Forests

21 pages, 4765 KiB

Open AccessArticle

Effect of Invasive Rhododendron ponticum L. on Natural Regeneration and Structure of Fagus orientalis Lipsky Forests in the Black Sea Region

by Zdeněk Vacek, Stanislav Vacek, Derya Eşen, Oktay Yildiz, Jan Král and Josef Gallo

Forests 2020, 11(5), 603; https://doi.org/10.3390/f11050603 - 25 May 2020

Cited by 14 | Viewed by 3680

Abstract

Biological invasions threaten global biodiversity and forest ecosystems; therefore, it is necessary to use appropriate strategies for combating the spread of invasive species. Natural regeneration of eastern beech (Fagus orientalis Lipsky) is considerably limited by an aggressive invasive shrub, pontic rhododendron ( [...] Read more.

Biological invasions threaten global biodiversity and forest ecosystems; therefore, it is necessary to use appropriate strategies for combating the spread of invasive species. Natural regeneration of eastern beech (Fagus orientalis Lipsky) is considerably limited by an aggressive invasive shrub, pontic rhododendron (Rhododendron ponticum L.), in the Black Sea Region of Turkey. Therefore, the future character of the region’s forests is uncertain. The aim of this research was to evaluate the structure of beech forests with different management regimes of rhododedron and to determine the interaction among tree layer, rhododendron cover, and natural regeneration in Düzce Province using the FieldMap technology. The following variants of forests were compared: without intervention (control) and three and six years after rhododendron clearance. The results showed that tree density ranged between 175–381 trees ha⁻¹ and stand volume between 331–589 m³ ha⁻¹. The horizontal structure of the tree layer was mostly random, and the spatial pattern of natural regeneration was aggregated. Recruit density and height in the beech stands were significantly differentiated due to the influence of presence or absence of invasive rhododendron. Rhododendron cover ranged between 81%–97%, and woody stems amounted to 72,178–86,884 ha⁻¹ in unmanaged forests. Canopy in the overstory did not have a significant effect on the density of regeneration and rhododendron cover. Tree layer had a significant negative influence on natural regeneration within a 4 m radius on the plots without rhododendron. However, on the plots with dense rhododendron cover, tree layer had a positive influence on regeneration within a 1.5 m radius. Natural regeneration density was significantly higher when rhododendron was cleared than the plots without intervention. On the plots without woody clearance, there was an insufficient regeneration (113–619 recruits ha⁻¹); however, they had higher mean height compared to the sites without rhododendron. After three and six years of rhododendron clearance, the numbers of recruits in natural regeneration were 63,981 ha⁻¹ and 105,075 ha⁻¹, respectively. In conclusion, invasive spread of rhododendron was a limiting factor of the prosperous regeneration and tree species diversity, and manual clearance of rhododendron is recommended in managed beech forests of the study region. Full article

(This article belongs to the Special Issue Control and Management of Invasive Species in Forest Ecosystems)

► Show Figures

Figure 1

10 pages, 1911 KiB

Open AccessArticle

The Effect of Topography on Long-Term Spontaneous Development of Soil and Woody Cover on Graded and Untreated Overburden

by Fabio Vicentini, Markéta Hendrychova, Karel Tajovský, Václav Pižl and Jan Frouz

Forests 2020, 11(5), 602; https://doi.org/10.3390/f11050602 - 25 May 2020

Cited by 13 | Viewed by 2695

Abstract

We studied the development of soil and soil fauna, as well as selected vegetation parameters important for litter input into soil, in two chronosequences of postmining sites after opencast lignite mining near the town of Most (Czechia). Both chronosequences did not have tree [...] Read more.

We studied the development of soil and soil fauna, as well as selected vegetation parameters important for litter input into soil, in two chronosequences of postmining sites after opencast lignite mining near the town of Most (Czechia). Both chronosequences did not have tree planting. On the first chronosequence, no leveling or any other measures had taken place after heaping, and the site kept the wavelike appearance created by the dumping process. The second chronosequence was formed by sites levelled by earthmoving machinery and in which shallow topsoil layers were spread. Both chronosequences were about 30 years old, and consisted of 8 and 11 sites for wavelike and levelled sites, respectively. In addition, samples were taken from a birch site outside of the heaps. Results showed differences in the development of tree and herb layers in both chronosequences. In the levelled sites, herb and tree cover increased after levelling, and woody cover developed much slower. In ungraded sites, woody cover developed faster, and the herb layer slower. Soil chemistry showed a similar pattern in both sites over time, characterized by a decrease in pH and sodium ion content. Soil macrofauna in levelled sites showed random oscillations, while it gradually increased with time in wavelike sites. The study suggested that site levelling alters long-term ecosystem development in postmining sites. Wavelike sites tend to develop towards pioneer forests, while leveled sites tend to be covered by grass and herb vegetation. Full article

(This article belongs to the Special Issue Role of Soil Organisms in Soil Formation and Nutrient Circulation in Forest Ecosystems)

► Show Figures

Figure 1

27 pages, 4667 KiB

Open AccessArticle

Naturalness Assessment of Forest Management Scenarios in Abies balsamea–Betula papyrifera Forests

by Sylvie Côté, Louis Bélanger, Robert Beauregard, Évelyne Thiffault and Manuele Margni

Forests 2020, 11(5), 601; https://doi.org/10.3390/f11050601 - 25 May 2020

Cited by 1 | Viewed by 2752

Abstract

Research Highlights: This research provides an application of a model assessing the naturalness of the forest ecosystem to demonstrate its capacity to assess either the deterioration or the rehabilitation of the ecosystem through different forest management scenarios. Background and Objectives: The model allows [...] Read more.

Research Highlights: This research provides an application of a model assessing the naturalness of the forest ecosystem to demonstrate its capacity to assess either the deterioration or the rehabilitation of the ecosystem through different forest management scenarios. Background and Objectives: The model allows the assessment of the quality of ecosystems at the landscape level based on the condition of the forest and the proportion of different forest management practices to precisely characterize a given strategy. The present work aims to: (1) verify the capacity of the Naturalness Assessment Model to perform bi-directional assessments, allowing not only the evaluation of the deterioration of naturalness characteristics, but also its improvement related to enhanced ecological management or restoration strategies; (2) identify forest management strategies prone to improving ecosystem quality; (3) analyze the model’s capacity to summarize the effect of different practices along a single alteration gradient. Materials and Methods: The Naturalness Assessment Model was adapted to the Abies balsamea–Betula papyrifera forest of Quebec (Canada), and a naturalness assessment of two sectors with different historical management strategies was performed. Fictive forest management scenarios were evaluated using different mixes of forestry practices. The sensitivity of the reference data set used for the naturalness assessment has been evaluated by comparing the results using data from old management plans with those based on Quebec’s reference state registry. Results: The model makes it possible to identify forest management strategies capable of improving ecosystem quality compared to the current situation. The model’s most sensitive variables are regeneration process, dead wood, closed forest and cover type. Conclusions: In the Abies balsamea–Betula papyrifera forest, scenarios with enhanced protection and inclusion of irregular shelterwood cuttings could play an important role in improving ecosystem quality. Conversely, scenarios with short rotation (50 years) could lead to further degradation of the ecosystem quality. Full article

(This article belongs to the Special Issue Protection and Management of Species, Habitats, Ecosystems and Landscapes)

► Show Figures

Figure 1

19 pages, 6991 KiB

Open AccessArticle

The Climatic Response of Tree Ring Width Components of Ash (Fraxinus excelsior L.) and Common Oak (Quercus robur L.) from Eastern Europe

by Cătălin-Constantin Roibu, Victor Sfeclă, Andrei Mursa, Monica Ionita, Viorica Nagavciuc, Francisca Chiriloaei, Ilarie Leșan and Ionel Popa

Forests 2020, 11(5), 600; https://doi.org/10.3390/f11050600 - 25 May 2020

Cited by 38 | Viewed by 5647

Abstract

This paper aims to develop the first differentiated (earlywood—EW, latewood—LW, and total ring width—RW) dendrochronological series for ash (Fraxinus excelsior L.) and oak (Quercus robur L.) trees from the Republic of Moldova, and to analyze their climatic response and their spatio-temporal [...] Read more.

This paper aims to develop the first differentiated (earlywood—EW, latewood—LW, and total ring width—RW) dendrochronological series for ash (Fraxinus excelsior L.) and oak (Quercus robur L.) trees from the Republic of Moldova, and to analyze their climatic response and their spatio-temporal stability. For this, 18 ash and 26 oak trees were cored from the Dobrușa protected area, Republic of Moldova, Eastern Europe, and new EW, LW, and RW chronologies were developed for ash and oak covering the last century. The obtained results showed that the RW and LW have a similar climatic response for both species, while EW is capturing interannual climate variations and has a different reaction. The analyses performed with monthly climatic data revealed a significant and negative correlation with the mean air temperature and a significant and positive correlation with precipitation and the Standardized Precipitation-Evapotranspiration Index (SPEI) for both ash and oak. The temperature during the vegetation period has a strong influence on all tree-ring components of ash, while for oak the strong correlation was found only for LW. The positive and significant correlation between LW and RW with precipitation for both species, suggests that ash and oak are sensitive to the hydrological component and the precipitation is the main tree growth-limiting factor. Despite the significant correlation with precipitation and temperature for the whole analyzed period, the 25-year moving correlation analyses show that they are not stable in time and can switch from positive to negative or vice versa, while the correlation with SPEI3 drought index, which is a integration of both climatic parameters, is stable in time. By employing the stability map analysis, we show that oak and ash tree ring components, from the eastern part of the Republic of Moldova, have a stable and significant correlation with SPEI3 and scPDSI drought indices from February (January) until September, over the eastern part of Europe. Full article

(This article belongs to the Special Issue Radial Tree-Ring Traits Variation in Relation to Climate Factors)

► Show Figures

Figure 1

13 pages, 1548 KiB

Open AccessArticle

Mechanisms by Which Pre-Commercial Thinning Increases Black Spruce Growth in Different Climates and Soil Types

by Amy Wotherspoon, Robert L. Bradley, Daniel Houle, Stéphane Tremblay, Martin Barrette and Krista Reicis

Forests 2020, 11(5), 599; https://doi.org/10.3390/f11050599 - 25 May 2020

Cited by 3 | Viewed by 3227

Abstract

In the province of Québec (Canada), pre-commercial thinning (PCT) is a common silvicultural practice applied to young black spruce (Picea mariana (Mill.) BSP) stands. PCT removes some of the competing vegetation and smaller black spruce stems, in order to improve growth rates [...] Read more.

In the province of Québec (Canada), pre-commercial thinning (PCT) is a common silvicultural practice applied to young black spruce (Picea mariana (Mill.) BSP) stands. PCT removes some of the competing vegetation and smaller black spruce stems, in order to improve growth rates and reduce forest rotation intervals. It is uncertain whether this positive response in black spruce growth is primarily due to lower competition for resources or to other mechanisms, which may vary according to climate or edaphic conditions. We sampled soils and black spruce needles in PCT-treated and non-treated control plots occurring in two climate regimes, as well as on two contrasting soil parent materials within one of these two climate regimes (i.e., three “site types”). We performed our sampling approximately 20 years after treatment. Paired treatment plots (i.e., PCT vs. control) were replicated at four independent sites in each of the three site types, for a total of 24 plots. Over two consecutive years, we measured stand structural characteristics, indices of soil N fertility, soil microbial activity, indices of soil moisture availability, canopy openness, and foliar characteristics in each plot. In each site type, PCT decreased total basal area but increased radial growth of individual trees. Across all plots, soil N mineralization rates measured in 2016 were positively related to foliar N concentrations of one-year-old needles collected in 2017. Annual precipitation, drainage class, potential evapotranspiration, and climate moisture index all indicated that plots occurring in the drier climate and on glacial till deposits were more prone to summer moisture deficits. Accordingly, PCT increased forest floor moisture only in this site type, which may benefit tree growth. In the wetter climate and on poorly drained soils, however, we found evidence that PCT reduces soil N fertility, presumably by increasing the spread of ericaceous shrubs in the understory. In the dry fertile site type, the range in canopy openness was substantially higher (12–37%) and correlated negatively with tree diameter, suggesting that greater light availability did not improve tree growth. Taken collectively, our data suggest that PCT increases black spruce growth across a broad range of site conditions found in Québec, presumably by lowering intraspecific competition for resources. However, on drier sites, PCT may also benefit trees by increasing soil moisture availability, whereas wetter climates may mitigate the beneficial effect of PCT due to a loss of soil N fertility. Full article

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

► Show Figures

Figure 1

14 pages, 4191 KiB

Open AccessArticle

Impact of Number of Operators and Distance to Branch Piles on Woodchipper Operation

by Łukasz Warguła, Mateusz Kukla, Piotr Krawiec and Bartosz Wieczorek

Forests 2020, 11(5), 598; https://doi.org/10.3390/f11050598 - 25 May 2020

Cited by 26 | Viewed by 2777

Abstract

Branch chipping machines with low-power engines are distinguished with an intermittent operation due to a periodical supply of branches. A conventional drive speed control of these machines is not adapted to adjust the operating mode depending on frequency of material supply for shredding. [...] Read more.

Branch chipping machines with low-power engines are distinguished with an intermittent operation due to a periodical supply of branches. A conventional drive speed control of these machines is not adapted to adjust the operating mode depending on frequency of material supply for shredding. This article discusses the issues related to the assessment of the application of adaptive systems similar in design to start–stop systems used in vehicles, as necessary in the driving of this type machine. During testing, an impact of a distance between a branch pile from the woodchipper, a number of operators on frequency of drive unit operating condition changes, and the mass and volume output (productivity) were considered. A percentage ratio of the active and passive (idle) operation in selected conditions of use was also determined. A low-power 9.5 kW engine-powered cylindrical-type woodchipper was used for testing. Material chopped in the chipper was freshly cut branches of oaks (Quercus L. Sp. Pl. 994. 1753) with a diameter in the largest cross-section ca. 80 mm and moisture content ca. 25%. Piles of branches were located at three different distances from the chipper, i.e., 3 m, 9 m and 15 m. Branches to the chipper were fed by one or two operators. It was demonstrated that the idle run time in tested conditions with one operator could be from 43% to 71% of the entire operating time. Frequency of operating condition changes when only one operator worked and fluctuated from ca. 6 to 2 times per minute. Increasing the number of operators from one to two had a slight impact on the frequency of operating condition changes (by ca. 7%) at the shortest distance from the chipper (3 m). However, at larger distances, the additional operator may increase the frequency of operating condition changes of the chipper by 77% for 9 m distance and 85% for 15 m distance. The mass and volumetric output of the cylindrical chipper in the most advantageous case is equal to 0.66 t/h and 3.5 m³/h, respectively. The increase of the branch pile distance from the chipper causes a drop in mass output by 32%, and volumetric output by 33.5%. The results of the tests confirmed the necessity for the development of low-power chipping machines designed for clearing operations rather than industrial production of biomass. A direction for development could be systems that adapt driving units to operating conditions, depending on a demand for the chipping process. Full article

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

► Show Figures

Figure 1

15 pages, 3396 KiB

Open AccessArticle

Comparison of Canopy Closure Estimation of Plantations Using Parametric, Semi-Parametric, and Non-Parametric Models Based on GF-1 Remote Sensing Images

by Jiarui Li and Xuegang Mao

Forests 2020, 11(5), 597; https://doi.org/10.3390/f11050597 - 25 May 2020

Cited by 23 | Viewed by 3450

Abstract

Canopy closure (CC) is an important parameter in forest ecosystems and has diverse applications in a wide variety of fields. Canopy closure estimation models, using a combination of measured data and remote sensing data, can largely replace traditional survey methods for CC. However, [...] Read more.

Canopy closure (CC) is an important parameter in forest ecosystems and has diverse applications in a wide variety of fields. Canopy closure estimation models, using a combination of measured data and remote sensing data, can largely replace traditional survey methods for CC. However, it is difficult to estimate the forest CC based on high spatial resolution remote sensing images. This study used China Gaofen-1 satellite (GF-1) images, and selected China’s north temperate Wangyedian Forest Farm (WYD) and subtropical Gaofeng Forest Farm (GF) as experimental areas. A parametric model (multiple linear regression (MLR)), non-parametric model (random forest (RF)), and semi-parametric model (generalized additive model (GAM)) were developed. The ability of the three models to estimate the CC of plantations based on high spatial resolution remote sensing GF-1 images and their performance in the two experimental areas was analyzed and compared. The results showed that the decision coefficient (R²), root mean square error (RMSE), and relative root mean square error (rRMSE) values of the parametric model (MLR), semi-parametric model (GAM), and non-parametric model (RF) for the WYD forest ranged from 0.45 to 0.69, 0.0632 to 0.0953, and 9.98% to 15.05%, respectively, and in the GF forest the R², RMSE, and rRMSE values ranged from 0.40 to 0.59, 0.0967 to 0.1152, and 16.73% to 19.93%, respectively. The best model in the two study areas was the GAM and the worst was the RF. The accuracy of the three models established in the WYD was higher than that in the GF area. The RMSE and rRMSE values for the MLR, GAM, and RF established using high spatial resolution GF-1 remote sensing images in the two test areas were within the scope of existing studies, indicating the three CC estimation models achieved satisfactory results. Full article

(This article belongs to the Special Issue Monitoring and Assessing Forest Attributes Based on Remote Sensing Technology)

► Show Figures

Figure 1

18 pages, 3746 KiB

Open AccessArticle

Host Range of Hymenoscyphus fraxineus in Slovak Arboreta

by Katarína Pastirčáková, Katarína Adamčíková, Marek Barta, Jozef Pažitný, Peter Hoťka, Ivana Sarvašová and Miriam Kádasi Horáková

Forests 2020, 11(5), 596; https://doi.org/10.3390/f11050596 - 25 May 2020

Cited by 11 | Viewed by 3185

Abstract

The health of 34 different Fraxinus taxa in association with the pathogenic fungus Hymenoscyphus fraxineus was assessed in four Slovak arboreta. Averaged across all arboreta, nearly one-quarter (24.9%) of all evaluated trees showed ash dieback symptoms. The damage was most serious on the [...] Read more.

The health of 34 different Fraxinus taxa in association with the pathogenic fungus Hymenoscyphus fraxineus was assessed in four Slovak arboreta. Averaged across all arboreta, nearly one-quarter (24.9%) of all evaluated trees showed ash dieback symptoms. The damage was most serious on the common ash F. excelsior, a native species. The percentage of dead trees did not exceed 2% for all evaluated trees. Generally, ash trees of all ages were affected, though the intensity of the damage varied among the sites. The identity of H. fraxineus was confirmed by conventional PCR targeting the internal transcribed spacer (ITS) sequences of the nuclear ribosomal DNA, as well as the 18S gene/ITS-2 region of the rDNA operon. In Slovakia, the pathogen has expanded its host range from native species not only to their ornamental cultivars, but also to introduced North American (F. cinerea, F. latifolia, F. pennsylvanica, F. quadrangulata) and Asian (F. bungeana, F. chinensis ssp. rhynchophylla, F. mandshurica) ash species. H. fraxineus was also observed on the previous year’s leaf petioles of the native European species F. ornus, considered a weakly susceptible host. In Slovak arboreta, H. fraxineus was found on 23 Fraxinus taxa; 21 of them represent first records for the country. F. bungeana is recorded as a new host species of H. fraxineus. Full article

(This article belongs to the Special Issue Pests and Pathogens of Urban Trees)

► Show Figures

Figure 1

25 pages, 7457 KiB

Open AccessArticle

National Set of MAES Indicators in Greece: Ecosystem Services and Management Implications

by Ioannis P. Kokkoris, Georgios Mallinis, Eleni S. Bekri, Vassiliki Vlami, Stamatis Zogaris, Irene Chrysafis, Ioannis Mitsopoulos and Panayotis Dimopoulos

Forests 2020, 11(5), 595; https://doi.org/10.3390/f11050595 - 24 May 2020

Cited by 35 | Viewed by 6069

Abstract

Research Highlights: The developed National Set of Indicators for the Mapping and Assessment of Ecosystems and their Services (MAES) implementation in Greece at the national level sets the official, national basis on which future studies will be conducted for MAES reporting for the [...] Read more.

Research Highlights: The developed National Set of Indicators for the Mapping and Assessment of Ecosystems and their Services (MAES) implementation in Greece at the national level sets the official, national basis on which future studies will be conducted for MAES reporting for the achievement of targets within the National and the European Union (EU) biodiversity Strategy. Background and Objectives: Greece is currently developing and implementing a MAES nation-wide program based on the region’s unique characteristics following the proposed methodologies by the European Commission, in the frame of the LIFE-IP 4 NATURA project (Integrated actions for the conservation and management of Natura 2000 sites, species, habitats and ecosystems in Greece). In this paper, we present the steps followed to compile standardized MAES indicators for Greece that include: (a) collection and review of the available MAES-related datasets, (b) shortcomings and limitations encountered and overcome, (c) identification of data gaps and (d) assumptions and framework setting. Correspondence to EU and National Strategies and Policies are also examined to provide an initial guidance for detailed thematic studies. Materials and Methods: We followed the requirements of the EU MAES framework for ecosystem services and ecosystem condition indicator selection. Ecosystem services reported under the selected indicators were assigned following the Common International Classification of Ecosystem Services. Spatial analysis techniques were applied to create relevant thematic maps. Results: A set of 40 MAES indicators was drafted, distributed in six general indicator groups, i.e., Biodiversity, Environmental quality, Food, material and energy, Forestry, Recreation and Water resources. The protocols for the development and implementation of an indicator were also drafted and adopted for future MAES studies in Greece, providing guidance for adaptive development and adding extra indicators when and where needed. Thematic maps representing ecosystem services (ES) bundles and ES hotspots were also created to identify areas of ES importance and simultaneously communicate the results at the national and regional levels. Full article

(This article belongs to the Special Issue Protection and Management of Species, Habitats, Ecosystems and Landscapes)

► Show Figures

Figure 1

14 pages, 1421 KiB

Open AccessArticle

Roads Impact Tree and Shrub Productivity in Adjacent Boreal Peatlands

by Saraswati Saraswati, Yubraj Bhusal, Andrew J. Trant and Maria Strack

Forests 2020, 11(5), 594; https://doi.org/10.3390/f11050594 - 24 May 2020

Cited by 9 | Viewed by 3907

Abstract

Peatlands in the western boreal plains of Canada are important ecosystems as they store over two percent of global terrestrial carbon. However, in recent decades, many of these peatlands have been fragmented by access roads constructed for resource extraction and transportation, challenging their [...] Read more.

Peatlands in the western boreal plains of Canada are important ecosystems as they store over two percent of global terrestrial carbon. However, in recent decades, many of these peatlands have been fragmented by access roads constructed for resource extraction and transportation, challenging their carbon storage potential. To investigate how roads have been impacting tree and shrub growth and productivity in these peatlands, this study was conducted in a forested bog and woody fen in Carmon Creek, Alberta, Canada. In 2017, vegetation surveys were conducted along 20 m transects that extended on both sides of the road with 4 m² circular plots at 2, 6 and 20 m distance from the road and were followed by disc or core collection from woody stems. Within 20 m of the road at the bog site, we observed a shift towards significantly larger radial growth of trees in the downstream areas (t = 3.23, p = 0.006) where water table position was deeper, while at the fen site, radial growth of tall shrubs had little response to the road. Combining the effects of direct tree clearing and hydrology induced shifts in growth, aboveground net primary productivity (NPPag) post-road construction was reduced significantly in areas where vegetation was cleared during the road construction (i.e., upstream areas of the bog: t = 5.21, p < 0.0001 and downstream areas of the fen: t = 2.64, p = 0.07). Substantially lower NPPag around the road construction areas compared to reference areas shows tremendous loss of carbon sink potential of trees and shrubs after road construction through peatlands. Altogether, roads constructed through peatlands perpendicular to the water flow may shift long-term carbon sinks into sources of carbon, at least for the initial few years following road construction. Full article

(This article belongs to the Special Issue Forest Carbon Dynamics under Changing Climate and Disturbance Regimes)

► Show Figures

Figure 1

18 pages, 5958 KiB

Open AccessArticle

Incorporating Landscape Character in Cork Oak Forest Expansion in Sardinia: Constraint or Opportunity?

by Ioannis N. Vogiatzakis, Geoffrey H. Griffiths and Maria Zomeni

Forests 2020, 11(5), 593; https://doi.org/10.3390/f11050593 - 24 May 2020

Cited by 2 | Viewed by 4006

Abstract

Cork oak (Quercus suber) is a declining woodland species across the island of Sardinia, despite its former economic importance for wine production and its significance for biodiversity. In particular, cork oak forests (COFs) on the island have seen a 29% decrease [...] Read more.

Cork oak (Quercus suber) is a declining woodland species across the island of Sardinia, despite its former economic importance for wine production and its significance for biodiversity. In particular, cork oak forests (COFs) on the island have seen a 29% decrease in the past 45 years. A spatial GIS model was developed to determine suitability for the expansion of cork oak forests on the island. The model uses a set of simple spatial decision rules based on principles of landscape ecology and expert opinion to assign a suitability score for pure cork oak forests to every land use parcel in Sardinia. These rules include the type of existing land parcel, its size, distance to existing cork oak forest, and the area of seminatural habitats in its neighborhood. This was coupled with a map of landscape types to assist with the development of policy for the protection of cork oak forests across Sardinia. The results show that there is an area of 116,785 ha potentially suitable for cork oak forest expansion in Sardinia, with the largest area of potential habitat on granitic mountains. There is a substantial overall agreement (Cohen’s kappa = 0.61) between the suitability map produced and the historical reference map. The model is flexible and can be rerun to reflect changes in policy relating to agri-environmental targets for habitats and species. Full article

(This article belongs to the Special Issue Impact of Land Use Change on Forest Biodiversity)

► Show Figures

Figure 1

10 pages, 1970 KiB

Open AccessArticle

Phylogenetic Relationships between Phlebiopsis gigantea and Selected Basidiomycota Species Inferred from Partial DNA Sequence of Elongation Factor 1-Alpha Gene

by Marcin Wit, Zbigniew Sierota, Anna Żółciak, Ewa Mirzwa-Mróz, Emilia Jabłońska and Wojciech Wakuliński

Forests 2020, 11(5), 592; https://doi.org/10.3390/f11050592 - 24 May 2020

Cited by 2 | Viewed by 3604

Abstract

Phlebiopsis gigantea (Fr.) Jülich has been successfully used as a biological control fungus for Heterobasidion annosum (Fr.) Bref., an important pathogen of pine and spruce trees. The P. gigantea species has been known for many years, but our understanding of the relationship between [...] Read more.

Phlebiopsis gigantea (Fr.) Jülich has been successfully used as a biological control fungus for Heterobasidion annosum (Fr.) Bref., an important pathogen of pine and spruce trees. The P. gigantea species has been known for many years, but our understanding of the relationship between various isolates of this fungus has been substantially improved through the application of DNA sequence comparisons. In this study, relationships between P. gigantea and selected Basidiomycota species was determined, based on elongation factor 1-alpha (EF1α) partial DNA sequence and in silico data. A total of 12 isolates, representing the most representatives of P. gigantea, with diverse geographic distributions and hosts, were included in this study. Phylogenetic trees generated for sequences obtained in this research, grouped the European taxa of P. gigantea and partial sequence of the genome deposed in NCBI database, in a strongly supported clade, basal to the rest of the strains included in the study. P. gigantea isolates originating from Poland, Finland, Sweden, Great Britain and partial sequence of genome formed a monophyletic group. Within this group, isolates of P. gigantea constituted two subclades, showing their partial difference like the two SNPs (single nucleotide polymorphisms) between one and the rest of isolates. The intron and exon relationships among P. gigantea isolates were moreover resolved. The results obtained using the EF1α region should be useful in the selection of more efficient P. gigantea isolates for limiting forest tree root pathogens. Full article

(This article belongs to the Special Issue Forest Pathology and Entomology)

► Show Figures

Figure 1

17 pages, 3487 KiB

Open AccessArticle

When Urban Environment Is Restorative: The Effect of Walking in Suburbs and Forests on Psychological and Physiological Relaxation of Young Polish Adults

by Emilia Janeczko, Ernest Bielinis, Roman Wójcik, Małgorzata Woźnicka, Wojciech Kędziora, Adrian Łukowski, Mohamed Elsadek, Katarzyna Szyc and Krzysztof Janeczko

Forests 2020, 11(5), 591; https://doi.org/10.3390/f11050591 - 24 May 2020

Cited by 83 | Viewed by 9282

Abstract

Background and Objectives: Physical activity, recreation and walks successfully counteract negative symptoms of stress in people, especially in large cities, and have many positive psychological and physiological effects. There are many studies showing that contact with nature plays an important role in the [...] Read more.

Background and Objectives: Physical activity, recreation and walks successfully counteract negative symptoms of stress in people, especially in large cities, and have many positive psychological and physiological effects. There are many studies showing that contact with nature plays an important role in the regeneration of the human body. The city is not without green enclaves such as forests, parks or greenery along the streets. However, it is not entirely clear how the different physical characteristics of the urban space affect mood improvement, increase of positive feelings, vitality level, etc. Materials and Methods: In the study, two urban environments (apartment and green suburbs) were used, as well as two forests (coniferous and deciduous) to measure the impact of these environments on human physiological and psychological relaxation during a walk in a randomized experiment. The participants of the experiment were 75 young adult Poles studying in the largest Polish agglomeration, Warsaw. Before each experiment, the physiological and psychological state of the participant was measured indoors (pre-test). Four psychological questionnaires were used in the project (Profile of Mood States; Positive and Negative Affect Schedule; Restorative Outcome Scale; Subjective Vitality Scale), and physiological measurements (heart rate, blood pressure) before and after the short walking program were evaluated. Results: As a result of the analyses, it was shown that both staying in an urban environment with greenery and staying in a forest environment have a positive effect on the physiological and psychological relaxation of the subjects. A short walk in the suburbs was no less attractive than a walk in the forest in fall. The above indicates that various places with urban vegetation can be successfully used for recreation, just as in a forest where forest bathing is practiced. This indicates that different places with urban greenery can be successfully used for recreation, as can the forests where forest bathing is carried out. Full article

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

► Show Figures

Figure 1

18 pages, 4607 KiB

Open AccessArticle

Effects of Hormones and Epigenetic Regulation on the Callus and Adventitious Bud Induction of Fraxinus mandshurica Rupr.

by Lei Yu, Xinyu Li, Hongmei Tian, Hualing Liu, Ying Xiao, Nansong Liang, Xingtang Zhao and Yaguang Zhan

Forests 2020, 11(5), 590; https://doi.org/10.3390/f11050590 - 24 May 2020

Cited by 18 | Viewed by 4328

Abstract

Fraxinus mandshurica Rupr. (hereafter “F. mandshurica”) is known as one of northeast China′s important, valuable hardwood timber species. However, tissue culture and micropropagation of the species are difficult and have low efficiency, limiting asexual propagation. In this manuscript, stem explants were [...] Read more.

Fraxinus mandshurica Rupr. (hereafter “F. mandshurica”) is known as one of northeast China′s important, valuable hardwood timber species. However, tissue culture and micropropagation of the species are difficult and have low efficiency, limiting asexual propagation. In this manuscript, stem explants were utilized to establish an effective regeneration system through adventitious bud organogenesis. The factors influencing callus regeneration in vitro were determined, and callus regeneration technology was established. The mechanism of adventitious bud formation was analyzed. Thidiazuron (TDZ) played a crucial role in the formation of adventitious buds. Elevated concentrations of TDZ were beneficial to callus induction and low concentrations of 6-benzyladenine (BA) led to loose state callus formation. The order of callus induction rates for different explants was stem cotyledon (100%) > segment (98.54%) > hypocotyl (92.56%) > root (50.71%). The effects of exogenous addition of 6-BA and TDZ on the endogenous hormone content of plants during the regeneration of adventitious buds were also assessed, as well as the expression characteristics of genes related to the regeneration pathway. The comprehensive analysis results showed that the suitable medium for callus induction and adventitious bud differentiation was c12 medium (MSB5 + 30 g/L sucrose + 7 g/L Agar + 5 mg/L 6-BA + 8 mg/L TDZ + 2 mg/L glycine + 0.1 mg/L IBA + 5% coconut water). The induction rates of callus and adventitious buds were 99.15% and 33.33%. The addition of 2.4 mg/L of the DNA demethylation reagent 5-azacytidine (5-aza) and 0.15 mg/L of the histone deacetylase inhibitor trichostatin A (TSA) increased the rates of adventitious bud induction by 17.78% over the control. This further laid the foundation for large-scale cultivation of excellent varieties and genetic transformation techniques. Full article

(This article belongs to the Special Issue Application of Tissue Culture in Plant Reproduction)

► Show Figures

Figure 1

9 pages, 2513 KiB

Open AccessArticle

Intake of Radionuclides in the Trees of Fukushima Forests 3. Removal of Radiocesium from Stem Wood, Cryptomeria Japonica (L.f.) D. Don.

by Tomoko Seyama, Ryohei Arakawa, Shogo Machida, Sota Yoshida, Akihiko Maru, Kei’ichi Baba, Yoshinori Kobayashi, Rumi Kaida, Teruaki Taji, Yoichi Sakata, Tomoaki Iijima and Takahisa Hayashi

Forests 2020, 11(5), 589; https://doi.org/10.3390/f11050589 - 23 May 2020

Cited by 1 | Viewed by 2257

Abstract

Nuclear power plant accidents have dispersed radiocesium into the atmosphere to contaminate trees with no turnover in heartwood, as occurred in Fukushima, and as has persisted for over 30 years around Chernobyl. Here we employ the ponding method, in which radiocesium can be [...] Read more.

Nuclear power plant accidents have dispersed radiocesium into the atmosphere to contaminate trees with no turnover in heartwood, as occurred in Fukushima, and as has persisted for over 30 years around Chernobyl. Here we employ the ponding method, in which radiocesium can be flushed out from the cross-cut edges of Japanese cedar, Cryptomeria japonica (L.f.) D. Don., stem with water due to xyloglucan degradation in tracheids. Furthermore, lab-scale ponding experiments have shown that a non-detectable level of radiocesium has been observed not only in the pool water used for 575 days but also in the water containing recombinant xyloglucanase. This traditional technology is now a new biotechnology. Full article

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

► Show Figures

Figure 1

19 pages, 4037 KiB

Open AccessArticle

Microsite Influence on Woody Plant Regeneration in a Pinus palustris Woodland Following Catastrophic Disturbance

by Alexandra T. Logan, Jonathan D. Goode, David J. Keellings and Justin L. Hart

Forests 2020, 11(5), 588; https://doi.org/10.3390/f11050588 - 23 May 2020

Cited by 4 | Viewed by 3276

Abstract

Information and material biological legacies that persist after catastrophic forest disturbance collectively constitute the ecological memory of the system and may strongly influence future stand development. Catastrophic disturbances often result in an influx of coarse woody debris (CWD), and this material legacy may [...] Read more.

Information and material biological legacies that persist after catastrophic forest disturbance collectively constitute the ecological memory of the system and may strongly influence future stand development. Catastrophic disturbances often result in an influx of coarse woody debris (CWD), and this material legacy may provide beneficial microsites that affect successional and structural developmental pathways. We examined how microenvironmental characteristics influence the regeneration of woody plants in a subtropical woodland that experienced a large influx of CWD from a catastrophic wind disturbance. Specifically, we asked (1) what microenvironmental factors best explain woody plant density, richness, and height in the regeneration layer and (2) does woody plant density, richness, and height benefit from the large influx of CWD to a degree that competition dynamics and succession may be modified? Data were collected in a Pinus palustris woodland that had experienced an EF3 tornado and was subjected to a four-year prescribed fire rotation. We documented live woody plants <5 cm diameter at breast height, soil, and site characteristics and tested for differences in seedling and sapling density, species richness, and height in relation to CWD proximity. We used a random forest machine learning algorithm to examine the influence of microenvironmental conditions on the characteristics of woody plants in the regeneration layer. Woody plant density and species richness were not significantly different by proximity to CWD, but plants near CWD were slightly taller than plants away from CWD. The best predictors of woody plant density, richness, and height were abiotic site characteristics including slope gradient and azimuth, organic matter depth and weight, and soil water content. Results indicated that the regeneration of woody plants in this P. palustris woodland was not strongly influenced by the influx of CWD, but by other biological legacies such as existing root networks and soil characteristics. Our study highlights the need to consider ecological memory in forest management decision-making after catastrophic disturbance. Information and material legacies shape recovery patterns, but, depending on the system, some legacies will be more influential on successional and developmental pathways than others. Full article

(This article belongs to the Special Issue Silviculture for Restoration and Regeneration)

► Show Figures

Figure 1

15 pages, 1149 KiB

Open AccessArticle

Scots Pine and Norway Spruce Wood Properties at Sites with Different Stand Densities

by Benas Šilinskas, Iveta Varnagirytė-Kabašinskienė, Marius Aleinikovas, Lina Beniušienė, Jūratė Aleinikovienė and Mindaugas Škėma

Forests 2020, 11(5), 587; https://doi.org/10.3390/f11050587 - 23 May 2020

Cited by 34 | Viewed by 4660

Abstract

Background and Objectives: The aim of this study was to determine the effects of different stand densities on wood density (WD), global modulus of elasticity (MOE), and bending strength (MOR) in 35-year-old Scots pine (Pinus sylvestris L.) and Norway spruce (Picea [...] Read more.

Background and Objectives: The aim of this study was to determine the effects of different stand densities on wood density (WD), global modulus of elasticity (MOE), and bending strength (MOR) in 35-year-old Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst) stands, representing the hemiboreal forest zone. Materials and Methods: Scots pine and Norway spruce sites, representing different stand densities of 3000–3100; 2000–2100 and 1000–1100 trees per hectare, were chosen. Visually healthy model pine and spruce trees were selected, and diameter at breast height (DBH) was measured for model trees; the competition index was calculated; the MOE and MOR were evaluated by the Standards EN 408:2006 and EN 384:2016, at 12% moisture content; WD and the knot diameter were measured; and the strength class of wood was determined by the Standard EN 338:2009. To predict wood quality characteristics based on stand and tree characteristics, linear regression models were developed. Results and Conclusions: Higher stand density led to a significant change in the main wood properties of both conifer species. The highest mean WD, MOE, and MOR were obtained at the sites with the highest stand density. The MOE and MOR were highly correlated, but relatively weak correlations were found between MOE and MOR with tree DBH and WD. Despite the lower quality of Scots pine wood, the Norway spruce wood from more dense sites corresponded to the strength class of C16, according the strength grading of softwoods. The linear regression models did not perform well in describing the relationship of wood properties with stand and tree characteristics. The models for MOR accounted for the highest variation of 62–65% for both Scots pine and Norway spruce. These relationships can be expected to change with increased stand age or with the inclusion of specific crown parameters. Full article

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

► Show Figures

Figure 1

17 pages, 3847 KiB

Open AccessArticle

The Spread and Role of the Invasive Alien Tree Quercus rubra (L.) in Novel Forest Ecosystems in Central Europe

by Damian Chmura

Forests 2020, 11(5), 586; https://doi.org/10.3390/f11050586 - 23 May 2020

Cited by 20 | Viewed by 3598

Abstract

Research Highlights: The factors that control the spread and regeneration of Quercus rubra (L.) and the functional diversity of invaded forest were studied in order to indicate the significant role of disturbances in a forest and the low functional richness and evenness of [...] Read more.

Research Highlights: The factors that control the spread and regeneration of Quercus rubra (L.) and the functional diversity of invaded forest were studied in order to indicate the significant role of disturbances in a forest and the low functional richness and evenness of sites that are occupied by red oak. Background and Objectives: Red oak is one of the most frequent invasive trees from North America in Central Europe. It is also one of the most efficient self-regenerating invasive alien species in forests. The main goal of the study is to identify the characteristics of forest communities with a contribution of Q. rubra, and to assess its role in shaping the species diversity of these novel phytocoenoses. Materials and Methods: A total of 180 phytosociological records that have a share of Q. rubra in southern Poland were collected, including 100 randomly chosen plots from which soil samples were taken. In addition, vegetation sampling was performed in 55 plots in the vicinities that were uninvaded. Results: The probability of the self-regeneration and cover of Q. rubra seedlings depends mainly on the availability of maternal trees, and the abundance of seedlings was highest in cutting areas. The vegetation with Q. rubra differed in the plant functional types and environmental factors. According to the three-table ordination method, while the cover of red oak only affected the canopy of the remaining species, a comparison of the invaded and uninvaded plots demonstrated that the sites that were occupied by Q. rubra had lower values of functional richness and evenness, thus indicating higher habitat filtering and a lower importance of competition. Conclusions: Forest management practices play the most crucial role in the self-regeneration and occurrence of Q. rubra. However, the role of red oak in shaping the species composition and functional diversity is rather low. Full article

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

► Show Figures

Figure 1

20 pages, 2077 KiB

Open AccessArticle

Regeneration Dynamics Following the Formation of Understory Gaps in a Slovakian Beech Virgin Forest

by Eike Feldmann, Jonas Glatthorn, Christian Ammer and Christoph Leuschner

Forests 2020, 11(5), 585; https://doi.org/10.3390/f11050585 - 23 May 2020

Cited by 27 | Viewed by 4388

Abstract

The frequency and size of canopy gaps largely determine light transmission to lower canopy strata, controlling structuring processes in the understory. However, quantitative data from temperate virgin forests on the structure of regeneration in gaps and its dynamics over time are scarce. We [...] Read more.

The frequency and size of canopy gaps largely determine light transmission to lower canopy strata, controlling structuring processes in the understory. However, quantitative data from temperate virgin forests on the structure of regeneration in gaps and its dynamics over time are scarce. We studied the structure and height growth of tree regeneration by means of sapling density, shoot length growth and cumulative biomass in 17 understory gaps (29 to 931 m² in size) in a Slovakian beech (Fagus sylvatica L.) virgin forest, and compared the gaps with the regeneration under closed-canopy conditions. Spatial differences in regeneration structure and growth rate within a gap and in the gap periphery were analyzed for their dependence on the relative intensities of direct and diffuse radiation (high vs. low). We tested the hypotheses that (i) the density and cumulative biomass of saplings are higher in gaps than in closed-canopy patches, (ii) the position in a gap influences the density and height growth of saplings, and (iii) height growth of saplings increases with gap size. Sapling density and biomass were significantly higher in understory gaps than under closed canopy. Density of saplings was positively affected by comparatively high direct, but low diffuse radiation, resulting in pronounced spatial differences. In contrast, sapling shoot length growth was positively affected by higher levels of diffuse radiation and also depended on sapling size, while direct radiation intensity was not influential. Conclusively, in this forest, regeneration likely becomes suppressed after a short period by lateral canopy expansion in small gaps (<100 m²), resulting in a heterogeneous understory structure. In larger gaps (≥100 m²) saplings may be capable even at low plant densities to fill the gap, often forming a cohort-like regeneration layer. Thus, gaps of different sizes imprint on the resulting canopy structure in different ways, enhancing spatial heterogeneity. Full article

(This article belongs to the Special Issue Role of Gap Factors in Forest Tree Regeneration and Plant Communities)

► Show Figures

Figure 1

20 pages, 6585 KiB

Open AccessArticle

Future Impacts of Land Use Change on Ecosystem Services under Different Scenarios in the Ecological Conservation Area, Beijing, China

by Zuzheng Li, Xiaoqin Cheng and Hairong Han

Forests 2020, 11(5), 584; https://doi.org/10.3390/f11050584 - 22 May 2020

Cited by 53 | Viewed by 5034

Abstract

Ecosystem services (ES), defined as benefits provided by the ecosystem to society, are essential to human well-being. However, it remains unclear how they will be affected by land-use changes due to lack of knowledge and data gaps. Therefore, understanding the response mechanism of [...] Read more.

Ecosystem services (ES), defined as benefits provided by the ecosystem to society, are essential to human well-being. However, it remains unclear how they will be affected by land-use changes due to lack of knowledge and data gaps. Therefore, understanding the response mechanism of ecosystem services to land-use change is critical for developing systematic and sound land planning. In this study, we aimed to explore the impacts of land-use change on the three ecosystem services, carbon storage (CS), flood regulation (FR), and soil conservation (SC), in the ecological conservation area of Beijing, China. We first projected land-use changes from 2015 to 2030, under three scenarios, i.e., Business as Usual (BAU), Ecological Land Protection (ELP), and Rapid Economic Development (RED), by interactively integrating the Markov model (Quantitative simulation) with the GeoSOS-FLUS model (Spatial arrangement), and then quantified the three ecosystem services by using a spatially explicit InVEST model. The results showed that built-up land would have the most remarkable growth during 2015–2030 under the RED scenario (2.52% increase) at the expense of cultivated and water body, while forest land is predicted to increase by 152.38 km² (1.36% increase) under the ELP scenario. The ELP scenario would have the highest amount of carbon storage, flood regulation, and soil conservation, due to the strict protection policy on ecological land. The RED scenario, in which a certain amount of cultivated land, water body, and forest land is converted to built-up land, promotes soil conservation but triggers greater loss of carbon storage and flood regulation capacity. The conversion between land-use types will affect trade-offs and synergies among ecosystem services, in which carbon storage would show significant positive correlation with soil conservation through the period of 2015 to 2030, under all scenarios. Together, our results provide a quantitative scientific report that policymakers and land managers can use to identify and prioritize the best practices to sustain ecosystem services, by balancing the trade-offs among services. Full article

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

► Show Figures

Figure 1

20 pages, 2921 KiB

Open AccessArticle

Searching for Pareto Fronts for Forest Stand Wind Stability by Incorporating Timber and Biodiversity Values

by Ján Merganič, Katarína Merganičová, Jozef Výbošťok, Peter Valent, Ján Bahýľ and Rasoul Yousefpour

Forests 2020, 11(5), 583; https://doi.org/10.3390/f11050583 - 22 May 2020

Cited by 15 | Viewed by 3544

Abstract

Selecting a variant of forest regeneration cuttings that would ensure fulfilling multiple, frequently conflicting forest functions is a challenging task for forest management planning. The aim of this work is to present an efficient and complex analysis of the impact of different forest [...] Read more.

Selecting a variant of forest regeneration cuttings that would ensure fulfilling multiple, frequently conflicting forest functions is a challenging task for forest management planning. The aim of this work is to present an efficient and complex analysis of the impact of different forest management scenarios on stand wind stability, timber production (economy), and biodiversity of a secondary mixed temperate forest in Central Europe. We evaluated four different harvest-regeneration systems: clear-cutting, shelter-wood, selection cutting, and no-cutting using theSIBYLA growth simulator. We simulated forest stand development over time and applied 450 variants of 4 harvest-regeneration systems. The selected outputs from the simulator were used as indicators of the fulfilment of wood-production and non-wood-production functions. The calculated indicators were forest stability (height/diameter ratio), economic efficiency (soil expectation value, SEV), and tree species diversity (Shannon index). These indicators were used as inputs for multi-criteria a posteriori decision analysis using the weighted summation method and Pareto fronts. The results revealed substantial trade-offs among the three investigated criteria. The decision space was highly sensitive to their weighting system and included all regeneration systems. The Pareto fronts for wind stability revealed that the maximum stability could be achieved with shelter-wood based on target diameter. This variant, however, fulfils the other two examined functions only to a limited extent (SEV and diversity only to 9% and 27% of their absolute maxima). Other similar variants achieve high stability by sacrificing the diversity and increasing SEV, simultaneously. If a high diversity level is favoured, optimal stability could be achieved by the selection system. The proposed approach enables objective testing of a large number of variants, and an objective assessment of stand management planning since it provides us with the complex multi-dimensional picture about the impact of criteria weights on the selection of optimal variants, and the relative fulfilment of individual criteria. Full article

(This article belongs to the Special Issue Decision Support to Address Multiple Ecosystem Services in Forest Management Planning)

► Show Figures

Figure 1

15 pages, 2563 KiB

Open AccessArticle

An Efficient Tool for the Maintenance of Thermophilous Oak Forest Understory—Sheep or Brush Cutter?

by Bogdan Jaroszewicz, Małgorzata Jankowska-Błaszczuk, Michał Żmihorski and Tomasz Hałatkiewicz

Forests 2020, 11(5), 582; https://doi.org/10.3390/f11050582 - 22 May 2020

Cited by 1 | Viewed by 2684

Abstract

Research Highlights: Thermophilous oak forests are among the most species-rich forest ecosystems in Central Europe. In the temperate zone, they evolved from mixed deciduous forests due to centuries-long livestock grazing. The abandonment of traditional forms of landscape use resulted in a constant decline [...] Read more.

Research Highlights: Thermophilous oak forests are among the most species-rich forest ecosystems in Central Europe. In the temperate zone, they evolved from mixed deciduous forests due to centuries-long livestock grazing. The abandonment of traditional forms of landscape use resulted in a constant decline in the number of patches of these communities, their area and species richness, which has been ongoing for decades and calls for their urgent conservation. The commonly used approaches to the conservation of this community are the reestablishment of grazing or mechanical removal of undergrowth. However, there are a limited number of works comparing their effects on the forest herb layer separately and in combination. Background and Objectives: The purpose of our research was to evaluate the effectiveness of grazing, mechanical brush removal and their combination for the conservation of the oak forest herb layer. Materials and Methods: Our work was based on a fully crossed experimental design set in a 60-year-old oak forest. The individual and combined influences of sheep grazing and brush cutting on forest floor vegetation were compared to control plots. We surveyed plant species twice—before the application of treatments and one year later on 600 one-square-meter subplots selected randomly in the limits of twelve fenced 20 m × 20 m treated and untreated study plots. Results: Both grazing by sheep and mechanical removal served well for total plant species richness and their cover, if applied separately. But these effects were not additive—plant species richness and plant cover on plots with combined treatment did not differ from plots, where just a single treatment was applied. Application of both treatments (but separately) had positive influence on species cover of the target group of plants typical to xerothermic oak forests and non-target species of mixed deciduous forests. Mechanical removal allowed also for successful control of woody species. Active conservation measures resulted also in negative effects—we observed increase in the species richness and cover of ruderal species on grazed plots. Conclusions: Both tested methods can be used for active conservation of open oak forest understorey vegetation. The method of active conservation should be chosen depending on the goal and the species composition of the forest floor and undergrowth found at the beginning of the restoration process, however, combining of these treatments does not bring any extra advantage. In our opinion a monitoring of the reaction of vegetation on treatments is of paramount importance. Full article

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

► Show Figures

Figure 1

22 pages, 2337 KiB

Open AccessArticle

Difference in Regeneration Conditions in Pinus ponderosa Dominated Forests in Northern California, USA, over an 83 Year Period

by Sushil Nepal, Bianca N.I. Eskelson and Martin W. Ritchie

Forests 2020, 11(5), 581; https://doi.org/10.3390/f11050581 - 22 May 2020

Cited by 1 | Viewed by 2923

Abstract

Forest inventories based on field surveys can provide quantitative measures of regeneration such as density and stocking proportion. Understanding regeneration dynamics is a key element that supports silvicultural decision-making processes in sustainable forest management. The objectives of this study were to: 1) describe [...] Read more.

Forest inventories based on field surveys can provide quantitative measures of regeneration such as density and stocking proportion. Understanding regeneration dynamics is a key element that supports silvicultural decision-making processes in sustainable forest management. The objectives of this study were to: 1) describe historical regeneration in ponderosa pine dominated forests by species and height class, 2) find associations of regeneration with overstory, soil, and topography variables, 3) describe contemporary regeneration across various management treatments, and 4) compare differences in regeneration between historical and contemporary forests. The study area, a ponderosa pine (Pinus ponderosae Dougl. ex P. and C. Law) dominated forest, is located within the Blacks Mountain Experimental Forest (BMEF) in northeastern California, United States, which was designated as an experimental forest in 1934. We used 1935 and 2018 field surveyed regeneration data containing information about three species—ponderosa pine, incense-cedar (Calocedrus decurrens (Torr.) Florin) and white fir (Abies concolor (Grod. and Glend)—and four height classes: class 1: 0–0.31 m, class 2: 0.31–0.91 m, class 3: 0.91–1.83 m, and class 4: >1.83 m and <8.9 cm diameter at breast height. We used stocking as proxy for regeneration density in this study. We found that historically, stocking in the BMEF was dominated by shade-intolerant ponderosa pine in height classes 2 and 3. Two variables—overstory basal area per hectare (m² ha⁻¹) and available water capacity at 150 cm, which is the amount of water that is available for plants up to a depth of 150 cm from the soil surface—were significantly associated with stocking, and a beta regression model fit was found to have a pseudo-R² of 0.49. We identified significant differences in contemporary stocking among six management scenarios using a Kruskal–Wallis non-parametric one-way ANOVA. Control compartments had the highest stocking followed by burned compartments. In contemporary forest stands, recent treatments involving a combination of burning and thinning resulted in high stocking in height classes 2 and 3. Overall, the stocking in historical BMEF stands was higher than in contemporary stands and was dominated by ponderosa pine. Full article

(This article belongs to the Special Issue Impacts of Complex Forest Structures on Tree Regeneration)

► Show Figures

Figure 1

24 pages, 1939 KiB

Open AccessArticle

Local People’s Participation in Mangrove Restoration Projects and Impacts on Social Capital and Livelihood: A Case Study in the Philippines

by Roswin B. Valenzuela, Youn Yeo-Chang, Mi Sun Park and Jung-Nam Chun

Forests 2020, 11(5), 580; https://doi.org/10.3390/f11050580 - 22 May 2020

Cited by 32 | Viewed by 11515

Abstract

Participatory forest management has been considered as a practical and effective strategy for sustainable forest management, especially in situations where land tenure is not securely settled. For effective forest restoration, local communities, as the cornerstone of participatory management, should be provided with incentives [...] Read more.

Participatory forest management has been considered as a practical and effective strategy for sustainable forest management, especially in situations where land tenure is not securely settled. For effective forest restoration, local communities, as the cornerstone of participatory management, should be provided with incentives to facilitate their participation and active role. We postulate that participation in mangrove restoration projects can not only provide financial rewards but also yield intangible benefits for communities, i.e., social capital. The study was conducted in the province of Quezon, Philippines, using face-to-face interviews as the main method for data collection. Regression analyses were undertaken to assess the impact of local community participation in mangrove restoration projects on social capital and its potential benefits to people in terms of access to information and services, which are key components of livelihood. Results revealed that people’s participation in mangrove restoration projects contributes to increasing social capital, consequently improving their access to information and services. Local people’s participation is beneficial to communities, as it can improve their livelihoods. Full article

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

► Show Figures

Figure 1

14 pages, 3908 KiB

Open AccessArticle

Forest Disturbances in Polish Tatra Mountains for 1985–2016 in Relation to Topography, Stand Features, and Protection Zone

by Adrian Ochtyra

Forests 2020, 11(5), 579; https://doi.org/10.3390/f11050579 - 21 May 2020

Cited by 17 | Viewed by 3439

Abstract

For more than four centuries, the Tatra Mountains were affected by many factors, such as forest and pastoral management, mining and metallurgy, windthrows, snow avalanches, and bark beetle outbreaks. Due to the availability of the long-running Landsat program enabling acquisition of spatially and [...] Read more.

For more than four centuries, the Tatra Mountains were affected by many factors, such as forest and pastoral management, mining and metallurgy, windthrows, snow avalanches, and bark beetle outbreaks. Due to the availability of the long-running Landsat program enabling acquisition of spatially and spectrally consistent information, it is possible to the use these data for forest disturbance analysis. The main aim of this study was to analyze the relationships between the frequency of disturbances detected over the period of 1985–2016 and selected topographic features, such as elevation, exposure, and slope, derived from a digital elevation model (DEM); stand features, such as vegetation community type, age, structure, and degree of naturalness of the stand; and the management protection zone, which was extracted from thematic layers of the Tatra National Park (TNP). Using the normalized difference moisture index (NDMI), we detected forest disturbances in each year and analyzed them in the context of these topographic features, forest stand characteristics, and the management protection zone. We observed that forest stands in the lower montane zone, slopes between 10°–30°, and eastern exposures were primarily affected by disturbances. These consisted of artificially planted spruce stands aged between 51 and 100 years old. Full article

(This article belongs to the Special Issue Effects of Disturbance on Forest Dynamics under Climate Changes)

► Show Figures

Figure 1

16 pages, 2198 KiB

Open AccessArticle

Ecosystem Management of Eastern Canadian Boreal Forests: Potential Impacts on Wind Damage

by Jean-Claude Ruel

Forests 2020, 11(5), 578; https://doi.org/10.3390/f11050578 - 21 May 2020

Cited by 3 | Viewed by 2667

Abstract

Research Highlights: Windthrow can interfere significantly with ecosystem management practices. In some cases, their goal could still be reached but this may prove more complex in other cases, like the partial cutting of old-growth stands. In situations where windthrow is common without any [...] Read more.

Research Highlights: Windthrow can interfere significantly with ecosystem management practices. In some cases, their goal could still be reached but this may prove more complex in other cases, like the partial cutting of old-growth stands. In situations where windthrow is common without any human intervention, the use of partial cutting to maintain some stand structures may lead to a feedback loop leading to additional windthrow. Background and Objectives: Forest ecosystem management using natural disturbances as a template has become the management paradigm in many regions. Most of the time, the focus is on fire regime and effects. However, windthrow can be common in some places or can interfere with practices implemented in an ecosystem management strategy. This paper looks at interactions between ecosystem management and windthrow. Materials and Methods: The paper builds on three case studies looking at various elements that could be part of ecosystem management strategies. The first one looks at the impact of green tree retention, while the second one looks at the impact of reducing the size and dispersing clearcuts, and the last one examines the impact of a range of cutting practices in irregular old-growth stands. Results: Green tree retention leads to increased windthrow, especially when applied within mature even-aged stands. Reducing the size of clearcuts and dispersing them over the landscape also involves substantial windthrow along edges. Partial cutting in old-growth stands can lead to relatively high mortality, but part of it is not necessarily related to wind since it occurs as standing dead trees. Differences in the amount of damage with tree size and species have been found and could be used to reduce wind damage. Conclusions: Approaches to minimize wind damage in ecosystem management can be designed using existing knowledge. However, using windthrow as a template to design management strategies would prove more complex. Full article

(This article belongs to the Special Issue Wind Impacts on Forests and Trees in a Changing Climate—A Special Issue in Collaboration with the IUFRO Working Party 8.03.06)

► Show Figures

Figure 1

15 pages, 3042 KiB

Open AccessArticle

Physiological and Biochemical Traits in Korean Pine Somatic Embryogenesis

by Chunxue Peng, Fang Gao, Hao Wang, Hailong Shen and Ling Yang

Forests 2020, 11(5), 577; https://doi.org/10.3390/f11050577 - 21 May 2020

Cited by 31 | Viewed by 3310

Abstract

Korean pine broadleaf mixed forest is an important ecosystem for maintaining biodiversity in Northeast China. Korean pine is also an important species for the production of timber and nuts in the mountainous areas of Northeast China. In this study, we compared three types [...] Read more.

Korean pine broadleaf mixed forest is an important ecosystem for maintaining biodiversity in Northeast China. Korean pine is also an important species for the production of timber and nuts in the mountainous areas of Northeast China. In this study, we compared three types of Korean pine callus and found that embryogenic callus had high amounts of storage substances (protein, sugar and starch). Non-embryonic callus had high levels of polyphenols and polyphenol oxidation, while callus that lost somatic embryogenesis potential had lower levels of storage substances (protein, sugar and starch) and higher contents of peroxidase and catalase. These results indicate that high contents of storage substances (protein, sugar and starch), and low levels of polyphenols and polyphenol oxidase can be used as physiological markers of callus with somatic embryogenic potential. During the development process of Korean pine somatic embryos, fresh weight and dry weight gradually increased, while water content gradually decreased. Soluble protein, starch, soluble sugar and superoxide dismutase also increased during development, while peroxidase and catalase levels reduced over time. These results indicate that somatic embryogenesis involves energy storage, and antioxidant enzymes cooperate to regulate the occurrence and development of embryos. These results provide physiological markers for identification of embryogenic callus with somatic embryogenesis, to evaluate callus suitable for somatic embryogenesis, and provide basis for further research on the molecular mechanisms of somatic embryogenesis. Full article

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

► Show Figures

Figure 1

12 pages, 2480 KiB

Open AccessArticle

Cost–Benefit Analysis of Measures to Reduce Windstorm Impact in Pure Norway Spruce (Picea abies L. Karst.) Stands in Latvia

by Valters Samariks, Oskars Krisans, Janis Donis, Ilze Silamikele, Juris Katrevics and Aris Jansons

Forests 2020, 11(5), 576; https://doi.org/10.3390/f11050576 - 21 May 2020

Cited by 25 | Viewed by 3269

Abstract

Wind is one of the major natural forest disturbances in Europe, and reduces the total economic (including carbon sequestration) value of forests. The aim of this study was to assess the financial benefit of silvicultural measures in young, pure, planted Norway spruce stands [...] Read more.

Wind is one of the major natural forest disturbances in Europe, and reduces the total economic (including carbon sequestration) value of forests. The aim of this study was to assess the financial benefit of silvicultural measures in young, pure, planted Norway spruce stands by reduction in the impact of wind damage over the rotation period. The analyzed measures are promptly applied precommercial thinning and low-density planting with improved plant material. Spatial information on factors affecting wind damage—wind climate and soil—were gathered and combined with the local growth model and empirical data from tree pulling experiments in Latvia to assess the economic value loss due to wind damage over a rotation period. Timely precommercial thinning and lower-density planting with improved plant material would ensure a positive net present value with an interest rate of 3%, using conservative estimates. The financial benefit is highest in windier (coastal) regions and for the planting, followed by moderate thinning. The results demonstrate that, even without changing the dominant tree species, a considerable reduction in wind-damage risk can be achieved. Full article

(This article belongs to the Special Issue Natural Disturbance Dynamics Analysis for Forest Ecosystem Management)

► Show Figures

Figure 1

12 pages, 1021 KiB

Open AccessArticle

Interspecific Variability of Water Storage Capacity and Absorbability of Deadwood

by Anna Klamerus-Iwan, Jarosław Lasota and Ewa Błońska

Forests 2020, 11(5), 575; https://doi.org/10.3390/f11050575 - 21 May 2020

Cited by 27 | Viewed by 3039

Abstract

The aim of the study was to determine the water storage capacity and absorbability of deadwood of different tree species with varying degrees of decomposition. Coniferous (Silver fir—Abies alba Mill.) and deciduous (Common hornbeam—Carpinus betulus L., Common ash—Fraxinus excelsior L., [...] Read more.

The aim of the study was to determine the water storage capacity and absorbability of deadwood of different tree species with varying degrees of decomposition. Coniferous (Silver fir—Abies alba Mill.) and deciduous (Common hornbeam—Carpinus betulus L., Common ash—Fraxinus excelsior L., Common alder—Alnus glutinosa Gaertn., and Common aspen—Populus tremula L.) species were selected for the research. The study focuses on the wood of dead trees at an advanced stage of decomposition. Deadwood samples were collected at the Czarna Rózga Nature Reserve in central Poland. Changes over time of the water absorbability and water storage capacity of deadwood were determined under laboratory conditions. The research confirmed the significance of the wood species and the degree of wood decomposition in shaping the water storage capacity and absorbability of deadwood in forest ecosystems. Fir wood was characterized by having the highest water storage capacity and water absorbability. Among deciduous species under analysis, aspen wood was characterized by having the highest water storage capacity and absorbability. Our research has confirmed that deadwood may be a significant reservoir of water in forests. Full article

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

► Show Figures

Figure 1

19 pages, 2352 KiB

Open AccessArticle

Restoration Treatments Improve Overstory Tree Resistance Attributes and Growth in a Ponderosa Pine/Douglas-Fir Forest

by Justin S. Crotteau and Christopher R. Keyes

Forests 2020, 11(5), 574; https://doi.org/10.3390/f11050574 - 21 May 2020

Cited by 5 | Viewed by 2437

Abstract

Research Highlights: This study provides much needed insight into the development of resistance to disturbance and growth dynamics of overstory trees in response to restoration-based fuel reduction, and will be useful to scientists and managers attempting to better grasp the relative merits of [...] Read more.

Research Highlights: This study provides much needed insight into the development of resistance to disturbance and growth dynamics of overstory trees in response to restoration-based fuel reduction, and will be useful to scientists and managers attempting to better grasp the relative merits of restoration treatment types. Background and Objectives: Restoration-based fuel reduction treatments are common in dry, fire-prone forests of the western United States. The primary objective of such treatments is to immediately reduce a stand’s crown fire hazard. However, the impact of these treatments on residual trees is relevant to assess their longevity and resistance to future disturbances. In this study, we evaluate the effects of restoration on retained overstory ponderosa pine (Pinus ponderosa Lawson & C. Lawson) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees in western Montana, where treatments were experimentally implemented 13 years prior as part of the national Fire and Fire Surrogate study. Materials and Methods: We examined tree attributes in response to the following replicated treatments: thin-only, burn-only, thin + burn, and a no-action control. We analyzed three different tree attributes that confer resistance to common disturbances: height-to-diameter ratio (resistance to wind), bark thickness (resistance to surface fire), and growth efficiency (resistance to bark beetles). Results: Our models suggest that thinning (with or without burning) alters tree attributes relative to the control in a manner that may increase tree resistance to wind and snow breakage, surface fire, and biotic agents such as bark beetles. Further analysis of annual growth of ponderosa pine and Douglas-fir varied by treatment type: thinning-based restoration (thin-only and thin + burn) increased diameter growth for both species, crown length and width in ponderosa pine, and crown length in Douglas-fir relative to unthinned treatments. Burning (burn-only and thin + burn) did not significantly affect tree growth relative to unburned treatments. Conclusions: While low-severity prescribed burning treatments are often used for restoration and have various ecosystem benefits, this study demonstrates that thinning (alone or in addition to burning) produces more measureable, beneficial results to overstory tree disturbance resistance metrics and growth. Full article

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

► Show Figures

Figure 1

Journal Menu

Journal Browser

Forests, Volume 11, Issue 5 (May 2020) – 121 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI