Forest Monocultures Research Articles

Short-Term Effects of the Management Intensities on Structure Dynamic in Monoculture Forests of Southern Subtropical China

Conversion from timber-dominated forestry to forest ecosystem management needs a rational management intensity to manage forest structure, which should be decided upon by managers and scientists as well as stakeholders. However, few studies have attempted to quantify optimal silvicultural measures for forest management intensity. Here, we examined the short-term effect of light and heavy management intensities on structure dynamics (tree composition, diversity, volumes and slenderness) in monoculture forests of southern subtropical China. Species diversity was generally lower in the heavy-intensity forests than in the light-intensity forests. The range in diameters was larger in the logged forest compared to control ones. The stand volume varied greatly between management intensities. Though higher trunk slenderness value (>80) indicates higher susceptibility to meteorological disturbance such as wind storm and heavy snow, trunk slenderness in the control and the heavy-intensity plots increased significantly compared to that in the light-intensity plot. These results suggest that stand structure dynamic are influenced by different management intensities. We conclude that light-intensity management enhances the richness and affects their patterns of diversity, and heavy-intensity management promotes an increase in understory diversity and regeneration but deficits in volumes and basal areas. In summary, we provide insights beyond traditional studies on different management intensities and levers to sustainable development of forestry. Our study also emphasises the importance for forest managers' understanding between management and conservation of monoculture forest. Nevertheless, variation in structure response to management intensity calls for careful consideration in future strategies, not only of which structure to favor during operations, but also, of how the treatments are applied.

木兰围场典型落叶松-杨桦混交林生物量及固碳能力研究

A mixed Dahurian larch and polar birch forest,artificial Larix principis-rupprechtii forest,natural Betula platyphylla secondary forest,and natural Populus davidiana secondary forest,which are all part of the Bei-gou Forest Farm in Mulan Forestry Bureau were studied here. The layered cut method was used to measure aboveground biomass in all four forests. The layered mining method was used to measure underground biomass. The trunks were divided into segments 0. 5m in diameter and 5 cm thick. The north-south diameter of each disk was recorded. Tree roots were divided into 0. 5 cm layers,and the crown projection area was dug up. Fresh weights of the trunks( with bark),branches,leaves,and roots of model trees were recorded in the open air. Samples of each organ were dried to( 105℃) constant weight and weighed. To determine biomass,leaf and branch samples were collected from different parts of the crown cover. They were weighed and dried,and their moisture content was calculated. For trunks,disk sections were obtained and weighed before and after drying. Moisture content was calculated. The leaf,branch,and root biomass of each model tree was calculated. Incrementswere measured in analytic trees. Then models of biomass and increments were established. Carbon reserve and carbon sequestration were estimated. Significant power functions and logistic equations were chosen as biomass prediction models.DBH( diameter at breast height) served as an independent variable and the napierian logarithm of biomass and total biomass of organs as the dependent variable. Optimization was performed according to regression curve and residual sum of squares( SSE),discriminant coefficient( R2),total relative error( RS),average relative error( E1),absolute value of average relative error( E2),AIC( Akaike Information Criterion),and BIC( Bayesian Information Criterion). DBH increments were measured with analytic trees,wooden cores,and DBH increments of the past five years as a baseline. A power function regression model was established. Then the DBH increments of trees over the past five years were estimated.Then the fixed carbon content of each forest was calculated for that period using the carbon content of different tree species and organs. Results showed the Dahurian larch and polar birch mixed forest stored more carbon than other forests. The Dahurian larch,Betula platyphylla,and Populus davidiana in the mixed forest were all superior to their respective artificial and natural forests. The mean DBH( diameter at breast height) was higher by about 6. 7%,12. 8%,and 4. 1%. The mean was higher by about 12. 1%,1. 4%,and 11. 1%. The fixed carbon content growth rates of Dahurian larch,Betula platyphylla,and Populus davidiana in the mixed forest were 29. 74%,28. 36%,and 34. 52%,respectively. The rate of carbon fixation was 27. 09% in the artificial Larix principis-rupprechtii forest; 26. 34% in the natural Betula platyphylla secondary forest; and 26. 24% in the natural Populus davidiana secondary forest. The rates of carbon fixation of Dahurian larch,Betula platyphylla,and Populus davidiana in the Dahurian larch and polar-birch mixed forest were 2. 65%,2.02%,and 8. 28% higher,respectively,than in the corresponding monoculture forests.

Modelling long-term water yield effects of forest management in a Norway spruce forest

Intensive forest management is one of the main land cover changes over the last century in Central Europe, resulting in forest monoculture. It has been proposed that these monoculture stands impact hydrological processes, water yield, water quality and ecosystem services. At the Lysina Critical Zone Observatory, a forest catchment in the western Czech Republic, a distributed physics-based hydrologic model, Penn State Integrated Hydrologic Model (PIHM), was used to simulate long-term hydrological change under different forest management practices, and to evaluate the comparative scenarios of the hydrological consequences of changing land cover. Stand-age-adjusted LAI (leaf area index) curves were generated from an empirical relationship to represent changes in seasonal tree growth. By consideration of age-adjusted LAI, the spatially-distributed model was able to successfully simulate the integrated hydrological response from snowmelt, recharge, evapotranspiration, groundwater levels, soil moisture and streamflow, as well as spatial patterns of each state and flux. Simulation scenarios of forest management (historical management, unmanaged, clear cutting to cropland) were compared. One of the critical findings of the study indicates that selective (patch) forest cutting results in a modest increase in runoff (water yield) as compared to the simulated unmanaged (no cutting) scenario over a 29-year period at Lysina, suggesting the model is sensitive to selective cutting practices. A simulation scenario of cropland or complete forest cutting leads to extreme increases in annual water yield and peak flow. The model sensitivity to forest management practices examined here suggests the utility of models and scenario development to future management strategies for assessing sustainable water resources and ecosystem services.Editor D. Koutsoyiannis

Diversity of arbuscular mycorrhizal fungi in undisturbed forest, slash-and-burn field, and monoculture forest of Indo-Burma megadiverse region

Conversion of pristine forests to agricultural lands is one of the leading causes of biodiversity loss worldwide. To assess the impact of such forest disturbance on microbial diversity, we investigated the diversity of arbuscular mycorrhizal fungi (AMF) in the rich forests of Karbi Anglong hills of Assam, a biodiversity hotspot part of Indo-Burma region. AMF spore diversity was assessed in distinct study sites with different intensities of disturbances that encompassed a pristine undisturbed forest (UF), slash-and-burn field (SBF), and monoculture forest (MF). A total of 35 arbuscular mycorrhizal (AM) fungal species belonging to 9 genera were isolated. Species forming glomoid spores were dominant in all the three sites followed by acaulosporoid spores. Highest spore density was found in UF and lowest in MF. Multivariate analyses revealed similarity in UF and SBF. It was found that in MF, AMF diversity was significantly modified and reduced, resulting in an ecological degraded ecosystem. Our results show that natural UF and SBF contained similar and a high AM fungal diversity. The AM fungal diversity is not significantly affected by the slash-and-burn agricultural land use practices practised by the ethnic hilly tribes and, therefore, could be a component of a tropical forest “conservation-agriculture matrix.” Also because of the high generic and species diversity found, this region can be considered as AMF hotspot and a priority place for conservation.

Comunidade de fungos Agaricomycetes em diferentes sistemas florestais no noroeste do Estado do Rio Grande do Sul, Brasil: Floresta Estacional Decídua e monocultura de eucalipto

As monoculturas diferem de matas nativas em relação à heterogeneidade vegetal, variedade de substratos e umidade do solo, podendo afetar a diversidade de organismos, tais como os fungos. O objetivo deste trabalho foi comparar a riqueza, abundância e composição de fungos Agaricomycetes em uma mata nativa e em uma monocultura de eucalipto. As coletas dos fungos foram realizadas em uma área de Floresta Estacional Decídua e em uma monocultura de Eucalyptus grandis, no noroeste do Estado do Rio Grande do Sul, Brasil. A abundância e riqueza de fungos na monocultura de eucalipto foram significativamente inferiores às encontradas na mata nativa, assim como a composição de espécies diferiu entre as áreas. Portanto, a monocultura de eucalipto afeta negativamente a comunidade de fungos Agaricomycetes.

Diversity of Arbuscular Mycorrhizal Fungi in Disturbed and Undisturbed Forests of Karbi Anglong Hills of Assam, India

Destruction of forests for agricultural purposes is a leading cause of forest disturbance and consequently of biodiversity loss. To assess the impact of such forest disturbance on microbial diversity, we investigated the diversity of arbuscular mycorrhizal fungi (AMF) in the rich forests of Karbi Anglong hills of Assam, India. Three forest types viz. undisturbed forests (UF), slash-and-burn field (SBF) and monoculture forest (MF) were selected. A total of 21 isolates of AMF belonging to 4 genera were extracted and identified from rhizospheric soil. ‘Species forming glomoid spores’ comprised Glomus sensu lato, Rhizophagus and Claroideoglomus were the dominant genera in all the three sites. Spore density was highest in UF and lowest in MF. Shannon–Wiener index of diversity and Simpson’s diversity index were almost similar in UF and SBF. Our results show that natural undisturbed forest and slash-and-burn field contained similar and a high AMF diversity compared to monoculture forest. The AMF diversity is not significantly affected by the slash-and-burn agricultural land use practices practised by the local tribes and, therefore, could be a component of a tropical forest ‘conservation–agriculture matrix’.

Habitat preferences of medium/large mammals in human disturbed forests in Central Japan

AbstractIt is a great concern whether human disturbed forest, i.e., secondary forest or monoculture forest, can be a habitat for the wildlife. We examined habitat preference of medium/large terrestrial mammal species in a human‐disturbed mountainous settlement area of Akiyama Region, Central Japan, by using camera‐traps, which were placed at conifer plantation forest, high/low‐disturbed deciduous broad‐leaved forest, and broad‐leaved/conifer mixed forest in 2008 and 2009. Camera‐traps were operational for 4568.6 trap‐nights producing 740 photo‐captures of 13 medium/large terrestrial mammal species. Japanese serow and Japanese hare dominated 54 % of all photo‐captures. Low‐disturbed deciduous broad‐leaved forest showed the richest mammal fauna (12 spp.). We suggested that fruit trees and understory vegetation provided suitable habitat for frugivorous as well as herbivorous mammals. The mixed forest showed the lowest mammal fauna (6 spp.), which located higher elevation. High‐disturbed deciduous broad‐leaved forest (9 spp.) was also supposed to be a better habitat for some frugivorous mammals and herbivorous mammals, but tended to be avoided by Japanese marten and Japanese macaque. Conifer plantation forest (7 spp.) with understory vegetation was supposed to be a better habitat for Japanese serow and Japanese hare, but not for the other species. Without fruit trees, conifer plantation forest was supposed to be non‐attractive habitat for frugivorous mammals. We demonstrated that, if a forest had been disturbed by human, the forest can be a habitat for terrestrial herbivores, but this was not always true for frugivores.

Convert Wasteland in Agriculture land by Development of MBFs (Multi-Beneficial Forests) in India

Present study emphasised for the development of MBFs on wastelands in India. The development strategy of MBFs on wastelands need to adopt in plain and hilly area separately. For canopy strata-wise MBFs development in both category of wastelands in India, author has prepared a list of about 50 plant species for each category which consisted a habit namely, tree, shrub, herb and climber for fulfil needs of local people. Simultaneously, author also emphasised that the man-made and natural monoculture forests should be converted in MBFs gradually and allow their natural regeneration, protect from fires and biotic disturbances. No doubt, MBFs will not only provide renewable plant resources to local community but this practice also helpful for the conservation of biodiversity, increase soil fertility, control soil erosion, landslides, proper regulate hydrological cycle, reduce environmental degradation and mitigation of climate change also.

Does forest stand structure impact the dynamics of snow on winter grazing grounds of reindeer (Rangifer t. tarandus)?

The landscape in boreal Sweden is dominated by even-aged, single-layered forest monocultures and clear cuts. Few forest stands with a more complex, multi-layered structure remain as landscape elements. We studied the impact that different forest management regimes have on snow conditions and the metamorphosis of snow, and discuss how these factors may affect suitability for reindeer grazing.Over two winters, we recorded the development of snow depth and hardness in clear cuts and two different forest types, and their changes with weather events. In the forests, the dynamics of snow characteristics were analyzed in relation to stand structure and at the level of individual trees.There were no clear differences in snow characteristics between single-layered and multi-layered stands, although snow hardness was more variable in the latter. In single-layered stands, snow depth and hardness were spatially uniformly distributed in relation to stand characteristics. Contrastingly, the complex structure of multi-layered stands did influence snow depth significantly. However, hardness was highly heterogeneous in these stands. Due to the absence of tree effects, clear cuts had deeper but softer snow than forested stands, although hardness increased towards spring.Weather affected the metamorphosis of the snow blanket. The magnitude of the effects depended on both timing and severity of discrete weather events and forest structure, but generally weather had a greater influence on snow cover characteristics than forest structure per se. In their interaction with weather, different forest structures affect the snow and thus suitability as winter grazing area for reindeer. Reindeer herders, therefore, require diversity in the landscape in order to respond to such weather variations and their impact on grazing conditions.

南亚热带人工针叶纯林近自然改造早期对群落特征和土壤性质的影响

Mixed conifer-broadleaved plantations within a framework of close-to-nature forest management can be a good silvicultural alternative to large-scale monocultures of coniferous plantations in southern subtropical China.In 1993,monoculture stands of Pinus massoniana and Cunninghamia lanceolata were established on the Fubo Forest Farm,which is located in Pingxiang County of Guangxi.To improve the productivity of the coniferous plantation forest monocultures and maintain their ecological balance,close-to-nature silvicultural technology was employed in 2007—2008.In this process,the native species Castanopsis hystrix and Michelia gioii were interplanted in thinned P.massoniana and C.lanceolata stands(hereinafter referred to as the P.massoniana close-to-nature forest and the C.lanceolata close-to-nature forest),with a density of 405 trees/hm2.In this study,P.massoniana and C.lanceolata plantation forest monocultures based on similarities in topography,soil texture,stand age,and management history were chosen as the reference to study the effects of close-to-nature transformation management in the early stages on the forest community structure and biodiversity,and soil properties,with the expectation of providing scientific reference points and a basis for the sustainable management of P.massoniana and C.lanceolata plantation forests.The results showed that:(1) The stand density and basal area of the P.massoniana and C.lanceolata close-to-nature forests were both significantly lower than those in corresponding plantation forest monocultures(P0.05),but their average DBH was higher than in the plantation forest monocultures and the average DBH of P.massoniana was significantly different(P0.05).(2) The stem number of adult trees(DBH≥10 cm) of the close-to-nature forests was lower than that in the plantation forest monocultures,and P.massoniana and C.lanceolata were still the dominant species,while the tree number and species number of trees(5≤DBH10 cm) and young trees(1≤DBH5 cm) of the close-to-nature forests were both higher than those in the plantation forest monocultures.The inter-planted C.hystrix and M.gioii turned out to be the young tree species with the highest importance value,and they grew better in the P.massoniana close-to-nature forest than in the C.lanceolata close-to-nature forest.(3) Species richness index,Shannon-Wiener index,Simpson index and Pielou index in the shrub and herbaceous layers of the P.massoniana close-to-nature forest were not significantly different from those in the P.massoniana plantation forest monocultures.The species richness index of the shrub layer and the Pielou index of the herbaceous layer of the C.lanceolata close-to-nature forest were significantly different from those in the C.lanceolata plantation forest monocultures(P0.05) while the other indexes showed no significant differences.(4) Bulk density and total porosity in the soil profile,and soil total P,total N,total K and available K all showed no significant differences between the close-to-nature forests and the plantation forest monocultures,but the organic carbon content and pH value of the P.massoniana close-to-nature forest were significantly lower than those in the plantation forest monocultures(P0.05),while soil available P in the C.lanceolata close-to-nature forest was significantly lower than in the plantation forest monocultures(P0.05).

Impact of plant species on the formation of carbon and nitrogen stock in soils under semi-desert conditions

The unique forest ecosystems investigated were created on the place of natural steppe biogeocoenoses 60 years ago. The aim of the study was to elucidate the effect of plant species on the formation of organic C and N stocks in soils and to estimate nitrogen availability for artificial wood plantation. For this purpose, 290 soil samples were taken from four forest monocultures (Quercus robur L., Pinus sylvestris L., Cotinus coggygria Scop., and Acer tataricum L.) and from virgin steppe ecosystem. The amounts and stocks of organic C, total and readily nitrified N, and seasonal dynamics of NO3 − and NH4 + ions activities were determined. It was shown that the species composition of the stands influenced the stock of organic C and N in soils. The storages of C and total N differed by 74 and 4.4 Mg/ha−1, respectively, in the litter and upper horizons (0–40-cm layer) in the stands studied. The differences in distribution of stocks of these elements in virgin steppe and artificial forest ecosystems were found. Organic C and N stocks increased 1.6–6.6 times in the forest litter compared to the steppe one, while in 5–40-cm layer, the storages of C and N decreased by 20–35% compared to the virgin soil. The impact of litter on total N content in arid climate was limited in 0–5-cm layer. The deficit of mineral N compounds was observed in autumn in soil with low stock of total N.

DIVERSITAS SERANGGA PADA HUTAN TANAMAN MONOKULTUR DAN HUTAN HETEROGEN DENGAN METODE WINDOW TRAPS

Insects are a very important role in an ecosystem. Among these roles are: herbivori, predation, parasitism, decomposition, pollination, and so on (Speight et al., 1999). In addition to the role of insects have been used as an indicator species. Several recent studies (Davids, 2000; Talvi, 2000; Castillo and Wagner, 2002; McGeoch, 1998 & 2002) shows that insects have a response that indicates the extent of damage to forest habitat. To see how much effect the change will see the diversity of insects flying at both locations using the window trap. This method was chosen because it will look at the role of flying insects that can be used as indicators of changes in land to the stratification of the existing trees at both locations. The expected goal in this study were 1) To determine the level of insect diversity in both forest site 2) To determine the effect of changes in forest insect conditions in each forest stratification. From this research it was found that it contained the highest density of heterogeneous forests there are 29 families of 41 species and 119 individuals from arrest (day and night) while in monoculture forests with 32 species of 22 families and 98 individuals in which the degree of diversity between the forest with a monoculture in the heterogeneous forest monoculture forests range 2.14 <H <2.84. Whereas in heterogeneous forests ranges between 2 <H <3 and the third similarity index was not significantly different strata.

Forestation and its Discontents: The Invention of an Uncertain Landscape in Southwestern France, 1850-Present

Abstract This article examines the politics of forestation and fire prevention in the Landes region of France, one of the largest contiguous forests in Europe. It argues that the monoculture forest of maritime pine, promoted by both the French state and local landowners in the nineteenth century, represents an uncertain environment that has eluded the control of its creators. The economic, social and political costs of this engineered forest, it is suggested, reflect the cultures of risk that have accompanied territorial transformation schemes in modern France.

Soil organic phosphorus fraction in pine–oak forest stands in Northeastern Germany

Pines ( Pinus sylvestris L.) have been widely used for monoculture forest stands in north-eastern Germany. However, several studies have discussed the need to convert monoculture into mixed forest stands such as pine–oak forest. In this study, we evaluated the impact of 102 years-old pine ( P. sylvestris L.) in monoculture and mixed forest stands of P. sylvestris + Quercus petraea (Matt.) Liebl. of different ages (10, 35, 106 and 124 years-old) on the dynamics of soil organic phosphorus (Po) pools. The study was carried out in the Northern German Lowlands of Brandenburg. Soil samples were taken from forest floor and two mineral soil layers at the depths of 0–10 and 10–20 cm. Different P forms of the sandy soil were obtained by sequential P fractionation, using acid and alkaline extractants. The soil total P (STP) ranged from 100 to 183 mg kg − 1 whereas total organic P (TPo) ranged from 77 to 148 mg kg − 1 . STP was higher in mixed forest stand than in monoculture and decreased with soil depth. The TPo and labile-P in both soil layers increased significantly with increase in age of oak trees. In addition, TPo content was lower in mineral soil compared to the forest floor and accounted for more than 50% of soil total P in the forest stands. The most available-P fraction–labile-P predominated in the oldest pine–oak forest stand (P + O124), accounting for 29% of STP at the 0–10 cm soil depth. The largest P fraction comprised NaOH–Po and represent 62% of STP. Results showed that forest transformation from pure pine monoculture forest into pine-oak mixed forest stands promoted an increase in the TPo and P available. Furthermore, the forms of labile available P increased with age of oak trees, which are capable of maintaining larger fractions of available P under mixed forest stands.

Effect of land-use on small mammal abundance and diversity in a forest–farmland mosaic landscape in south-eastern Norway

During the last century the boreal forests of south-eastern Norway have been converted into patchworks of agricultural areas, clear-cuts and even-aged conifer monocultures. Even though Scandinavian forest ecosystems are strongly influenced by small mammals’ dynamics, the effects of anthropogenic changes on these communities are still debated. We conducted an extensive capture–mark–recapture study to examine the relative abundance and distribution of 11 species of small mammals during the reproductive season with respect to all available landscape-scale habitat types and fine-scale vegetation characteristics. At the landscape scale, the highest abundance and diversity of small mammals was recorded in abandoned meadows. The community was dominated by Myodes glareolus in old abandoned meadows sparsely colonized by trees and bushes, and by Microtus agrestis in younger grass-dominated meadows, likely reflecting inter-specific competition and niche separation. Notwithstanding the remarkably low availability of both types of meadows, these habitats sustained by far the highest abundance of small mammals. Intensively managed forest monocultures at logging age and cultivated fields sustained the lowest abundance of small mammals. However, while the former also supported the lowest species diversity, the latter unexpectedly sustained the highest number of species. Only Apodemus sylvaticus attained highest densities in cultivated fields, but its marked association with forest edges clearly indicates its need for landscape-scale complexity. Contrary to previous theories, clear-cuts and forests overall did not support the highest abundance of M. agrestis and M. glareolus. Both young and mature forests failed to explain a significant amount of variation in community structure when taking into account other habitat types. However, a few old clear-cuts characterized by higher vegetational complexity, and a few stands preserving characteristics typical of late successional stages (moss, berries, woody debris) were able to support relatively high abundance of small mammals. Our study shows that sampling in all available habitats at different spatial scales is essential for a comprehensive understanding of community dynamics in forest–farmland ecosystems, as even habitat types that are under-represented at the landscape scale might play a significant role for the community dynamics. Forest–farmland mosaic landscapes with a high degree of heterogeneity at both large spatial scale ( e.g. meadows, shelterbelts) and at fine-scales ( e.g. varied and multi-layered ground cover) allow for the conservation of small mammal diversity and abundance in human-dominated areas. Nonetheless, the low number of Myodes rufocanus trapped in this highly fragmented mosaic landscape supports the hypothesis that habitat fragmentation negatively affects the dynamic of this forest specialist.

Effects of Insect Mass Outbreaks on Throughfall Composition in Even Aged European Pine Stands - Implications for the C and N Cycling

In this paper we report on the herbivore-affected C and N concentrations in the throughfall and altered canopy to soil transfer during a Pine Lappet (Dendrolimus pini L) mass infestation in 60-year-old Scots Pine (Pinus sylvestris L) forests. Our investigations covered a period of 7 months and could show, that herbivore defoliation significantly altered C and N concentrations in the throughfall solution and enhanced organic matter input situation to the forest floor. Compared to the uninfested site mean concentrations of the throughfall solution at the infested site under strong frass activity contained 80% more C and 61% more N. Additionally, C and N inputs were with 131 kg C ha-1 time-1 and 9.6 kg N ha-1 time-1 higher under strong frass activity during 3 months compared to the input at the uninfested site. We assume that outbreaks of phytophagous insects play an important key role in monoculture forest by influencing the nutrient turnover.

Landscape mosaic of Araucaria forest and forest monocultures influencing understorey spider assemblages in southern Brazil

Abstract This study investigates how abundance, diversity and composition of understorey spiders were influenced by four different forest habitats in a southern Brazilian Araucaria forest. The study area encompasses a landscape mosaic comprised of Araucaria forest, Araucaria plantation, Pinus plantation, and Eucalyptus plantation. Understorey spiders were collected by beating the vegetation inside three patches of each forest habitat. To assess possible predictors of spider assemblage structure, several patch features were analysed: potential prey abundances, estimation of vegetation cover, diversity index of vegetation types, patch ages, patch areas, and geographical distance between patches. To assess the influence of high‐level taxa approaches on spider assemblage patterns, analyses were carried out individually for family, genera and species levels. Additionally, Mantel tests were carried out in underlying similarity matrices between each taxon. Significant differences in spider abundances among forest habitats were found. Pinus plantations showed the highest abundance of spiders and Eucalyptus plantations showed the lowest abundance. Spider abundance was significantly influenced by patch ages, geographical distance and vegetation cover. Expected numbers of families, genera and species did not vary among forest habitats. Spider composition of two Eucalyptus patches differed from the other forest patches, probably due to their low vegetation cover and isolation. Genera composition was the best correlate of species composition, showing that a higher‐level surrogate can be an alternative to the species approach. The understorey spider diversity in this managed area could be maintained when suitable habitat structures are provided, thus ensuring the connectivity between different habitat types. Further studies should focus on individual species responses to the conversion of native forest to monocultures.

The effect of the tree species ratio of European beech ( Fagus sylvatica L.) and Norway spruce ( Picea abies (L.) Karst.) on polyphagous and monophagous pest species – Lymantria monacha L. and Calliteara pudibunda L. (Lepidoptera: Lymantriidae) as an example

Forest monocultures with tree species outside their native range are assumed to be more prone to insect outbreaks than mixed forests. The present study examined this thesis by observing two lepidopteran pests with different dietary spectra. Lymantria monacha L. (Nun moth) is a pest of the Norway spruce [ Picea abies (L.) Karst.] that feeds polyphagously on coniferous and deciduous tree species. The second target species, Calliteara pudibunda L. (Pale tussock moth), is a monophagous pest of European beech ( Fagus sylvatica L.). We investigated the relative abundances of these two pests in six forest types: pure spruce, pure beech and four mixed stands with different ratios of both tree species. The moths were caught with light traps. The relative abundances of C. pudibunda appeared to be linked to the tree species composition of the investigated forests. The number of individuals and the values of species dominance of C. pudibunda decreased with rising spruce ratio. Beech forests with a small portion of spruce (25%) showed a remarkably strong decrease in the number of C. pudibunda individuals compared to pure beech forests. No significant effects were observed concerning L. monacha and the beech/spruce ratio of the forests, though there was a trend for the dominance of this pest to decrease with rising beech ratio in the forests.

Altitude and forest type effects on soils in the Jizera Mountains region

This paper is focused on the Jizera Mountains as a region strongly influenced by man in the past. The structure of the natural forest was changed. Species monocultures with similar tree ages were planted. High acidificants concentrations in atmosphere led to the decline of these monoculture forests in the top parts of the mountains and the high acidificants deposition damaged the soils in the whole region. The goals of this study are to describe the distribution of the soil properties in altitude transects, where temperature, precipitation, and vegetation gradients are recorded, and to compare the soil properties in spruce and beech forests. The soil samples were collected from soil pits in a surviving nature-close beech forest, in a production spruce forest, and also in the top dead forest area with a grass cover. Soil samples from sufficiently deep diagnostic horizons were taken for the study of chemical properties. The basic soil characteristics were determined by the commonly used methods (pH, effective cation exchange capacity − eCEC, and the contents of cations in the sorption complex, A<sub>400</sub>/A<sub>600</sub> as humus quality parameter, the contents of available Ca, Mg, K and P, pseudototal content of Ca and Mg, and two differently extracted Fe and Al forms contents). The soils of the Jizera Mts. are strongly acid with a low eCEC which is the result of the natural and anthropogenic acidification processes. Soil chemical properties of the most affected top mountainous parts are in some aspects more favourable than lower parts (binding of potentially toxic Al in organic matter, slightly higher pH), but in other aspects they are still endangered by the acidification symptoms (higher leaching of base cations, especially Mg). The soils of nature-close beech forests represent more favourable soil properties than those of planted spruce forests. Generally, it can be concluded that the natural systems have higher resilience, and that natural mechanisms are able to mitigate slightly the soil degradation.

Diversity of Arbuscular Mycorrhizal Fungi in Disturbed and Undisturbed Forests of Karbi Anglong Hill District of Assam

Conversion of tropical forests to agricultural lands is one of the leading causes of biodiversity loss. To assess the impact of such forest conversion on microbial diversity, the present study investigated the diversity of Arbuscular Mycorrhizal Fungi (AMF) in undisturbed forests (UF), Slash-and-Burn Fields (SBF) and Monoculture Forests (MF). The study sites are located adjacently on a hilly slope. Arbuscular Mycorrhizal (AM) fungal spores were extracted by wet-sieving and decanting technique from the three sites. A total of 12 AM fungal taxa belonging to 4 different genera were extracted and identified. Glomus was the dominant genus in all three sites. Spore density was highest in UF, lower in SBF, and lowest in MF. The high diversity of AM fungi in undisturbed forest with naturally higher plant species diversity suggested that disturbance affect the abundance and richness of arbuscular mycorrhizal spores. Our results show that the forests of Karbi Anglong Hill District of Assam contained a high AM fungal diversity and species richness. The AMF diversity is significantly affected by the land use practices practiced by the people and no step has been initiated to restore this important group of microorganisms by forest management practices.