Forests

14 pages, 2205 KiB

Open AccessArticle

Identifying the Determinants of the Increase in Native Forests in Southern Chile

by Lisandro Roco, José Grebe, Patricia Rosales and Carmen Bravo

Forests 2023, 14(9), 1926; https://doi.org/10.3390/f14091926 - 21 Sep 2023

Cited by 1 | Viewed by 1377

In Chile, the native forest has suffered anthropic pressure that has resulted in the reduction in its surface and increased degradation, which has led to the development of public policies to reverse this scenario and encourage its sustainable management and conservation. This study [...] Read more.

In Chile, the native forest has suffered anthropic pressure that has resulted in the reduction in its surface and increased degradation, which has led to the development of public policies to reverse this scenario and encourage its sustainable management and conservation. This study examines the socioeconomic variables that influence the area increase in native forests in southern Chile, based on the analysis of 154 properties in the regions of Los Ríos, La Araucanía and Los Lagos. Georeferenced information from the 2015 SIMEF program survey and the Cadastre and Evaluation of Native Vegetation Resources of Chile were used. A Probit regression model was implemented, which associates a traceable increase in the native forest area with the variables regarding the owner: location, gender, age, schooling, management plan and technical advisory; and regarding the exploitation: farm size, percentage of native forest, scrub and forest plantations of the property and number of animal units. The econometric results show that smaller farms and those located in Los Lagos presented less probability of increasing their native forests. In the same way, an increase in the share of forest plantations area decreases the probability. Conversely, the scrub area share is related to the recovery of native forests in the sample. No significant effects of the variables associated with the implementation of management plans and technical assistance were found. Full article

(This article belongs to the Special Issue Innovation, Transition and Reconstruction of Forestry Oriented by Policies)

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14 pages, 825 KiB

Open AccessReview

Quercus suber L. Genetic Resources: Variability and Strategies for Its Conservation

by Joana Silva, Susana de Sousa Araújo, Hélia Sales, Rita Pontes and João Nunes

Forests 2023, 14(9), 1925; https://doi.org/10.3390/f14091925 - 21 Sep 2023

Cited by 1 | Viewed by 1719

Abstract

Quercus suber L. is an evergreen cork oak tree that can produce cork, one of the most important valuable natural bioresources in Portugal, with a high impact for the bioeconomy. Given its socio-economic relevance and the upcoming biotic and abiotic threats cork oak [...] Read more.

Quercus suber L. is an evergreen cork oak tree that can produce cork, one of the most important valuable natural bioresources in Portugal, with a high impact for the bioeconomy. Given its socio-economic relevance and the upcoming biotic and abiotic threats cork oak faces, it is of extreme importance that genetic conservation of its genetic variability occurs so that cork oaks can adapt to new conditions. This work represents a review of the current knowledge on Quercus suber genetic resources, focusing on the existing genetic variability and the strategies for its conservation. Furthermore, we highlight genetic knowledge on tolerance and response to abiotic and biotic stresses and cork quality, which are useful for further studies on stress response pathways and mechanisms and improvement regarding stress tolerance. Full article

(This article belongs to the Special Issue Sustainable Management of Forest Genetic Resources)

10 pages, 7358 KiB

Open AccessArticle

Study on the Milling Machinability of Bamboo-Based Fiber Composites

by Yucheng Ding, Tongbin Liu, Yaqiang Ma, Chunmei Yang, Changyu Shi, Yongjian Cao and Jiawei Zhang

Forests 2023, 14(9), 1924; https://doi.org/10.3390/f14091924 - 21 Sep 2023

Cited by 2 | Viewed by 1461

Abstract

Bamboo-based fiber composites, known as recombinant bamboo, have emerged as a new material in the construction and decoration industry. With its excellent mechanical and ornamental properties, recombinant bamboo is gaining popularity. However, its high hardness and abrasion resistance pose challenges in the milling [...] Read more.

Bamboo-based fiber composites, known as recombinant bamboo, have emerged as a new material in the construction and decoration industry. With its excellent mechanical and ornamental properties, recombinant bamboo is gaining popularity. However, its high hardness and abrasion resistance pose challenges in the milling process. To address this, we conducted an experimental study to investigate the milling machinability of recombinant bamboo. We studied the impact of various factors—fiber angle, feed rate, and spindle speed—on the tangential and normal roughness of milled surfaces. Our findings indicated that increasing the spindle speed within an acceptable range can effectively mitigate issues such as carbonization and endface cracking on a milled surface. Additionally, we developed a prediction model to assess the probability of end splitting in recombinant bamboo. This research aimed to enhance the milling quality of recombinant bamboo, improve control over surface roughness, reduce the likelihood of end splitting, and, ultimately, expand application possibilities. Full article

(This article belongs to the Special Issue New Development of Smart Forestry: Machine and Automation)

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14 pages, 5428 KiB

Open AccessArticle

Development of Commercial Eucalyptus Clone in Soil with Indaziflam Herbicide Residues

by Josiane Costa Maciel, Tayna Sousa Duque, Aline Cristina Carvalho, Brenda Thaís Barbalho Alencar, Evander Alves Ferreira, José Cola Zanuncio, Bárbara Monteiro de Castro e Castro, Francisca Daniele da Silva, Daniel Valadão Silva and José Barbosa dos Santos

Forests 2023, 14(9), 1923; https://doi.org/10.3390/f14091923 - 21 Sep 2023

Cited by 1 | Viewed by 1318

Abstract

The pre-emergent herbicide indaziflam is efficient in the management of weeds in eucalyptus crops, but this plant may develop less in soil contaminated with it. The objective was to evaluate the levels of chlorophylls a and b, the apparent electron transport rate (ETR), [...] Read more.

The pre-emergent herbicide indaziflam is efficient in the management of weeds in eucalyptus crops, but this plant may develop less in soil contaminated with it. The objective was to evaluate the levels of chlorophylls a and b, the apparent electron transport rate (ETR), growth and dry mass of leaves, stems and roots of Clone I144, in clayey soil, contaminated with the herbicide indaziflam and the leaching potential of this herbicide. The design was completely randomized in a 3 × 5 factorial scheme, with four replications. The leaching of indaziflam in the clayey soil profile (69% clay) was evaluated in a bioassay with Sorghum bicolor, a plant with high sensitivity to this herbicide. The injury and height of this plant were evaluated at 28 days after sowing (DAS). We believe that this is the first work on Eucalyptus in soil with residues of the herbicide indaziflam. Chlorophyll a and b contents and ETR, and height and stem dry mass of Clone I144, were lower in soil contaminated with indaziflam residues. The doses of indaziflam necessary to cause 50% (C₅₀) of injury and the lowest height of sorghum plants were 4.65 and 1.71 g ha⁻¹ and 0.40 and 0.27 g ha⁻¹ in clayey soil and sand, respectively. The sorption ratio (SR) of this herbicide was 10.65 in clayey soil. The herbicide indaziflam leached up to 30 cm depth at doses of 37.5 and 75 g ha⁻¹ and its residue in the soil reduced the levels of chlorophylls a and b, the apparent ETR and the growth of Clone I144. Full article

(This article belongs to the Special Issue Chemical Ecology in Forests)

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22 pages, 3395 KiB

Open AccessArticle

Different Adaptive Potential of Norway Spruce Ecotypes in Response to Climate Change in Czech Long-Term Lowland Experiment

by Václav Šimůnek, Jan Stejskal, Jaroslav Čepl, Jiří Korecký, Zdeněk Vacek, Stanislav Vacek, Lukáš Bílek and Michal Švanda

Forests 2023, 14(9), 1922; https://doi.org/10.3390/f14091922 - 21 Sep 2023

Viewed by 1160

Abstract

As a result of climate change, Norway spruce (Picea abies [L.] Karst.) is dying across Europe. One of the primary reasons for this is the cultivation of unsuitable spruce provenances and ecotypes. This study deals with the growth and genetics of the [...] Read more.

As a result of climate change, Norway spruce (Picea abies [L.] Karst.) is dying across Europe. One of the primary reasons for this is the cultivation of unsuitable spruce provenances and ecotypes. This study deals with the growth and genetics of the ecotypes of Norway spruce, the most important tree species of the Czech Republic. At the study site, namely Cukrák, an experimental site was established in 1964 to plant three basic spruce ecotypes: low-elevation (LE), medium-elevation (ME) and high-elevation (HE) ecotype. A dendrometric inventory, dendrochronological sampling and genetic analyses were carried out on individual trees in 45 to 46 years old spruce stands. The ME ecotype was the most productive in terms of its carbon sequestration potential, while the HE ecotype had the lowest radial growth. All ecotypes exhibited a noteworthy negative correlation between tree-ring growth and seasonal temperature, annual temperature, previous year September to current year August temperature, June to July temperature, as well as individual monthly temperatures from previous May to current August. The relationship of annual and seasonal precipitation to growth was significant only for the LE and ME ecotypes, but precipitation from previous year September to current year August and precipitation from current June to July were the most significant for all ecotypes, where the ME had the highest r value. The HE ecotype does not adapt well to a dry climate and appears to be unsuitable compared to the other ecotypes under the studied conditions. This study also documented intra-population genetic variation within years of low growth, as evidenced by significant clonal heritability. The selection of the appropriate spruce ecotypes is essential for the stability and production of future stands and should become an important pillar of forest adaptation to climate change. Full article

(This article belongs to the Special Issue Tree Growth and Physiological Properties under Ongoing Global Climate Change)

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18 pages, 12383 KiB

Open AccessArticle

Stability and Spatial Structure of Chinese Pine (Pinus tabuliformis Carr.) Plantations in Loess Hilly Region: A Case Study from Huanglong Mountain

by Boheng Wang, Chaofan Zhou, Di Liu, Le Kang, Gaohui Duan, Dianjing He, Xuan Zhao, Pengxiang Zhao and Weizhong Li

Forests 2023, 14(9), 1921; https://doi.org/10.3390/f14091921 - 21 Sep 2023

Viewed by 1235

Abstract

In contrast to intensive management practices focused on wood production, plantations designed to safeguard fragile environments prioritize the sustainable fulfillment of ecological functions. To assess the potential for Chinese pine (Pinus tabuliformis Carr.) plantations in the Loess Hilly Region to effectively serve [...] Read more.

In contrast to intensive management practices focused on wood production, plantations designed to safeguard fragile environments prioritize the sustainable fulfillment of ecological functions. To assess the potential for Chinese pine (Pinus tabuliformis Carr.) plantations in the Loess Hilly Region to effectively serve their ecological protection role over the long term, we selected nine indices representing biological stability, resistance stability, and functional stability. Employing a novel unit circle method, we evaluated the total stability (sum of the three stability components) of 44 plantation plots in Huanglong Mountain. We also explored the connections between total stability and standing spatial structure parameters to offer insights for promptly enhancing stability through thinning. The findings revealed that 79.5% of Chinese pine plantations exhibited moderate total stability, with 20.5% demonstrating good stability. Most plots displayed a random distribution pattern, moderate size differentiation, low species spatial mixing, and high stand crowding. Among the correlations analyzed, mingling exhibited the highest coefficient, followed by differentiation, while the uniform angle index showed the weakest correlation, and crowding displayed an insignificant correlation. While the presence of good functional stability contributed to the moderate total stability, addressing inadequate biological and resistance stability necessitates thinning measures. This study identifies spatial structure types negatively linked to total stability, offering targeted management insights for enhancing the stability of Chinese pine plantations. The stability assessment methodology and indicators presented in this study can serve as a valuable reference for similar plantations with comparable functions and planting conditions. Full article

(This article belongs to the Special Issue Restoring the Diversity, Resilience and Stability of Forest Ecosystems)

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14 pages, 13129 KiB

Open AccessArticle

Collectible Cell Lines of Larix sibirica Obtained by Somatic Embryogenesis and Their Ability to Regenerate

by Iraida N. Tretyakova and Maria E. Park

Forests 2023, 14(9), 1920; https://doi.org/10.3390/f14091920 - 21 Sep 2023

Viewed by 1107

Abstract

A protocol for the cultivation of Larix sibirica Ledeb. by somatic embryogenesis was developed (RF Patent No. 2456344, 2012). The L. sibirica collection consisted of 22 actively proliferating cell lines (CLs) obtained from immature zygotic embryos. The age of CLs ranged from 1 [...] Read more.

A protocol for the cultivation of Larix sibirica Ledeb. by somatic embryogenesis was developed (RF Patent No. 2456344, 2012). The L. sibirica collection consisted of 22 actively proliferating cell lines (CLs) obtained from immature zygotic embryos. The age of CLs ranged from 1 to 14 years. CLs differed in their growth intensity, embryonic productivity, hormonal balance, and genetic stability, as well as in their regenerative ability. In most proliferating CLs, the formation of globular somatic embryos continued for 2–4 years. Here, a number of CLs actively proliferated for 9–14 years or more. The formation of embryogenic cultures in L. sibirica is associated with the content of phytohormones and their localization in embryo cells. The cytogenetic studies revealed the genetic stability of young CLs (up to 1 year), in which the karyotype consisted of the diploid number of chromosomes (2n = 24). Genomic mutations were observed in the long-term proliferation of CLs. Individual CLs can maintain cytogenetic stability for many years; such CLs can successfully be used to preserve germplasm, obtain planting material, and for plantation reforestation. Full article

(This article belongs to the Special Issue Advances in Tree Germplasm Innovation and High-Efficiency Propagation)

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12 pages, 2493 KiB

Open AccessArticle

Modification of Density Dependence and Habitat Filtering on Seedling Survival of Different Mycorrhizal-Type Tree Species in Temperate Forests

by Jian Li and Xiuhai Zhao

Forests 2023, 14(9), 1919; https://doi.org/10.3390/f14091919 - 21 Sep 2023

Cited by 1 | Viewed by 1173

Abstract

Conspecific negative density dependence (CNDD) and habitat filtering are critical to seedling survival. However, the relative importance of the two processes in affecting survival of seedlings with different types of mycorrhizae remains unclear. In this study, the effects of CNDD and habitat filtering [...] Read more.

Conspecific negative density dependence (CNDD) and habitat filtering are critical to seedling survival. However, the relative importance of the two processes in affecting survival of seedlings with different types of mycorrhizae remains unclear. In this study, the effects of CNDD and habitat filtering on the survival of tree seedlings with different mycorrhizal types were investigated at different successional stages of a temperate forest in the Changbai Mountain Natural Reserve, Northeast China. Conspecific negative density dependence and habitat filtering significantly affected seedling survival. In the early successional stage, the interactions between conspecific neighbor tree density and light availability and soil properties significantly negatively affected survival of all species and arbuscular mycorrhizal (AM) seedlings in the community, but not that of ectomycorrhizal (EcM) seedlings, and the CNDD effect was stronger on AM seedlings than on EcM seedlings. In the mid-successional stage, CNDD effects were stronger on EcM seedlings. Therefore, different types of mycorrhizal seedlings responded differently to CNDD and habitat filtering mechanisms during community succession, and thus, tree mycorrhizal association could determine the effects of CNDD and habitat filtering on seedling survival in temperate forests. Full article

(This article belongs to the Special Issue Restoring the Diversity, Resilience and Stability of Forest Ecosystems)

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16 pages, 4544 KiB

Open AccessArticle

COVID-19 and Rural Households’ Environmental Incomes in Iran

by Sajad Ghanbari, Carsten Smith-Hall, Mostafa Jafari and Ivan Eastin

Forests 2023, 14(9), 1918; https://doi.org/10.3390/f14091918 - 20 Sep 2023

Viewed by 1235

Abstract

The COVID-19 pandemic negatively impacted rural livelihoods in the Global South. Environmental products, such as medicinal plants and fodder harvested in forests and rangelands, are a major source of income in many rural communities. In this paper, we investigate environmental product-related income and [...] Read more.

The COVID-19 pandemic negatively impacted rural livelihoods in the Global South. Environmental products, such as medicinal plants and fodder harvested in forests and rangelands, are a major source of income in many rural communities. In this paper, we investigate environmental product-related income and economic responses to the COVID-19 pandemic using face-to-face interviews with randomly selected household heads (n = 384) in 26 villages in northwestern Iran. We found that the main impacts of the COVID-19 pandemic were a decrease in income (reported by 72% of households), an increased health risk (48%), and persistent fear of infection by COVID-19 (45%). Household economies were found to be particularly reliant on animal husbandry (26% of total annual household income) and farming (26%). Environmental products contributed an average of 18% of total household income. Almost half of the households (45%) experienced lower livestock prices, a lack of buyers (49%), and a lockdown of animal markets (38%). Fodder (collected by 45% of households), medicinal plants (42%), and wild fruits (29%) were the most important environmental products harvested during the COVID-19 pandemic. We found a negative but not significant effect of the COVID-19 pandemic on total rural household income and that the COVID-19 pandemic led to a slight non-significant decrease in relative forest income. The negative impact on relative forest income resonates well with existing scholarship on livelihoods and negative shocks. It is noteworthy, however, that there is substantial scope for increasing environmental incomes and, thus, the potential of environmental products as a response option in the face of covariant shocks such as COVID-19. Full article

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

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17 pages, 3523 KiB

Open AccessArticle

A 900-Year Isotopic Proxy Rainfall Record from Northeastern Botswana

by Roxana T. Patrut, Adrian Patrut, Grant Hall, Christiaan W. Winterbach, Iain Robertson, Ileana Andreea Ratiu, Victor Bocos-Bintintan, Laszlo Rakosy and Stephan Woodborne

Forests 2023, 14(9), 1917; https://doi.org/10.3390/f14091917 - 20 Sep 2023

Cited by 1 | Viewed by 1453

Abstract

A high-resolution climate archive was reconstructed based on carbon isotope analysis and radiocarbon dating of the Chapman baobab in northeastern Botswana. The Chapman baobab, which exhibited an open ring-shaped structure composed of six stems, collapsed in January 2016 during an intense El Niño [...] Read more.

A high-resolution climate archive was reconstructed based on carbon isotope analysis and radiocarbon dating of the Chapman baobab in northeastern Botswana. The Chapman baobab, which exhibited an open ring-shaped structure composed of six stems, collapsed in January 2016 during an intense El Niño event. Two samples belonging to the oldest stems were investigated in order to obtain a proxy rainfall record, which provides insight into the precipitation regime over the last millennium, evincing centennial and decadal scale variability. The results indicate that the Medieval Warm Period was marked by relatively stable precipitation, whereas rainfall variability and drought frequency increased during the Little Ice Age. The investigated area has experienced both wetter and drier conditions in the past. The wettest conditions of the last millennium were registered before 1450 while the driest period occurred in 1835. For southern Africa, inter-annual rainfall variability is mainly associated with sea surface temperatures in the Agulhas Current core region, which determine the east–west displacement of tropical temperate troughs. Previous studies suggested that positive sea surface temperature anomalies in the Mozambique Channel led to an eastward movement of the troughs but the Chapman record demonstrates a westward displacement in the past, causing drought in northeastern South Africa and wetter conditions in the central part of southern Africa. The positive rainfall correlation with SST anomalies reversed after 1900, causing a gradual decrease in precipitation and confirming the current aridity trend for Botswana. The results contribute to a better understanding of the past climate of southern Africa for which paleoclimate reconstructions remain scarce. Full article

(This article belongs to the Special Issue Age and Growth Assessment of Trees by Radiocarbon Dating)

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31 pages, 6598 KiB

Open AccessArticle

Maximizing the Use of Out-of-Grade Hybrid Pine in Engineered Wood Products: Bond Performance, the Effect of Resin Streaking, Knots, and Pith

by Rebecca Cherry, Warna Karunasena and Allan Manalo

Forests 2023, 14(9), 1916; https://doi.org/10.3390/f14091916 - 20 Sep 2023

Cited by 2 | Viewed by 1220

Abstract

The evolution toward small-diameter and fast-growing plantation timbers such as the Pinus elliotti var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze) (PEE×PCH) hybrids around the world is producing large volumes of core wood that are falling short of structural sawn timber grading [...] Read more.

The evolution toward small-diameter and fast-growing plantation timbers such as the Pinus elliotti var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze) (PEE×PCH) hybrids around the world is producing large volumes of core wood that are falling short of structural sawn timber grading requirements. Engineered timber products such as cross-laminated timber (CLT) and glue-laminated (glulam) offer potential solutions to value-adding this resource, but the bond performance of this feedstock and the extent to which current standards and guides address its common characteristics for bond performance need to be understood. This study investigated the bond quality and performance of clear defect-free, low stiffness out-of-grade PEE×PCH and evaluated this performance using the pass/fail criteria of the CLT bond performance requirements of three national CLT standards. 5-layer CLT delamination samples and shear block test samples were glued using one-component polyurethane (PUR). This process was repeated for common occurring characteristics in this resource of resin, knots, and pith to understand their impact and inform an evaluation on the need to restrict their inclusion. Clear samples had an average glue line delamination of 2.9% and an average glue line wood failure of 96.7%. Resin achieved 9.3% and 92.6%, respectively. While knots had the lowest performance at 24.4% and 77.4%, respectively. When pith was at or adjacent to the glue line, wood failure occurred through the pith and its immediate surrounding fiber. Shear strength and wood failure tests were carried out on glulam and CLT-oriented samples. CLT knot samples were tested in two load orientations. Glulam-oriented samples in clear, resin, pith, and knots achieved an average shear strength of 8.5 MPa, 8.2 MPa, 7.9 MPa, and 8.2 MPa, respectively, and wood failure of 86%, 85%, 90%, and 69%, respectively. CLT-oriented samples in clear and resin both achieved average shear strengths of 4.0 MPa; 0°-loaded and 90°-loaded pith samples achieved 3.6 MPa and 2.4 MPa, while 0°-loaded and 90°-loaded knot samples achieved 4.2 MPa and 4.7 MPa respectively. Average wood failures were 90%, 89%, 96%, 96%, 83%, and 51%, respectively. PRG320 was found to be the most restrictive standard. Resin, knots, and pith were not addressed in the evaluation of delamination or shear strength in any standard, and PRG320 was the only standard to restrict these characteristics over and above structural grading rules. The amount and type of characteristics present vary considerably in structurally graded wood, and even more so for this out-of-grade resource. It was determined that the negative impact that resin, knots, and pith have on bond quality and bond performance calls for some restriction of their inclusion in order to achieve the author’s interpretation of the intended bond performance requirements of the CLT standards, which currently do not address these characteristics well or at all. A proposed modification to the PRG320 effective bond area was presented as a proactive solution. Full article

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

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18 pages, 5724 KiB

Open AccessArticle

Effects of Prescribed Burning on Surface Dead Fuel and Potential Fire Behavior in Pinus yunnanensis in Central Yunnan Province, China

by Jin Wang, Ruicheng Hong, Cheng Ma, Xilong Zhu, Shiying Xu, Yanping Tang, Xiaona Li, Xiangxiang Yan, Leiguang Wang and Qiuhua Wang

Forests 2023, 14(9), 1915; https://doi.org/10.3390/f14091915 - 20 Sep 2023

Cited by 1 | Viewed by 1316

Abstract

Prescribed burning is a widely used fuel management employed technique to mitigate the risk of forest fires. The Pinus yunnanensis Franch. forest, which is frequently prone to forest fires in southwestern China, serves as a prime example for investigating the effects of prescribed [...] Read more.

Prescribed burning is a widely used fuel management employed technique to mitigate the risk of forest fires. The Pinus yunnanensis Franch. forest, which is frequently prone to forest fires in southwestern China, serves as a prime example for investigating the effects of prescribed burning on the flammability of surface dead fuel. This research aims to establish a scientific foundation for managing dead fuel in forests, as well as fire prevention and control strategies. Field data was collected from P. yunnanensis forests located in central Yunnan Province in 2021 and 2022. The study implemented a randomized complete block design with two blocks and three treatments: an unburned control (UB), one year after the prescribed burning (PB1a), and three years after the prescribed burning (PB3a). These treatments were evaluated based on three indices: surface dead-bed structure, physicochemical properties, and potential fire behavior parameters. To analyze the stand characteristics of the sample plots, a paired t-test was conducted. The results indicated no significant differences in the stand characteristics of P. yunnanensis following prescribed burning (p > 0.05). Prescribed burning led to a significant decrease in the average surface dead fuel load from 10.24 t/ha to 3.70 t/ha, representing a reduction of 63.87%. Additionally, the average fire−line intensity decreased from 454 kw/m to 190 kw/m, indicating a decrease of 58.15%. Despite prescribed burning, there were no significant changes observed in the physical and chemical properties of dead fuels (p > 0.05). However, the bed structure of dead fuels and fire behavior parameters exhibited a significant reduction compared with the control sample site. The findings of this study provide essential theoretical support for the scientific implementation of prescribed burning programs and the accurate evaluation of ecological and environmental effects post burning. Full article

(This article belongs to the Special Issue Fire Ecology and Management in Forest)

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16 pages, 2916 KiB

Open AccessArticle

Soil Microbial Community and Soil Abiotic Factors Are Linked to Microorganisms’ C:N:P Stoichiometry in Larix Plantations

by Mengke Cai, Xiaoqin Cheng, Li Liu, Xinhao Peng, Tianxiong Shang and Hairong Han

Forests 2023, 14(9), 1914; https://doi.org/10.3390/f14091914 - 20 Sep 2023

Cited by 1 | Viewed by 1266

Abstract

Ecological stoichiometry is an essential tool to understand carbon (C), nitrogen (N), and phosphorus (P) cycles and nutrient limitations. Plantations are usually managed to maintain specific age structures, but the impact of such management on microbial biomass and stoichiometric ratios remains unclear. We [...] Read more.

Ecological stoichiometry is an essential tool to understand carbon (C), nitrogen (N), and phosphorus (P) cycles and nutrient limitations. Plantations are usually managed to maintain specific age structures, but the impact of such management on microbial biomass and stoichiometric ratios remains unclear. We compared the stand ages of four Larix principis-rupprechtti Mayr. Plantations that were 15 years old, (young plantation, Lar15), 24 years old, (middle aged plantation, Lar24), 40 years old, (near-mature plantation, Lar40), and 50 years old, (mature plantation, Lar50), respectively, to determine the main factors that drive differences in the C:N:P stoichiometry of microorganisms. We demonstrated that the temperature, moisture, and nutrient concentrations in surface soil increased significantly with forest age. The stoichiometric ratios of elements in soil and microorganisms reached their maxima in the Lar40 and Lar50 plantations. Additionally, forest stand ages had a great influence on the biomass of microbial communities. Moreover, soil microbial community and soil abiotic factors are closely related to soil microorganisms’ C:N:P stoichiometric ratios. Specifically, changes in the microbial biomass C:N (MBC:MBN) were primarily correlated with bacteria, Gram-positive bacteria (G⁺), temperature, NH₄⁺-N, and moisture in soil. Shifts in G⁺, actinobacteria, soil temperature, and total phosphorus were primarily associated with variation in microbial biomass C:P (MBC:MBP). Alterations in microbial biomass N:P (MBN:MBP) were correlated with bacteria, NH₄⁺-N, water content, Gram-negative bacteria, and soil temperature. Overall, these results suggest that microbial elemental stoichiometric ratios could be affected by stand age and emphasize the importance of microbial communities and soil abiotic factors in shifting this dynamic change process. Full article

(This article belongs to the Special Issue Soil Carbon, Nitrogen and Phosphorus Changes in Forests)

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23 pages, 32183 KiB

Open AccessArticle

Harmonization Approach to Spatial and Social Techniques to Define Landscape Restoration Areas in a Colombian Andes Complex Landscape

by Carlos Barrera-Causil and Jose González-Montañez

Forests 2023, 14(9), 1913; https://doi.org/10.3390/f14091913 - 20 Sep 2023

Cited by 2 | Viewed by 1338

Abstract

Landscape restoration activities must be conducted through a transdisciplinary process, integrating social, economic, environmental, and governance aspects. Combining visions from the natural and social sciences is a challenge in highly complex territories, where unique ecosystem characteristics, economic processes, stakeholders of diverse nature, and [...] Read more.

Landscape restoration activities must be conducted through a transdisciplinary process, integrating social, economic, environmental, and governance aspects. Combining visions from the natural and social sciences is a challenge in highly complex territories, where unique ecosystem characteristics, economic processes, stakeholders of diverse nature, and different normativity converge. The harmonization of multiple techniques, such as multicriteria spatial analysis, expert knowledge elicitation, and social mapping, allows for an approach to defining landscape restoration areas in complex regions. This paper employs multiple techniques to define ecosystem restoration areas in a complex Colombian Andes landscape, integrating ecological and social components for sustainable development. We observed that areas of high and very high feasibility for ecological restoration, encompassing 179.5 hectares (4.84% of the study area), are predominantly located near primary forests. Although some areas have a low feasibility for conservation processes, they should not be disregarded as they still require protection. Landowners prioritize watershed and soil restoration as the most important landscape restoration activity due to their interest in improving water-related ecosystem services. This proposal enables the identification of areas with a higher restoration potential at the property level, facilitating prioritization and investment allocation for future implementation. Full article

(This article belongs to the Section Forest Soil)

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8 pages, 692 KiB

Open AccessArticle

Comparing the Effects of Prescribed Burning on Soil Chemical Properties in East Texas Forests with Longleaf and Other Southern Pines in the Overstory

by Cassady P. Dunson, Brian P. Oswald and Kenneth W. Farrish

Forests 2023, 14(9), 1912; https://doi.org/10.3390/f14091912 - 20 Sep 2023

Cited by 1 | Viewed by 1018

Abstract

Little has been reported on the effects of repeated prescribed burning on southern United States’ forest soils, especially when site preparation is not the prescribed fire objective. This study was aimed at identifying any correlations between the soil chemical properties among differing burn [...] Read more.

Little has been reported on the effects of repeated prescribed burning on southern United States’ forest soils, especially when site preparation is not the prescribed fire objective. This study was aimed at identifying any correlations between the soil chemical properties among differing burn intervals and the effects prescribed burning has on them. Sampling was performed in 36 plots at three sites with two different burn intervals (2–3 years and biannually) and measured properties: (1) pre-burn (before the fire), (2) post-burn (one month after the fire), and (3) at vegetation green-up (three months after the fire). Sites varied by overstory species with longleaf pine (Pinus palustris) and shortleaf pine (Pinus echinata Mill.) in the overstory on one site, a mix of loblolly pine (P taeda L.) and shortleaf pine on another, and longleaf and loblolly pines on the third. SAS was used to determine the effects of prescribed burning between different time spans (pre-burn to post-burn, post-burn to green-up, and pre-burn to green-up) and between the two different burn intervals. We found that there could be short-term responses in soil chemical properties from repeated burning treatments including nitrogen in the forms of ammonium and nitrate, the carbon-to-nitrogen ratio, and electrical conductivity, all of which decreased following fire regardless of overstory species. Full article

(This article belongs to the Special Issue Longleaf Pine Ecology, Restoration, and Management)

12 pages, 2855 KiB

Open AccessArticle

Trends in Brazil’s Forestry Education—Part 3: Employment Patterns of Forest Engineering Graduates from Two Public Universities in the Last 15 Years

by Rodrigo Hakamada, Silvio Frosini de Barros Ferraz, Belkis Sulbarán-Rangel, Luiza Lucena and Hasbleidy Palacios Hinestroza

Forests 2023, 14(9), 1911; https://doi.org/10.3390/f14091911 - 20 Sep 2023

Cited by 1 | Viewed by 1374

Abstract

The employment rate of graduates and the interest of organizations in a high-skilled professional workforce are essential drivers of actions within the universities to improve the qualifications of college students. Our objective was to identify the sectors of employment pursued by graduates from [...] Read more.

The employment rate of graduates and the interest of organizations in a high-skilled professional workforce are essential drivers of actions within the universities to improve the qualifications of college students. Our objective was to identify the sectors of employment pursued by graduates from forestry engineering programs of the Luiz de Queiroz College of Agriculture (ESALQ/USP) and of the Federal Rural University of Pernambuco (UFRPE). We also conducted a survey among companies affiliated with the Forest Science and Research Institute (IPEF) to understand the percentage of forest engineers employed by these organizations to gain insights into the scale of this occupation in Brazil. We established two graduate cohorts to investigate the impact of changes in the last five years. In the first cohort (2008–2017), 82% and 40% of graduates from ESALQ/USP and UFRPE were involved in the forestry sector, respectively. However, in the second cohort (2018–2022), the percentage increased from 82% to 97% for graduates from ESALQ/USP, and after changes in the program, the percentage of graduates from UFRPE engaged in the forestry industry significantly rose from 40% to 73%. We discussed the reasons for these increases, mainly in terms of the growing market demand for forestry professionals. In the case of UFRPE, the boost in employment was attributed to the creation of a group for forestry practices along with actions to approach the private sector. We also found a strong ratio of one forest engineer to 4000 ha of planted forest among the enterprises associated with IPEF, indicating a substantial potential of employment in the forestry sector. Full article

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

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20 pages, 2081 KiB

Open AccessArticle

Charcoal Trade in Niger—Product Flows and Business Models

by Mahamane Larwanou, Doris Mutta, Chemuku Wekesa and Anders Roos

Forests 2023, 14(9), 1910; https://doi.org/10.3390/f14091910 - 19 Sep 2023

Viewed by 1523

Abstract

Charcoal is used in Africa for household energy, and the sector involves different actors with specific business strategies. Based on theories on sustainable business models and livelihoods, charcoal traders in five cities in Niger were surveyed about supply chains and strategies. Most charcoal [...] Read more.

Charcoal is used in Africa for household energy, and the sector involves different actors with specific business strategies. Based on theories on sustainable business models and livelihoods, charcoal traders in five cities in Niger were surveyed about supply chains and strategies. Most charcoal is imported from Nigeria, and smaller quantities come from Benin and Burkina Faso or domestically. Men dominate the trade. Customers value charcoal quality, tree species, packaging, and low prices. Three groups of traders and their business models were identified: small-scale retailers, large-scale retailers, and wholesalers. The charcoal trade is typically combined with trade in other products and is frequently conducted with family members or friends; laborers are employed for loading and unloading. The charcoal business provides a complementary income for the traders’ livelihoods. Most respondents believed that trade would increase in the future; wholesalers expected promising future business opportunities. This study concludes that improvements should focus on quality, better marketing skills, and more sustainable charcoal sourcing. Charcoal use in the Sahel region of Africa should also be studied further to enable the development of effective policies in the West African bioenergy sector. The cross-border charcoal trade creates a need for coordinated policies for a sustainable charcoal sector in the Sahel region. Full article

(This article belongs to the Special Issue Biomass and Bioenergy from Forests: Challenges and Prospects for the Future)

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13 pages, 2696 KiB

Open AccessArticle

Soil Quality Evaluation of Typical Vegetation and Their Response to Precipitation in Loess Hilly and Gully Areas

by Ting Xiang, Fangfang Qiang, Guangquan Liu, Changhai Liu, Yingfei Liu, Ning Ai and Huan Ma

Forests 2023, 14(9), 1909; https://doi.org/10.3390/f14091909 - 19 Sep 2023

Cited by 5 | Viewed by 1606

Abstract

The selection of suitable tree species and the reasonable allocation of planting areas are important measures for improving soil quality. This study aimed to investigate the characteristics of typical vegetation type soil quality differences and their dominant factors in loess hilly–gully areas after [...] Read more.

The selection of suitable tree species and the reasonable allocation of planting areas are important measures for improving soil quality. This study aimed to investigate the characteristics of typical vegetation type soil quality differences and their dominant factors in loess hilly–gully areas after returning farmland to the forest (grassland). The soil quality status and dominant factors of arbors, shrubs and grasslands in the study area were comprehensively analyzed using the soil quality index (SQI) and structural equation modeling (SEM). The results showed the following: (1) In the study area, the shrub forest had a high capacity for air permeability, water retention and nitrogen fixation. (2) The soil quality of the three vegetation types improved with increasing precipitation, and the soil quality indicator of shrubs was the highest, indicating a better soil quality improvement. However, the soil quality of the arbors and grasslands showed a greater percentage increase. In the precipitation range of 400–410 mm, the soil quality of shrub forests was significantly higher than that of arbors and grasslands. (3) Structural equation modeling analysis indicated that precipitation, vegetation and soil factors are closely related to soil quality. Further analysis showed that soil bulk density, porosity, capillary water-holding capacity, soil organic carbon and total phosphorus were the dominant factors affecting the soil quality in the study area. The purpose of this study was to evaluate quantitatively the soil quality after different vegetation types under different precipitation gradients, to clarify the variation trend of soil quality at different vegetation types with different precipitation gradients and to provide a scientific basis and data support for the quantitative evaluation of vegetation restoration and selection of tree species and vegetation configuration within different precipitation gradients in loess hilly and gully regions in the future. Full article

(This article belongs to the Special Issue Organic Fertilization and Sustainable Soil Management Practices in Trees)

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15 pages, 790 KiB

Open AccessArticle

Assessing the Role of Forest Certification and Macroeconomic Indicators on Croatian Wood Exports to the EU: A Panel Data Approach

by Kristina Klarić, Andreja Pirc Barčić and Martina Basarac Sertić

Forests 2023, 14(9), 1908; https://doi.org/10.3390/f14091908 - 19 Sep 2023

Cited by 2 | Viewed by 1567

Abstract

In the wood industry, forest certification stands as a pivotal factor that supports the implementation of sustainability and market acceptance. Recognizing its significance for both the wood sector and exports, this study explores the impact of Forest Stewardship Council (FSC) Chain of Custody [...] Read more.

In the wood industry, forest certification stands as a pivotal factor that supports the implementation of sustainability and market acceptance. Recognizing its significance for both the wood sector and exports, this study explores the impact of Forest Stewardship Council (FSC) Chain of Custody certificates on the export of Croatian wood to European Union (EU) countries. Through a dynamic panel data analysis using the system Generalized Method of Moments (GMM) estimator, our aim is to uncover the implications of this certification on wood industry exports. Additionally, the model assesses other determinants of wood exports, such as GDP, GDP per capita, remoteness, manufacturing value added, unemployment, and the real effective exchange rate. The results indicate that the number of FSC certificates during the observed period (2000–2021) have a positive and significant impact on wood exports from Croatia, suggesting that wood certification plays a predominant role in shaping such exports. Furthermore, the econometric analysis confirms the statistical significance of selected macroeconomic indicators, including nominal Gross Domestic Product (GDP), GDP per capita, unemployment, added value of manufacturing and real effective exchange rate, on wood exports. This study emphasizes the importance of forest certification in promoting wood exports and improving market competitiveness, offering a unique contribution to the literature by considering a range of macroeconomic factors in the analysis. Full article

(This article belongs to the Special Issue Impact of Global Economic Changes on the Wood-Based Industry)

19 pages, 2887 KiB

Open AccessArticle

Ultra-High-Density Genetic Maps of Jatropha curcas × Jatropha integerrima and Anchoring Jatropha curcas Genome Assembly Scaffolds

by Anoop Anand Malik, Pratima Sinha, Madan Singh Negi, Om P. Rajora and Shashi Bhushan Tripathi

Forests 2023, 14(9), 1907; https://doi.org/10.3390/f14091907 - 19 Sep 2023

Cited by 1 | Viewed by 1136

Abstract

Genetic maps facilitate an understanding of genome organization and the mapping of genes and QTLs for traits of interest. Our objective was to develop a high-density genetic map of Jatropha and anchoring scaffolds from genome assemblies. We developed two ultra-high-density genetic linkage maps [...] Read more.

Genetic maps facilitate an understanding of genome organization and the mapping of genes and QTLs for traits of interest. Our objective was to develop a high-density genetic map of Jatropha and anchoring scaffolds from genome assemblies. We developed two ultra-high-density genetic linkage maps of Jatropha curcas × Jatropha intergerrima using a backcross (BC₁) population using SNP, AFLP and SSR markers. First, SNPs were identified through genotyping-by-sequencing (GBS). The polymorphic SNPs were mapped to 3267 Jat_r4.5 scaffolds and 484 Wu_JatCur_1.0 scaffolds, and then these genomic scaffolds were mapped/anchored to the genetic linkage groups along with the AFLP and SSR markers for each genome assembly separately. We successfully mapped 7284 polymorphic SNPs, and 54 AFLP and SSR markers on 11 linkage groups using the Jat_r4.5 genomic scaffolds, resulting in a genome length of 1088 cM and an average marker interval of 0.71 cM. We mapped 7698 polymorphic SNPs, and 99 AFLP and SSR markers on 11 linkage groups using the Wu_JatCur_1.0 genomic scaffolds, resulting in a genome length of 870 cM and an average marker interval of 1.67 cM. The mapped SNPs were annotated to various regions of the genome, including exon, intron and intergenic regions. We developed two ultra-high-density linkage maps anchoring a high number of genome scaffolds to linkage groups, which provide an important resource for the structural and functional genomics as well as for molecular breeding of Jatropha while also serving as a framework for assembling and ordering whole genome scaffolds. Full article

(This article belongs to the Section Genetics and Molecular Biology)

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18 pages, 3547 KiB

Open AccessArticle

Processing and Properties of Wood-Plastic Composite Containing Alkali-Treated Birch Wood Shavings and Bioadditive Obtained by Biorefinery of Birch Bark

by Galia Shulga, Janis Rizhikovs, Brigita Neiberte, Anrijs Verovkins, Sanita Vitolina, Talrits Betkers and Raimonds Makars

Forests 2023, 14(9), 1906; https://doi.org/10.3390/f14091906 - 19 Sep 2023

Cited by 4 | Viewed by 1346

Abstract

In the last two decades, there has been increased interest in research focused on developing innovative polymer composite materials for food packaging, obtained by compounding polymers with organic fillers, intended for the manufacture of food storage containers. Woodplastic composites (WPCs), due to high [...] Read more.

In the last two decades, there has been increased interest in research focused on developing innovative polymer composite materials for food packaging, obtained by compounding polymers with organic fillers, intended for the manufacture of food storage containers. Woodplastic composites (WPCs), due to high content of lignocellulosic filler, are consideredbiocomposites and can be used for the fabrication of such types of containers. Their formulations include, along with the matrix and the filler, functional additives. One of the most important considerations while developing a food packaging material is to choose eco-friendly additives. The suberinic acids (SAs), extracted from birch outer bark by hydrolysis in KOH water solution, were examined as lubricants in the formulation of recycled polypropylene/polylactic acid (rPP/PLA) composite filled with the alkali-treated milled birch shaving microparticles and proceeded by extrusion and injection molding. The incorporation of Sas in a birch wood-rPP/PLA composite was performed by treaing the wood microparticles with the SAs water suspension at the defined concentration. Their presence at the optimal content in the composite improved its processing by reducing the extruder rotor torque and injection pressure, which increased the mechanical properties and decreased the wettability of the composite. Full article

(This article belongs to the Special Issue Development and Utilization of Lignocellulose and Other Wood Biomass)

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9 pages, 1135 KiB

Open AccessArticle

Response of Seedling Growth Characteristics to Seed Size and Cotyledon Damage in Quercus wutaishanica

by Yonghong Luo, Jinfeng Zhang, Xingfu Yan, Min Zhang, Shuhua Wei, Hui Yang, Yan Shen, Jinbao Zhang and Jiming Cheng

Forests 2023, 14(9), 1905; https://doi.org/10.3390/f14091905 - 19 Sep 2023

Cited by 1 | Viewed by 1524

Abstract

The successful establishment of seedlings is very important for plant regeneration, but it is vulnerable to many factors at this stage. Cotyledon damage will directly affect the health of seedlings, thus affecting the regeneration of the plant population. However, little is known about [...] Read more.

The successful establishment of seedlings is very important for plant regeneration, but it is vulnerable to many factors at this stage. Cotyledon damage will directly affect the health of seedlings, thus affecting the regeneration of the plant population. However, little is known about the effects of different cotyledon loss degrees of large and small seeds on seedling growth. We investigated the effects of 1/4 (light excision), 1/2 (moderate excision), and complete excision of cotyledons (heavy excision) on the growth characteristics of seedlings germinating from different sizes of seeds. The results showed that (1) shoot height, basal stem diameter, number of leaves, leaf area per plant, specific leaf area, and biomass were significantly higher in large-seeded seedlings than in small-seeded seedlings; (2) slight cotyledon excision had no effect on the biomass of large-seeded seedlings but significantly reduced the biomass of small-seeded seedlings. Our study highlights that large-seeded seedlings are more tolerant than small-seeded seedlings in the early seedling recruitment, suggesting that large-seeded seedlings have a strong fitness for recruitment in young populations of Q. wutaishanica. Full article

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

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13 pages, 5771 KiB

Open AccessArticle

Physical Activity in Forest and Psychological Health Benefits: A Field Experiment with Young Polish Adults

by Emilia Janeczko, Jarosław Górski, Małgorzata Woźnicka, Krzysztof Czyżyk, Wojciech Kędziora and Natalia Korcz

Forests 2023, 14(9), 1904; https://doi.org/10.3390/f14091904 - 19 Sep 2023

Cited by 8 | Viewed by 1689

Abstract

Recently, many studies have been conducted on the impact of various elements of the natural environment, including forests, on human physical and mental health. However, little is known about the level of health benefits resulting from contact with forests depending on the type [...] Read more.

Recently, many studies have been conducted on the impact of various elements of the natural environment, including forests, on human physical and mental health. However, little is known about the level of health benefits resulting from contact with forests depending on the type of physical activity undertaken. Therefore, in order to measure the impact of physical activity on the level of mental relaxation, a randomized experiment was conducted, which took into account three types of human physical activity: walking, cycling, and passive (without movement) observation of the forest. The study was carried out in the same forest and at the same time. Forty young people studying in Warsaw took part in the study. Four psychological questionnaires were used in the project before and after the experiment (Profile of Mood States, Schedule of Positive and Negative Affects, Recovery Scale, Subjective Vitality Scale). A pre-test was also performed in a university classroom. Research has shown that staying in the forest, regardless of the type of physical activity, brings positive health benefits in the form of an increase in positive feelings while reducing negative feelings. The results indicate that people who walk have the broadest range of benefits (cumulative benefits), in the form of less tension, reduced anger, fatigue, depression, increased concentration and greater vigor. Cyclists experienced significant benefits only in the form of reduced depression and greater vigor. The group passively observing the forest achieved statistically significant benefits only in terms of reducing fatigue and improving concentration. However, overall, the between-group results showed no statistically significant differences between the restorative effects of walking, cycling, and viewing the forest landscape. Each analyzed form of contact with the forest has a regenerating/regenerating effect (ROS scale) and contributes to the increase in vitality (SVS scale). Full article

(This article belongs to the Special Issue Forest Bathing and Forests for Public Health—Series II)

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17 pages, 2995 KiB

Open AccessArticle

Mapping Above-Ground Carbon Stocks at the Landscape Scale to Support a Carbon Compensation Mechanism: The Chocó Andino Case Study

by Francisco Cuesta, Marco Calderón-Loor, Paulina Rosero, Noam Miron, Andrei Sharf, Carolina Proaño-Castro and Felipe Andrade

Forests 2023, 14(9), 1903; https://doi.org/10.3390/f14091903 - 19 Sep 2023

Cited by 5 | Viewed by 2752

Abstract

(1) Background: Tropical Mountain forests (TMF) constitute a threatened major carbon sink due to deforestation. Carbon compensation projects could significantly aid in preserving these ecosystems. Consequently, we need a better understanding of the above-ground carbon (AGC) spatial distribution in TMFs to provide project [...] Read more.

(1) Background: Tropical Mountain forests (TMF) constitute a threatened major carbon sink due to deforestation. Carbon compensation projects could significantly aid in preserving these ecosystems. Consequently, we need a better understanding of the above-ground carbon (AGC) spatial distribution in TMFs to provide project developers with accurate estimations of their mitigation potential; (2) Methods: integrating field measurements and remote sensing data into a random forest (RF) modelling framework, we present the first high-resolution estimates of AGC density (Mg C ha⁻¹) over the western Ecuadorian Andes to inform an ongoing carbon compensation mechanism; (3) Results: In 2021, the total landscape carbon storage was 13.65 Tg in 194,795 ha. We found a broad regional partitioning of AGC density mediated primarily by elevation. We report RF-estimated AGC density errors of 15% (RMSE = 23.8 Mg C ha⁻¹) on any 10 m pixel along 3000 m of elevation gradient covering a wide range of ecological conditions; (4) Conclusions: Our approach showed that AGC high-resolution maps displaying carbon stocks on a per-pixel level with high accuracy (85%) could be obtained with a minimum of 14 ground-truth plots enriched with AGC density data from published regional studies. Likewise, our maps increased precision and reduced uncertainty concerning current methodologies used by international standards in the Voluntary Carbon Market. Full article

(This article belongs to the Special Issue Biodiversity and Ecosystem Functioning in Forests)

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15 pages, 7759 KiB

Open AccessArticle

Analysis of Spatial-Temporal Changes and Driving Factors of Vegetation Coverage in Jiamusi City

by Meibo Wang, Yingbin Wang, Zhijun Li and Hengfei Zhang

Forests 2023, 14(9), 1902; https://doi.org/10.3390/f14091902 - 18 Sep 2023

Cited by 4 | Viewed by 1677

Abstract

This study of vegetation coverage in Jiamusi City provides theoretical support for local urban development, land use, and ecological environmental protection. Based on the land cover data and Landsat remote sensing image data from 2000 to 2020, the vegetation cover and land use [...] Read more.

This study of vegetation coverage in Jiamusi City provides theoretical support for local urban development, land use, and ecological environmental protection. Based on the land cover data and Landsat remote sensing image data from 2000 to 2020, the vegetation cover and land use data of Jiamusi City were extracted. The study includes the following aspects: (1) an analysis of the spatio-temporal changes in vegetation coverage; (2) analysis of the land use situation in Jiamusi City; and (3) investigation of the impact of natural and human factors on vegetation coverage in Jiamusi City using the Geodetector model. The results show that (1) over the past 20 years, the vegetation coverage of Jiamusi has shown a decreasing trend, declining from 25.22% in 2000 to 17.13% in 2020, representing a decrease of 32%. In terms of spatial distribution, the areas of Fuyuan City and Tongjiang City have experienced more significant decreases in vegetation coverage, decreasing by 73.6% and 54.0%, respectively. (2) The land use pattern of Jiamusi City has undergone significant changes during the study period; except for paddy fields (PF), unused land (UL), and construction land (CL), the areas of all the land categories have decreased. The ranking of the single land use dynamic degree in terms of magnitude is as follows: PF, UL, CL, dry farmland (DF), vegetation coverage land (VCL), and wetland (WET). (3) The changes in vegetation coverage were influenced by both natural and human activities and, according to the Geodetector results, the main influencing factors were CL and DF. The key findings of this study emphasize the need for comprehensive land use planning and ecological environmental protection that focus on sustainable development and conservation practices, and lay the groundwork for future ecosystem management and urban planning efforts in Jiamusi City. Full article

(This article belongs to the Special Issue Vegetation Change at Multiple Time Scales under Climate Change and Human Activities)

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10 pages, 1652 KiB

Open AccessArticle

Leachability of Fast-Growing Wood Impregnated with Low Concentrations of Furfuryl Alcohol

by He Sun, Yizhi Gong, Yuntian Yan, Changqing Fu, Ke Zhan, Chunlei Dong, Linkun Xie and Taian Chen

Forests 2023, 14(9), 1901; https://doi.org/10.3390/f14091901 - 18 Sep 2023

Viewed by 1162

Abstract

Furfurylation can effectively improve the quality of fast-growing wood, but its leachability is unclear. In this study, fast-growing poplar (Populus sp.) and Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) were impregnated with low concentrations of 5%–20% furfuryl alcohol (FA), and the chemical [...] Read more.

Furfurylation can effectively improve the quality of fast-growing wood, but its leachability is unclear. In this study, fast-growing poplar (Populus sp.) and Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) were impregnated with low concentrations of 5%–20% furfuryl alcohol (FA), and the chemical and microscopic changes during leaching tests were analyzed by UV spectra and confocal laser scanning microscopy (CLSM). The results show that FA impregnation can regulate the weight percentage gain, but its effectiveness in regulating the cell wall bulking coefficient decreased as the impregnation concentration was increased. Impregnation with 15% and 20% FA showed no significant difference in the effect on volume swelling efficiency. The inverse relationship between the concentration of FA and the leaching rate was demonstrated by leaching tests, UV spectra, and CLSM. Notably, the leaching rate of poplar and Chinese fir wood was more than 30% when impregnated with 5% FA. Although the entirety of the furfuryl alcohol was deposited in the cell wall when impregnated with low concentrations of FA, the binding was not stable. The weight percentage gain of furfurylated Chinese fir was greater than that of poplar, but its leaching rate was lower, indicating that the cured furfuryl alcohol resin in poplar was not as stable as that in Chinese fir. Therefore, differences in tree species should be considered in low-concentration FA impregnation, as the improvement effect of concentrations below 10% on the properties of fast-growing wood is weak and the leaching rate of FA is significant. Full article

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

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15 pages, 3603 KiB

Open AccessArticle

Quasistatic and Dynamic Nanoindentation Measurements of Pinus radiata D. Don S2 and CCML Cell Wall Layers

by Oswaldo Erazo, Joseph E. Jakes, Nayomi Z. Plaza, Judith Vergara-Figueroa, Paulina Valenzuela and William Gacitúa

Forests 2023, 14(9), 1900; https://doi.org/10.3390/f14091900 - 18 Sep 2023

Cited by 1 | Viewed by 1372

Abstract

Quasistatic nanoindentation is a proven tool that provides information on the micromechanical behavior of wood cell walls. However, quasistatic tests cannot probe the time-dependent mechanical behavior shown by wood. Nanoindentation dynamic mechanical analysis (nanoDMA) can measure the viscoelastic properties of wood cell walls. [...] Read more.

Quasistatic nanoindentation is a proven tool that provides information on the micromechanical behavior of wood cell walls. However, quasistatic tests cannot probe the time-dependent mechanical behavior shown by wood. Nanoindentation dynamic mechanical analysis (nanoDMA) can measure the viscoelastic properties of wood cell walls. This research aimed to study the quasistatic and viscoelastic properties of individual radiata pine wood (Pinus radiata D. Don) cell wall layers. To minimize variability and retrieve both properties at the same locations, a load function composed of a multiload-quasistatic function followed by dynamic reference frequency segments was developed. Nanoindentations were then performed on the S2 layer and compound corner middle lamella (CCML) of unembedded latewood cells. Because the S2 layer is anisotropic, both transverse and longitudinal–tangential wood planes were studied. In the transverse plane, the average results of the quasistatic elastic moduli

(E_{s})

for the S2 layer and CCML were 15.7 GPa and 4.6 GPa, respectively. In the longitudinal–tangential plane, the

E_{s}

was 3.9 GPa. In the transverse section, the hardness

(H)

of the S2 layer and CCML were 331 MPa and 277 MPa, respectively, and in the longitudinal–tangential section H was 244 MPa. To acquire the viscoelastic properties, measurements were made over more than three decades of frequency. An increase of the storage modulus

(E^{'}),

and a reduction of the loss modulus

(E^{″})

and loss factor

(\tan δ)

as frequency increased were found in both wood orientations. The quasi-static and dynamic indentations equivalent at 0.1 Hz showed similar values for

E_{s}

and E′. This study contributes to our knowledge of wood cell wall micromechanical properties. Full article

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

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19 pages, 5417 KiB

Open AccessArticle

Relative Availability of Nitrogen and Calcium Regulates the Growth of Poplar Seedlings Due to Transcriptome Changes

by Xiaohang Weng, Hui Li, Yongbin Zhou, Chengshuai Ren, Songzhu Zhang and Liying Liu

Forests 2023, 14(9), 1899; https://doi.org/10.3390/f14091899 - 18 Sep 2023

Viewed by 1228

Abstract

The concentrations of exogenous nitrogen and calcium can significantly regulate plant growth and photosynthesis and mutually affect their absorption and utilization. However, whether there is an optimal nitrogen–calcium ratio (N:Ca ratio) in poplar seedling growth and physiological adaptation and what the mechanism of [...] Read more.

The concentrations of exogenous nitrogen and calcium can significantly regulate plant growth and photosynthesis and mutually affect their absorption and utilization. However, whether there is an optimal nitrogen–calcium ratio (N:Ca ratio) in poplar seedling growth and physiological adaptation and what the mechanism of changes in the transcriptome is remain unclear. In this study, three different N:Ca ratios were used to grow poplar seedlings, and physiological and transcriptomic methods were used to study the molecular mechanisms of poplar growth under nitrogen–calcium synergy and to determine the optimal N:Ca ratio for poplar seedling growth. The results of this study showed that maximum poplar seedling growth occurred in the treatment with an N:Ca ratio of 2, which resulted in significantly greater induction of growth than the two other treatments (p < 0.05). Under the lowest N:Ca ratio, poplar seedlings can ensure normal development by regulating photosynthesis, while under the highest N:Ca ratio, regulating nitrogen metabolism can achieve the same result. These results contribute to a better understanding of the molecular mechanisms by which poplar seedlings respond to different ratios of N:Ca. This study provides a valuable basis for exploring the synergistic effects of nitrogen and calcium on the growth of poplar shelterbelts. Full article

(This article belongs to the Section Genetics and Molecular Biology)

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17 pages, 13946 KiB

Open AccessArticle

The Spatio-Temporal Variations of GPP and Its Climatic Driving Factors in the Yangtze River Basin during 2000–2018

by Chong Nie, Xingan Chen, Rui Xu, Yanzhong Zhu, Chenning Deng and Queping Yang

Forests 2023, 14(9), 1898; https://doi.org/10.3390/f14091898 - 18 Sep 2023

Cited by 2 | Viewed by 1193

Abstract

Terrestrial gross primary productivity (GPP) is the major carbon input to the terrestrial ecosystem. The Yangtze River Basin (YRB) holds a key role in shaping China’s economic and social progress, as well as in ecological and environmental protection. However, how the GPP in [...] Read more.

Terrestrial gross primary productivity (GPP) is the major carbon input to the terrestrial ecosystem. The Yangtze River Basin (YRB) holds a key role in shaping China’s economic and social progress, as well as in ecological and environmental protection. However, how the GPP in the YRB responds to the climate factors remain unclear. In this research, we applied the Vegetation Photosynthesis Model (VPM) GPP data to explore the spatial and temporal variations of GPP in the YRB during 2000–2018. Based on the China Meteorological Forcing Dataset (CMFD), the partial least squares regression (PLSR) method was employed to identify the GPP responses to changes in precipitation, temperature, and shortwave radiation between 2000 and 2018. The findings showed that the long-term average of GPP in the YRB was 1153.5 ± 472.4 g C m⁻² yr⁻¹ between 2000 and 2018. The GPP of the Han River Basin, the Yibin-Yichang section of the Yangtze River mainstream, and the Poyang Lake Basin were relatively high, while the GPP of the Jinsha River Basin above Shigu and the Taihu Lake Basin were relatively low. A significant upward trend in GPP was observed over the 19-year period, with an annual increase rate of 8.86 g C m⁻² yr⁻¹ per year. The GPP of the Poyang Lake Basin and Jialing River Basin grew much faster than other water resource regions. Savannas and forests also had relatively higher GPP rate of increase compared to other vegetation types. The relative contributions of precipitation, temperature, and shortwave radiation to GPP variations in the YRB were 13.85 ± 13.86%, 58.87 ± 9.79%, and 27.07 ± 15.92%, respectively. Our results indicated that temperature was the main climatic driver on the changes of GPP in the YRB. This study contributes to an in-depth understanding of the variations and climate-impacting factors of vegetation productivity in the YRB. Full article

(This article belongs to the Section Forest Meteorology and Climate Change)

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21 pages, 10385 KiB

Open AccessEssay

Changes in the Potential Habitat Distribution of Typical Fire-Resistant Forest Species under Climate Change in the Subtropical Regions of China

by Wenxin Ouyang, Hanqing Qiu, Zhiming Chen, Yiheng Wu and Jianjun Li

Forests 2023, 14(9), 1897; https://doi.org/10.3390/f14091897 - 18 Sep 2023

Cited by 4 | Viewed by 1120

Abstract

Ecological fire prevention forest belts can effectively alleviate the spread of forest fires and reduce the harm caused by forest fires. Exploring the distribution and changes in suitable growth areas for fire-resistant forest species under the effects of climate change can provide effective [...] Read more.

Ecological fire prevention forest belts can effectively alleviate the spread of forest fires and reduce the harm caused by forest fires. Exploring the distribution and changes in suitable growth areas for fire-resistant forest species under the effects of climate change can provide effective references for the introduction of ecological fire prevention and tree species preservation in the region. This study is based on the distribution data of six typical ecological fire prevention forest species in the subtropical regions of China. The maximum entropy model (MaxEnt), optimized by the ENMeval data package, was used to analyze the potential relationship between the ecological environment variables and fire prevention forest species. The potential distribution of certain tree species in the historical period and in future periods is simulated. In addition, the area changes, migration trends, and stable areas of tree species under climate change are also discussed. The research results indicated the following: (1) The AUC values of the optimized model are all higher than 0.9, indicating the optimal prediction results. (2) The climate variables that have the greatest impact on the suitable habitat of Schima superba were the annual mean temperature, precipitation of the driest month, and mean diurnal range. Quercus glauca was mainly influenced by the minimum temperature of the coldest month and the precipitation of the warmest quarter. Castanopsis eyrei was mainly influenced by the precipitation of the driest month and the annual precipitation. The distribution of suitable growth areas for Symplocos sumuntia is mainly influenced by the precipitation of the driest month. The distribution of Camellia oleifera was influenced by the minimum temperature of the coldest month. The potential habitat distribution of Photinia serratifolia was greatly influenced by annual precipitation. (3) Until 2090, the expansion degree of the suitable growth area will be Symplocos sumuntia (51.05%) > Schima superba (19.41%) > Camellia oleifera (10.14%) > Quercus glauca (6.80%) > Castanopsis eyrei (2.34%) > Photinia serratifolia (−6.97%). (4) The centroid of Schima superba will migrate northward. Quercus glauca will migrate northeast. The suitable areas for the migration of Symplocos sumuntia and Castanopsis eyrei will move in a northwest direction, with repeated changes in alum migration, as well as with the largest migration span for Castanopsis eyrei. In addition, Camellia oleifera will move southwest. The centroid of Photinia serratifolia will migrate to the southeast. (5) The six fire-resistant tree species in this study were noted to have excellent stability in Guizhou, Hunan, Jiangxi, Fujian, Guangdong, and Guangxi. This conclusion can provide an effective reference for the introduction of ecological fire prevention tree species and the protection of tree species under climate change in subtropical forest-fire-prone areas in China. Full article

(This article belongs to the Special Issue Soil and Plant Restoration after Wildfire)

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Forests, Volume 14, Issue 9 (September 2023) – 235 articles

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