Density of Scots pine undergrowth after ground fires in a zone of industrial air pollution

The effects of two exogenous factors, ground fires and industrial air pollution, on natural regeneration of Scots pine (Pinus sylvestris L.) cenopopulations have been studied in the Transural region. It has been found that an increased level of air pollution leads to a decrease in the abundance and occurrence frequency of pine undergrowth; as the intensity of ground fire increases, these parameters of the postfire generation of undergrowth increase as well, especially in background areas. As shown by two-way ANOVA, either of these factors and their interaction have a significant effect on the density of pine undergrowth, with this effect being stronger in the case of ground fires.     

Differences in plant species diversity between conifer (<Emphasis Type="Italic">Pinus tabulaeformis</Emphasis>) plantations and natural forests in middle of the Loess plateau

We compared differences in plant species diversity between conifer (Pinus tabulaeformis) plantations and natural secondary forests in the middle of the Loess plateau. The goal of the study was to examine the differences in the effect of stand development on species diversity and in species responses to changes between forest types and between forest layers. To clarify the effects of differences in forest management, we emphasized the functional types of plant species occurring in each forest type. The result as follow: (1) The H′ and S of tree layer were significantly lower in natural conifer forest than old conifer and secondary forest, but were not different compared with mid aged conifer forest. The H′ and S of shrub layer were significantly lower in mid aged conifer forest compared with other forest types. The H′ of herb layer showed no significant differences in the four forest types. The evenness index (J′) of tree layer of mid aged conifer forest was lower than other forest communities and its J′ of shrub layer was highest although its richness of shrub layer was lower than in the other forest types. (2) The analysis of β diversity index also indicated large differences between conifer plantations and natural forests. Although the tree layer species were similar in old plantation and natural conifer forests, they differed greatly between the natural conifer and secondary forests. The natural conifer and secondary forest species composition in shrub layer differed significantly from those in plantation and secondary plots. Tree species were significantly less common in plantations than in abandoned coppice forests. Species composition in the herb layer of different forest types was similar. (3) The management of P. tabulaeformis plantations alters plant species composition considerably; the number of sub tall-tree species is increased in old aged conifer forest, especially species dispersed by animals. Plantation management appears to affect ecological processes through seed dispersal. From the perspective of management, the change in the structure and composition of the canopy in plantations could affect the behavior of dispersers and regeneration.     

Influence of Clear Fellings on the Bryophyte Component of the Broad-leaved Forests of the Bashkir Cis-Ural Region

The change in the composition of the bryophyte component of succession communities that occur in the process of natural regeneration at the site of clear felling of the indigenous elm—maple–linden forests of the Bashkir Cis-Ural Region has been studied. The vulnerability of species to the consequences of felling is affected by their substrate confinement, ecological amplitude in relation to the factors of temperature, humidity, variability of soil moisture, and type of life strategy. In the secondary aspen forests, the absence or low constancy of nemoral epiphytic and ground mosses was noted.     

Competition factors of edificator tree stand: Quantitative analysis and synthesis

To analyze and quantitatively estimate the contribution of different factors of competition from the edificator tree stand to its effect on plants comprising the lower forest vegetation layer, a set of ecophysiologically based indices of root, light, and integrated competition has been proposed and tested. The results obtained in pine and spruce forests forests of Western Siberia and the Urals show that the growth of the conifer undergrowth is more closely correlated with the index of root competition, and that of heather (Calluna vulgaris (L.) Hull.), with the index of light competition from the edificator tree stand. Moreover, the correlation of their growth with the integrated competition index is 15?C25% stronger than the correlation with the indices of root and light competition, irrespective of forest type.     

Land-use legacies in the forest structure of silvopastoral oak woodlands in the Eastern Mediterranean

Eastern Mediterranean silvopastoral oak woodlands have been greatly damaged through forest conversion, illegal lumbering, overgrazing, and forest fires. The aim of this study was to assess land-use changes and the legacies that they have imprinted on the forest structure of Quercus macrolepis and accompanying Quercus pubescens and Quercus cerris woodlands on Lesvos Island, Greece. The size structures of adult oak populations were analyzed as indicators of long-term oak regeneration, while short-term recruitment was determined by counting oak seedlings and saplings. The size structure of the adult Q. macrolepis population was similar to the inverse J-shaped distribution typical for natural Mediterranean oak forests, indicating continuous recruitment with a constant mortality rate of mature individuals. Seedling and sapling densities were highly variable, but generally low in relation to adult oak densities. Recruitment of oak seedlings and saplings was positively related to determinants such as forest cover, adult oak density and basal area, woody plant richness, and litter cover. Both seedling and sapling occurrence were negatively associated with dung frequency, which suggests that sheep grazing imposes a barrier to oak recruitment. The study outlines a comprehensive land-use transition from the 1950 to 1970s, during which a complex and multifunctional agrosilvopastoral land-use system was simplified to an intensive grazing system. The discrepancy between the successful long-term regeneration and the less successful short-term recruitment of oaks illustrates that intensified livestock grazing has been a major driver of vegetation change. Grazing impact is likely to interact with increasing drought conditions, which may trigger a negative feedback cycle that undermines the capacity of woodlands to sustain ecosystem services.     

Microecosystem Analysis of the Structure and Functions of Forest Biogeocenoses

The microecosystem approach and an adequate system of quantitative methods have been used to study the relationship between the chorologic changes in the structure and functions of edificator tree stand and other components of the pine (Pinus sylvestris L.) forest cenoecosystems of the Transural and Northern Turgai regions. Significant correlations of the density of pine undergrowth with the litter thickness; of its growth with root competition, stand closeness, and, to a lower degree, photosynthetically active radiation (PAR); and of the numbers of small mammals and groups of soil mesofauna with herbaceous phytomass have been found. The possibility of the synthesis of population-ecological, synecological, and biogeocenological methods has been demonstrated.     

Forest structure and regeneration along the altitudinal gradient in the Binsar Wildlife Sanctuary,Uttarakhand Himalaya,India

Forest structure and regeneration were studied along the altitudinal gradient in the Binsar Wildlife Sanctuary of Uttarakhand Himalaya in India. Stratified random sampling of tree species was done by placing minimum 15 quadrats of 10 × 10 m at each aspect and altitude. The results reveal that along the altitudinal gradient there were three types of forest communities in the Sanctuary viz., chir pine (Pinus roxburghii), oakchir pine (Quercus leucotrichophora and Pinus roxburghii) and oak (Quercus floribunda and Quercus leucotrichophora). Rhododendron arboreum, Cornus macrophylla and Lyonia ovalifolia were main associates of these forest communities. The oak forests had larger shrub population as compared to chir pine. Myrsine africana was the most dominant shrub across the altitudinal gradient, whereas few shrub species were restricted to a certain altitudinal range. The regeneration of chir pine was best at lower altitude on south and east aspects, which indicates that it mostly regenerates on warm and dry slopes. In general, the regeneration potential in most of the tree species declines with the altitude. The density of saplings and seedlings also represented the dominant species at each altitudinal range, which indicates the cyclic regeneration of forests in the Sanctuary area.     

The role of remittances and decentralization of forest management in the sustainability of a municipal-communal pine forest in eastern Guatemala

At the national scale, forest cover in Guatemala declined at an annual rate of 1.2% during the past quarter century because of settlement that removed primary forests in the northern region of the country; however, the majority of the population of Guatemala still resides in the densely populated central highlands and has extracted timber and fuelwood from adjacent forests for centuries. Using baseline data recorded in 1987 and 1996, this article reexamined the sustainability of a municipal-communal pine forest in San José La Arada, a municipality in eastern Guatemala. The pine forest declined from the period 1987 to 1996 because of overextraction of timber and fuelwood. Forest structure and forest use were reexamined from the period 1996 to 2007 to test the hypothesis that the forest continued to decline. Forest characteristics such as stand density, basal area, tree height, and evidence of forest use were measured to replicate the procedures from previous work at the study area. To understand changes in forest structure and forest use in the context of the rise in remittances and the introduction of decentralized forest governance that emerged since 1996, a household survey was conducted in two adjacent villages. Forest structure improved from 1996 to 2007. From 1996 to 2007, forest characteristics such as stand density, basal area, tree height, and forest regeneration improved and evidence of forest use decreased in the municipal-communal pine forest. The influence of large amounts of remittances from the United States and other regions of Guatemala to households in the adjacent villages and the decentralization of forest governance largely explains the shift toward forest sustainability in San José La Arada.     

Autumn bed site selection by sika deer (<Emphasis Type="Italic">Cervus nippon</Emphasis>) in the Taohongling National Nature Reserve,China

To better understand the habitat requirements of sika deer in the Taohongling National Nature Reserve, transect lines were set out to collect data on bed sites used by sika deer during the autumn. The results showed that sika deer displayed a preference for bed sites with a moderate height of grass fallow and brush fallow, lower shrub density, higher herb density, lower canopy coverage, and higher undergrowth coverage. The bed sites were also characterized as being located on sunny slopes, gentle slopes, and upper slopes, with high elevation. In addition, most bed sites were located far away from human disturbance (more than 1000 m). A logistic regression analysis model indicated that undergrowth coverage, slope location, canopy coverage, and height of undergrowth were important factors that contributed to the difference between used and non-used plots. The habitat–animal relationship is one of the most important types of information, which could provide important references for the conservation and management of sika deer and their habitats in the Taohongling reserve.     

森林对污染物（SO2-4）的过滤器效应研究

森林的过滤器效应是指森林对污染物所具有的净化缓冲作用，这是森林生态系统所具有的重要生态服务功能之一。森林生态系统对污染物的截留、吸附与净化一般是通过污染物在森林生态系统中的乔木层与灌草层植物、枯落物和土壤（微生物）等组分间的转化过程来实现，阐明森林生态系统各组分对污染物的净化效应是正确评估森林过滤器效应的关键。系统综述了森林生态系统各组分对污染物净化效应的国内外主要研究成果，指明了目前该方面研究存在的问题和努力的方向,并指出目前国内已有的大多数研究还处于实验观测与现象揭示阶段，缺乏对过程与机理的深入研究，很少进行多因素的动态综合研究和系统分析，这都限制了我们对森林生态系统对污染物净化过程内在运行机制和客观规律的正确认识和评估。把整个森林生态系统当作一个过滤器，从植物、凋落物、土壤、微生物几个亚系统方面介绍了森林过滤器对污染物净化缓冲作用方面的主要研究进展。     

Divergence of biogeocenoses within pine forest types

The paper is devoted to the analysis and generalization of the results of stationary studies on differentiation of factors of the epi-soil environment, natural forest regeneration, and formation of secondary dendrocenoses on burns and clean cuts in two pine forest types most prevalent in the pre-forest–steppe subzone of Western Siberia (Pripyshmiskian pine forests). It is shown that the same primary forest type (or even biogeocenosis) in burns, on the one hand, and in clean cuts, on the other hand, is replaced by two types of biogeocenoses that are alternative to each other in terms of structure and functions and represent qualitatively different, diverging ecodynamic series of natural regeneration and development of the primary, autochthonous forest type.     

New Development in Study of the Faustmann Optimal Forest Harvesting

Abstract

Chinese forest resources have become very scarce in the face of rapid economic growth demand, while the reform of collective forest right system is in full swing across the country. It will directly affect the regeneration level of forest resources and the diverse ecological value functions. In this article, the mainstream model paradigm of forest economics, that is, the basic framework of the Faustmann model and its evolution process are made in a more detailed explanation, especially the extended model including considered silvicultural effort, tax subsidies, risk dynamic management, and forest regeneration factors are made in more detailed explanations. This article concludes with the future further research directions of forest economics, including the design of dynamic models that includes considered uneven-aged forest management, non-timber goods and services, dynamic forest models. The research reflects the general trend of interdisciplinary and cross-border.     

Irregularity in frequency of mast seed years in <Emphasis Type="Italic">Quercus floribunda</Emphasis> a late successional species of Central Himalaya

The mid altitudinal oak, Quercus floribunda forms predominantly evergreen forest in Central Himalaya between 2000–2400 m. It is late successional, mature phase species that has limited regeneration on disturbance prone sites. This oak produces mast seed crops at an interval of 2–3 years. During masting in Q. floribunda the seed fall and germination is upto ten times greater than in normal years, emphasizing the importance of mast year crop in forest maintenance. However, no mast year in this species since the last nine years (1997–2005) is a matter of serious concern. The rise in the summer and winter temperature over a period of 15 years appear to have affected the frequency of masting in this oak. The importance of masting can be adjudged from the fact that 97% of the surviving seedlings m⁻² are of the mast year crop.     

Effect of temperature and precipitation on linear increment of <Emphasis Type="Italic">Sphagnum fuscum</Emphasis> and <Emphasis Type="Italic">S. magellanicum</Emphasis> in Western Siberia

The linear increment of Sphagnum fuscum and S. magellanicum in ombrotrophic mires of Western Siberia has been measured during two years over a transect about 2500 km long extending from forest–steppe to forest–tundra. Along the latitudinal gradient, the increment of both species has proved to be correlated with annual average air temperature and, in S. magellanicum, also with annual precipitation. The determinants of their growth differ between the southern, central, and northern parts of the study region. At the regional level, the annual and summer precipitation plays a more important role than the average air temperature. The increment of S. fuscum in the southern part is positively correlated with the amount of precipitation and negatively correlated with summer temperature, whereas the situation in the central part is inverse. In S. magellanicum, the linear increment is directly dependent on the annual average temperature and annual and summer precipitation in the south and on the annual and summer precipitation in the north of Western Siberia. The dynamics of linear growth of both species in bog pine forests during the growing season are similar: its rate is the highest in June, when the linear increment of S. fuscum and S. magellanicum amounts to 60 and 85% of the annual total, respectively.     

Tree vegetation of the forest-tundra ecotone in the Western Sayan mountains and climatic trends

Parameters of reproduction of the Siberian stone pine (Pinus sibirica), including radial and apical tree increments, the age structure of stands, the amount of young growth, and its distribution along an altitudinal gradient, have been studied in the forest-tundra ecotone of the Western Sayan. The results show that, over the past 30 years, P. sibirica undergrowth has expanded to the mountain tundra belt, the apical and radial tree increments and stand density have increased, and the life form of many P. sibirica plants has changed from prostrate to erect (single-or multistemmed). These changes correlate with the dynamics of summer temperatures and monthly (in May and June) and annual precipitation. The rise of summer temperatures by 1°C promotes the expansion of P. sibirica undergrowth for approximately 150 m up the altitudinal gradient.     

The Occurrence of Carpinus,Fagus, Tilia,and Quercus Pollen in Subrecent Spore–Pollen Spectra from the East European Plain: On the Possibility of Long-Distance Pollen Transfer

Subrecent spore–pollen spectra have been analyzed for the occurrence Carpinus, Fagus, Tilia, and Quercus pollen in the East European Plain to evaluate the possibility of long-distance pollen transfer. Analysis was based on the material from the Russian Palynological Database on 250 points in different regions of European Russia and neighboring countries and on data from published sources. Pollen of oak, linden, and hornbeam has been found in surface samples taken within the natural ranges of these species and in regions of their introduction, with linden and oak pollen being transferred by air for several tens of kilometers, and hornbeam pollen, for about 200 km. Beech pollen can be transferred by wind for long distances, and its presence in spectra has been recorded farther than 1000 km from the species range boundaries. The proportion of components transferred from long distances increases in spore–pollen spectra from regions with sparse or poorly developed plant cover, and single occurrences of broadleaf tree pollen are also possible in such regions.

     

Small mammal communities in forest ecosystems affected by urbanization

A set of characters has been used to evaluate transformations in forest phytocenoses and their small mammal communities affected by urbanization, compared to conditionally undisturbed phytocenoses (communities). In park forests of the city of Yekaterinburg, the understory and subordinate shrub and herb-dwarf shrub layers of phytocenosis are transformed to a greater extent. The undergrowth of conifer forestforming species is as a rule sparse or absent, and that of deciduous trees often consists mainly of invasive species. Small mammal communities in pine forests transformed under the effect of urbanization also undergo changes leading to the formation of relatively stable (for an urbanized environment) zoocenoses differing both in species composition and in parameters characterizing community diversity.     

Influence of aspect and location of stands on biodiversity in a Sal mixed broadleaved forest in Kumaun central Himalaya

In the present study total 21 forest stands on different aspects and locations (Hill base, mid slope and ridge top) on the slope were studied to assess the importance of these two parameters in supporting species regeneration and biodiversity in a mixed broadleaved forest between 380 and 850 m elevation in the Kumauau Himalayan region. A total of 36 tree species were recorded in the forest. In all aspects the tree, sapling and shrub richness was higher at hill base stands in comparison to mid slope and ridge top stand. Maximum tree richness (average across all aspects) was 9.7 and shrub richness was 9.3. Higher richness at hill base may be attributed to more soil moisture and deeper soils which accumulate the hill base where the slope steepness declines. The tree richness was higher in the northern aspect whereas southern aspect was more suitable for the shrub species. From the present study it becomes evident that the base of the hills can support higher biodiversity and are instrumental in supporting regeneration of several tree and shrub species in sal mixed broadleaved forest.     

Spatial Distribution of Heavy Metals and <Superscript>137</Superscript>Cs in Spruce Forest Soil under Conditions of Regional Pollution

The influence of horizontal structure of spruce forest on the spatial distribution of acid-soluble Zn, Cd, Pb compounds and ¹³⁷Cs in the litter and the humus horizon of soddy podzolic soil has been studied in the territory with the regional background level of industrial fallout. It has been found that the distribution pattern of Zn in the forest litter is a result of biogeochemical processes. The litter in fern–wood sorrel microplots contains increased amounts of Zn and Cd, while the contents of Pb and ¹³⁷Cs are decreased. The distribution patterns of Pb and ¹³⁷Cs in the litter are positively correlated with each other, since both elements are deposited from the atmosphere, and similar mechanisms account for their redistribution in the spruce forest ecosystem.     

Chronosequence-based population structure and natural regeneration of <Emphasis Type="Italic">Haloxylon ammodendron</Emphasis> plantation in the southern edge of the Gurbantunggut Desert,Northwestern China

In the Gurbantunggut Desert of Northwestern China, we surveyed the population structure and regeneration characteristics of six Haloxylon ammodendron plantations based on chronosequencing. The results showed that the age class of an individual H. ammodendron plant from youngest to oldest showed growth potential under the present environment. The optimal termination stage of H. ammodendron occurred at 20 years of age, which was accompanied by a regeneration phase at 17 years. The H. ammodendron plantations started to regenerate after 7 years. The maximal height and basal stem diameter of a grade III seedling reached 1.2 m and 1.9 cm in a 17-year-old plantation. In a 33-year-old plantation, the transformation rate of the seedling from grade I to grade III increased up to 92.3%. Although the seedling bank was plentiful in the plantations, the replenishment of the canopy was not continuous and timely. Therefore, measures to further the stability and sustainability of H. ammodendron plantation were necessary.