Forests

16 pages, 1487 KiB

Open AccessArticle

Effect of Yeast Extract on Seedling Growth Promotion and Soil Improvement in Afforestation in a Semiarid Chestnut Soil Area

by Qin Xi, Wenhao Lai, Youyuan Cui, Hailong Wu and Tingning Zhao

Forests 2019, 10(1), 76; https://doi.org/10.3390/f10010076 - 21 Jan 2019

Cited by 21 | Viewed by 4376

Abstract

Yeast extract, which is environmentally friendly, nutritious, and convenient to use, has advantages over common plant growth regulators and soil conditioners. It is worth verifying the effect of the application of yeast extract to afforestation in a semiarid chestnut soil area. This study [...] Read more.

Yeast extract, which is environmentally friendly, nutritious, and convenient to use, has advantages over common plant growth regulators and soil conditioners. It is worth verifying the effect of the application of yeast extract to afforestation in a semiarid chestnut soil area. This study was conducted through a wild field afforestation experiment in Inner Mongolia, northern China. We designed an orthogonal experiment of 25 treatments with 30 repetitions on Pinus sylvestris(Pinus sylvestris var. mongolica Litv.) sand Armeniaca sibirica（Armeniaca sibirica (L.) Lam）. Three factors with different levels were considered: application to rhizosphere soil with the amounts of 0 g, 10 g, 20 g, 30 g, and 40 g; foliar spraying with concentrations of 0%, 0.5%, 1%, 1.5%, and 2%; and spraying at three moments. The results showed that yeast extract could enhance the seedlings of Pinus sylvestris and Armeniaca sibirica. When applying 40 g of yeast extract, the survival rates and root parameters were significantly boosted. Foliar spraying plays an important role in promoting the growth of seedlings. It was most effective for the two species to be sprayed with a concentration of 2% after leafing of the seedlings. The data also revealed that the application of yeast extract improved the properties of the rhizosphere soil. The porosities and moisture contents were increased, and the bulk densities were reduced. Forty grams (40 g) was the best amount to apply, especially for the soil at 20–40 cm where the seedling roots are mainly located. The chemical properties were also improved, as there was a significant increase in the conductivities, organic matter, nitrogen, and phosphorus as well as a slight reduction in the calcium carbonate content and pH. Therefore, yeast extract has a beneficial effect on both seedling growth promotion and soil improvement. It is considered to be an environmentally efficient method for afforestation and ecological remediation in semiarid chestnut soil areas. Full article

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

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17 pages, 2532 KiB

Open AccessReview

Abiotic and Biotic Disturbances Affecting Forest Health in Poland over the Past 30 Years: Impacts of Climate and Forest Management

by Zbigniew Sierota, Wojciech Grodzki and Andrzej Szczepkowski

Forests 2019, 10(1), 75; https://doi.org/10.3390/f10010075 - 21 Jan 2019

Cited by 50 | Viewed by 9810

Abstract

The current nature of forest management in Poland reflects its history and more than 100 years of economic activity affecting forests since independence in 1918. Before that time, different forest management models were used, related to the nature of the Prussian economy in [...] Read more.

The current nature of forest management in Poland reflects its history and more than 100 years of economic activity affecting forests since independence in 1918. Before that time, different forest management models were used, related to the nature of the Prussian economy in the north of the country, the Russian economy in the central-eastern part, and the Austrian economy in south-eastern Poland. The consequence of these management models, as well as the differing climate zones in which they were used, resulted in varied forest health. Since the end of World War II, forest coverage within Poland‘s new borders has increased from 20.8% to currently 29.6%, mainly as a result of afforestation of wastelands and former agricultural lands. This paper describes changes in the health of forests and their biological diversity in Poland in the context of weather extremes, species composition, forest management, the forest industry, and damage from insects and pathogenic fungi over the last 30 years. Full article

(This article belongs to the Special Issue Impacts, Monitoring and Management of Forest Pests and Diseases)

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13 pages, 1361 KiB

Open AccessArticle

Effect of Herbaceous Layer Interference on the Post-Fire Regeneration of a Serotinous Pine (Pinus pinaster Aiton) across Two Seedling Ages

by Jorge Castro and Alexandro B. Leverkus

Forests 2019, 10(1), 74; https://doi.org/10.3390/f10010074 - 20 Jan 2019

Cited by 11 | Viewed by 3471

Abstract

Herbaceous vegetation is a major source of interference with the regeneration of woody species. This is particularly the case after forest fires, as a dense herbaceous layer usually regenerates naturally. Although the competitive effect of the herbaceous vegetation upon tree seedlings has been [...] Read more.

Herbaceous vegetation is a major source of interference with the regeneration of woody species. This is particularly the case after forest fires, as a dense herbaceous layer usually regenerates naturally. Although the competitive effect of the herbaceous vegetation upon tree seedlings has been widely studied, there are still gaps in knowledge for management related to the effect of tree seedling age and size on the outcome of the interaction. In this study, we seek to determine the response of maritime pine (Pinus pinaster Aiton) seedlings to herbaceous competition at two different seedling ages. For that, two treatments of herbaceous competition were implemented, namely unweeded (no action around pine seedlings) and weeded (herbaceous cover removed around pine seedlings). Treatments were conducted twice (2 and 4 years after the fire), and we monitored seedling survival and growth at the end of each growing season. The treatments were implemented across three adjacent landscape units that differed in the management of burned wood and that are representative of common post-fire scenarios: no intervention, salvage logging, and an intermediate degree of intervention. Weeding increased seedling survival from 44.7% to 67.8% when seedlings were 2 years old, but had no effect for four-year-old seedlings, which showed 99% survival. Seedling growth also increased in the weeding treatment, but only slightly. Moreover, growth (and survival for two-year-old seedlings) was strongly correlated with initial seedling size, particularly in the case of two-year-old seedlings. Initial pine seedling height was strongly and positively correlated with the height of the herbaceous layer, supporting the existence of microsite features that promote plant growth above competitive effects. The results support that management actions conducive to foster post-fire pine forest restoration in this Mediterranean ecosystem should reduce herbaceous competition at early stages after fire (second or third year) and focus on larger seedlings. Full article

(This article belongs to the Special Issue Forest Post-Fire Regeneration)

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34 pages, 5778 KiB

Open AccessArticle

Landscape-Scale Mixtures of Tree Species are More Effective than Stand-Scale Mixtures for Biodiversity of Vascular Plants, Bryophytes and Lichens

by Steffi Heinrichs, Christian Ammer, Martina Mund, Steffen Boch, Sabine Budde, Markus Fischer, Jörg Müller, Ingo Schöning, Ernst-Detlef Schulze, Wolfgang Schmidt, Martin Weckesser and Peter Schall

Forests 2019, 10(1), 73; https://doi.org/10.3390/f10010073 - 19 Jan 2019

Cited by 33 | Viewed by 5948

Abstract

Tree species diversity can positively affect the multifunctionality of forests. This is why conifer monocultures of Scots pine and Norway spruce, widely promoted in Central Europe since the 18th and 19th century, are currently converted into mixed stands with naturally dominant European beech. [...] Read more.

Tree species diversity can positively affect the multifunctionality of forests. This is why conifer monocultures of Scots pine and Norway spruce, widely promoted in Central Europe since the 18th and 19th century, are currently converted into mixed stands with naturally dominant European beech. Biodiversity is expected to benefit from these mixtures compared to pure conifer stands due to increased abiotic and biotic resource heterogeneity. Evidence for this assumption is, however, largely lacking. Here, we investigated the diversity of vascular plants, bryophytes and lichens at the plot (alpha diversity) and at the landscape (gamma diversity) level in pure and mixed stands of European beech and conifer species (Scots pine, Norway spruce, Douglas fir) in four regions in Germany. We aimed to identify compositions of pure and mixed stands in a hypothetical forest landscape that can optimize gamma diversity of vascular plants, bryophytes and lichens within regions. Results show that gamma diversity of the investigated groups is highest when a landscape comprises different pure stands rather than tree species mixtures at the stand scale. Species mainly associated with conifers rely on light regimes that are only provided in pure conifer forests, whereas mixtures of beech and conifers are more similar to beech stands. Combining pure beech and pure conifer stands at the landscape scale can increase landscape level biodiversity and conserve species assemblages of both stand types, while landscapes solely composed of stand scale tree species mixtures could lead to a biodiversity reduction of a combination of investigated groups of 7 up to 20%. Full article

(This article belongs to the Special Issue Causes and Consequences of Species Diversity in Forest Ecosystems)

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17 pages, 6948 KiB

Open AccessArticle

Forests’ First Decade: A Bibliometric Analysis Overview

by Juan Uribe-Toril, José Luis Ruiz-Real, Julia Haba-Osca and Jaime de Pablo Valenciano

Forests 2019, 10(1), 72; https://doi.org/10.3390/f10010072 - 19 Jan 2019

Cited by 28 | Viewed by 4152

Abstract

Forests is a Swiss open access journal in the field of forestry and forest ecology founded in 2010. Currently, the journal celebrates its 10th anniversary. Therefore, the purpose of this research for the special issue A Decade of Forests Open Access Publishing is [...] Read more.

Forests is a Swiss open access journal in the field of forestry and forest ecology founded in 2010. Currently, the journal celebrates its 10th anniversary. Therefore, the purpose of this research for the special issue A Decade of Forests Open Access Publishing is to present a whole bibliometric overview of the journal and highlight the state of the art of forestry as an interdisciplinary knowledge area. A bibliometric analysis of 2094 articles, reviews, editorials and corrections was conducted using two different scientific information platforms which publish indexes in online databases: Web of Science (WoS) and Scopus. The most influential countries and their relationship with funding institutions, the most leading and outstanding authors and the most significant articles published in Forests have been analyzed. A complete keyword concurrence network with a graphical visualization and a cluster analysis are adopted for identifying the main trends and opening issues to address in the coming decade, such as genetic diversity, forest productivity, resistance or resilience. This article has identified climate change, remote sensing, biomass and forest management as the main trends in forestry research during the last ten years. Full article

(This article belongs to the Special Issue A Decade of Forests Open Access Publishing)

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23 pages, 3876 KiB

Open AccessArticle

Exploring the Sensitivity of Subtropical Stand Aboveground Productivity to Local and Regional Climate Signals in South China

by Hua Zhou, Yang Luo, Guang Zhou, Jian Yu, Sher Shah, Shengwang Meng and Qijing Liu

Forests 2019, 10(1), 71; https://doi.org/10.3390/f10010071 - 18 Jan 2019

Cited by 3 | Viewed by 3060

Abstract

Subtropical forest productivity is significantly affected by both natural disturbances (local and regional climate changes) and anthropogenic activities (harvesting and planting). Monthly measures of forest aboveground productivity from natural forests (primary and secondary forests) and plantations (mixed and single-species forests) were developed to [...] Read more.

Subtropical forest productivity is significantly affected by both natural disturbances (local and regional climate changes) and anthropogenic activities (harvesting and planting). Monthly measures of forest aboveground productivity from natural forests (primary and secondary forests) and plantations (mixed and single-species forests) were developed to explore the sensitivity of subtropical mountain productivity to the fluctuating characteristics of climate change in South China, spanning the 35-year period from 1981 to 2015. Statistical analysis showed that climate regulation differed across different forest types. The monthly average maximum temperature, precipitation, and streamflow were positively correlated with primary and mixed-forest aboveground net primary productivity (ANPP) and its components: Wood productivity (WP) and canopy productivity (CP). However, the monthly average maximum temperature, precipitation, and streamflow were negatively correlated with secondary and single-species forest ANPP and its components. The number of dry days and minimum temperature were positively associated with secondary and single-species forest productivity, but inversely associated with primary and mixed forest productivity. The multivariate ENSO (EI Niño-Southern Oscillation) index (MEI), computed based on sea level pressure, surface temperature, surface air temperature, and cloudiness over the tropical Pacific Ocean, was significantly correlated with local monthly maximum and minimum temperatures (Tmax and Tmin), precipitation (PRE), streamflow (FLO), and the number of dry days (DD), as well as the monthly means of primary and mixed forest aboveground productivity. In particular, the mean maximum temperature increased by 2.5, 0.9, 6.5, and 0.9 °C, and the total forest aboveground productivity decreased by an average of 5.7%, 3.0%, 2.4%, and 7.8% in response to the increased extreme high temperatures and drought events during the 1986/1988, 1997/1998, 2006/2007, and 2009/2010 EI Niño periods, respectively. Subsequently, the total aboveground productivity values increased by an average of 1.1%, 3.0%, 0.3%, and 8.6% because of lagged effects after the wet La Niña periods. The main conclusions of this study demonstrated that the influence of local and regional climatic fluctuations on subtropical forest productivity significantly differed across different forests, and community position and plant diversity differences among different forest types may prevent the uniform response of subtropical mountain aboveground productivity to regional climate anomalies. Therefore, these findings may be useful for forecasting climate-induced variation in forest aboveground productivity as well as for selecting tree species for planting in reforestation practices. Full article

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

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31 pages, 12914 KiB

Open AccessArticle

A Nonlinear Mixed-Effects Height-to-Diameter Ratio Model for Several Tree Species Based on Czech National Forest Inventory Data

by Ram P. Sharma, Zdeněk Vacek, Stanislav Vacek and Miloš Kučera

Forests 2019, 10(1), 70; https://doi.org/10.3390/f10010070 - 17 Jan 2019

Cited by 35 | Viewed by 9235

Abstract

Height-to-diameter at breast height (DBH) ratio (HDR) is an important tree and stand stability measure. Several factors such as stand dynamics, natural and anthropogenic disturbances, and silvicultural tending significantly affect HDR, and, therefore, in-depth investigation of HDR is essential for better understanding of [...] Read more.

Height-to-diameter at breast height (DBH) ratio (HDR) is an important tree and stand stability measure. Several factors such as stand dynamics, natural and anthropogenic disturbances, and silvicultural tending significantly affect HDR, and, therefore, in-depth investigation of HDR is essential for better understanding of ecological processes in a forest. A nonlinear mixed-effects HDR model applicable to several tree species was developed using the Czech national forest inventory data comprising 13,875 sample plots and 348,980 trees. The predictive performance of this model was evaluated using the independent dataset which was originated from 25,146 trees on 220 research sample plots. Among various tree- and stand-level variables describing tree size, site quality, stand development stage, stand density, inter-tree spacing, and competition evaluated, dominant height (HDOM), dominant diameter (DDOM), relative spacing index (RS), and DBH-to-quadratic mean DBH ratio (dq) were identified as the most important predictors of HDR variations. A random component describing sample plot-specific HDR variations was included through mixed-effects modelling, and dummy variables describing species-specific HDR variations and canopy layer-specific HDR variations were also included into the HDR model through dummy variable modelling. The mixed-effects HDR model explained 79% of HDR variations without any significant trends in the residuals. Simulation results showed that HDR for each canopy layer increased with increasing site quality and stand development stage (increased HDOM) and increasing competition (increased RS, decreased DDOM and dq). Testing the HDR model on the independent data revealed that more than 85% of HDR variations were described for each individual species (Norway spruce, Scots pine, European larch, and European beech) and group of species (fir species, oak species, birch and alder species) without significant trends in the prediction errors. The HDR can be predicted with a higher accuracy using the calibrated mixed-effects HDR model from measurements of its predictors that can be obtained from routine forest inventories. To improve the prediction accuracy, a model needs to be calibrated with the random effects estimated using one to four randomly selected trees of a particular species or group of species depending on the availability of their numbers per sample plot. The HDR model can be applied for stand stability assessment and stand density regulation. The HDR information is also useful for designing a stand density management diagram. Brief implications of the HDR model for designing silviculture strategies and forest management planning are presented in the article. Full article

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

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12 pages, 898 KiB

Open AccessArticle

Logging Contractors’ Growth in the Southern Cone: An Analysis of Contractor Business Strategies, Innovation, and Mechanization

by Patricio Mac Donagh, Santiago José Elías Velazco, Guido F. Botta, Tomas Schlichter and Frederick Cubbage

Forests 2019, 10(1), 69; https://doi.org/10.3390/f10010069 - 16 Jan 2019

Cited by 4 | Viewed by 3282

Abstract

Forest plantations have increased in South America for several decades. Harvesting is performed mainly through contractor companies. Our hypothesis is that logging contractors that innovate, grow more than others. We analyzed logging contractors through production and innovation, working in Argentina (22), Brazil (35) [...] Read more.

Forest plantations have increased in South America for several decades. Harvesting is performed mainly through contractor companies. Our hypothesis is that logging contractors that innovate, grow more than others. We analyzed logging contractors through production and innovation, working in Argentina (22), Brazil (35) and Uruguay (10), through surveys between 2008 and 2012. Factors that affected firm growth were analyzed with linear mixed effect models. In all three countries there was a preponderance of logging contractors with cellulose companies. Our results show that logging firms that had mutualistic supply chain relations with the contracting organizations had better production indicators and lower cost per ton than other independent harvesting contractors. In the last 10 years, mechanization increased significantly, reducing the number of employees. Innovation was the most significant variable in enhanced logging production. For the period from 10 to 5 years before the survey period, the number of employees and type of contracting company were most significant on loggers’ growth. During the last 5-year period before the survey period, the number of employees and innovation were significant. Thus, during the last 10 years, logging companies shifted from growth based on type of the firm to the amount of innovation by firms, and contracting companies. Full article

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

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22 pages, 2370 KiB

Open AccessArticle

Input-Output Budgets of Nutrients in Adjacent Norway Spruce and European Beech Monocultures Recovering from Acidification

by Michal Růžek, Oldřich Myška, Jiří Kučera and Filip Oulehle

Forests 2019, 10(1), 68; https://doi.org/10.3390/f10010068 - 16 Jan 2019

Cited by 7 | Viewed by 3627

Abstract

Soil acidification has constituted an important ecological threat to forests in Central Europe since the 1950s. In areas that are sensitive to acid pollution, where the soil buffering capacity is naturally low, tree species can significantly modulate the extent of soil acidification by [...] Read more.

Soil acidification has constituted an important ecological threat to forests in Central Europe since the 1950s. In areas that are sensitive to acid pollution, where the soil buffering capacity is naturally low, tree species can significantly modulate the extent of soil acidification by affecting throughfall deposition and the composition of litter. A principal difference can be expected between coniferous and broadleaf tree species. The aim of our study was to compare long-term trends in element cycling in two stands representing the main types of forest ecosystem in the region (Picea abies vs. Fagus sylvatica). In the period of 2005–2017, we continually measured element concentrations and fluxes in bulk precipitation, throughfall precipitation, and soil leachates. A continuous decline of acid deposition was detected in both bulk precipitation and throughfall. Declining deposition of S and N in both forests has led to the recovery of soil solution chemistry in the mineral soil, manifested by rising pH from 4.25 to 4.47 under spruce and from 4.42 to 4.69 in the beech stand. However, soil water in the spruce stand was more acidic, with higher concentrations of SO₄²⁻ and Al when compared to the beech stand. While the acidity of soil leachates from organic horizons was driven mainly by organic anions, in lower mineral horizons it was controlled by inorganic acid anions. NO₃⁻ concentrations in deeper horizons of the spruce stand have diminished since 2006; however, in the beech plot, episodically elevated NO₃⁻ concentrations in mineral horizons are a sign of seasonal processes and of nearby perturbations. Higher output of S when compared to the input of the same element indicates slow S resorption, delaying the recovery of soil chemistry. Our results indicate that, although forest ecosystems are recovering from acidification, soil S retention and the ability to immobilize N is affected by the dominant tree species. Full article

(This article belongs to the Special Issue Effects of Climate Change and Air Pollutants on Forest Tree Species)

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14 pages, 2003 KiB

Open AccessArticle

Dry Season Irrigation Promotes Leaf Growth in Eucalyptus urophylla × E. grandis under Fertilization

by Fei Yu, Thuy Van Truong, Qian He, Lei Hua, Yan Su and Jiyue Li

Forests 2019, 10(1), 67; https://doi.org/10.3390/f10010067 - 15 Jan 2019

Cited by 10 | Viewed by 3326

Abstract

Leaves are essential for photosynthesis and gas exchange, and their growth characteristics are the key factors that influence the carbon budget. Eucalyptus is widely afforested in south China due to its fast-growing and high-yield features. Water and fertilizer are the main factors affecting [...] Read more.

Leaves are essential for photosynthesis and gas exchange, and their growth characteristics are the key factors that influence the carbon budget. Eucalyptus is widely afforested in south China due to its fast-growing and high-yield features. Water and fertilizer are the main factors affecting plant growth. Studying the effects of different water and fertilizer treatments on the growth of Eucalyptus leaves under seasonal drought could further elucidate the optimal additions for Eucalyptus productivity. In this study, we investigated the leaf area, length, width, perimeter, and expansion rates of the commercial species E. urophylla × E. grandis under different treatments of dry season irrigation and fertilizer application to elucidate the growth dynamics of the leaves. The results indicated that both dry season irrigation and fertilizer could affect whole leaf expansion. Leaf area was largest when water and fertilizer were added at the same time. In this experiment, we found that fertilization had a significant effect on the leaf shape index of the Eucalyptus leaves. The leaf shape index was larger with the fertilizer treatment, which made the leaves slender. Dry season irrigation shorten the peak period of leaf growth and increase the leaf area. Our results help to further understand the mechanism of Eucalyptus productivity under seasonal drought and provide theoretical support for Eucalyptus production. Full article

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

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13 pages, 1721 KiB

Open AccessReview

Excess Nitrogen in Temperate Forest Ecosystems Decreases Herbaceous Layer Diversity and Shifts Control from Soil to Canopy Structure

by Frank S. Gilliam

Forests 2019, 10(1), 66; https://doi.org/10.3390/f10010066 - 15 Jan 2019

Cited by 20 | Viewed by 3568

Abstract

Research Highlights: Excess N from atmospheric deposition has been shown to decrease plant biodiversity of impacted forests, especially in its effects on herbaceous layer communities. This work demonstrates that one of the mechanisms of such response is in N-mediated changes in the response [...] Read more.

Research Highlights: Excess N from atmospheric deposition has been shown to decrease plant biodiversity of impacted forests, especially in its effects on herbaceous layer communities. This work demonstrates that one of the mechanisms of such response is in N-mediated changes in the response of herb communities to soil resources and light availability. Background and Objectives: Numerous studies in a variety of forest types have shown that excess N can cause loss of biodiversity of herb layer communities, which are typically responsive to spatial patterns of soil resource and light availability. The objectives of this study were to examine (1) gradients of temporal change in herb composition over a quarter century, and (2) spatial patterns of herb cover and diversity and how they are influenced by soil resources and canopy structure. Materials and Methods: This study used two watersheds (WS) at the Fernow Experimental Forest, West Virginia, USA: WS4 as an untreated reference and WS3 as treatment, receiving 35 kg N/ha/yr via aerial application. Herb cover and composition was measured in seven permanent plots/WS from 1991 to 2014. In 2011, soil moisture and several metrics of soil N availability were measured in each plot, along with measurement of several canopy structural variables. Backwards stepwise regression was used to determine relationships between herb cover/diversity and soil/canopy measurements. Results: Herb diversity and composition varied only slightly over time on reference WS4, in contrast to substantial change on N-treated WS3. Herb layer diversity appeared to respond to neither soil nor canopy variables on either watershed. Herb cover varied spatially with soil resources on WS4, whereas cover varied spatially with canopy structure on WS3. Conclusions: Results support work in many forest types that excess N can decrease plant diversity in impacted stands. Much of this response is likely related to N-mediated changes in the response of the herb layer to soil N and light availability. Full article

(This article belongs to the Special Issue Causes and Consequences of Species Diversity in Forest Ecosystems)

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29 pages, 4249 KiB

Open AccessArticle

Effects of Fertilization Ratios and Frequencies on the Growth and Nutrient Uptake of Magnolia wufengensis (Magnoliaceae)

by Shixin Deng, Kankan Shi, Jiang Ma, Lili Zhang, Luyi Ma and Zhongkui Jia

Forests 2019, 10(1), 65; https://doi.org/10.3390/f10010065 - 15 Jan 2019

Cited by 16 | Viewed by 4409

Abstract

Through this study, the most suitable fertilization ratio, amount and frequency were determined, providing a scientific reference for further fertilization management for Magnolia wufengensis (Magnoliaceae) seedlings. Fertilization is an important cultivation and management measure to maintain forest seedling health and rapid growth. However, [...] Read more.

Through this study, the most suitable fertilization ratio, amount and frequency were determined, providing a scientific reference for further fertilization management for Magnolia wufengensis (Magnoliaceae) seedlings. Fertilization is an important cultivation and management measure to maintain forest seedling health and rapid growth. However, improper fertilization can also have unexpected effects: inhibiting seedling growth, increasing the cost of production and contaminating the environment. Thus, to explore the most suitable fertilization treatment for Magnolia wufengensis growth, one-year-old Magnolia wufengensis seedlings and the orthogonal design method were used in this study. Three different fertilization frequencies were used combined with 9 NPK ratios. The growth index, chlorophyll content, nutrient content in tissues, nutrient transport efficiency, nutrient uptake, and soil properties were analyzed. Fertilization can increase chlorophyll content, promoting the vegetative growth and biomass accumulation of Magnolia wufengensis. Fertilization reduced the proportion of root biomass to whole plant biomass, resulting in an increase in stem biomass with little effect on leaf biomass. Additionally, fertilization also increased the proportion of N in roots, P in stems and K in leaves. Under fertilization, the K transport efficiency was higher than that of N and P. Furthermore, there was a positive correlation between the nutrient use efficiencies of N and K. Overall, the effects of six fertilizer applications were much better than those of four and eight fertilizer applications on the promotion of vegetative growth, biomass and nutrient accumulation, nutrient uptake and transport efficiency. The results showed that six fertilizer applications with an NPK ratio of 3:2:1 as follows: N application at 480 mg/plant, P application at 320 mg/plant, and K application at 160 mg/plant was the most suitable fertilization method for plant growth. Full article

(This article belongs to the Special Issue Forest Stand Management and Biomass Growth)

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7 pages, 2304 KiB

Open AccessArticle

Nondestructive Near-Infrared Spectroscopic Analysis of Oils on Wood Surfaces

by Noboru Ito, Naoya Okubo and Yohei Kurata

Forests 2019, 10(1), 64; https://doi.org/10.3390/f10010064 - 15 Jan 2019

Cited by 5 | Viewed by 3350

Abstract

The further use of wood resources is expected in an environmentally conscious society. Added-value, such as durability enhancement and preservation by painting, are needed to expand the applicability of wood. Assessment of wood properties such as surface and coat adhesion can be made [...] Read more.

The further use of wood resources is expected in an environmentally conscious society. Added-value, such as durability enhancement and preservation by painting, are needed to expand the applicability of wood. Assessment of wood properties such as surface and coat adhesion can be made by studying perviousness to liquid oils, with the aim of developing wood products that deter insects and are weather-resistant; hence, discriminant analysis of oil type is important. Near-infrared (NIR) spectroscopy is a powerful tool for nondestructive characterization of organic materials and has been widely used in many industries. Here, NIR detection of oil on wood surfaces is applied for the distinguishing of three different types of oil (hereafter, “Oil_1”, “Oil_2” and “Oil_3”) via soft independent modeling of class analogy (SIMCA). Oil_1 was antiseptic vehicle or cutting oil. Oil_2 was used as a motor oil for an oil pressure machine. Oil_3 was plant-derived oil. Two types of wood that are commonly used in Japanese construction (Cryptomeria japonica and Chamaecyparis obtuse) were analyzed after applying oil. The NIR spectra measured after the oil was applied were greater in the ranges 1700–1800 nm and 2300–2500 nm than spectra for the bare wood sample. As SIMCA analyses were performed by using spectral data that included the moving average, baseline correction and second derivatives, good results were obtained for Oil_3 for both wood samples. However, the correct classification percentages were low for Oil_1, and the percentage of samples classified within several categories was high. If the components are very different, such as those for Oil_3, NIRS can be a powerful non-destructive method for identifying oil in the context of wood products testing. Full article

(This article belongs to the Special Issue Wood Productions and Renewable Materials)

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16 pages, 753 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Forests in 2018

by Forests Editorial Office

Forests 2019, 10(1), 63; https://doi.org/10.3390/f10010063 - 14 Jan 2019

Viewed by 3106

Abstract

Rigorous peer-review is the corner-stone of high-quality academic publishing [...] Full article

15 pages, 2681 KiB

Open AccessArticle

Modeling the Effect of Climate Change on the Potential Distribution of Qinghai Spruce (Picea crassifolia Kom.) in Qilian Mountains

by Zhanlei Rong, Chuanyan Zhao, Junjie Liu, Yunfei Gao, Fei Zang, Zhaoxia Guo, Yahua Mao and Ling Wang

Forests 2019, 10(1), 62; https://doi.org/10.3390/f10010062 - 14 Jan 2019

Cited by 54 | Viewed by 4303

Abstract

Qinghai spruce forests play a key role in water conservation in the dry region of northwest China. So, it is necessary to understand the impacts of climate change on the species to implement adaptation strategies. Based on the four-emission scenario (i.e., RCP2.6 (Representative [...] Read more.

Qinghai spruce forests play a key role in water conservation in the dry region of northwest China. So, it is necessary to understand the impacts of climate change on the species to implement adaptation strategies. Based on the four-emission scenario (i.e., RCP2.6 (Representative Concentration Pathway), RCP4.5, RCP6.0 and RCP8.5) set by the Intergovernmental Panel on Climate Change (IPCC) fifth assessment report, in the study, we predicted the potential distribution of Qinghai spruce (Picea crassifolia Kom.) under current and future scenarios using a maximum entropy (Maxent) model. Seven variables, selected from 22 variables according to correlation analysis combining with their contribution rates to the distribution, are used to simulate the potential distribution of the species under current and future scenarios. Simulated results are validated by area under the operating characteristic curve (AUC). Results demonstrate that elevation, mean temperature of wettest quarter, annual mean temperature, and mean diurnal range are more important in dominating the potential distribution of Qinghai spruce. Ratios of the suitable area to the total study area are 34.3% in current climate condition, 34% in RCP2.6, 33.9% in RCP4.5, 33.8% in RCP6.0, and 30.5% in RCP8.5, respectively. The warmer the climate condition is, the more area of higher suitable classification is changed to that of lower suitable classification. The ratios of real distribution area in simulated unsuitable class to the real distribution area change from 4.3% (60.7 km²) in the current climate to 13% (185 km²) in RCP8.5, suggesting that the real distribution area may decrease in the future. We conclude that there is a negative effect of climate change on the distribution of Qinghai spruce forest. The result can help decision-makers to draft adaptation countermeasures based on climate change. Full article

(This article belongs to the Special Issue Influence of Climate Change on Tree Growth and Forest Ecosystems)

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22 pages, 11528 KiB

Open AccessArticle

Illegal Selective Logging and Forest Fires in the Northern Brazilian Amazon

by Tiago M. Condé, Niro Higuchi and Adriano J. N. Lima

Forests 2019, 10(1), 61; https://doi.org/10.3390/f10010061 - 14 Jan 2019

Cited by 23 | Viewed by 8201

Abstract

Illegal selective logging and forest fires occur on a large scale in the northern Brazilian Amazon, contributing to an increase in tree mortality and a reduction in forest carbon stock. A total of 120 plots of 0.25 ha (30 ha) were installed in [...] Read more.

Illegal selective logging and forest fires occur on a large scale in the northern Brazilian Amazon, contributing to an increase in tree mortality and a reduction in forest carbon stock. A total of 120 plots of 0.25 ha (30 ha) were installed in transitional ecosystems or ecotones (LOt) between the forested shade-loving campinarana (Ld) and dense-canopy rainforest, submontane (Ds), in the National Forest (Flona) of Anauá, southern Roraima. Measuring the diameters at breast height (DBH ≥ 10 cm) and the heights of 171 dead trees (fallen naturally, illegally exploited, and affected by forest fires), enabled the estimation of carbon content from the application of a biomass equation developed at Manaus, and the calculation of a correction factor, using the average height of the largest trees. From 2015–2017, we mapped the real extent of illegal selective logging and forest fires across the region with CLASlite and INPE/Queimadas. From measurements of 14,730 live and dead trees across 30 hectares (491 ± 15 trees·ha⁻¹), the illegal selective logging and associated forest fires, and aggravation by severe El Niño droughts resulted in an 8.2% mortality of trees (40 ± 9 dead trees·ha⁻¹) and a 3.5% reduction in forest carbon stock (6 ± 3 Mg·ha⁻¹) in the short-term. The surface area or influence of forest fires of very high density were estimated in the south-central region of Roraima (8374 km²) and the eastern region of the Flona Anauá (37 km²). Illegal selective logging and forest fires in forest areas totaled 357 km² in the mosaic area, and 6 km² within Flona Anaua. Illegal selective logging and forest fires in the years of severe El Niño droughts threatened the maintenance of environmental services provided by Amazonian forests. Full article

(This article belongs to the Special Issue Application of Remote Sensing on Fire Ecology)

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21 pages, 4414 KiB

Open AccessArticle

Validation and Application of European Beech Phenological Metrics Derived from MODIS Data along an Altitudinal Gradient

by Veronika Lukasová, Tomáš Bucha, Jana Škvareninová and Jaroslav Škvarenina

Forests 2019, 10(1), 60; https://doi.org/10.3390/f10010060 - 14 Jan 2019

Cited by 20 | Viewed by 3869

Abstract

Monitoring plant phenology is one of the means of detecting the response of vegetation to changing environmental conditions. One approach for the study of vegetation phenology from local to global scales is to apply satellite-based indices. We investigated the potential of phenological metrics [...] Read more.

Monitoring plant phenology is one of the means of detecting the response of vegetation to changing environmental conditions. One approach for the study of vegetation phenology from local to global scales is to apply satellite-based indices. We investigated the potential of phenological metrics from moderate resolution remotely sensed data to monitor the altitudinal variations in phenological phases of European beech (Fagus sylvatica L.). Phenological metrics were derived from the NDVI annual trajectories fitted with double sigmoid logistic function. Validation of the satellite-derived phenological metrics was necessary, thus the multiple-year ground observations of phenological phases from twelve beech stands along the altitudinal gradient were employed. In five stands, the validation process was supported with annual (in 2011) phenological observations of the undergrowth and understory vegetation, measurements of the leaf area index (LAI), and with laboratory spectral analyses of forest components reflecting the red and near-infrared radiation. Non-significant differences between the satellite-derived phenological metrics and the in situ observed phenological phases of the beginning of leaf onset (LO_10); end of leaf onset (LO_100); and 80% leaf coloring (LC_80) were detected. Next, the altitude dependent variations of the phenological metrics were investigated in all beech-dominated pixels over the area between latitudes 47°44′ N and 49°37′ N, and longitudes 16°50′ E and 22°34′ E (Slovakia, Central Europe). In all cases, this large-scale regression revealed non-linear relationships. Since spring phenological metrics showed strong dependence on altitude, only a weak relationship was detected between autumn phenological metric and altitude. The effect of altitude was evaluated through differences in local climatic conditions, especially temperature and precipitation. We used normal values from the last 30 years to evaluate the altitude-conditioned differences in the growing season length in 12 study stands. The approach presented in this paper contributes to a more explicit understanding of satellite data-based beech phenology along the altitudinal gradient, and will be useful for determining the optimal distribution range of European beech under changing climate conditions. Full article

(This article belongs to the Special Issue Remote Sensing of Leaf Area Index (LAI) and Other Vegetation Parameters)

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12 pages, 3512 KiB

Open AccessArticle

Changes in the Profiles of Yield, Yield Component, Oil Content, and Citral Content in Litsea cubeba (Lour.) Persoon Following Foliar Fertilization with Zinc and Boron

by Ming Gao, Yicun Chen, Liwen Wu and Yangdong Wang

Forests 2019, 10(1), 59; https://doi.org/10.3390/f10010059 - 13 Jan 2019

Cited by 10 | Viewed by 3457

Abstract

Mountain pepper (Litsea cubeba (Lour.) Persoon) is an important oil plant used as an ingredient in edible oil, cooking condiments, cosmetics, pesticides, and potential biofuels. Zinc and boron are essential micronutrients for plant growth. However, the effects of zinc and boron on [...] Read more.

Mountain pepper (Litsea cubeba (Lour.) Persoon) is an important oil plant used as an ingredient in edible oil, cooking condiments, cosmetics, pesticides, and potential biofuels. Zinc and boron are essential micronutrients for plant growth. However, the effects of zinc and boron on the yield, yield component, oil content, and citral content in L. cubeba have not been determined. This study was conducted to evaluate the efficacy of the foliar application of zinc, boron, and multiple micronutrients (zinc + boron) on the yield, yield component, oil content, and citral content of three varieties (Fuyang 1 (FY1), Jianou 2 (JO2), and Jianou 3 (JO3)) of L. cubeba. Zinc sulfate (0.25%), boric acid (0.25%), and zinc sulfate (0.25%) + boric acid (0.25%) were sprayed on selected trees at five different times at full bloom and 28 days before harvest, once every seven days. The results indicated that Zn had a negative effect on the yield, yield component, oil content, and citral content of the FY1, JO2, and JO3 varieties compared to the untreated trees. B had positive effects on the yield, yield component, oil content, and citral content of the JO2 and JO3 varieties but not on those of the FY1 variety when compared to the untreated trees. The highest levels of yield, yield component, oil content, and citral content for all three varieties were obtained with the combined application of zinc sulfate + boric acid. Hence, the foliar application of multiple micronutrients (zinc + boron) is an effective method to improve the yield, oil content, and citral content in L. cubeba. In addition, the 100-fruit weight (HFW) was positively correlated with the yield, oil content, and citral content and could be used as a tool to select new cultivars with high yield, high oil content, and high citral content under zinc sulfate, boric acid, and zinc sulfate + boric acid applications in L. cubeba. Full article

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

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23 pages, 6200 KiB

Open AccessArticle

Associations between Road Density, Urban Forest Landscapes, and Structural-Taxonomic Attributes in Northeastern China: Decoupling and Implications

by Yanbo Yang, Hailiang Lv, Yujie Fu, Xingyuan He and Wenjie Wang

Forests 2019, 10(1), 58; https://doi.org/10.3390/f10010058 - 12 Jan 2019

Cited by 21 | Viewed by 4078

Abstract

A better understanding on the associations between road density (RD), urban forest structural-taxonomic attributes, and landscape metrics is vital for forest ecological service evaluations and suitable management in sprawling urban areas with increasing road networks. We chose Harbin, a fast growing provincial capital [...] Read more.

A better understanding on the associations between road density (RD), urban forest structural-taxonomic attributes, and landscape metrics is vital for forest ecological service evaluations and suitable management in sprawling urban areas with increasing road networks. We chose Harbin, a fast growing provincial capital city in northeast China, as a case study to address this issue. We utilized ArcGIS software (Esri, version 10.0; Redlands, CA, USA) and FRAGSTATS (V4.2.589) to digitize GF-1 images (Gaofen No.1 remote sensing images) to acquire road net characteristic information and landscape metrics of urban forests in Harbin. Together with forest structural-taxonomic attributes from a stratified random sampling survey, statistical methods such as an analysis of variance, a regression analysis, and a redundancy analysis were used to determine the road-dependent differences and to decouple the associations between them. The results indicated that road area percentages, road length/imperious surface area (ISA) ratios, road area/ISA ratios, and road cross-points sharply increased from low to heavy RD areas. This road intensification was strongly associated with increased urban forest area, patch density, and diverse patch shapes; smaller tree sizes, lower tree densities, and diverse tree species compositions were generally observed. Redundancy-based variation partitioning showed that part of the variations in structural-taxonomic attributes of forests could be explained by road intensity characteristics. In low RD (0–1.5 km/km²) regions, the road characteristics significantly affected forest characteristics (Shannon Wiener diversity index, species richness, and evenness index); however, such associations weakened with increasing forest landscape-related associations in medium to heavy RD (1.5–6 km/km²) regions. Our findings highlighted that road development is strongly associated with forest characteristics in Harbin city, and RD-dependent forest landscape regulating management could favor the maximization of forest ecological services that are related to structural and species identities. Full article

(This article belongs to the Special Issue New Technical Advances: Explore Forest Landscape Ecology and Biodiversity Using Geographic Information Science)

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19 pages, 4258 KiB

Open AccessArticle

Genetic Variation of Growth Traits and Genotype-by-Environment Interactions in Clones of Catalpa bungei and Catalpa fargesii f. duclouxii

by Yao Xiao, Wenjun Ma, Nan Lu, Zhi Wang, Nan Wang, Wenji Zhai, Lisheng Kong, Guanzheng Qu, Qiuxia Wang and Junhui Wang

Forests 2019, 10(1), 57; https://doi.org/10.3390/f10010057 - 12 Jan 2019

Cited by 23 | Viewed by 3745

Abstract

Clones of Catalpa bungei and Catalpa fargesii f. duclouxii were studied over several years in central China to explore genetic variation in growth traits and to identify clones of high wood yield and high stability. The genetic parameters for height, diameter at breast [...] Read more.

Clones of Catalpa bungei and Catalpa fargesii f. duclouxii were studied over several years in central China to explore genetic variation in growth traits and to identify clones of high wood yield and high stability. The genetic parameters for height, diameter at breast height (DBH), and stem volume of clones, were estimated. The effect of clone × year on the increment of stem volume in the two species was analyzed by genotype and genotype × environment (GGE) biplot methods. Significant differences in growth traits among clones and between species were found. The growth of C. bungei exceeded that of C. fargesii f. duclouxii after 4 years. Furthermore, from the 5th year, the repeatability and genetic variation coefficient (GCV) of the C. bungei clones were higher than those of the C. fargesii f. duclouxii clones in most cases. The phenotypic variation coefficient (PCV) of the C. fargesii f. duclouxii clones was significantly lower than that of the C. bungei clones. The repeatability of stem volume was intermediate or high in the two species. ANOVA revealed significant effects of the clone by year interaction in these two species. GGE biplot analysis revealed that wood yield and stability were largely independent in C. bungei; clones 22-03, 19-27, and 20-01 were the optimal clones in this species. In contrast, the optimal clones 63 and 128 of C. fargesii f. duclouxii combined the desired characteristics of high yield and high stability. In conclusion, our results indicated that the height and stem volume of C. bungei was under strong genetic control, whereas that of C. fargesii f. duclouxii was influenced by the environment more than by genetic effects. Genetic improvement by clone selection can be expected to be effective, as the repeatability of stem volume was high. Francis and Kannenberg’s method and GGE biplot analysis were used in combination to evaluate the clones. C. bungei clone 22-03 and C. fargesii f. duclouxii clones 63 and 128 were identified as the optimal clones, which exhibited both a high increment of stem volume and high stability. Full article

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

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13 pages, 5399 KiB

Open AccessArticle

DNA Barcoding Analysis and Phylogenetic Relation of Mangroves in Guangdong Province, China

by Feng Wu, Mei Li, Baowen Liao, Xin Shi and Yong Xu

Forests 2019, 10(1), 56; https://doi.org/10.3390/f10010056 - 12 Jan 2019

Cited by 19 | Viewed by 5317

Abstract

Mangroves are distributed in the transition zone between sea and land, mostly in tropical and subtropical areas. They provide important ecosystem services and are therefore economically valuable. DNA barcoding is a useful tool for species identification and phylogenetic reconstruction. To evaluate the effectiveness [...] Read more.

Mangroves are distributed in the transition zone between sea and land, mostly in tropical and subtropical areas. They provide important ecosystem services and are therefore economically valuable. DNA barcoding is a useful tool for species identification and phylogenetic reconstruction. To evaluate the effectiveness of DNA barcoding in identifying mangrove species, we sampled 135 individuals representing 23 species, 22 genera, and 17 families from Zhanjiang, Shenzhen, Huizhou, and Shantou in the Guangdong province, China. We tested the universality of four DNA barcodes, namely rbcL, matK, trnH-psbA, and the internal transcribed spacer of nuclear ribosomal DNA (ITS), and examined their efficacy for species identification and the phylogenetic reconstruction of mangroves. The success rates for PCR amplification of rbcL, matK, trnH-psbA, and ITS were 100%, 80.29% ± 8.48%, 99.38% ± 1.25%, and 97.18% ± 3.25%, respectively, and the rates of DNA sequencing were 100%, 75.04% ± 6.26%, 94.57% ± 5.06%, and 83.35% ± 4.05%, respectively. These results suggest that both rbcL and trnH–psbA are universal in mangrove species from the Guangdong province. The highest success rate for species identification was 84.48% ± 12.09% with trnH-psbA, followed by rbcL (82.16% ± 9.68%), ITS (66.48% ± 5.97%), and matK (65.09% ± 6.00%), which increased to 91.25% ± 9.78% with the addition of rbcL. Additionally, the identification rate of mangroves was not significantly different between rbcL + trnH-psbA and other random fragment combinations. In conclusion, rbcL and trnH-psbA were the most suitable DNA barcode fragments for species identification in mangrove plants. When the phylogenetic relationships were constructed with random fragment combinations, the optimal evolutionary tree with high supporting values (86.33% ± 4.16%) was established using the combination of matK + rbcL + trnH-psbA + ITS in mangroves. In total, the 476 newly acquired sequences in this study lay the foundation for a DNA barcode database of mangroves. Full article

(This article belongs to the Special Issue Genetic and Morphological Variation in Tropical and Temperate Plant Species)

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15 pages, 4521 KiB

Open AccessArticle

Low Water Availability Increases Necrosis in Picea abies after Artificial Inoculation with Fungal Root Rot Pathogens Heterobasidion parviporum and Heterobasidion annosum

by Eeva Terhonen, Gitta Jutta Langer, Johanna Bußkamp, David Robert Rӑscuţoi and Kathrin Blumenstein

Forests 2019, 10(1), 55; https://doi.org/10.3390/f10010055 - 12 Jan 2019

Cited by 17 | Viewed by 7037

Abstract

Research Highlights: Dedicated experiments to investigate how disturbances will affect Heterobasidion sp.—Norway spruce pathosystems are important, in order to develop different strategies to limit the spread of Heterobasidion annosum s.l. under the predicted climate change. Here, we report on a greenhouse experiment to [...] Read more.

Research Highlights: Dedicated experiments to investigate how disturbances will affect Heterobasidion sp.—Norway spruce pathosystems are important, in order to develop different strategies to limit the spread of Heterobasidion annosum s.l. under the predicted climate change. Here, we report on a greenhouse experiment to evaluate the effects of water availability on the infection severity of Heterobasidion parviporum or Heterobasidion annosum, respectively, on Picea abies saplings. Background and Objectives: Changes in climatic conditions and intense logging will continue to promote H. annosum s.l. in conifer forests, increasing annual economic losses. Thus, our aim was to test if disease severity in Norway spruce was greater after infection with H. parviporum or H. annosum in low water availability conditions, compared to seedlings with high water availability. Materials and Methods: We performed inoculation studies of three-year-old saplings in a greenhouse. Saplings were treated as high (+) or low (−) water groups: High water group received double the water amount than the low water group. The necrosis observed after pathogen inoculation was measured and analyzed. Results: The seedling growth was negatively influenced in the lower water group. In addition, the water availability enhanced the necrosis length of H. parviporum in phloem and sapwood (vertical length) in the low water group. H. annosum benefited only in horizontal length in the phloem. Conclusions: Disturbances related to water availability, especially low water conditions, can have negative effects on the tree host and benefit the infection ability of the pathogens in the host. Full article

(This article belongs to the Special Issue Physiological Responses to Abiotic and Biotic Stress in Forest Trees)

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21 pages, 2723 KiB

Open AccessArticle

Growth and Needle Properties of Young Pinus koraiensis Sieb. et Zucc. Trees across an Elevational Gradient

by Ying Fan, W. Keith Moser and Yanxia Cheng

Forests 2019, 10(1), 54; https://doi.org/10.3390/f10010054 - 11 Jan 2019

Cited by 7 | Viewed by 4226

Abstract

A better understanding of the response of plant growth to elevational gradients may shed light on how plants respond to environmental variation and on the physiological mechanisms underlying these responses. This study analyzed whole plant growth and physiological and morphological properties of needles [...] Read more.

A better understanding of the response of plant growth to elevational gradients may shed light on how plants respond to environmental variation and on the physiological mechanisms underlying these responses. This study analyzed whole plant growth and physiological and morphological properties of needles in young Pinus koraiensis Sieb. et Zucc. trees at thirteen points along an elevational gradient ranging from 750 to 1350 m above sea level (a.s.l.) at the end of a growing season on Changbai Mountain in northeastern China. Sampling and analyses indicated the following; (1) many needle properties of P. koraiensis varied with forest type along the elevational gradient though some needle properties (e.g., intrinsic water use efficiency, concentration of chlorophyll, and leaf mass per area) did not change with elevation and forest types; (2) growth was significantly influenced by both forest type and elevation and growth of saplings in P. koraiensis and mixed broadleaved forests was greater than that in evergreen forests and increased with elevation in both forest types; (3) in P. koraiensis and mixed broadleaved forests, there were significant correlations between growth properties and light saturation point, leaf water potential, mean within-crown humidity, annual precipitation, cumulative temperature (≥5

^{\circ}

C), within-crown air temperature, and atmospheric pressure; while in evergreen forests, the leaf C, leaf P content, net rate of light saturation in photosynthesis, water content of soil, within-crown humidity, annual precipitation, cumulative temperature (≥5

^{\circ}

C), within-crown air temperature, and total soil P content displayed a significant relationship with plant growth. These results may help illuminate how P. koraiensis responds to environmental variation and evaluate the adaptive potential of Pinus koraiensis to climate change. Data presented here could also contribute to the more accurate estimation of carbon stocks in this area and to refinement of a plant trait database. Full article

(This article belongs to the Special Issue Physiological Responses to Abiotic and Biotic Stress in Forest Trees)

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14 pages, 3236 KiB

Open AccessArticle

Effects of Topography on Tree Community Structure in a Deciduous Broad-Leaved Forest in North-Central China

by Hang Shi, Fenglin Xie, Quan Zhou, Xiao Shu, Kerong Zhang, Chaoqi Dang, Shuiyuan Feng, Quanfa Zhang and Haishan Dang

Forests 2019, 10(1), 53; https://doi.org/10.3390/f10010053 - 11 Jan 2019

Cited by 14 | Viewed by 4509

Abstract

Topography strongly influences the compositional structure of tree communities and plays a fundamental role in classifying habitats. Here, data of topography and 16 dominant tree species abundance were collected in a fully mapped 25-ha forest plot in the Qinling Mountains of north-central China. [...] Read more.

Topography strongly influences the compositional structure of tree communities and plays a fundamental role in classifying habitats. Here, data of topography and 16 dominant tree species abundance were collected in a fully mapped 25-ha forest plot in the Qinling Mountains of north-central China. Multivariate regression trees (MRT) were used to categorize the habitats, and habitat associations were examined using the torus-translation test. The relative contributions of topographic and spatial variables to the total community structure were also examined by variation partitioning. The results showed the inconsistency in association of species with habitats across life stages with a few exceptions. Topographic variables [a + b] explained 11% and 19% of total variance at adult and juvenile stage, respectively. In contrast, spatial factors alone [c] explained more variation than topographic factors, revealing strong seed dispersal limitation in species composition in the 25-ha forest plot. Thus, the inconsistent associations of species and habitats coupled with high portion of variation of species composition explained by topographic and spatial factors might suggest that niche process and dispersal limitation had potential influences on species assemblage in the deciduous broad-leaved forest in north-central China. Full article

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

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27 pages, 3670 KiB

Open AccessArticle

Economic Impacts and Land Use Change from Increasing Demand for Forest Products in the European Bioeconomy: A General Equilibrium Based Sensitivity Analysis

by Salwa Haddad, Wolfgang Britz and Jan Börner

Forests 2019, 10(1), 52; https://doi.org/10.3390/f10010052 - 11 Jan 2019

Cited by 11 | Viewed by 6766

Abstract

The European forestry sector is a potential driver of transformation towards a sustainable bioeconomy. Forest products are increasingly used in high-tech and high-value-added industries, e.g., chemicals and the automotive industry. So far, however, research on the European bioeconomy has largely focused on agriculture [...] Read more.

The European forestry sector is a potential driver of transformation towards a sustainable bioeconomy. Forest products are increasingly used in high-tech and high-value-added industries, e.g., chemicals and the automotive industry. So far, however, research on the European bioeconomy has largely focused on agriculture as a provider of food, feed, fuel, and fiber to bio-based industries. Here we assess the potential impacts of a stronger reliance on forestry sector inputs to the European Union (EU28) bioeconomy on output, prices, final demand, and land use. Specifically, we run a sensitivity analysis of a 1% increase of input use of forest products in the EU28 economy in a Computable General Equilibrium (CGE) framework accounting for land use by Agro-Ecological Zones (AEZ) and greenhouse gas (GHG) emissions at high regional and sectoral resolution. We find that such a shift to a more forest-based bioeconomy would provoke small indirect land use effects globally due to existing international trade linkages and land market effects. Simulated increases in planted forest cover are associated with net GHG emission savings, but our scenario analysis also points to higher imports of forest products from countries with vulnerable tropical forest biomes, such as Brazil and Indonesia. Full article

(This article belongs to the Special Issue Forest Bioenergy and Bioproducts)

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14 pages, 1158 KiB

Open AccessArticle

Carbon Footprint Analysis of Bamboo Scrimber Flooring—Implications for Carbon Sequestration of Bamboo Forests and Its Products

by Lei Gu, Yufeng Zhou, Tingting Mei, Guomo Zhou and Lin Xu

Forests 2019, 10(1), 51; https://doi.org/10.3390/f10010051 - 11 Jan 2019

Cited by 43 | Viewed by 8295

Abstract

Bamboo forest is characterized by large carbon sequestration capability and it plays an important role in mitigating climate change and global carbon cycling. Previous studies have mostly focused on carbon cycling and carbon stocks in bamboo forest ecosystems, whereas the carbon footprints of [...] Read more.

Bamboo forest is characterized by large carbon sequestration capability and it plays an important role in mitigating climate change and global carbon cycling. Previous studies have mostly focused on carbon cycling and carbon stocks in bamboo forest ecosystems, whereas the carbon footprints of bamboo products have not received attention. China is the largest exporting country of bamboo flooring in the world. Estimating the carbon footprint of bamboo flooring is of essential importance for the involved enterprises and consumers to evaluate their own carbon footprints. In this study, we investigated the production processes of bamboo scrimber flooring for outdoor use, a typical bamboo flooring in China. Based on business-to-business (B2B) evaluation method, we assessed CO₂ emission and carbon transfer ratio in each step of the production process, including transporting bamboo culms and producing and packing the products. We found that to produce 1 m³ of bamboo scrimber flooring, direct carbon emissions from fossil fuels during transporting raw materials/semi-finished products, from power consumptions during production, and indirect emissions from applying additives were 30.94 kg CO₂ eq, 143.37 kg CO₂ eq, and 78.34 kg CO₂ eq, respectively. After subtracting the 267.54 kg CO₂ eq carbon stocks in the product from the 252.65 kg CO₂ eq carbon emissions derived within the defined boundary, we found that the carbon footprint of 1 m³ bamboo scrimber flooring was −14.89 kg CO₂ eq. Our results indicated that the bamboo scrimber flooring is a negative carbon-emission product. Finally, we discussed factors that influence the carbon footprint of the bamboo flooring and gave suggestions on carbon emission reduction during production processes. This study provided a scientific basis for estimating carbon stocks and carbon footprints of bamboo products and further expanded knowledge on carbon cycling and lifespan of carbon in the bamboo forest ecosystem. Full article

(This article belongs to the Special Issue Forest Carbon Inventories and Management)

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15 pages, 2942 KiB

Open AccessArticle

Drought Impact on Leaf Phenology and Spring Frost Susceptibility in a Quercus robur L. Provenance Trial

by Ivica Čehulić, Krunoslav Sever, Ida Katičić Bogdan, Anamarija Jazbec, Željko Škvorc and Saša Bogdan

Forests 2019, 10(1), 50; https://doi.org/10.3390/f10010050 - 11 Jan 2019

Cited by 15 | Viewed by 4441

Abstract

Research highlights: The susceptibility of oaks to late spring and early autumn frosts is directly related to their leaf phenology. Drought may alter the leaf phenology and therefore frost tolerance of oaks. However, the effects of drought on oak leaf phenology and frost [...] Read more.

Research highlights: The susceptibility of oaks to late spring and early autumn frosts is directly related to their leaf phenology. Drought may alter the leaf phenology and therefore frost tolerance of oaks. However, the effects of drought on oak leaf phenology and frost resistance have not been thoroughly studied. Background and objectives: One of the consequences of climate change is an increase in the frequency of dry episodes during the vegetation period. Pedunculate oak (Quercus robur L.) is an economically and ecologically important forest tree species that prefers humid habitats. Therefore, knowledge of the impact of drought on this species is of great importance for the adaptation of forestry strategies and practices to altered environmental conditions. The aim of this study was to determine the impact of drought on leaf phenology and spring frost susceptibility in nine provenances. Materials and methods: One-year-old saplings originating from nine European provenances were used in the trial. The saplings were exposed to experimental drought and then re-watered in two subsequent years. Spring and autumn leaf phenology were scored. The trial was impacted by a late spring frost in the third year, and the resulting leaf frost injury was scored. The effects of drought treatment on the phenology and frost susceptibility of plants from the provenances were analysed. Results: Leaf phenology of plants from most of the studied provenances was significantly influenced by the drought treatment (p < 0.001). Drought induced a carry-over effect on flushing phenology, which was observed as delayed bud burst (from 0.6 to 2.4 days) in the second year and as advanced bud burst (from 0.1 to 6.3 days) in the third year. Therefore, opposite shifts in flushing phenology may be induced as a result of differences in the time span when plants sense water deficits. In contrast to flushing, autumn leaf phenology was unambiguously delayed following the drought treatments for all studied provenances (from 2.1 to 25.8 days). Differences in late frost susceptibility were predominantly caused by among-provenance differences in flushing phenology. However, the drought treatment significantly increased frost susceptibility in the plants (the rate of frost-injured plants per provenance increased from 3% to 78%). This higher susceptibility to spring frost was most likely caused by the advanced flushing phenology that resulted from the drought treatment in the previous year. Full article

(This article belongs to the Special Issue Genetic and Morphological Variation in Tropical and Temperate Plant Species)

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18 pages, 2530 KiB

Open AccessArticle

Relationships among Root–Shoot Ratio, Early Growth, and Health of Hybrid Poplar and Willow Clones Grown in Different Landfill Soils

by Elizabeth R. Rogers, Ronald S. Zalesny, Jr., Richard A. Hallett, William L. Headlee and Adam H. Wiese

Forests 2019, 10(1), 49; https://doi.org/10.3390/f10010049 - 10 Jan 2019

Cited by 24 | Viewed by 4589

Abstract

Root–shoot allocation of biomass is an underrepresented criterion that could be used for tree selection in phytoremediation. We evaluated how root–shoot allocations relate to biomass production and overall health of poplar and willow clones grown in landfill soil treatments. Fifteen poplar clones and [...] Read more.

Root–shoot allocation of biomass is an underrepresented criterion that could be used for tree selection in phytoremediation. We evaluated how root–shoot allocations relate to biomass production and overall health of poplar and willow clones grown in landfill soil treatments. Fifteen poplar clones and nine willows were grown in a greenhouse for 65 days in soils from five Wisconsin landfills and one greenhouse control. We tested for treatment, clone, and interaction differences in root–shoot ratio (RSR), health, and growth index, along with relationships between RSR with diameter, health, height, total biomass, and growth index. Treatments, clones, and their interactions were not significantly different for poplar RSR, but willow clones differed (p = 0.0049). Health significantly varied among willow clones (p < 0.0001) and among the clone × treatment interaction for poplars (p = 0.0196). Analysis of means showed that willow clones ‘Allegany’ and ‘S365’ exhibited 28% and 21% significantly greater health scores than the overall mean, respectively. Root–shoot ratio was not significantly correlated with health in either genus but was positively correlated with growth index for poplars, which was corroborated via regression analyses. Selecting clones based on a combination of biomass allocation, health, and growth indices may be useful for using phyto-recurrent selection to satisfy site-specific ecosystem services objectives. Full article

(This article belongs to the Special Issue Short Rotation Woody Crop Production Systems for Ecosystem Services and Phytotechnologies)

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5 pages, 686 KiB

Open AccessEditorial

Introduction to the Special Issue on Tropical Forests: Management and Ecology in the Anthropocene

by Ariel E. Lugo and Grizelle González

Forests 2019, 10(1), 48; https://doi.org/10.3390/f10010048 - 10 Jan 2019

Cited by 1 | Viewed by 2917

Abstract

This Special Issue of Forests is based on papers presented at the 75th anniversary of the United States Department of Agriculture (USDA) Forest Service International Institute of Tropical Forestry as well as other papers relevant to the topic of the Special Issue. The [...] Read more.

This Special Issue of Forests is based on papers presented at the 75th anniversary of the United States Department of Agriculture (USDA) Forest Service International Institute of Tropical Forestry as well as other papers relevant to the topic of the Special Issue. The Institute is but one leg of a conservation relay among cultures and institutions that began in Puerto Rico a millennium ago. The Institute began operations in 1939 and celebrated its 75th anniversary on May, 2014. Over its 75 years of operation, the Institute has focused its research on tropical forests, with the scope of the research expanding over the years. An analysis of the lines of research of the Institute showed that over its history about 69 lines of research have been established and that of the original 17 lines of research between 1939 and 1949, all but one remained active in 2014. This history and continuity of the research program has allowed the Institute to observe ecological phenomena over decades, including the evolving forest structure and functioning on degraded land restoration experiments that began before the formal establishment of the Institute and are now over 80 years old. Full article

(This article belongs to the Special Issue Tropical Forest Ecology and Management for the Anthropocene)

16 pages, 1469 KiB

Open AccessArticle

Assessing Forest Governance in the Countries of the Greater Mekong Subregion

by David Gritten, Sophie Rose Lewis, Gijs Breukink, Karen Mo, Dang Thi Thu Thuy and Etienne Delattre

Forests 2019, 10(1), 47; https://doi.org/10.3390/f10010047 - 10 Jan 2019

Cited by 15 | Viewed by 9038

Abstract

The forest landscapes of the Greater Mekong Subregion (GMS) are changing dramatically, with a multitude of impacts from local to global levels. These changes invariably have their foundations in forest governance. The aim of this paper is to assess perceptions of key stakeholders [...] Read more.

The forest landscapes of the Greater Mekong Subregion (GMS) are changing dramatically, with a multitude of impacts from local to global levels. These changes invariably have their foundations in forest governance. The aim of this paper is to assess perceptions of key stakeholders regarding the state of forest governance in the countries of the GMS. The work is based on a quantitative and qualitative analysis of the perceptions of forest governance in the five GMS countries, involving 762 representatives from government, civil society, news media, and rural communities. The work identified many challenges to good forest governance in the countries in the region, as well as noting reasons for optimism. Generally speaking, there was a feeling that the policies, legislation, and institutional frameworks were supportive, but there are numerous challenges in terms of implementation, enforcement, and compliance. The work also presents a program of activities recommended by the research participants to address governance challenges and opportunities in the GMS countries. These include the development of a forest governance monitoring system, and initiatives that support informed decision-making by forest product consumers in the region as well as the implementation of a capacity development program for non-state actors (e.g., civil society, news media) to ensure they are more able to support the diverse, and often demanding, forest governance initiatives. Full article

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

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Forests, Volume 10, Issue 1 (January 2019) – 76 articles

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