Hasil untuk "Forestry"

M. Hansen, P. Potapov, R. Moore et al.

G. A. Blackburn

Hongsen LIU, Yibo WANG, Yuanyuan ZHANG et al.

Loess is a typical water-sensitive soft soil widely distributed in northwest China. It typically exhibits low cohesiveness and easy subsidence when immersed in water, thus severely restricting the development of infrastructure construction such as highways, railways, and bridges. To solve the issues of high carbon emissions, low economic benefits, and increased environmental alkalinity caused by conventional cement-based curing materials, alkali-activated slag/fly ash (S/F) geopolymers (referred to as “geopolymer”) were adopted to improve collapsible loess in this study. The influence laws of the precursor S/F mass ratios (i.e., 0∶10, 2∶8, 4∶6, 5∶5, 6∶4, 8∶2, and 10∶0), alkaline activator (i.e., sodium hydroxide/sodium silicate, N/G), mass ratios (i.e., 0∶10, 1∶4, 4∶1, and 10∶0), and curing age (i.e., 7 d and 28 d) on the physical and mechanical properties of solidified loess were systematically investigated through measurements of unconfined compressive strength (UCS) tests, moisture content, and dry density. The strength-formation mechanism of solidified soil was revealed through X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. The results show that as the proportion of slag in the precursor increases from 0% to 100%, the UCS of solidified loess increases significantly. The UCS of solidified soil increases significantly with curing age, i.e., the UCS of the 28-d solidified sample is 2.1 ～ 3.8 times higher than that of the 7 d solidified sample. After 7 d of curing, the moisture content of the solidified samples decreases as the slag proportion increases. By contrast, the change in moisture content of the solidified samples after 28 d of curing shows the opposite law. The proportion of alkali activator imposes a threshold effect on the solidified soil: the UCS of the high-slag system (the slag content exceeding 80%) first increases and then decreases as the proportion of sodium hydroxide increases, whereas that of the high-fly-ash system (the fly-ash content exceeding 80%) increases continuously with the proportion of sodium hydroxide. Microstructure characterization based on XRD and SEM analyses shows that the alkali-activated S/F geopolymers in the solidified samples primarily generate hydrated calcium silicate (C–S–H) and hydrated calcium aluminosilicate (C–A–S–H) gels, which cement the soil particles. The cementation effect of these gels is identified as the dominant mechanism for strength enhancement (particularly the C–S–H/C–A–S–H in slag system), whereas the pore filling effect is a secondary contributing factor. The optimized formula (S∶F = 8∶2, N∶G = 8∶2) results in a 28 d UCS of 8.69 MPa, which significantly exceeds the performance of conventional cement-stabilized loess while offering favorable economic benefits. Alkali-activated solidification improvement reduces the collapsibility of loess as well as enhances its strength, bearing capacity, and road usability. This study provides a scientific basis for the resource utilization of industrial solid waste and the green reinforcement of loess subgrade. Additionally, it demonstrates the feasibility and superior performance of geopolymer technology.

Esra Bayar, Fadime Doğu

In this study, it was aimed to determine the drought tolerance of different aged Anatolian black pine [Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe] individuals within the Isparta Regional Forest Directorate. Three different age classes and growth stages of natural Anatolian black pine individuals were studied under the same growing conditions. Soil water content, midday water potential and water potential components (water potential at turgor loss point and osmotic potential at full turgor, free water content at turgor loss point, relative water content at turgor loss point, symplastic water content per unit dry weight, relative water content, and dry weight fraction) were determined in shoot samples taken in May, July and September. In addition, chlorophyll pigment content was determined in summer, the dry period. Soil water content, which was high in May (average 19.2%), decreased in July (average 6.4%), along with midday water potential (average -1.8 MPa and -2.5 MPa). Generally, first age class (about 13 years old) individuals of Pinus nigra exhibit significantly higher midday water potential (May: –1.4 MPa and July: –2.2 MPa). Among the water potential component, the water potential at turgor loss point in July was highest in the first age class (-2.5 MPa) and lowest in the second age class (-3.2 MPa). Chlorophyll pigment content in July was also found to be lowest in the second age class. In conclusion, it can be said that individuals of the Anatolian black pine in the first age class exhibit lower drought tolerance in response to decreasing water content during the dry season.

Dong Ma, Qin Tian, Yunqiang Wang et al.

Abstract Background The family Hypoxidaceae (order Asparagales) is a predominantly Southern Hemisphere lineage comprising approximately 11 genera and 200 species, many of which possess significant medicinal and ornamental value. Despite their economic importance, Hypoxidaceae has received limited research attention, leading to problematic identification of species and misuse of wild resources in traditional medicine markets. Taxonomically, the phylogenetic position of Hypoxidaceae and the intergeneric relationships within this family remain controversial and unresolved, particularly concerning the delimitation of Curculigo and Molineria. Previous studies based on morphological traits and molecular markers have yielded inconsistent results, highlighting the need for more robust genomic evidence. In angiosperms, complete chloroplast genomes have proven highly effective in resolving systematic uncertainties considering their conserved structure and high informational content. However, such genomic data remain scarce for Hypoxidaceae, limiting phylogenetic clarity. In this research, the complete chloroplast genomes of six species representing three key genera (Curculigo, Molineria, and Hypoxis) were sequenced and characterized for a comparative and phylogenetic analysis. Results The chloroplast genomes of six species exhibited conserved quadripartite structures, measured 157,472 bp to 158,550 bp in length. The overall GC content of these genomes ranged between 37.3 and 37.5%. Gene annotations identified 132 genes, 19 duplicated in the inverted repeat regions, and had complete ndh gene. Comparative analysis of six complete chloroplast genomes revealed highly similarity, but they were varied in repeats sequence, codon usage bias, contractions and expansions in the IR region. Five molecular markers showed the highest degree of variability between the six cp genomes. Phylgenetic analysis based on cp genomic data confirmed that Hypoxidaceae was a monophyly, being a sister to Asteliaceae with higher supports than the previous research. Three main clades were recognized in Hypoxidaceae, including Curculigo clade, Hypoxis clade, and Pauridia–Empodium clade. And what’s more, Curculigo clade could be divided into three subclades, containing Molineria subclade, Curculigo subclade, and Seychellean subclade, indicating significantly phylogenetic insights. Conclusions The complete cp genomes of six species of three representative genera from Hypoxidaceae were sequenced and analyzed in detail, including the general data on the genome length, repeat sequence, codon usage, IR expansion and contraction, structural comparison and divergence hotspot identification analyses, and phylogenetic analysis. A comparative analysis revealed that the cp genome was highly consistent of four Molineria species, but varied greatly at the generic level between Hypoxis , Curculigo, and Molineria, which could be used for generic delimitation. Five DNA barcodes (psbK–psbI, rpoB–trnC, ndhF–rpl32, ycf1, and trnE–trnT) were selected for authentication of Hypoxidaceae medicinal materials. Hypoxidaceae was a monophyletic lineage, containing three major clades, being a sister to Asteliaceae with stronger supports than before. The three main clades in Hypboxidaceae were re-confirmed as the three stable lineages for this family. In the Curculigo Clade, three subclades were identified with significant phylogenetic insights. The phylogenetic evidence presented here, combined with distinct chloroplast genome features, supports Molineria Subclade separated from Curuculigo Subclade, being a monophyletic group by transferring Sinocurculigo taishanica and two Borneo Curculigo species into Molineria. Further research should provide a better understanding of the intergeneric relationships among Hypoxidaceae, adding more genomic data with extensive samplings across the center distribution of Southern Hemisphere.

Tingwei Song, Liang Guo, Qian Sun et al.

Abstract Soil water retention is a critical aspect of water conservation. To quantitatively assess the Soil Water-Holding Capacity (SWHC), this study focused on a typical wild fruit forest in Xinjiang, China. The spectral characteristics of the forest canopy were employed as a bridge to enhance the sensitivity between the SWHC and various vegetation indices using mathematical statistical methods. This study integrated hyperspectral technology with machine learning algorithms to model complex nonlinear relationships and to select the optimal SWHC model. The spatial distribution of SWHC in the wild fruit forests of Emin County was retrieved using Sentinel-2 imagery. The results revealed a significant negative correlation between SWHC and the smoothed leaf spectral reflectance, with the best correlation coefficient was r = − 0.59. The use of third-order derivatives and logarithmic second-order derivatives further enhanced this correlation, yielding optimal coefficients of r = − 0.78 and r = − 0.72, respectively. Moreover, uncertainty analysis demonstrated that the SWHC estimation model constructed using the Random Forest (RF) algorithm exhibited the highest stability, with a coefficient of determination R2 = 0.73, RMSE = 0.158, and RPD = 1.90. The spatial inversion results indicated that SWHC values were relatively higher in areas with dense wild fruit forest coverage and valley terrain. This study is the first to jointly incorporate high-order spectral derivatives and uncertainty analysis into the modeling of SWHC in wild fruit forests, underscoring the advantages of spectral feature enhancement and variable perturbation analysis for improving model stability. The findings provide novel insights into SWHC inversion and offer valuable references for ecological restoration, enhancing the water conservation function of wild fruit forests, and formulating targeted management strategies.

Rui Xie, Zhenhong Zhuang, Qionghui Chen et al.

Aspergillus flavus and its secondary metabolites, aflatoxins (AFs), especially aflatoxin B1 (AFB1), seriously affect agricultural production, food storage, and human health. Succinyl-CoA synthase ADP-forming subunit β (SCS) is involved in the synthesis of succinate from succinyl-CoA in the tricarboxylic acid cycle. In this study, we demonstrated that SCS led to decreased aflatoxin production. Bioassay results showed that deletion of sucB (the gene coding for SCS) led to increased succinyl-CoA accumulation. Catalyzed by succinyl transferase (STA), the increased amount of succinyl-CoA in ΔsucB leads to increased levels of global protein succinylation, which causes upregulation of AFB1 accumulation in ΔsucB. To elucidate the mechanism of increased AFB1 accumulation in ΔsucB, the relevant enzymes and metabolites involved in the aflatoxin biosynthesis pathway were examined through proteome and metabolome analyses. These data illustrate that the deletion of sucB results in an increase in (1’S, 5’S) – averufin catalyzed by AflK, (1’S)-averantin catalyzed by AflD, and aflatoxin G2/O- methylsterigmatocystin catalyzed by AflP. We also found that AflM is not only upregulated but also succinylated in ΔsucB; Ach1 (acetyl-CoA hydrolase, Ach1) is downregulated in ΔsucB and interacts with SCS. Therefore, we deduce a pathway of Ach1/STA-SCS-succinylated AflM for AFB1 biosynthesis, which provides knowledge for the control of A. flavus and AFs.

Yong YANG, Jiajia CHEN, Songyan LIU et al.

Objectives: With the development of modern processing technology, heat accumulation has become an urgent processing problem that needs to be solved. A heat pipe is a heat exchange element that efficiently transfers heat through the gas-liquid phase change of the working fluid inside the pipe. Gravity heat pipe have advantages such as simple structure, stable operation, and low cost, and are widely used in various heat exchange scenarios in industrial production. They have played a significant role in energy conservation, the development and utilization of new energy, and in strengthening heat exchange during processing. This article prensents experimental research on diamond nanofluids, exploring the influence of different parameters on the heat transfer performance of diamond nanofluid gravity heat pipes, laying a foundation for the research and application of heat pipe technology in heat dissipation during machining processes such as drilling, milling, and grinding. Methods: The evaporation section is heated using a DC power supply and thermal resistance wire. K-type thermocouples and temperature acquisition cards are used to record the temperature of the evaporation and condensation sections of the gravity heat pipe. The influence of heating power, filling rate, nanofluid concentration, and nanoparticle size on the heat transfer performance of the gravity heat pipe is analyzed using thermal resistance R as an indicator. Results: The heat transfer performance of gravity heat pipes is investigated under a power range of 3-18 W, while maintaining a filling rate of 20% and a nanoparticle concentration of 1%. The results show that as the heating power increases, the temperatures of the evaporation and the condensation sections gradually increase, while the rise time gradually shortenes. The temperature difference between the evaporation and condensation sections shows a decreasing trend. When the heating power increases for the same concentration and filling rate of nanoparticles, the total thermal resistance shows a decreasing trend, but the magnitude of the decrease continues to decrease. Keeping the concentration of nanoparticles at 2% and the heating power at 6 W, the heat transfer performance of gravity heat pipes is investigated under conditions of filling rates of 8%, 14%, 20%, and 26%. The results show that the overall temperature of the 20 nm diamond nanofluid is higher than those of other filling rates at a 20% filling rate, while the overall temperature at a 26% filling rate is lower than at other filling rates. The overall temperature at a 26% filling rate is higher than at other filling rates. With the same mass fraction and heating power, as the filling rate increases, the total thermal resistance shows a trend of first decreasing and then increasing, with the minimum value of the total thermal resistance appearing at a filling rate of 14%. By maintaining a filling rate of 26% and a heating power of 12 W, the heat transfer performance of gravity heat pipes under 0.5%, 1.0%, 1.5%, and 2.0% mass fraction conditions is investigated. The results show that the overall temperature of 20 nm diamond nanofluid heat pipes is the highest at a 1% mass fraction, while the overall temperature is lower at a 2.0% mass fraction. The hot-end temperature of 50 nm diamond nanofluid heat pipes is the highest at a 1.5% mass fraction, and the cold-end temperature is the lowest. At a mass fraction of 2.0%, there is a situation where the hot-end temperature is lower and the cold-end temperature is higher. With the same filling rate and heating power, as the mass fraction increases, the total thermal resistance first increases and then decreases. At a mass fraction of 2.0%, the minimum total thermal resistance will appears. In addition, for diamond nanofluids with different particle sizes, there is a trend of heat transfer capacity decreasing first and then improving with increasing mass fraction. Maintaining a filling rate of 14% and a mass fraction of 2.0%, the heat transfer performance of gravity heat pipes with particle sizes of 20 nm and 50 nm was investigated. The total thermal resistance of 50 nm diamond nanofluid gravity heat pipes was always lower than that of 20 nm diamond nanofluid gravity heat pipes. However, as the heating power increases, the advantage of 50 nm diamond nanofluid gravity heat pipes tends to weaken. Maintaining a liquid filling rate of 14% and a mass fraction of 2.0%, the heat transfer performance of gravity heat pipes with and without a liquid absorbing core was investigated. The total thermal resistance of gravity heat pipes with suction cores is lower than that of heat pipes without suction cores, but as the heating power increases, the advantage tends to weaken. Conclusions: When the mass fraction is 2.0%, gravity heat pipes have the best heat transfer performance, with a total thermal resistance increase of approximately 28.4%-64.7% compared to the maximum value. When the filling rate is 14%, the heat transfer performance is the best, and the total thermal resistance decreases by about 6.1%-8.5% compared to the maximum value. When using diamond nanofluids with a particle size of 50 nm, the overall heat transfer performance of gravity heat pipes is better than that of 20 nm. When the heating power of the power supply increases, the heat exchange performance also improves. When using a gravity heat pipe with a liquid absorbing core, its overall heat transfer performance is better than that of a gravity heat pipe without a liquid absorbing core.

Lance W. Robinson, Jeff N. Robinson, Len M. Hunt

In Canada, the most widespread approach to citizen participation in forestry decision-making is forest advisory committees. In this paper, we report on the results of a survey of forest advisory committee members that has been repeated every few years since 2001. We clustered the survey questions to create composite variables representing seven dimensions of the functioning and effectiveness of forest advisory committees: efficiency, representation, voice, decision-making process, trust in forest managers, effectiveness, and the availability, relevance, complexity and trustworthiness of information. While most committee members continue to view the process positively, after a steady improvement of committee members’ overall assessments since 2001, in the most recent survey, the proportion of those who are unsatisfied has grown. Moreover, effectiveness has consistently been assessed less favourably than the other six dimensions that we considered—dimensions upon which effectiveness presumably depends. Part of the reason is that a significant minority of committee members feel that they have little meaningful influence over forest management and that the relevance of the committees has declined. This points to the need for continual attention from policymakers to the matter of how and how much forest advisory committees are enabled to influence the direction of forest management.

Feng Liu, Yu Deng, Fei-Hu Wang et al.

The fungal genus Microcera consists of species mostly occurring as parasites of scale insects, but are also commonly isolated from soil or lichens. In the present study, we surveyed the diversity and assess the taxonomy of entomopathogenic fungi in Sichuan Province, China. Two new species of Microcera, viz. M. chrysomphaludis and M. pseudaulacaspidis, were isolated from scale insects colonising walnut (Juglans regia). Maximum Likelihood and Bayesian Inference analyses of ITS, LSU, tef1-α, rpb1, rpb2, acl1, act, tub2, cmdA and his3 sequence data provide evidence for the validity of the two species and their placement in Nectriaceae (Hypocreales). Microcera pseudaulacaspidis primarily differs from similar species by having more septate and smaller cylindrical macroconidia, as well as DNA sequence data. Meanwhile, Microcera chrysomphaludis has elliptical, one-septate ascospores with acute ends and cylindrical, slightly curved with 4–6 septate macroconidia up to 78 µm long. Morphological descriptions with illustrations of the novel species and DNA-based phylogeny generated from analyses of multigene dataset are also provided to better understand species relationships.

Luca Di Nuzzo, Giulia Canali, Paolo Giordani et al.

Lichens are poikilohydric organisms, whose internal water content tends to reflect external humidity conditions. After drying, they can reactivate their metabolic activity through water vapor uptake or liquid water input. Thus, lichen water-related functional traits are important as they are involved in the duration of the hydrated period. Models predicting the effect of environmental conditions on lichens are based mainly on the presence or absence of adult thalli. Nevertheless, ecological conditions required by lichens might vary during their life cycle, for example during propagule establishment or in the first stages of thallus development. Little is known about the different ecological requirements at the different development stages in lichens. In this work, we measured water holding capacity (WHC) and specific thallus mass (STM) of adult and juvenile thalli of the model species Lobaria pulmonaria along a climatic gradient to constrain the process-based model LiBry. The LiBry model allows accounting for the productivity of lichens with different physiological strategies under various environmental conditions. We simulated the activity and performance of adult and juvenile thalli in 9 regions of Italy and Corsica. The model was used to test if adult thalli of L. pulmonaria have a higher survival probability due to their higher aerodynamic resistance. In the current climatic condition, the LiBry model predicts a higher survival probability of adults with decreasing absolute survival rates of both life stages with increasing temperature. Adult thalli also result in having higher active time, STM, and relative growth rate (RGR). We discuss the main implications of our simulation outputs, provide future perspectives and possible implementations of the LiBry model.

A. Juutinen, A. Tolvanen, T. Koskela

Forest owners' intentions to apply alternative management practices were examined to increase the understanding of the factors that influence forest management on non-industrial private forests. Randomly selected Finnish forest owners were surveyed to determine their management intentions for five management practices: traditional management; short rotation management; long rotation management; uneven-aged management; and other management. A fractional multinomial logit model was used to analyse the influence of variables from three factor groups on management intentions: (i) property characteristics and the past experience of forest owners; (ii) beliefs in how well forests are generally managed; and (iii) the socioeconomic characteristics of forest owners. Forest owners intended to use multiple management practices in their forests. The most typical practice was traditional management (51.5% of respondents' total forest area), followed by uneven-aged (25.0%) and long rotation management (15.3%). Our results show that forest owners still maintain the use of traditional even-aged forestry as the most commonly applied forestry practice in Finland, but they intent to use increasingly uneven-aged forestry in future. Several variables influenced on management intentions. For example, men, agricultural entrepreneur and older respondents tended to allocate a smaller proportion of their forest area to uneven-aged forestry. Ongoing socio-economic changes may enforce the change in forest management practices.

Zhang L, Zhao S, Lin Q et al.

Lirong Zhang,1 Shaocong Zhao,1 Qiong Lin,2 Minmin Song,3 Shouren Wu,2 Hua Zheng4 1Department of Physical Education, Xiamen University of Technology, Xiamen, Fujian, People’s Republic of China; 2Department of Physical Education, JiMei University, Xiamen, Fujian, People’s Republic of China; 3Department of Physical Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, People’s Republic of China; 4College of Physical Education and Health Sciences, Chongqing Normal University, Chongqing, People’s Republic of ChinaCorrespondence: Shaocong ZhaoDepartment of Physical Education, Xiamen University of Technology, Xiamen, Fujian, People’s Republic of ChinaTel +86-13806063882Email 358945018@qq.comPurpose: This study aims to identify potential risk factors associated with anxiety or depression and propose algorithms to predict anxiety and depression especially among university students.Methods: We included and analyzed 881 university students from eight colleges in China in November 2020. Student’s basic information, lifestyles, sport habits, comorbidities, and mental health conditions were collected. Anxiety and depression were measured using the generalized anxiety disorder 7 (GAD-7) and the patient health questionnaire 9 (PHQ-9), respectively. A multiple linear regression analysis was used to assess the ability of 25 potential risk factors for predicting anxiety and depression, and significant risk factors were included in the algorithms.Results: Of all the included students, 44.27% lived with mild or above anxious symptoms and 50.62% had mild or above depressive symptoms. According to the multiple linear regression model, grade levels (P< 0.01), member of college sports dance team (P=0.05), sedentary time (P=0.02), exercise frequency (P< 0.01), only child status (P=0.05), addiction of drinking (P< 0.01), and prefer eating vegetable (P< 0.01) were significantly associated with anxiety; grade levels (P< 0.01), member of college sports dance team (P< 0.01), sedentary time (P< 0.01), exercise frequency (P< 0.01), academic study period during free time (P=0.03), only child status (P< 0.01), addiction of drinking (P< 0.01), prefer eating vegetables (P< 0.01), and main types of drinking water (P< 0.01) were significantly associated with depression. Based on these significant factors, two algorithms were successfully developed, and two risk groups were created according to the algorithms.Conclusion: The study proposed two algorithms to calculate anxiety and depression, respectively, which can be useful tools to identify students with different risk of anxiety or depression. Effective measures are warranted to improve student’s sport habits and healthy lifestyles in order to mitigate anxiety and depression, especially among students in the high risk group.Keywords: students, public health, anxiety, depression, risk factors, algorithms

Mehdi Rezaei, Ladan Rokni, Doo Hwan Kim

No Abstract

S. Bockel, S. Harling, J. Konnerth et al.

Abstract Subject to this study is the modification of an experimental two-component polyurethane (2C PUR) as an alternative adhesive for structural hardwood bonding. The 2C PUR has been adapted by calcium carbonate as filler to increase its modulus of elasticity with the aim of increasing the modulus analogue to the ones typically observed for classic amino- and phenol based adhesives. The 2C PUR system was compared with a commercial one-component polyurethane (1C PUR) and a phenol resorcinol formaldehyde (PRF) adhesive. The wetting properties of the adhesives were tested in terms of surface tension, polar and dispersive part and contact angle on European beech wood (Fagus sylvatica L.). In addition, adhesive polymer films of 2C PUR were tested for tensile strength and modulus of elasticity (E-Modulus) following ISO 527-1. The adhesives bond performance on beech wood was determined by lap-joints according to EN 302-1 in various climate conditions. The results show that 2C PUR has proper wettability properties on beech wood. Adding 60% wt filler to the polyol component increased the E-Modulus from 2.3 GPa (0%) to 4.4 GPa. The tensile strength of the modified 2C PUR polymer films was comparable with the industrial 1C PUR. Tensile shear strength and wood failure percentage of 2C PUR lap-joints were increased by adding filler and met requirements in dry and re-dried conditions according to EN 302-1. However, the addition of filler didn’t result in an improvement in wet conditions. The present study shows sufficient performance for bonding hardwood with 2C PUR in dry conditions, while the system still needs to be improvement regarding its performance in humid conditions.

Pashupati Nath, P. C. Joshi, Induja Mishra et al.

Dams are playing a significant role in utilizing the resources of water and have a larger impact on the river ecosystem. It has an enormous deal of positive and negative effects on the environment in addition to their benefits like managing stream regimes, as a result preventing floods, obtaining domestic and irrigation water from the stored water and producing energy. The acute and chronic effects due to the construction of the dam are various and categorized according to the area, the services provided by the dams to the community and also its unsocial impacts, advantageous and detrimental impacts on nearby communities and to the aquatic environment These consequences of the construction of any dam project may be commanded in a rigorous and complicated approach resembling climatic, hydraulic, biological, communal, intellectual, archaeological etc. The role of Dams and their benefits are much more and impact directly in our social and environmental life, but it is also a key point that we have to focus about the negative effects of these developmental activities and major and minor dam construction projects by the way of water resource engineering and sustainable development. Dams have the majority of significant functions in utilizing water resources. All through the history of the world, dams have been used successfully in collecting, storing and managing water needed to uphold civilization. Dams have a great deal of affirmative and pessimistic effects on the environment. The advantages are also varying from modest to many folds to the community like controlling stream regime as a result of preventing floods, obtaining domestic and irrigation water from stored water and generating energy from hydropower. Whereas dam endows with significant benefit to our civilization, their impact on the surrounding includes resettlement and relocation, socioeconomic impact, environmental concerns, sedimentation issue, safety aspects etc. Over and above their incredibly important communal and ecological benefits, it is significant to moderate the negative effects of the dam on the environment regarding sustainable development.

Wang Runyu, Dong Daming, Ji Zengtao et al.

Harmful gases such as ammonia and hydrogen sulfide in livestock and poultry houses can seriously damage the health of livestock and poultry as well as animal keepers, so it is great significant to detect these harmful gases rapidly and accurately for the improvement of the welfare of animals and the health of animal keepers. Laser absorption spectroscopy is a gas detection method with the advantages of high sensitivity and selectivity, and is widely used in industrial gas detection. However, it needs further exploring to verify whether laser absorption spectroscopy is useful in detecting low concentration harmful gases in livestock and poultry houses. This paper researches on the method for high-sensitivity detection of harmful gases in livestock and poultry houses based on laser absorption spectroscopy by detecting the absorption signals of ammonia with a self-designed system including a tunable laser wavelength scanning system, a photoelectric detecting system and a long light path gas absorption well, and verifies that laser absorption spectroscopy can be used for detecting harmful gases in livestock and poultry houses.

Adeniyi P. Asiyanbi

This paper offers a critical assessment of REDD+ in Nigeria through a political ecology perspective. Focusing on questions of property rights and resource access, it maps the discursive articulations and contestations through which carbon rights are being determined. It also shows how these articulations and contestations are linked to land and forest rights, and how they shape everyday access to the forest. Evidence from the Nigerian case suggests that factors that complicate rights and undermine access to resources for forest communities under REDD+ are immanent to the contested terrain constituted in part by REDD+ proposals, proponents’ discourses and practices geared towards securing the forest for REDD+. Efforts to secure property rights and guarantee the permanence of REDD+ forests align with economic, ecological and ideological aspirations of state and non-state actors to produce a regime of militarised protectionism. I demonstrate how, in addition to its material and symbolic facilitation of the emergent carbon forestry economy, militarised protectionism as a regime of exclusion also constitutes collateral political economies of ‘more-than-carbon’ forest resources (such as timber and non-timber forest products) which perpetuate capital accumulation by the elites. It is this kind of exclusion–accumulation dialectic, legitimised by carbon forestry claims that this paper describes as carbonised exclusion. The paper thus furthers debates on the political ecology of REDD+ and other carbon forestry projects, while productively engaging technocentric literature on REDD+ and property rights.

N.V. Baranovskiy, A.V. Zakharevich

Forest fires occur as a result of natural and man-made causes. It is known that particles heated to high temperatures are a common source of high temperature. The purpose of the work is the physical simulation of the typical forest fuel ignition (spruce needles ignition) by the carbon particle heated to high temperatures and the identification of the typical forest fuel ignition conditions. Every year, field observations and collection of forest fuel samples for experimental studies are carried out in Timiryazevskiy forestry of Tomsk Region. A typical forest fuel (spruce needles) is considered. The sources of heating during the ignition of forest fuel were simulated by the particles made of graphite in the shape of a parallelepiped with characteristic dimensions in three coordinate directions (14 mm, 8 mm, 8 mm). The weight of such a graphite particle was 1.3 g. Experiments were performed in the range of changes in initial temperatures T0 from 1113 K to 1273 K. Numerical analysis shows that at a low sedimentation height, the particle retains its heat content to the maximum, cooling only in the near-surface layers. Initially, the mechanism of ignition as a result of the action of a burning graphite particle was investigated. The physical mechanism of the forest fuel layer ignition is established when a carbon particle heated to high temperatures falls out in a flameless mode. A series of experiments was carried out and the dependence of the ignition delay on the initial temperature of the particle was obtained. The analysis showed that the dependence of the ignition delay on the initial temperature of a particle can be approximated to a first approximation by a straight line. The obtained results can be used for the development and verification of mathematical models to simulate ignition of forest fuel by the particle heated to high temperatures.

Najme Heidarian, سلیمان محمدی لیمایی, علیرضا امیرتیموری

The aim of this study is to measure the technical and scale efficiencyes of forest nursery in Guilan, Mazandaran and gorgan Provinces using data envelopment analysis. In this study, data of 12 forest nursery during of 4 years (2010-2013) with two inputs (fixed costs and variable costs) and two outputs (number of plant production and revenue) was collected from General Office of Guilan natural resources, Shafaroud forest Company as well as Forest Rangeland and Watershed Managements Organization. CCR and BCC models were used in order to investigate the technical efficiency. DRS model was used in order to investigate the rate of return scale in efficiency. Results indicated that Shanderman, Jokandan, Peseson and Ghrogh nurserys was completely efficient (efficiency score were 1 or 100%). Furthermore, nurseries such as Kani, Safrabaste, pelambara, Shahr posht and Lakans had the lowest efficiency, respectively. This can be due to the nature of the input models and optimal management of nurseries in the input and output.