article belongs to the Special Issue Nature-Based Solutions in Urban Forestry Planning and Management)

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17 pages, 4647 KiB

Open AccessArticle

Effect of Shelterwood and Clear-Cutting Regeneration Method on Wood Density of Scots Pine

by Ondřej Schönfelder, Aleš Zeidler, Vlastimil Borůvka, Lukáš Bílek and Jan Vítámvás

Forests 2020, 11(8), 868; https://doi.org/10.3390/f11080868 - 10 Aug 2020

Cited by 9 | Viewed by 2672

Abstract

With the gradual decline in the proportion of spruce as the most important tree species in the Czech Republic, the importance of pine will increase. The test material for this study was selected from two localities with important representation of pure Scots pine [...] Read more.

With the gradual decline in the proportion of spruce as the most important tree species in the Czech Republic, the importance of pine will increase. The test material for this study was selected from two localities with important representation of pure Scots pine stands. Two stands, representing clear-cutting and shelterwood regeneration methods were selected from each locality. In the case of shelterwood method, tree samples from a lower layer were cut down and subsequently evaluated in terms of the impact of the regeneration method on the density of the wood, the density of earlywood and latewood, the proportion of latewood and the width of the annual rings. These qualitative parameters of the wood were compared before and after the release of the parent stand canopy. The clear-cutting regeneration method served as a reference. The values obtained before the release of the parent stand canopy are significantly different from values after its removal (share of latewood 47.7% and 48.1% before the release in contrast to 39.5% and 39.1% after the release for the locality 1 and the locality 2 respectively). The shelterwood regeneration method has not a significant impact on the overall investigated characteristics. Most significant was the impact of the regeneration method on the distribution of properties along the trunk radius, where the shelterwood method shows a uniform density distribution from the pith to the bark. From the view of industry, therefore, it is not important for the final processing which part of the trunk the wood comes from. Full article

(This article belongs to the Section Forest Ecology and Management)

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Forests, Volume 11, Issue 8 (August 2020) – 112 articles

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