Forests

2057 KiB

Open AccessArticle

Soil Degradation and the Decline of Available Nitrogen and Phosphorus in Soils of the Main Forest Types in the Qinling Mountains of China

by Xiaofeng Zheng, Jie Yuan, Tong Zhang, Fan Hao, Shibu Jose and Shuoxin Zhang

Forests 2017, 8(11), 460; https://doi.org/10.3390/f8110460 - 21 Nov 2017

Cited by 15 | Viewed by 4706

Abstract

Soil degradation has been reported worldwide. To better understand this degradation, we selected Pinus armandii and Quercus aliena var. acuteserrata forests, and a mixed forest of Q. aliena var. acuteserrata and P. armandii in the Qinling Mountains in China for our permanent plots [...] Read more.

Soil degradation has been reported worldwide. To better understand this degradation, we selected Pinus armandii and Quercus aliena var. acuteserrata forests, and a mixed forest of Q. aliena var. acuteserrata and P. armandii in the Qinling Mountains in China for our permanent plots and conducted three investigations over a 20-year period. We determined the amounts of available nitrogen (N) and phosphorus (P) in the soil to track the trajectory of soil quality and compared these with stand characteristics, topographic and climatic attributes to analyze the strength of each factor in influencing the available N and P in the soil. We found that the soil experienced a severe drop in quality, and that degradation is continuing. Temperature is the most critical factor controlling the soil available N, and species composition is the main factor regulating the soil available P. Given the huge gap in content and the increasing rate of nutrients loss, this reduction in soil quality will likely negatively affect ecosystem sustainability. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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1740 KiB

Open AccessArticle

Identification of Floral Relicts Based on Spatial Distance of Isolation

by Attila Molnár, Zsolt Végvári and Béla Tóthmérész

Forests 2017, 8(11), 459; https://doi.org/10.3390/f8110459 - 21 Nov 2017

Cited by 4 | Viewed by 4085

Abstract

The identification of climatic relicts is seldom straightforward. These species are threatened owing to current climatic trends, which underlines the importance of carrying out ecological and biogeographic investigations of them. Here we introduce a novel approach to improve the identification of climatic relicts. [...] Read more.

The identification of climatic relicts is seldom straightforward. These species are threatened owing to current climatic trends, which underlines the importance of carrying out ecological and biogeographic investigations of them. Here we introduce a novel approach to improve the identification of climatic relicts. We are focusing on thermophilic relict plants of the Pannonian biogeographic region from the Holocene Thermal Maximum (HTM). We argue that a minimal mean annual temperature difference (MATD) of the HTM compared to the recent climate allowed a continuous northward expansion for the taxa investigated. We measured latitudinal distances between the recent occurrences of relicts and those of the main distribution found further south. Regarding estimates for MATD (1.0–2.5 °C), we only consider species with a distribution which has a 150–350 km North-South gap, since a latitudinally directed distance can be translated into temperature, showing a poleward cooling trend. Of the 15 selected species, 12 were recorded with values of 1.0–1.7 °C MATD, and three with values of 1.8–2.5 °C, some of which are presumably interglacial species. Woody species are over-represented among them (four species), using the Hungarian flora as a reference. The proposed method allows the prediction of potential climate-related changes in the future distribution of species, constrained by the topographic features of their habitats. Full article

(This article belongs to the Special Issue How Topography Impacts Forests under Global Change?)

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2511 KiB

Open AccessFeature PaperArticle

Phenotypical and Molecular Characterisation of Fusarium circinatum: Correlation with Virulence and Fungicide Sensitivity

by Martin Mullett, Ana Pérez-Sierra, Josep Armengol and Mónica Berbegal

Forests 2017, 8(11), 458; https://doi.org/10.3390/f8110458 - 21 Nov 2017

Cited by 17 | Viewed by 5977

Abstract

Fusarium circinatum, causing pine pitch canker, is one of the most damaging pathogens of Pinus species. This study investigated the use of phenotypical and molecular characteristics to delineate groups in a worldwide collection of isolates. The groups correlated with virulence and fungicide [...] Read more.

Fusarium circinatum, causing pine pitch canker, is one of the most damaging pathogens of Pinus species. This study investigated the use of phenotypical and molecular characteristics to delineate groups in a worldwide collection of isolates. The groups correlated with virulence and fungicide sensitivity, which were tested in a subset of isolates. Virulence tests of twenty isolates on P. radiata, P. sylvestris and P. pinaster demonstrated differences in host susceptibility, with P. radiata most susceptible and P. sylvestris least susceptible. Sensitivity to the fungicides fludioxonil and pyraclostrobin varied considerably between isolates from highly effective (half-maximal effective concentration (EC₅₀) < 0.1 ppm) to ineffective (EC₅₀ > 100 ppm). This study demonstrates the potential use of simply acquired phenotypical (cultural, morphological) and molecular metrics to gain a preliminary estimate of virulence and sensitivity to certain fungicides. It also highlights the necessity of including a range of isolates in fungicide tests and host susceptibility assays, particularly of relevance to tree breeding programmes. Full article

(This article belongs to the Special Issue Pine Pitch Canker—Strategies for Management of Gibberella Circinata in Greenhouses and Forests (PINESTRENGTH))

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4929 KiB

Open AccessArticle

Allometry of Sapwood Depth in Five Boreal Trees

by M. Rebeca Quiñonez-Piñón and Caterina Valeo

Forests 2017, 8(11), 457; https://doi.org/10.3390/f8110457 - 20 Nov 2017

Cited by 13 | Viewed by 5755

Abstract

This paper analyzes sapwood variability and allometry within individuals of Populus tremuloides, Pinus contorta, Pinus banksiana, Picea mariana, and Picea glauca. Outside bark diameter at breast height (DBH) and sapwood depth (sd) in four cardinal [...] Read more.

This paper analyzes sapwood variability and allometry within individuals of Populus tremuloides, Pinus contorta, Pinus banksiana, Picea mariana, and Picea glauca. Outside bark diameter at breast height (DBH) and sapwood depth (sd) in four cardinal directions were measured in individuals in stands in Alberta and Saskatchewan, Canada. The microscopical analysis of wood anatomy was used to measure sd, and the error associated with the measures was observed. Sapwood allometry analyses examined the influence of DBH on sd and on sapwood area (SA). All species were observed to have varying sapwood depths around the trunk with statistical analyses showing that Pinus banksiana has a well defined preference to grow thicker in the North-East side. The largest sd values were observed for the Populus tremuloides set. Unlike Populus tremuloides and Picea glauca, for the species Pinus contorta, Pinus banksiana, and Picea mariana, incremental growth in DBH does not directly drive sapwood growth in any direction. For these three species, SA increases only because of increases in DBH as sd remains nearly constant. These results show that sapwood depth and sapwood area seem to behave differently in each studied species and are not always proportional to the tree size as is normally assumed. Full article

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

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2529 KiB

Open AccessArticle

Incidence of Trailer Frame Structure on Driver’s Safety during Log Transportation

by Marco Manzone and Angela Calvo

Forests 2017, 8(11), 456; https://doi.org/10.3390/f8110456 - 18 Nov 2017

Viewed by 4906

Abstract

The frame structure of the trailer may influence both the traction and the tractor-trailer stability, especially along sloped paths. The aim of this research was to analyze a trailer overturning and the strains on the connected tractors (wheeled, or crawled) during log transportation [...] Read more.

The frame structure of the trailer may influence both the traction and the tractor-trailer stability, especially along sloped paths. The aim of this research was to analyze a trailer overturning and the strains on the connected tractors (wheeled, or crawled) during log transportation (loose or tied) along a hillside. Two two-axle trailers were used: tandem and turntable steering. Three types of measurements were carried out during the field tests: (i) the detachment from the ground of the rear upstream wheels (or crawler); (ii) the transversal and longitudinal strains occurring when the trailer overturned (and released the hooking system of the tractor); (iii) the lateral deviation of the rear wheels (or crawler) of the tractor. The study highlighted that the two-axle trailer with turntable steering combined with the crawl tractor gave better results in terms of safety during trailer overturning. In addition, independent of the type of trailer, a tied load was found to be more dangerous than a load restrained only by steel struts, because when overturning, the load forms a single unit with the trailer mass which increases the strains. Full article

(This article belongs to the Special Issue Forest Operations, Engineering and Management)

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Open AccessArticle

Climate Change Mitigation Potential in Boreal Forests: Impacts of Management, Harvest Intensity and Use of Forest Biomass to Substitute Fossil Resources

by Tarit Kumar Baul, Ashraful Alam, Antti Ikonen, Harri Strandman, Antti Asikainen, Heli Peltola and Antti Kilpeläinen

Forests 2017, 8(11), 455; https://doi.org/10.3390/f8110455 - 18 Nov 2017

Cited by 29 | Viewed by 5676

Abstract

The impacts of alternative forest management scenarios and harvest intensities on climate change mitigation potential of forest biomass production, utilization and economic profitability of biomass production were studied in three boreal sub-regions in Finland over a 40-year period. Ecosystem modelling and life cycle [...] Read more.

The impacts of alternative forest management scenarios and harvest intensities on climate change mitigation potential of forest biomass production, utilization and economic profitability of biomass production were studied in three boreal sub-regions in Finland over a 40-year period. Ecosystem modelling and life cycle assessment tools were used to calculate the mitigation potential in substituting fossil materials and energy, expressed as the net CO₂ exchange. Currently recommended management targeting to timber production acted as a baseline management. Alternative management included maintaining 20% higher or lower stocking in forests and final felling made at lower breast height diameter than used in the baseline. In alternative management scenarios, logging residues and logging residues with coarse roots and stumps were harvested in final felling in addition to timber. The net CO₂ exchange in the southern and eastern sub-regions was higher compared to the western one due to higher net ecosystem CO₂ exchange (NEE) over the study period. Maintaining higher stocking with earlier final felling and intensified biomass harvest appeared to be the best option to increase both climate benefits and economic returns. Trade-offs between the highest net CO₂ exchange and economic profitability of biomass production existed. The use of alternative displacement factors largely affected the mitigation potential of forest biomass. Full article

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

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Open AccessArticle

Sustainable Forest Management and Social-Ecological Systems: An Institutional Analysis of Caatinga, Brazil

by Joana Mattei Faggin, Jelle Hendrik Behagel and Bas Arts

Forests 2017, 8(11), 454; https://doi.org/10.3390/f8110454 - 18 Nov 2017

Cited by 15 | Viewed by 6732

Abstract

Sustainable Forest Management (SFM) has globally gained support as a strategy to use and manage forest resources while maintaining forest ecosystem services. However, type, relevance, and utilisation of forest ecosystem services vary across eco-regions, countries, and policy implementation pathways. As such, the concept [...] Read more.

Sustainable Forest Management (SFM) has globally gained support as a strategy to use and manage forest resources while maintaining forest ecosystem services. However, type, relevance, and utilisation of forest ecosystem services vary across eco-regions, countries, and policy implementation pathways. As such, the concept of SFM is subject to a series of translations within the social-ecological context in which it is implemented. This article discusses translations of SFM in Caatinga biome—a tropical dry forest in the north-eastern semi-arid region of Brazil. Our analysis is based on a qualitative analysis of 24 semi-structured interviews and 30 documents. We discuss SFM and the interplay of resources, governance, and actors. Results for Caatinga show that (1) a technical approach to SFM that focuses on firewood and charcoal production is dominant; that (2) SFM implementation practices hardly address the needs and interests of local populations; and that (3) local actors show little support for the implementation of SFM. We conclude that the social-ecological context of Caatinga shapes translations of SFM mostly in a techno-bureaucratic rather than a socially embedded way. As a result, local practices of forest use are excluded from the regional SFM approach, which negatively affects its implementation. Full article

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

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Open AccessArticle

Decision Support System for Adaptive Regional-Scale Forest Management by Multiple Decision-Makers

by Yusuke Yamada and Yuichi Yamaura

Forests 2017, 8(11), 453; https://doi.org/10.3390/f8110453 - 17 Nov 2017

Cited by 10 | Viewed by 4773

Abstract

Various kinds of decision support approaches (DSAs) are used in adaptive management of forests. Existing DSAs are aimed at coping with uncertainties in ecosystems but not controllability of outcomes, which is important for regional management. We designed a DSA for forest zoning to [...] Read more.

Various kinds of decision support approaches (DSAs) are used in adaptive management of forests. Existing DSAs are aimed at coping with uncertainties in ecosystems but not controllability of outcomes, which is important for regional management. We designed a DSA for forest zoning to simulate the changes in indicators of forest functions while reducing uncertainties in both controllability and ecosystems. The DSA uses a Bayesian network model based on iterative learning of observed behavior (decision-making) by foresters, which simulates when and where zoned forestry activities are implemented. The DSA was applied to a study area to evaluate wood production, protection against soil erosion, preservation of biodiversity, and carbon retention under three zoning alternatives: current zoning, zoning to enhance biodiversity, and zoning to enhance wood production. The DSA predicted that alternative zoning could enhance wood production by 3–11% and increase preservation of biodiversity by 0.4%, but decrease carbon stock by 1.2%. This DSA would enable to draw up regional forest plans while considering trade-offs and build consensus more efficiently. Full article

(This article belongs to the Special Issue Decision Support Approaches in Adaptive Forest Management—Selected Papers from the IUFRO 125th Anniversary Congress)

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2283 KiB

Open AccessArticle

Effects of Nitrogen Deposition on Soil Dissolved Organic Carbon and Nitrogen in Moso Bamboo Plantations Strongly Depend on Management Practices

by Zhaofeng Lei, Huanfa Sun, Quan Li, Junbo Zhang and Xinzhang Song

Forests 2017, 8(11), 452; https://doi.org/10.3390/f8110452 - 17 Nov 2017

Cited by 12 | Viewed by 4312

Abstract

Soil dissolved organic carbon (DOC) and nitrogen (DON) play significant roles in forest carbon, nitrogen and nutrient cycling. The objective of the present study was to estimate the effect of management practices and nitrogen (N) deposition on soil DOC and DON in Moso [...] Read more.

Soil dissolved organic carbon (DOC) and nitrogen (DON) play significant roles in forest carbon, nitrogen and nutrient cycling. The objective of the present study was to estimate the effect of management practices and nitrogen (N) deposition on soil DOC and DON in Moso bamboo (Phyllostachys edulis (Carrière) J. Houz) plantations. This experiment, conducted for over 36 months, investigated the effects of four N addition levels (30, 60 and 90 kg N ha⁻¹ year⁻¹, and the N-free control) and two management practices (conventional management (CM) and intensive management (IM)) on DOC and DON. The results showed that DOC and DON concentrations were the highest in summer. Both intensive management and N deposition independently decreased DOC and DON in spring (p < 0.05) but not in winter. However, when combined with IM, N deposition increased DOC and DON in spring and winter (p < 0.05). Our results demonstrated that N deposition significantly increased the loss of soil DOC and DON in Moso plantations, and this reduction was strongly affected by IM practices and varied seasonally. Therefore, management practices and seasonal variation should be considered when using ecological models to estimate the effects of N deposition on soil DOC and DON in plantation ecosystems. Full article

(This article belongs to the Special Issue Carbon and Nitrogen in Forest Ecosystems—Series I)

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Open AccessArticle

Genetic Variation in Quercus acutissima Carruth., in Traditional Japanese Rural Forests and Agricultural Landscapes, Revealed by Chloroplast Microsatellite Markers

by Yoko Saito, Yoshiaki Tsuda, Kentaro Uchiyama, Tomohide Fukuda, Yasuhiro Seto, Pan-Gi Kim, Hai-Long Shen and Yuji Ide

Forests 2017, 8(11), 451; https://doi.org/10.3390/f8110451 - 17 Nov 2017

Cited by 10 | Viewed by 5625

Abstract

Quercus acutissima Carruth. is an economically important species that has long been cultivated in Japan, so is a valuable subject for investigating the impact of human activities on genetic variation in trees. In total, 2152 samples from 18 naturally regenerated populations and 28 [...] Read more.

Quercus acutissima Carruth. is an economically important species that has long been cultivated in Japan, so is a valuable subject for investigating the impact of human activities on genetic variation in trees. In total, 2152 samples from 18 naturally regenerated populations and 28 planted populations in Japan and 13 populations from the northeastern part of Eurasia, near Japan, were analyzed using six maternally inherited chloroplast (cpDNA) simple sequence repeat (SSR) markers. Although 23 haplotypes were detected in total, both the Japanese natural and artificial populations exhibited much lower genetic diversity than the continental populations. The level of genetic differentiation among natural populations in Japan was also much lower (G’_ST = 0.261) than that on the continent (G’_ST = 0.856). These results suggest that human activities, such as historical seed transfer, have reduced genetic diversity within and among populations and resulted in a homogeneous genetic structure in Japan. The genetic characteristics of natural and artificial populations of Quercus acutissima in Japan are almost the same and it is likely that most of the natural populations are thought to have originated from individuals that escaped from plantations. Full article

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

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3384 KiB

Open AccessArticle

Responses of Contrasting Tree Functional Types to Air Warming and Drought

by Elisabet Martínez-Sancho, Lizeth K. Vásconez Navas, Hannes Seidel, Isabel Dorado-Liñán and Annette Menzel

Forests 2017, 8(11), 450; https://doi.org/10.3390/f8110450 - 17 Nov 2017

Cited by 17 | Viewed by 5936

Abstract

Climate change-induced rise of air temperatures and the increase of extreme climatic events, such as droughts, will largely affect plant growth and hydraulics, leading to mortality events all over the globe. In this study, we investigated the growth and hydraulic responses of seedlings [...] Read more.

Climate change-induced rise of air temperatures and the increase of extreme climatic events, such as droughts, will largely affect plant growth and hydraulics, leading to mortality events all over the globe. In this study, we investigated the growth and hydraulic responses of seedlings of contrasting functional types. Pinus sylvestris, Quercus spp. and Castanea sativa seedlings were grown in a common garden experiment under four treatments: control, air warming, drought and their combination during two consecutive growing periods. Height and diameter increments, stomatal conductance and stem water potentials were measured during both growing seasons. Additionally, hydraulic parameters such as xylem-specific native and maximum hydraulic conductivities, and native percentage of loss of conductivity were measured at the end of the entire experiment. Our results clearly pointed to different adaptive strategies of the studied species. Scots pine displayed a relatively isohydric behavior with a strict stomata control prohibiting native embolism whereas sweet chestnut and oak as relatively anisohydric species displayed an increased loss of native conductivity as a results of low water potentials. Seasonal timing of shoot and diameter growth also differed among functional types influencing drought impacts. Additionally, the possibility of embolism reversal seemed to be limited under the study conditions. Full article

(This article belongs to the Special Issue Effect of Drought on Forests—Plant Water Relations and Ecological Consequences)

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2195 KiB

Open AccessArticle

Exploring the Regional Potential of Lignocellulosic Biomass for an Emerging Bio-Based Economy: A Case Study from Southwest Germany

by Joachim Maack, Marcus Lingenfelder, Thomas Smaltschinski, Dirk Jaeger and Barbara Koch

Forests 2017, 8(11), 449; https://doi.org/10.3390/f8110449 - 17 Nov 2017

Cited by 7 | Viewed by 4630

Abstract

The globally emerging concepts and strategies for a “bioeconomy” rely on the vision of a sustainable bio-based substitution process. Fossil fuels are scarce and their use contributes to global warming. To replace them in the value chains, it is essential to gain knowledge [...] Read more.

The globally emerging concepts and strategies for a “bioeconomy” rely on the vision of a sustainable bio-based substitution process. Fossil fuels are scarce and their use contributes to global warming. To replace them in the value chains, it is essential to gain knowledge about quantities and spatial distributions of renewable resources. Decision makers specifically require knowledge-based models for rational development choices. In this paper, we demonstrate such an approach using remote sensing-derived maps that represent the potential available biomass of forests and trees outside forests (TOF). The maps were combined with infrastructure data, transport costs and wood pricing to calculate the potentially available biomass for a regional bioeconomy in the federal state of Baden-Württemberg in Southwest Germany. We estimated the spatially explicit regional supply of biomass using routable data in a GIS environment, and created an approach to find the most suitable positions for biomass conversion facilities by minimizing transport distances and biomass costs. The approach resulted in the theoretical, regional supply of woody biomass with transport distances between 10 and 50 km. For a more realistic assessment, we subsequently applied several restrictions and assumptions, compiled different scenarios, optimised transport distances and identified wood assortments. Our analysis demonstrated that a regional bioeconomy using only local primary lignocellulosic biomass is possible. There would be, however, strong competition with traditional wood-processing sectors, mainly thermal utilisation and pulp and paper production. Finally, suitable positions for conversion facilities in Baden-Württemberg were determined for each of the six most plausible scenarios. This case study demonstrates the value of remote sensing and GIS techniques for a flexible, expandable and upgradable spatially explicit decision model. Full article

(This article belongs to the Special Issue New Application based on Advanced Remote Sensing Data in Forests and Wood Land Areas)

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2983 KiB

Open AccessArticle

Soil Organic Matter Accumulation and Carbon Fractions along a Moisture Gradient of Forest Soils

by Ewa Błońska and Jarosław Lasota

Forests 2017, 8(11), 448; https://doi.org/10.3390/f8110448 - 17 Nov 2017

Cited by 30 | Viewed by 7263

Abstract

The aim of the study was to present effects of soil properties, especially moisture, on the quantity and quality of soil organic matter. The investigation was performed in the Czarna Rózga Reserve in Central Poland. Forty circular test areas were located in a [...] Read more.

The aim of the study was to present effects of soil properties, especially moisture, on the quantity and quality of soil organic matter. The investigation was performed in the Czarna Rózga Reserve in Central Poland. Forty circular test areas were located in a regular grid of points (100 × 300 m). Each plot was represented by one soil profile located at the plot’s center. Sample plots were located in the area with Gleysols, Cambisols and Podzols with the water table from 0 to 100 cm. In each soil sample, particle size, total carbon and nitrogen content, acidity, base cations content and fractions of soil organic matter were determined. The organic carbon stock (SOCs) was calculated based on its total content at particular genetic soil horizons. A Carbon Distribution Index (CDI) was calculated from the ratio of the carbon accumulation in organic horizons and the amount of organic carbon accumulation in the mineral horizons, up to 60 cm. In the soils under study, in the temperate zone, moisture is an important factor in the accumulation of organic carbon in the soil. The highest accumulation of carbon was observed in soils of swampy variant, while the lowest was in the soils of moist variant. Large accumulation of C in the soils with water table 80–100 cm results from the thick organic horizons that are characterized by lower organic matter decomposition and higher acidity. The proportion of carbon accumulation in the organic horizons to the total accumulation in the mineral horizons expresses the distribution of carbon accumulated in the soil profile, and is a measure of quality of the organic matter accumulated. Studies have confirmed the importance of moisture content in the formation of the fractional organic matter. With greater soil moisture, the ratio of humic to fulvic acids (HA/FA) decreases, which may suggest an increase in carbon mobility in soils. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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1871 KiB

Open AccessArticle

Biomass Losses Caused by Teratosphaeria Leaf Disease in Eucalyptus globulus Short Rotation Forestry

by Severiano Pérez, Carlos J. Renedo, Alfredo Ortiz, Félix Ortiz and Agustín Santisteban

Forests 2017, 8(11), 447; https://doi.org/10.3390/f8110447 - 17 Nov 2017

Cited by 4 | Viewed by 3813

Abstract

This article presents the results of a study that examines the loss of biomass and energy, per hectare, caused by Teratosphaeria leaf disease (TLD) in Eucalyptus globulus short rotation forestry. The 95 Eucalyptus globulus taxa analyzed are from seeds of open pollinated families [...] Read more.

This article presents the results of a study that examines the loss of biomass and energy, per hectare, caused by Teratosphaeria leaf disease (TLD) in Eucalyptus globulus short rotation forestry. The 95 Eucalyptus globulus taxa analyzed are from seeds of open pollinated families of both Spanish and Australian origin. Tree height and diameter were measured and the crown damage index (CDI) assessed at 27 months of age. Taxa that have a certain tolerance to the disease have been identified. The taxon identified as code 283 is the one that shows lower CDI (42%) and with an average volume that exceeded 0.017 m³ at 27 months of age. Biomass losses were determined for each fraction of dry biomass of the tree (leaves, branches, twigs and bark) based on CDI. These losses were translated into terms of energy lost per hectare, depending on the CDI. A comparison was then carried out between the productivity of Eucalyptus globulus exhibiting various levels of TLD severity and poplar and willow clones used for bioenergy in Europe. In our region, the results show that despite the losses of biomass associated with TLD, Eucalyptus globulus remains competitive as long as CDI values are lower than 56%. Full article

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

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2836 KiB

Open AccessArticle

Using Linear Mixed-Effects Models with Quantile Regression to Simulate the Crown Profile of Planted Pinus sylvestris var. Mongolica Trees

by Yunxia Sun, Huilin Gao and Fengri Li

Forests 2017, 8(11), 446; https://doi.org/10.3390/f8110446 - 17 Nov 2017

Cited by 29 | Viewed by 6070

Abstract

Crown profile is mostly related to the competition of individual trees in the stands, light interception, growth, and yield of trees. A total of 76 sample trees with a total number of 889 whorls and 3658 live branches were used to develop the [...] Read more.

Crown profile is mostly related to the competition of individual trees in the stands, light interception, growth, and yield of trees. A total of 76 sample trees with a total number of 889 whorls and 3658 live branches were used to develop the outer crown profile model of the planted Pinus sylvestris var. mongolica trees in Heilongjiang Province, China. The power-exponential equation, modified Kozak equation, and simple polynomial equation were used and the model which showed the best performance was used as the basic model. The dummy variable approach was used to analyze the effect of stand age and stand density on the crown profile. Quantile regression for linear mixed-effects model, where the correlations between the series measurements on the same subject were considered, was used to model the outer crown profile. The results indicated that the power-exponential equation had the smallest error and was used as the basic model. Based on the dummy variable approach, stand age and stand density showed significant effects on the crown profile on the whole. Thus, they were directly included into the linear form of the power-exponential equation by a natural logarithm transformation to develop the quantile regression for the linear mixed-effects model. The 0.95th quantile regression model performed best in modeling the outer crown profile when compared to other quantiles. The prediction accuracy of the 0.95th quantile regression model by adding the random effects increased when compared to the quantile regression without random effect. The quantile regression for the linear mixed-effects model also showed an excellent performance in the largest crown radius prediction when compared to the quantile regression model. From suppressed trees to dominant trees, the crown radius increased, with tree size increasing for the same stand age and stand density increases. The crown radius of the suppressed trees from 21 to 40 year stands was the largest and the smallest was from older (>40 years) stands. The crown radius for both the intermediate and dominant trees from 21 to 40 year stands were similar and were larger than the younger (10–20 years) stands. The crown radius increased with tree size when the stand variables were constant. Furthermore, the crown radius increased with the increase of stand age, decreased with increasing stand density, and decreased with increased ratio of tree height to diameter at the breast height (HD) for trees with the same tree variables. Stand density had a weaker effect on the crown profile when compared to the HD. The growth rate of the crown radius of planted Pinus sylvestris var. mongolica trees increased with increasing stand age, and decreased with decreasing stand density. The growth rate of the crown radius decreased with increasing HD. Full article

(This article belongs to the Special Issue Successional Dynamics of Forest Structure and Function)

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Open AccessArticle

Private Forest Governance, Public Policy Impacts: The Forest Stewardship Council in Russia and Brazil

by Lisa McIntosh Sundstrom and Laura A. Henry

Forests 2017, 8(11), 445; https://doi.org/10.3390/f8110445 - 16 Nov 2017

Cited by 16 | Viewed by 6361

Abstract

Under what conditions do private forest governance standards influence state policy and behavior to become more oriented toward sustainability? We argue that governance schemes targeting firms may indirectly shape state behavior, even when designed to bypass state regulation. Through an examination of the [...] Read more.

Under what conditions do private forest governance standards influence state policy and behavior to become more oriented toward sustainability? We argue that governance schemes targeting firms may indirectly shape state behavior, even when designed to bypass state regulation. Through an examination of the Forest Stewardship Council (FSC) in Russia and Brazil, we find that the FSC has influenced domestic rhetoric, laws, and enforcement practices. FSC has had a more disruptive and consequential impact on Russia’s domestic forest governance; in Brazil, earlier transnational environmental campaigns had already begun to shift domestic institutions toward sustainability. Based on interview data and textual analysis of FSC and government documents, we identify the mechanisms of indirect FSC influence on states—professionalization, civil society mobilization, firm lobbying, and international market pressure, and argue that they are likely to be activated under conditions of poor and decentralized governance, overlapping and competing regulations and high foreign market demand for exports. Full article

(This article belongs to the Special Issue Sustainable Forest Management and Forest Certification)

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Open AccessArticle

An Examination of Diameter Density Prediction with k-NN and Airborne Lidar

by Jacob L. Strunk, Peter J. Gould, Petteri Packalen, Krishna P. Poudel, Hans-Erik Andersen and Hailemariam Temesgen

Forests 2017, 8(11), 444; https://doi.org/10.3390/f8110444 - 16 Nov 2017

Cited by 12 | Viewed by 3953

Abstract

While lidar-based forest inventory methods have been widely demonstrated, performances of methods to predict tree diameters with airborne lidar (lidar) are not well understood. One cause for this is that the performance metrics typically used in studies for prediction of diameters can be [...] Read more.

While lidar-based forest inventory methods have been widely demonstrated, performances of methods to predict tree diameters with airborne lidar (lidar) are not well understood. One cause for this is that the performance metrics typically used in studies for prediction of diameters can be difficult to interpret, and may not support comparative inferences between sampling designs and study areas. To help with this problem we propose two indices and use them to evaluate a variety of lidar and k nearest neighbor (k-NN) strategies for prediction of tree diameter distributions. The indices are based on the coefficient of determination (R²), and root mean square deviation (RMSD). Both of the indices are highly interpretable, and the RMSD-based index facilitates comparisons with alternative (non-lidar) inventory strategies, and with projects in other regions. K-NN diameter distribution prediction strategies were examined using auxiliary lidar for 190 training plots distribute across the 800 km² Savannah River Site in South Carolina, USA. We evaluate the performance of k-NN with respect to distance metrics, number of neighbors, predictor sets, and response sets. K-NN and lidar explained 80% of variability in diameters, and Mahalanobis distance with k = 3 neighbors performed best according to a number of criteria. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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Open AccessArticle

Assessment of Flammability of Moroccan Forest Fuels: New Approach to Estimate the Flammability Index

by Salaheddine Essaghi, M’hamed Hachmi, Mohammed Yessef, Mohammed Dehhaoui and Fahed El Amarty

Forests 2017, 8(11), 443; https://doi.org/10.3390/f8110443 - 15 Nov 2017

Cited by 14 | Viewed by 4796

Abstract

A new flammability index (FI) was developed, which integrated two parameters that are highly correlated to fuel moisture content (MC). These parameters are time-to-ignition and flame height. The newly obtained FI-values belong to the variation interval of {0; 20}. In addition to the [...] Read more.

A new flammability index (FI) was developed, which integrated two parameters that are highly correlated to fuel moisture content (MC). These parameters are time-to-ignition and flame height. The newly obtained FI-values belong to the variation interval of {0; 20}. In addition to the six flammability classes defined in the earlier work, a seventh class (FI > 16.5) was proposed to include fuel species with a high content of volatile flammable-compounds. Flammability testing and MC measurement were performed at a range of MC obtained through a drying process of samples. As a result, FI was statistically highly correlated with MC for all 13 Moroccan forest fuels tested in this study. Following this, linear regression equations were established to predict the FI-value as a function of MC. Therefore, the classification of flammability would depend on the species as well as the MC-value of the samples and the season in which they were collected. Full article

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

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Open AccessArticle

The Optimum Slash Pile Size for Grinding Operations: Grapple Excavator and Horizontal Grinder Operations Model Based on a Sierra Nevada, California Survey

by Takuyuki Yoshioka, Rin Sakurai, Shohei Kameyama, Koki Inoue and Bruce Hartsough

Forests 2017, 8(11), 442; https://doi.org/10.3390/f8110442 - 15 Nov 2017

Cited by 6 | Viewed by 15059

Abstract

The processing of woody biomass waste piles for use as fuel instead of burning them was investigated. At each landing of slash pile location, a 132 kW grapple excavator was used to transfer the waste piles into a 522 kW horizontal grinder. Economies [...] Read more.

The processing of woody biomass waste piles for use as fuel instead of burning them was investigated. At each landing of slash pile location, a 132 kW grapple excavator was used to transfer the waste piles into a 522 kW horizontal grinder. Economies of scale could be expected when grinding a larger pile, although the efficiency of the loading operation might be diminished. Here, three piles were ground and the operations were time-studied: Small (20 m long × 15 m wide × 4 m high), Medium (30 × 24 × 4 m), and Large (35 × 30 × 4 m) piles. Grinding the Medium pile was found to be the most productive at 30.65 bone dry tons per productive machine hour without delay (BDT/PMH₀), thereby suggesting that there might be an optimum size of slash pile for a grinding operation. Modeling of the excavator and grinder operations was also examined, and the constructed simulation model was observed to well-replicate the actual operations. Based on the modeling, the productivity of grinding at a landing area of 710 m² of slash pile location was estimated to be 31.24 BDT/PMH₀, which was the most productive rate. Full article

(This article belongs to the Special Issue Forest Operations, Engineering and Management)

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Open AccessEditorial

Variability and Disturbances as Key Factors in Forest Pathology and Plant Health Studies

by Matteo Garbelotto and Paolo Gonthier

Forests 2017, 8(11), 441; https://doi.org/10.3390/f8110441 - 15 Nov 2017

Cited by 8 | Viewed by 3973

Abstract

The plant disease triangle (PDT) is as old as the field of modern plant pathology, and it postulates that any plant disease is the outcome of the interaction between a pathogen, a host, and the environment. Recently, the need has emerged to study [...] Read more.

The plant disease triangle (PDT) is as old as the field of modern plant pathology, and it postulates that any plant disease is the outcome of the interaction between a pathogen, a host, and the environment. Recently, the need has emerged to study not only how the three elements of the PDT directly influence disease, but to focus on how they indirectly affect one another, consequently modifying the final outcome. It is also essential to structure such analyses within three major external frameworks provided by landscape level disturbances, climate change, and anthropogenic effects. The studies included in this issue cover a wide range of topics using an equally varied list of approaches, and they showcase the important role these indirect and often non-linear processes have on the development of forest diseases. Full article

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

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Open AccessArticle

Occupational Safety and Health Concerns in Logging: A Cross-Sectional Assessment in Virginia

by Sunwook Kim, Maury A. Nussbaum, Ashley L. Schoenfisch, Scott M. Barrett, Michael Chad Bolding and Deborah E. Dickerson

Forests 2017, 8(11), 440; https://doi.org/10.3390/f8110440 - 15 Nov 2017

Cited by 14 | Viewed by 4854

Abstract

Increased logging mechanization has helped improve logging safety and health, yet related safety risks and concerns are not well understood. A cross-sectional study was completed among Virginia loggers. Participants (n = 122) completed a self-administered questionnaire focusing on aspects of safety and [...] Read more.

Increased logging mechanization has helped improve logging safety and health, yet related safety risks and concerns are not well understood. A cross-sectional study was completed among Virginia loggers. Participants (n = 122) completed a self-administered questionnaire focusing on aspects of safety and health related to logging equipment. Respondents were at a high risk of workplace injuries, with reported career and 12-month injury prevalences of 51% and 14%, respectively. Further, nearly all (98%) respondents reported experiencing musculoskeletal symptoms. Over half (57.4%) of respondents reported symptoms related to diesel exhaust exposure in their career. Few (15.6%), however, perceived their jobs to be dangerous. Based on the opinions and suggestions of respondents, three priority areas were identified for interventions: struck-by/against hazards, situational awareness (SA) during logging operations, and visibility hazards. To address these hazards, and to have a broader and more substantial positive impact on safety and health, we discuss the need for proactive approaches such as incorporating proximity technologies in a logging machine or personal equipment, and enhancing logging machine design to enhance safety, ergonomics, and SA. Full article

(This article belongs to the Special Issue Forest Operations, Engineering and Management)

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Open AccessArticle

Spore Dispersal Patterns of Fusarium circinatum on an Infested Monterey Pine Forest in North-Western Spain

by Miloň Dvořák, Patrik Janoš, Leticia Botella, Gabriela Rotková and Rafael Zas

Forests 2017, 8(11), 432; https://doi.org/10.3390/f8110432 - 15 Nov 2017

Cited by 21 | Viewed by 5386

Abstract

The airborne inoculum of Fusarium circinatum Nirenberg & O’Donnell, the fungal pathogen causing Pine Pitch Canker (PPC), is one of the main means of spread of the disease in forest stands and forest nurseries. Since this world-wide known pathogen was introduced in Europe, [...] Read more.

The airborne inoculum of Fusarium circinatum Nirenberg & O’Donnell, the fungal pathogen causing Pine Pitch Canker (PPC), is one of the main means of spread of the disease in forest stands and forest nurseries. Since this world-wide known pathogen was introduced in Europe, its biology in this newly infested area still remains scarcely known. To shed more light on this topic, we set up an experiment on a naturally PPC infested forest of Monterey pine in Galicia (NW Spain) with the following two goals: (i) to describe the seasonal spore dispersal pattern during one year of regular sampling and (ii) to assess the spatial spore dispersal pattern around the infested plot. Portable rotating arm spore traps were used and complemented with meteorological measurements. The abundance of F. circinatum spores in the samples was assessed by quantitative PCR (qPCR) with a hydrolysis probe. The results showed almost permanent occurrence of the air inoculum throughout the whole year, being detected in 27 of the 30 samplings. No clear temporal trends were observed, but a higher air inoculum was favoured by previous lower air temperatures and lower leaf wetness. Conversely, neither rainfall nor air humidity seemed to have any significant importance. The spatial spread of the inoculum was noted to be successful up to a distance of 1000 m in the wind direction, even with winds of just 5 m·s⁻¹. Our study shows that rotating arm spore traps combined with qPCR may be an efficient tool for F. circinatum detection. Full article

(This article belongs to the Special Issue Pine Pitch Canker—Strategies for Management of Gibberella Circinata in Greenhouses and Forests (PINESTRENGTH))

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Open AccessArticle

Product and Residue Biomass Equations for Individual Trees in Rotation Age Pinus radiata Stands under Three Thinning Regimes in New South Wales, Australia

by Xin Wang, Huiquan Bi, Fabiano Ximenes, Jorge Ramos and Yun Li

Forests 2017, 8(11), 439; https://doi.org/10.3390/f8110439 - 14 Nov 2017

Cited by 16 | Viewed by 3900

Abstract

Using data from 239 trees that were destructively sampled and completely weighed in the field, four systems of nonlinear additive equations were developed for the estimation of product and residue fresh and dry weight of individual trees in rotation age (28 to 42 [...] Read more.

Using data from 239 trees that were destructively sampled and completely weighed in the field, four systems of nonlinear additive equations were developed for the estimation of product and residue fresh and dry weight of individual trees in rotation age (28 to 42 years) Pinus radiata stands under three thinning regimes: unthinned (T0), one thinning (T1) and two thinnings (T2). To cater for all practical applications, the four systems of equations included diameter at breast height overbark (DBHOB) as the only independent variable or both DBHOB and total tree height as predictors either with or without the incorporation of dummy variables for stand types. For all systems, the property of additivity was guaranteed by placing constraints on the structural parameters of the system equations. The parameter estimates were obtained by the generalized methods of moments (GMM) following a comparison with weighted nonlinear seemingly unrelated regression (WNSUR). Based on the predicted values from the system that had DBHOB as the predictor and dummy variables for stand types, the percentage of total tree fresh weight accounted for by residues increased from 14.8% to 20.5%, from 15.6% to 22.2% and from 13.9% to 18.7% for trees in the T0, T1 and T2 stands, respectively, as DBHOB increased from 15 to 70 cm. The corresponding changes in the percentage of residue dry weight were from 15.1% to 16.1%, from 15.7% to 17.1% and from 14.9% to 15.8% for the three stand types. In addition, two systems of allocative equations were developed to allocate the predicted product and residue biomass to their respective subcomponents. The system of allocative equations for product biomass predicted that sawlogs with bark accounted for 83% to 85% of product fresh weight and 82% to 87% of product dry weight over the same range of DBHOB. The predicted allocation of total residue dry weight to stump changed little, between 12% and 13%, over the same diameter range, but it was slightly higher for trees with DBHOB between 30 and 45 cm. The predicted allocation of total residue biomass to branches increased from 18% to 65% in fresh weight and from 18% to 57% in dry weight and that to waste decreased from 71% to 27% in fresh weight and from 70% to 32% in dry weight as DBHOB increased from 15 to 70 cm. Among the five biomass components, prediction accuracy was the lowest for pulpwood and waste. The systems of additive and allocative biomass equations developed in this study provided the first example of how the two approaches could be used together for the estimation of total tree, major and sub-component biomass. They will provide forest management with an enhanced capacity to more accurately estimate product and residue biomass of rotation age trees and thus to include the production of biomass for renewable energy generation in their management systems for P. radiata plantations. Full article

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Open AccessArticle

Planting Waterscapes: Green Infrastructures, Landscape and Hydrological Modeling for the Future of Santa Cruz de la Sierra, Bolivia

by Giulio Castelli, Cristiano Foderi, Boris Hinojosa Guzman, Lorenzo Ossoli, Yandery Kempff, Elena Bresci and Fabio Salbitano

Forests 2017, 8(11), 437; https://doi.org/10.3390/f8110437 - 13 Nov 2017

Cited by 20 | Viewed by 8302

Abstract

The expansion of cities is an emerging and critical issue for the future of the planet. Water is one of the most important resources provided by urban and peri-urban landscapes, as it is directly or indirectly connected with the quality of the environment [...] Read more.

The expansion of cities is an emerging and critical issue for the future of the planet. Water is one of the most important resources provided by urban and peri-urban landscapes, as it is directly or indirectly connected with the quality of the environment and life. Santa Cruz de la Sierra is the leading city in Bolivia (and the second in Latin America) in regard to population growth and soil sealing. Water is available to the city mostly from the Piraí River basin, and is expected to be totally inadequate to support such powerful urban development. The project Aguacruz, which is financed by the Italian Agency for Cooperation and Development, aimed to (1) restructure and harmonize existing data on the landscape ecology, hydrological features, and functional aspects of the Piraí River; (2) build hydrological scenarios for the future of the basin by introducing a landscape ecology approach, and (3) involve stakeholders and local actors in decision-making processes oriented to increase the resilience of the urban–rural landscape of the Piraì River and the city of Santa Cruz. SWAT (Soil and Water Assessment Tools) tested five scenarios through simulating different landscape settings, from the current previsions for urban expansion to a sound implementation of green infrastructures, agroforestry, and regreening. The results indicate that integrated actions in rural–urban systems can lead to a substantial reversal of the trend toward a decline in water supply for the city. From a governance and planning perspective, the proposed actions have been configured as to induce (i) integrated waterscape ecological planning; and (ii) the preparation and approval of departmental regulations for the incorporation of green infrastructures in the municipalities. Full article

(This article belongs to the Special Issue What Role Can Ecological Factors Play in Supporting Ecosystem Services in Urban and Peri-Urban Forests?)

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Open AccessArticle

Forest Type and Tree Characteristics Determine the Vertical Distribution of Epiphytic Lichen Biomass in Subtropical Forests

by Su Li, Shuai Liu, Xian-Meng Shi, Wen-Yao Liu, Liang Song, Hua-Zheng Lu, Xi Chen and Chuan-Sheng Wu

Forests 2017, 8(11), 436; https://doi.org/10.3390/f8110436 - 12 Nov 2017

Cited by 7 | Viewed by 7222

Abstract

Epiphytic lichens are an important component in subtropical forests and contribute greatly to forest biodiversity and biomass. However, information on epiphytic lichens still remains scarce in forest conservation owing to the difficulty of accessing all canopy layers for direct observation. Here, epiphytic lichens [...] Read more.

Epiphytic lichens are an important component in subtropical forests and contribute greatly to forest biodiversity and biomass. However, information on epiphytic lichens still remains scarce in forest conservation owing to the difficulty of accessing all canopy layers for direct observation. Here, epiphytic lichens were quantified on 73 whole trees in five forest types in Southwest China to clarify the vertical stratification of their biomass in subtropical forests. Lichen biomass was significantly influenced by forest type and host attributes, varying from 187.11 to 8.55 g∙tree⁻¹ among forest types and from 289.81 to <0.01 g∙tree⁻¹ among tree species. The vertical stratification of lichen biomass was also determined by forest type, which peaked at the top in primary Lithocarpus forest and middle-aged oak secondary forest and in the middle upper heights in other forests. Overall, the proportion of lichen biomass accounted for 73.17–100.00% of total lichen biomass on branches and 0.00–26.83% on trunks in five forests, and 64.53–100.00% and 0.00–35.47% on eight host species. Seven functional groups showed marked and various responses to tree height between and among forest types. This information improves our understanding of the distribution of epiphytic lichens in forest ecosystems and the promotion of forest management in subtropical China. Full article

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

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Open AccessArticle

De Novo Transcriptome Sequencing in Passiflora edulis Sims to Identify Genes and Signaling Pathways Involved in Cold Tolerance

by Sian Liu, Anding Li, Caihui Chen, Guojun Cai, Limin Zhang, Chunyan Guo and Meng Xu

Forests 2017, 8(11), 435; https://doi.org/10.3390/f8110435 - 12 Nov 2017

Cited by 26 | Viewed by 5960

Abstract

The passion fruit (Passiflora edulis Sims), also known as the purple granadilla, is widely cultivated as the new darling of the fruit market throughout southern China. This exotic and perennial climber is adapted to warm and humid climates, and thus is generally [...] Read more.

The passion fruit (Passiflora edulis Sims), also known as the purple granadilla, is widely cultivated as the new darling of the fruit market throughout southern China. This exotic and perennial climber is adapted to warm and humid climates, and thus is generally intolerant of cold. There is limited information about gene regulation and signaling pathways related to the cold stress response in this species. In this study, two transcriptome libraries (KEDU_AP vs. GX_AP) were constructed from the aerial parts of cold-tolerant and cold-susceptible varieties of P. edulis, respectively. Overall, 126,284,018 clean reads were obtained, and 86,880 unigenes with a mean size of 1449 bp were assembled. Of these, there were 64,067 (73.74%) unigenes with significant similarity to publicly available plant protein sequences. Expression profiles were generated, and 3045 genes were found to be significantly differentially expressed between the KEDU_AP and GX_AP libraries, including 1075 (35.3%) up-regulated and 1970 (64.7%) down-regulated. These included 36 genes in enriched pathways of plant hormone signal transduction, and 56 genes encoding putative transcription factors. Six genes involved in the ICE1–CBF–COR pathway were induced in the cold-tolerant variety, and their expression levels were further verified using quantitative real-time PCR. This report is the first to identify genes and signaling pathways involved in cold tolerance using high-throughput transcriptome sequencing in P. edulis. These findings may provide useful insights into the molecular mechanisms regulating cold tolerance and genetic breeding in Passiflora spp. Full article

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

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Open AccessArticle

Policy Recommendation from Stakeholders to Improve Forest Products Transportation: A Qualitative Study

by Anil Koirala, Anil Raj Kizha and Sandra M. De Urioste-Stone

Forests 2017, 8(11), 434; https://doi.org/10.3390/f8110434 - 12 Nov 2017

Cited by 20 | Viewed by 5728

Abstract

With recently announced federal funding and subsidies to redevelop vacant mills and the communities they were in, the forest products industry in Maine is poised to gain its momentum once again. One of the important components influencing the cost of delivered forest products [...] Read more.

With recently announced federal funding and subsidies to redevelop vacant mills and the communities they were in, the forest products industry in Maine is poised to gain its momentum once again. One of the important components influencing the cost of delivered forest products is transportation. A recent study in the region has shown that the location and availability of markets along with lack of skilled labor force are the major challenges faced by the forest products transportation sector in Maine. This study was focused on developing a management guideline which included various field level options for improving trucking enterprises in Maine. For this, a qualitative research approach utilizing a case study research tradition was employed, with in-depth semi-structured interviews with professionals directly related to the forest products transportation sector used for data generation. Thirteen semi-structured interviews were conducted, with each being audio recorded and later transcribed verbatim. Interview transcriptions were analyzed using NVivo 11. Suggestions, like increasing benefits to drivers and providing training, were proposed for challenges related to manpower shortage, while the marketing of new forest products and adjustment in some state-level policies were proposed for challenges related to the forest products market condition of the state. Full article

(This article belongs to the Special Issue Forest Operations, Engineering and Management)

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Open AccessArticle

Comparisons of Soil Properties, Enzyme Activities and Microbial Communities in Heavy Metal Contaminated Bulk and Rhizosphere Soils of Robinia pseudoacacia L. in the Northern Foot of Qinling Mountain

by Yurong Yang, Miao Dong, Yaping Cao, Jinlong Wang, Ming Tang and Yihui Ban

Forests 2017, 8(11), 430; https://doi.org/10.3390/f8110430 - 12 Nov 2017

Cited by 35 | Viewed by 6416

Abstract

The toxic effects of heavy metal (HM) contamination on plant metabolism and soil microorganisms have been emphasized recently; however, little is known about the differences in soil physical, chemical, and biological properties between bulk and rhizosphere soils contaminated with HMs in forest ecosystem. [...] Read more.

The toxic effects of heavy metal (HM) contamination on plant metabolism and soil microorganisms have been emphasized recently; however, little is known about the differences in soil physical, chemical, and biological properties between bulk and rhizosphere soils contaminated with HMs in forest ecosystem. The present study was conducted to evaluate the rhizosphere effect on soil properties, enzyme activities and bacterial communities associated with Robinia pseudoacacia L. along a HM contamination gradient. Soil organic matter (SOM), available nitrogen (AN) and phosphorus (AP) contents were significantly higher in rhizosphere soil than those in bulk soil at HM contaminated sites (p < 0.05). Compared to bulk soil, activities of four soil enzymes indicative of C cycle (β-glucosidase), N cycle (protease, urease) and P cycle (alkaline phosphatase) in rhizosphere soil across all study sites increased by 47.5%, 64.1%, 52.9% and 103.8%, respectively. Quantitative PCR (qPCR) and restriction fragment length polymorphism (RFLP) were used to determine the relative abundance, composition and diversity of bacteria in both bulk and rhizosphere soils, respectively. The copy number of bacterial 16S rRNA gene in bulk soil was significantly lower than that in rhizosphere soil (p < 0.05), and it had significantly negative correlations with total/DTPA-extractable Pb concentrations (p < 0.01). Alphaproteobacteria, Gammaproteobacteria and Firmicutes were the most dominant groups of bacteria at different study sites. The bacterial diversity index of Species richness (S) and Margalef (d_Ma) were significantly higher in rhizosphere soil compared with those in bulk soil, although no difference could be found in Simpson index (D) between bulk and rhizosphere soils (p > 0.05). Redundancy analysis (RDA) results showed that soil pH, EC, SOM and total/DTPA-extractable Pb concentrations were the most important variables affecting relative abundance, composition and diversity of bacteria (p < 0.05). Our study highlights the importance of rhizosphere effect on soil nutrient content, enzyme activity, bacterial abundance and community in HM contaminated forest soils. Further study is still required to understand the specific processes in the rhizosphere to achieve a suitable rhizosphere biotechnology for restoration of degraded forest ecosystem. Full article

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Open AccessArticle

Carbon Sequestration in Protected Areas: A Case Study of an Abies religiosa (H.B.K.) Schlecht. et Cham Forest

by Pablo I. Fragoso-López, Rodrigo Rodríguez-Laguna, Elena M. Otazo-Sánchez, César A. González-Ramírez, José René Valdéz-Lazalde, Hermann J. Cortés-Blobaum and Ramón Razo-Zárate

Forests 2017, 8(11), 429; https://doi.org/10.3390/f8110429 - 12 Nov 2017

Cited by 11 | Viewed by 6065

Abstract

The effects of global climate change have highlighted forest ecosystems as a key element in reducing the amount of atmospheric carbon through photosynthesis. The objective of this study was to estimate the amount of carbon content and its percentage capture in a protected [...] Read more.

The effects of global climate change have highlighted forest ecosystems as a key element in reducing the amount of atmospheric carbon through photosynthesis. The objective of this study was to estimate the amount of carbon content and its percentage capture in a protected Abies religiosa forest in which the study area was zoned with satellite image analysis. Dendrometric and epidometric variables were used to determine the volume and increase of aerial biomass, and stored carbon and its capture rate using equations. The results indicate that this forest contains an average of 105.72 MgC ha⁻¹, with an estimated sequestration rate of 1.03 MgC ha⁻¹ yr⁻¹. The results show that carbon capture increasing depends on the increase in volume. Therefore, in order to achieve the maximum yield in a forest, it is necessary to implement sustainable forest management that favors the sustained use of soil productivity. Full article

(This article belongs to the Special Issue Carbon and Nitrogen in Forest Ecosystems—Series I)

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Open AccessArticle

Short-Term Effects of Low Intensity Thinning on the Fine Root Dynamics of Pinus massoniana Plantations in the Three Gorges Reservoir Area, China

by Yafei Shen, Na Wang, Ruimei Cheng, Wenfa Xiao, Shao Yang and Yan Guo

Forests 2017, 8(11), 428; https://doi.org/10.3390/f8110428 - 12 Nov 2017

Cited by 14 | Viewed by 4083

Abstract

Fine roots play an important role in plant growth as well as carbon (C) and nutrient cycling in terrestrial ecosystems. Fine roots are important for understanding the contribution of forests to the global C cycle. Knowledge about this topic is still limited, especially [...] Read more.

Fine roots play an important role in plant growth as well as carbon (C) and nutrient cycling in terrestrial ecosystems. Fine roots are important for understanding the contribution of forests to the global C cycle. Knowledge about this topic is still limited, especially regarding the effects of different forest management practices. This study investigated the seasonal dynamics of fine roots (<2 mm) in masson pine (P. massoniana) plantations for one year after low intensity thinning by using a sequential soil coring method. The fine roots showed pronounced seasonal dynamics, with a peak of fine root biomass (FRB) occurring in September. Significant differences were noted in the seasonal dynamics of FRB for the different diameter size sub-classes (≤0.5 mm, 0.5–1 mm and 1–2 mm); also FRB was inversely related to soil depth. Moreover, the FRB (≤0.5 mm and 0.5–1 mm except 1–2 mm) in the thinning plots was greater than that in the control only in the upper soil layer (0–10 cm). Furthermore, the FRB varied significantly with soil temperature, moisture and nutrients depended on the diameter sub-class considered. Significant differences in the soil temperature and moisture levels were noted between low-intensity thinned and control plots. Soil nutrient levels slightly decreased after low-intensity thinning. In addition, there was a more sensitive relationship between the very fine roots (diameter < 0.5 mm) and soil nutrients. Our results showed an influence of low-intensity thinning on the fine root dynamics with a different magnitude according to fine root diameter sub-classes. These results provide a theoretical basis to promote the benefits of C cycling in the management of P. massoniana forests. Full article

(This article belongs to the Special Issue Forest Fine Roots in Changing Climate)

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