Forest In Winter Research Articles

Effects of forest age and season on soil microbial communities in Chinese fir plantations.

Understanding changes in the distribution patterns and diversity of soil microbial communities from the perspectives of age-related changes, seasonal variations, and the interaction between the two factors can facilitate the management of plantations. In Chinese fir plantations, we collected soils from different depths in over-mature forests, mature forests, near-mature forests, middle-aged forests, and young forests in summer, autumn, and winter in China's subtropical regions. As the forests developed, bacterial and fungal communities' diversity changed, reached a minimum value at near-mature forests, and then increased in mature forests or over-mature forests. Near-mature forests had the lowest topological properties. The Shannon index of microbial communities varied with seasonal changes (P < 0.05). Bacterial and fungal community composition at genus level was more closely related to temperature indicators (including daily average temperature, daily maximum temperature, and daily minimum temperature) (P < 0.01, 0.5554 < R2 <0.8185) than daily average precipitation (P > 0.05, 0.0321 < R2 <0.6773). Bacteria were clustered by season and fungi were clustered by forest age. We suggested that extending the tree cultivation time of plantations could promote microbial community recovery. In addition, we found some species worthy of attention, including Bacteroidetes in autumn in over-mature forests, and Firmicutes in summer in young forests.IMPORTANCEChinese fir [Cunninghamia lanceolata (Lamb.) Hook] is an important fast-growing species with the largest artificial forest area in China, with the outstanding problems of low quality in soil. Soil microorganisms play a crucial role in soil fertility by decomposing organic matter, optimizing soil structure, and releasing essential nutrients for plant growth. In order to maintain healthy soil quality and prevent nutrient depletion and land degradation, it is crucial to understand the changes of soil microbial composition and diversity. Our study determined to reveal the change of soil microbial community from stand age, season, and the interaction between the two aspects, which is helpful to understand how interannual changes in different years and seasonal changes in one year affect soil fertility restoration and sustainable forest plantation management. It is a meaningful exploration of soil microbial communities and provides new information for further research.

Children’s choir in the works of Valentyna Drobiazhina

Relevance of the research topic. Music for children’s choir is represented by a significant layer in the creative heritage of Ukrainian composers. However, children’s choral music has hardly been considered in musicolo-gical research. Among the composers of the Kharkiv region, the choral works of V. Drobiazhina received special recognition. The lack of musicological research on the composer’s work has determined the relevance of this work.&#x0D; The purpose of the article is to analyze the peculiarities of the artistic aesthetics and compositional style of V. Drobiazhina’s choral music for children.&#x0D; The methodology of the theoretical analysis combines fundamental methods and approaches to modeling a holistic picture of the composer’s children’s choral heritage: genre-stylistic; functional-structural; systemic.&#x0D; The results. The first collection “Merry Songs” for junior children’s choir, was published in 1976. Jazz rhythms and harmonies, alternating recitation and singing, consonant intonation characterize this cycle. “In the Forest Workshop” is the most popular one among V. Drobiazhina’s works, and it is performed by many children’s choirs in Ukraine. The choir imitates the sounds of the winter forest and creates a premonition of spring. “Spring” is one of V. Drobiazhina’s last compositions. The artist’s extremely delicate sensual soul, passionate love for Ukraine and its musical culture are fully reflected here.&#x0D; The scientific novelty of the research. The genre-stylistic aspect of V. Drobiazhina’s choral music for children, the peculiarities of aesthetics and composer’s style are highlighted in the article for the first time.&#x0D; The practical significance of the article lies in the fact that these materials can be used in the courses “Choral Literature” and “History and Theory of Choral Performance”.&#x0D; Conclusions. Music for children’s choir is one of the most outstanding pages of V. Drobiazhina’s composi-tional heritage. The uniqueness of V. Drobiazhina’s children’s choral music lies in the combination of the extraordinary richness of the musical material with accessibility both for perception and performance. The composer’s music organically combines Ukrainian national traditions with modern means of expression.

Wątki ekologiczne zwerbalizowane w albumie przyrodniczym Niny Grzelak "Poznajemy las"

&#x0D; &#x0D; &#x0D; Ecology, as it is broadly understood, is an integral part of the contemporary life of humankind. Numerous ecology principles stated in various publishing proposals remind us of a human’s duties to the environment around them (including the forest). Acccordingly, the purpose of this article is to discuss selected ecological themes presented in Nina Grzelak’s naturalist album „Poznajemy Las”. The subject of linguocultural considerations, on the other hand, is the verbal content: verbal texts and/or verbal comments complementing the beautiful and carefully selected visual texts; photographs and drawings, which together fit not only into the nowadays fashionable ecological discourse, but also contemporary didactics and, above all, education. A thorough reading of the excerpted ecological and biological proposal makes the following clearer to understand: the peculiarities of the forest ecosystem; the habitat of the dead forest trees; the acoustic qualities of the forest, and it reminds us, among other things, of the pragmatic use of the forest tree, and pro-ecological human activities in the forest in winter. All this „linguistic and visual data” make Nina Grzelak’s proposal an unforgettable ecolecture, which while arousing people’s curiosity, and it has an eco-educational purpose.&#x0D; &#x0D; &#x0D;

Camera traps reveal seasonal variation in activity and occupancy of the Alpine mountain hare Lepus timidus varronis

Mountain hare is a cold‐adapted species threatened by climate change, but despite its emblematic nature, our understanding of the causes of population decline remains limited. Camera traps are increasingly used in ecology as a tool for monitoring animal populations at large spatial and temporal scales. In mountain environments where field work is constrained by difficult access and harsh conditions, camera traps constitute a promising tool for surveying rare and elusive species such as the mountain hare. Our study explored the use of camera traps as a tool for studying seasonal habitat occupancy and daily activity patterns of the mountain hare, in order to carry out long‐term monitoring of populations. We installed 46 camera traps along elevation gradients in the Mont‐Blanc massif (France) from January 2018 to June 2022. We measured habitat variables at each camera trap site in order to define vegetation composition and habitat structure. We performed multi‐season and single‐season occupancy models to respectively describe habitat occupancy of the mountain hare throughout the year and identify the environmental variables influencing mountain hare presence during the breeding season. Mountain hares occupy coniferous forest in winter, and then switch to mixed areas of shrubland and grassland above treeline in spring and the beginning of summer. In spring, occupancy probability of the mountain hare increases with relative cover of mixed low shrub and herbaceous layer (i.e. the 10–40 cm vegetation layer), suggesting a link to food resources and protection from predation. Our results also confirm the nocturnal and crepuscular activity of the mountain hare during the breeding season, and strictly nocturnal activity in winter. Our results demonstrate the efficiency of camera traps as tools for monitoring mountain hare habitat occupancy in mountain environments and underline the importance of diverse habitat mosaics for the preservation of the species.

Диалоги в сказке «Морозко»: правила разговора и магия

Russian — and not only Russian — folk tales are often scary and paradoxical. Characters of the Morozko fairy tale are particularly cruel. At the beginning of the story the father does not hesitate to send his own daughter to die in a winter forest at the whim of his wife. Then Morozko himself kills the heroine for her words that it is cold in the winter forest. In this text we will try to find some logic in the tale with the help of Harvey Sacks’ theory. We will also try to explain why one cannot say that it is cold in a cold forest in fairy tales.

Divergent seasonal patterns and drivers of soil respiration in alpine forests of northwestern China

Uncertainty about winter carbon (C) fluxes and their drivers hinders the accurate estimation of C budgets in high-latitude and high-altitude ecosystems. We conducted 3-year-long field observations of soil respiration (Rs) in an alpine forest in northwestern China. The results showed that the mean winter Rs ranged from 193.79 to 233.03 g C m−2 year−1 and significantly increased with elevation, while the mean growing season Rs ranged from 467.29 to 711.25 g C m−2 year−1 and significantly decreased with elevation. The ratio of winter to annual soil CO2 emissions ranged from 21.96 to 34.24 %. The Q10 value (temperature sensitivity of Rs) also varied seasonally, with significantly higher values in winter (3.00–3.85) than in the growing season (2.08–2.22). During the growing season, the Rs was directly regulated by soil temperature (ST), fine root biomass, and microbial activity and indirectly regulated by nitrate nitrogen via an increase in fine root biomass and microbial activity. In addition to the direct effects of soil moisture (SM), ST, and the ratio of fungi to bacteria (F/B) on winter Rs, we revealed another effect: the indirect effect on Rs of the interaction of ST with SM (decreasing ST and increasing SM) with elevation by reducing the soil aggregate stability, probably improving the organic substrate availability, and decreasing the F/B. The ST was the most important factor affecting the growing season Rs, and SM had the greatest effect on the winter Rs. Overall, our findings indicated that the patterns and underlying mechanisms of Rs dynamics in alpine forests in winter are different from those in the growing season and that research on winter Rs dynamics in alpine forests under future climate conditions is needed due to the greater temperature response of Rs in winter than in the growing season.

Objects Camouflage Possibilities Analysis in the Modern Military Conflicts Conditions

The article analyses the methods of camouflage used in modern military conflicts. The article gives a historical overview of camouflage of military equipment and personnel since the beginning of the twentieth century. The mathematical and physical principles that should be taken into account in the manufacture of camouflage nets are discussed, the requirement for which is the difficulty in recognising and differentiating between an artificial surface and real terrain. The mathematical model of a camouflage net pattern is a fractal, a self-similar scale-invariant object of noninteger topological dimension. From the point of view of physics, the fractal dimension is a statistical value that demonstrates how densely a fractal fills a space. This means, in particular, that by dividing a photo of a real surface into cells and then counting the number of black cells in relation to all of them (in the simplest case of a photo of a winter forest, for example), you can find out the average indicator of the landscape's scale similarity, which can be reproduced on a camouflage grid. In the context of active military operations caused by russian aggression, for effective camouflage, it is proposed to use the concepts and methods of fractal geometry in the manufacture of camouflage means, in particular camouflage nets, to maximise the imitation of natural landscapes and structures that will not be easy to recognise.

К. Коровин –эмигрант: родной край в воспоминаниях художника

Konstantin Korovin is a famous Russian artist, one of the first Russian impressionists, as well as a theater decorator. The artist was highly sensitive to the beauties of the nature of his native land, and his oeuvre consists mostly of landscapes. In 1922, being at his senior age, Korovinwas forced to move to one of the centers of Russian emigration –Paris. Life away from his motherland becomes one of the reasons for the painter’s artistic crisis. It was during these difficult years that Korovin began to engage in literary work. Korovin writes memoirs, significant part of which is memories of the abandoned but much beloved motherland.The article provides a comparative study of pictorial and verbal figurativeness in Korovin’s works. The cycle On the Huntincludes a short story Frost, where the landscape plays a key role in the plot. Ananalysis of the poetics of figurativeness in this story reveals the features of pictorial impressionism in the verbal images. The article analyzes the techniques that the memoirist employs to create the image of his motherland. The key words-leitmotifs, color palette, lighting effects, and other means of creating a lyrical landscape are also analyzed. There are found to be some parallels between Korovin’s literary descriptions of landscapes and his landscape paintings of winter forest. The paper draws a conclusion about the similarity of impressionistic techniques in paintings and the story by Korovin; the features specific to literary (verbal) fig-urativeness are noted, for example, folklore traditions and allusions to Russian poetic classics, the change in the narrator’s points of view, changes in emotional tonality, which forms the basis of the lyrical plot in the story Frost.The methodological framework of the study is based on comparative-typologicaland system-semantic principles of analysis, with elements of genre and style analysis.

Evaluation of IMERG Precipitation Products in the Southeast Costal Urban Region of China

The intensification of extreme precipitation has aggravated urban flood disasters, which makes timely and reliable precipitation information urgently needed. As the high-quality and widely used satellite precipitation products, Integrated Multi-satellitE Retrievals for GPM (IMERG), have not been well investigated in coastal urban agglomerations where damages from precipitation-related disasters are more severe. With precipitation measurements from local high-density gauge stations, this study evaluates three IMERG runs (IMERG ER, IMERG LR, and IMERG FR) in the southeast coastal urban region of China. The evaluation shows that the three IMERG products severely overestimate weak precipitation and underestimate heavy precipitation. Among the three runs, the post-corrected IMERG FR does not show a substantial improvement compared to the near-real-time IMERG ER and IMERG LR. The performance of IMERG varies depending on the precipitation pattern and intensity, with the best estimation ability occurring in the coastal urban region in summer and in the northern forests in winter. Due to the year-round urban effect on precipitation variability, IMERG cannot detect precipitation events well in the central high-density urban areas, and has its best detection ability on cultivated lands in summer and forests in winter. Within the urban agglomeration, IMERG shows a poorer performance in areas with higher urbanization levels. Thus, the IMERG products for coastal urban areas need considerable improvements, such as regionalized segmental corrections based on precipitation intensity and the adjustment of short-duration estimates by daily or sub-daily precipitation measurements.

Analytical Model for the Load-Bearing Capacity Analysis of Winter Forest Roads: Experiment and Estimation

In northern forests, winter is the preferred time for logging operations, since, when wet soils freeze, their strength increases, which ensures a high load-bearing capacity of winter forest roads and reduces the cost of forestry work by increasing the load on forestry equipment, including when driving through frozen lowlands. The present article analyzes frozen loamy–sandy soil, which, at subzero temperatures, behaves like a brittle material with a sufficiently high, but limited, strength. Well-known models commonly use empirical parameters, correlations, and numerical methods to estimate the strength of such materials. An analytical model of the full load–displacement curve would reduce the number of necessary calculations and increase the ability to predict the bearing capacity of winter forest roads. However, there are few of these models. Such models were developed, as a rule, to study stress–strain in concrete and rocks, meaning that researchers have to recalculate the load into stress and displacement into deformation, which is not always simple. This work aimed at theoretically justifying a new analytical model for quantifying the bearing capacity of winter forest roads and assessing the adequacy of the model by comparing it with experimental data. To achieve this purpose, the concepts of fracture mechanics and methods of mathematical modeling were used. The model was verified using experimental data, and model examples for determining the peak load were provided. Prospects for development of the research topic were also considered, taking into account new developments in forest road monitoring for logging management.

Robust Algorithms for Drone-Assisted Monitoring of Big Animals in Harsh Conditions of Siberian Winter Forests: Recovery of European elk (Alces alces) in Salair Mountains.

Simple SummaryForest animals can be used as a sensitive indicator of the real state of biodiversity. The research objective was to study the potential of drone planes equipped with thermal infrared imaging cameras for large animal monitoring in the conditions of Siberian winter forests with snow background at temperatures of −5 °C to −30 °C. The surveyed territory included the Salair State Nature Reserve in the Kemerovo Region, Russia. Drone planes were effective in covering large areas, while thermal infrared cameras provided accurate information in the harsh winter conditions of Siberia. The research featured the population of the European elk (Alces alces), which is gradually deteriorating due to poaching and deforestation. The designed technical methods and analytic algorithms are cost-efficient and they can be applied for monitoring large areas of Siberian, Canadian and Alaskan winter forests.There are two main reasons for monitoring the population of forest animals. First, regular surveys reveal the real state of biodiversity. Second, they guarantee a prompt response to any negative environmental factor that affects the animal population and make it possible to eliminate the threat before any permanent damage is done. The research objective was to study the potential of drone planes equipped with thermal infrared imaging cameras for large animal monitoring in the conditions of Siberian winter forests with snow background at temperatures −5 °C to −30 °C. The surveyed territory included the Salair State Nature Reserve in the Kemerovo Region, Russia. Drone planes were effective in covering large areas, while thermal infrared cameras provided accurate statistics in the harsh winter conditions of Siberia. The research featured the population of the European elk (Alces alces), which is gradually deteriorating due to poaching and deforestation. The authors developed an effective methodology for processing the data obtained from drone-mounted thermal infrared cameras. The research provided reliable results concerning the changes in the elk population on the territory in question. The use of drone planes proved an effective means of ungulate animal surveying in snow-covered winter forests. The designed technical methods and analytic algorithms are cost-efficient and they can be applied for monitoring large areas of Siberian and Canadian winter forests.

Higher canopy interception capacity of forests restored to the climax stage in subtropical China

AbstractCanopy interception loss is an important hydrological process that affects rainfall redistribution, nutrient cycling, and soil and water conservation in forest ecosystems. However, the manner in which interception loss is affected in forests that are in restoration stages dominated by different tree species has not been fully understood. In this study, interception loss, throughfall, and stemflow were measured consecutively for 2 years (May 2017 through April 2019) in three secondary forests in subtropical China: a coniferous and broadleaved mixed forest (Pinus massoniana, Lithocarpus glaber, PM) in early restoration stage, a deciduous broadleaved forest (Choerospondias axillaris, CA) in middle restoration stage, and an evergreen broadleaved forest (L. glaber–Cyclobalanopsis glauca, LG) in late restoration stage. For a given amount of rainfall, the relative interception loss in the CA was significantly lower than that in the evergreen forests in summer, spring, or winter. The amount of interception loss during light rain, moderate rain, or heavy storms was also significantly lower in CA as compared to that in evergreen forests, owing to the lesser leaf area and phenology of deciduous tree species as well as a higher leaf area index (LAI) and stand density in PM and LG. Meanwhile, the highest relative interception loss, interception loss amount, canopy storage capacity, canopy cover fraction, and mean evaporation rate was observed in the climax forest (LG), which has a higher LAI and stand density. Further, the revised Gash's analytical model (RGAM) and the sparse Rutter models were successfully applied to simulate interception loss in these forests, with the RGAM performing better as compared to the sparse Rutter model. The results of the field measurements and model simulations depict that the climax community at the late restoration stage can effectively reduce the amount of rainwater reaching the soil surface, thus weakening the effect of flood peaks.

Generation of secondary organic aerosols on needle surfaces and their entry into the winter forest canopy under radiometric photophoresis

Generation of secondary organic aerosols on needle surfaces and their entry into the winter forest canopy under radiometric photophoresis

Latitudinal difference in the molecular distributions of lipid compounds in the forest atmosphere in China

Lipids are important biogenic markers to indicate the sources and chemical process of aerosol particles in the atmosphere. To better understand the influences of biogenic and anthropogenic sources on forest aerosols, total suspended particles (TSP) were collected at Mt. Changbai, Shennongjia, and Xishuangbanna that are located at different climatic zones in northeastern, central and southwestern China. n-Alkanes, fatty acids and n-alcohols were detected in the forest aerosols based on gas chromatography-mass spectrometry. The total concentrations of aliphatic compounds ranged from 15.3 ng m−3 to 566 ng m−3, and fatty acids were the most abundant (44–95%) followed by n-alkanes and n-alcohols. Low molecular weight- (LFAs) and unsaturated fatty acids (UnFAs) showed diurnal variation with higher concentrations during the nighttime in summer, indicating the potential impact from microbial activities on forest aerosols. The differences of oleic acid (C18:1) and linoleic acid (C18:2) concentrations between daytime and nighttime increased at lower latitude, indicating more intense photochemical degradation occurred at lower latitude regions. High levels of n-alkanes during daytime in summer with higher values of carbon preference indexes, combining the strong odd carbon number predominance with a maximum at C27 or C29, implied the high contributions of biogenic sources, e.g., higher plant waxes. In contrast, higher concentrations of low molecular weight n-alkanes were detected in winter forest aerosols. Levoglucosan showed a positive correlation (R2 > 0.57) with high- and low molecular weight aliphatic compounds in Mt. Changbai, but such a correlation was not observed in Shennongjia and Xishuangbanna. These results suggest the significant influence of biomass burning in Mt. Changbai, and fossil fuel combustion might be another important anthropogenic source of forest aerosols. This study adds useful information to the current understanding of forest organic aerosols at different geographical locations in China.

Seasonal dynamics of VOCs released from Cinnamomun camphora forests and the associated adjuvant therapy for geriatric hypertension

Cinnamomun camphora is an important species for afforestation in southern China and is widely used in landscaping. To explore the seasonal dynamics of the volatile organic compounds (VOCs) released from Cinnamomun camphora forests and the adjuvant therapeutic effect of forest bathing on elderly patients with hypertension (HTN), the components and relative contents of VOCs released by a Cinnamomun camphora forest were analysed, and the blood pressure and inflammation of elderly patients with HTN experiencing forest bathing were studied. Variations in the components and relative contents of VOCs released by the Cinnamomun camphora forest were detected among the seasons, and the alkanes varied more widely than the other kinds of VOCs. The relative contents of alkanes and organic acids were greater than those of the other kinds of VOCs in spring and winter, while the VOCs released in autumn and summer contained higher proportions of terpenes. Forest bathing in Cinnamomun camphora forests in autumn, summer and spring had a high auxiliary regulatory effect on blood pressure and inflammation in elderly patients with HTN, which may be closely related to terpenes and negative oxygen ions. However, forest bathing in Cinnamomun camphora forests in winter was not conducive to the therapy of elderly patients with HTN. The results not only lay the foundation for research on the release of VOCs from Cinnamomun camphora forests but also provide a reference for studies on the influences of forest bathing on human health.

Seasonal variations in soil physicochemical properties and microbial community structure influenced by Spartina alterniflora invasion and Kandelia obovata restoration

Spartina alterniflora invasion has initiated one of the greatest changes to occur in coastal wetlands in China, and ecological replacement using mangrove species such as Kandelia obovata is an effective method for controlling these invasions. The effects of S. alterniflora invasions and subsequent K. obovata restorations on soil microbial community structures in different seasons are still not fully understood. In this study, soil samples were collected from six vegetation types (unvegetated mudflat, invasive S. alterniflora stands, one-/eight-/ten-year K. obovata restoration areas, and native mature K. obovata forests) in summer and winter. The variations in the soil microbial community structure between the vegetation types across two seasons were then characterized based on 16S rRNA gene sequencing, and the physicochemical properties that shaped the microbial communities were also determined. The invasion and restoration processes significantly influenced microbial community diversity, composition, and putative functions in different seasonal patterns. Microbial communities from a ten-year restoration area and a native mature K. obovata area shared more similarities than other areas. In both seasons, the key environmental factors driving microbial community included total carbon and nitrogen content, the ratio of carbon to nitrogen, and the soil pH. In addition, total sulfur and total phosphorus contents significantly contributed to structuring microbial communities in summer and winter, respectively. This study provides insights into microbial diversity, composition, and functional profiles in association with physicochemical impacts, with the aim of understanding microbial ecological functions during the invasion and restoration processes in wetland ecosystems.

Seasonal dynamics of soil nutrients and microbial activity due to colonization by bracken ferns (Pteridium aquilinum (L.) Kuhn) in a pine forest

Bracken (Pteridium aquilinum) is an aggressive colonizer of disturbed and other successional habitats in temperate forests. However, little is known about how bracken colonization modifies soil microbial activity and nutrient cycling. We questioned whether bracken presence alters soil nutrient pools and soil microbial respiration throughout a growing season and whether this effect depends on the size of the bracken patch. To answer these questions, we sampled the soil in bracken patches of different sizes (large, medium and small) and in the surrounding pine forest (paired sampling design) in summer, autumn, winter and spring. We analyzed the samples to determine nutrient contents (C, N and P) and soil microbial respiration. Patch size did not influence soil microbial activity or nutrient pools. Bracken acted as nutrient sink for N pools through the growing season and as source or sink for C and P pools depending on season. Moreover, the effect on nutrient pools did not depend on bracken characteristics (area, density or height). Bracken presence enhanced soil microbial respiration proportionally to patch area. The control that bracken exerts over nutrient pools may determine the successful (or otherwise) establishment of other plant species. This contributes to making bracken a successful colonizer as no particular population threshold (area, density) has to be reached before nutrients becomes limiting to other plant species.

The effects of viewing a winter forest landscape with the ground and trees covered in snow on the psychological relaxation of young Finnish adults: A pilot study.

Forest bathing is an outdoor activity, and it might be a promising preventive treatment for social problems involving stress. A vast number of studies confirm the positive effects of this activity on people's health. Nevertheless, little is known about the influence of winter forest bathing when conducted in an environment with snow cover on the ground and trees. Thus, a crossover experiment was designed in this study, with the participation of twenty-two healthy university students from Finland. During the experiment, a short exposition by a forest environment or landscape with buildings (as a control) was applied. Participants self-reported their psychological relaxation before and after the exposition, and the results were analyzed and compared. The mood, emotions, restorativeness, and subjective vitality were recorded as indices reflecting the psychological relaxation effect. The negative mood indices decreased significantly after exposition by the snow-covered environment, but the positive 'vigor' indices did not increase or decrease significantly. The level of negative emotions increased after the exposition with the control environment. Likewise, positive emotions decreased after the interaction with the control. Restorativeness was significantly increased after the exposition by the experimental forest but decreased after the viewing of the control buildings. The size of the effect in terms of restorativeness was the highest in this experiment. The subjective vitality was lowered as affected by the control, but it did not increase or decrease after the exposition with the experimental forest. There is probably an effect from the slight interruption in the process from the influence of the forest greens on participants because their vigor and vitality did not increase after the exposition with this environment in the study. However, snow might influence the participants as a calming and emotion-lowering component of the environment, but this idea needs to be further explored with the involvement of participants from other countries who would be viewing forest environments with snow cover and whose psychological relaxation could be measured.

三种不同类型亚高山森林凋落物输入对土壤腐殖化的影响

森林凋落物既是土壤腐殖质的主要来源，也可以通过新鲜凋落物中易降解组分的输入激发土壤原有腐殖质的降解，导致其相互关系并不明确。以王朗国家级自然保护区内的典型亚高山针叶林、针阔混交林以及阔叶林为研究对象，开展土壤原位培养试验，设置允许凋落物正常输入和去除凋落物两种处理，分析2017年-2019年期间不同凋落物处理下森林土壤可提取腐殖物质的光密度特征，研究土壤腐殖化程度与凋落物的关系。结果表明，在2年的试验过程中，3种森林土壤的腐殖化程度整体表现为针叶林>混交林>阔叶林，均展现出在冬季降低，生长季增加的动态规律；凋落物对3个森林的土壤腐殖化程度均无显著影响，但凋落物输入明显改变了土壤腐殖化程度的季节性变化趋势，且在冬季的阔叶林和混交林中表现更为突出。冬季凋落物的输入使得阔叶林和混交林土壤的腐殖化程度明显降低，而生长季凋落物输入对3种森林土壤腐殖化程度无显著影响。这些结果表明气候变暖情景下冬季温度的上升可能导致土壤的腐殖化程度增加，但凋落物的存在可以减缓增加的趋势。这些结果对于具有明显季节性冻融且对气候变化敏感的亚高山森林土壤肥力管理及可持续经营具有一定的科学意义。;Humus is the main component of soil organic matter, which is important for soil fertility and nutrient cycling. Forest litterfall as a carrier of nutrients and carbon plays an essential role in the formation of soil humus. The input of litterfall can provide raw materials for the synthesis of soil humus. However, the evidence shows that the incorporation of fresh organic matter into soil can increase microbial activity due to the higher availability of energy released, then stimulate the degradation of soil humus. These conflicted results can lead to a confusing relationship between litterfall and soil humus. Therefore, we carried out a field incubation experiment in three typical subalpine forests (coniferous, mixed and broadleaved forests) on the eastern Qinghai-Tibetan Plateau. There are two treatments in this experiment. One allowed litterfall to enter the soil normally and the other prevented litterfall to enter the soil. Soils were sampled in October (the end of the growing season), March (the end of the winter season), and September (the middle of the growing season) from 2017 to 2019. Litterfall production, and the values of ΔlogK (the ratio of absorbance at 400 to that at 600 nm on a logarithmic scale), E4/E6 (the ratio of absorption at 465 to that at 665 nm), and A600/C ratios of soil extracted humic substances were analyzed in each period. The results showed that, during the two-year experiment, the overall performance of the soil humification degree in the three forests showed the order as coniferous forest>mixed forest>broadleaved forest, and exhibited an obvious dynamic pattern with decreasing in winter and increasing in the growing season. Statistical analysis indicated that litterfall had insignificant effects on the degree of soil humification in the three forests, but the input of litterfall significantly changed the seasonal tendency of soil humification, which was more prominent in broadleaf and mixed forests in winter. The input of litterfall significantly reduced the degree of soil humification in broadleaved and mixed forest in winter, while had no significant effect on the three forest soils in the growing season. These results suggested that the increase of temperature in winter under the condition of climate warming might lead to an increase in the degree of soil humification, and the presence of litterfall could slow the increase proceeding, which are scientifically significant for soil fertility management and sustainable management in subalpine forests due to seasonal frequent freeze-thaw cycles and the sensitivity to climate change.

Latitudinal Difference in the Molecular Distributions of Lipid Compounds in the Forest Atmosphere in China

Lipids are important biological markers to indicate the sources and chemical process of aerosol particles in the atmosphere. To better understand the influences of biological and anthropogenic sources on forest aerosols, total suspended particles (TSP) were collected at Mt. Changbai, Shennongjia, and Xishuangbanna that are located at different climatic zones in northeastern, central and southwestern China. n-Alkanes, fatty acids and n-alcohols were detected in the forest aerosols based on gas chromatography-mass spectrometry. The total concentrations of aliphatic compounds ranged from 33.2 ng m-3 to 520 ng m-3, and fatty acids were the most abundant (44-95%) followed by n-alkanes and n-alcohols. Low molecular weight- (LFAs) and unsaturated fatty acids (UnFAs) showed diurnal variation with higher concentrations during the nighttime in summer, indicating the potential impact from microbial activities on forest aerosols. The differences of oleic acid (C18:1) and linoleic acid (C18:2) concentrations between daytime and nighttime increased at lower latitude, indicating more intense photochemical degradation occurred at lower latitude regions. High levels of n-alkanes during daytime in summer with higher values of carbon preference indexes, combining the strong odd carbon number predominance with a maximum at C27 or C29, implied the high contributions of biological sources, e.g., higher plant waxes. In contrast, higher concentrations of low molecular weight n-alkanes were detected in winter forest aerosols. Levoglucosan showed a positive correlation (R2>0.57) with high- and low molecular weight aliphatic compounds in Mt. Changbai, but such a correlation was not observed in Shennongjia and Xishuangbanan. These results suggest the significant influence of biomass burning in Mt. Changbai, and fossil fuel combustion might be another important anthropogenic source in Northeast China. This study adds useful information to the current understanding of forest organic aerosols at different geographical locations in China.