Tree Layer Diversity Research Articles

Comparison of species composition and community characteristics of Quercus forests on south and north slopes of Taibai Mountain, China.

We examined species composition, community characteristics, diversity, and community similarity of five Quercus communities composed of three Quercus species (Q. variabilis, Q. aliena var. acutiserrata, Q. wutaishanica) on the altitudinal gradient on the south and north slopes of Taibai Mountain. The results showed that there was an altitudinal transition pattern from Q. variabilis pure forest to Q. variabilis-Q. aliena var. acutiserrata mixed forest, Q. aliena var. acutiserrata pure forest, Q. aliena var. acutiserrata-Q. wutaishanica mixed forest and Q. wutaishanica pure forest on the south and north slopes of Taibai Mountain. The main companion species of Quercus community on the north slope were Pinus armandii, Castanea seguinii, and Sorbus alnifolia, and were Pinus tabuliformis, C. seguinii, Carpinus cordata, and Q. spinosa on the south slope. Species richness, woody plant density, and Quercus species dominance on the north slope of Taibai Mountain were higher than those on the south slope. α diversity of tree layer in Quercus community on the south and north slopes of Taibai Mountain increased first, then decreased and then increased with altitude. α diversity of tree layer was higher in mixed forests than pure forests. α diversity of shrub layer was higher than that of tree layer and herb layer in Quercus community on south and north slopes. β diversity fluctuated greatly along the altitudinal gradient on the south and north slopes, indicating that species composition changed greatly with altitude. Results of redundancy analysis showed that mean warmest month temperature, altitude and tree height accounted for 79.0% of the community diversity on the north slope, and that soil water content, tree height, canopy density and mean annual temperature accounted for 79.6% of the community diversity on the south slope. Overall, Quercus dominance was higher on the north slope of Taibai Mountain, and the substitution distribution pattern of Quercus species was clearer than that on the south slope. Environmental factors related to temperature and precipitation jointly affected α diversity of Quercus communities.

Effects of environmental factors and management on dynamics of mixed calcareous forests under climate change in Central European lowlands

Mixed lowland forests reserved for natural succession are sparse in the Czech Republic. However, their development provides essential insights into the natural processes of these forests and recommendations for forest management in a changing climate. The research describes the dynamics, productivity, structure, diversity, dead wood, and radial growth of hornbeam-oak groves and calcareous beech-dominated forests in the Karlštejn National Nature Reserve (Czechia) based on inventory in 2002, 2008, 2014 and 2020. The objective was to evaluate changes in differently managed stands (high forest, coppice with standards, and coppice) after leaving the stands to spontaneous development in 2004. The tree density increased by 2–10% from 2002 to 2014 and decreased by 6–18% in 2020. In the high forest, an increase in the stand volume was observed during the whole period, while in the coppice with standards and coppice, only until 2014. The stand volume ranged from 190 (coppice) to 630 (high forest) m³ ha−1 in 2020 and increased by an average of 28% over 18 years. Overall diversity of tree layer showed an uneven structure in the high forest and a substantially diverse structure in the other variants. The deadwood volume has been steadily increasing (18–35 m³ ha−1 in 2020), accumulating an average of 1 m³ ha−1 yr−1. A lack of precipitation and high temperatures from June to August were the main limiting factors of the radial growth of tree species, while the number of negative pointer years has increased in the last decade. European beech (Fagus sylvatica L.) was the most sensitive tree species to climate compared to the resilient European ash (Fraxinus excelsior L.). The lowest fluctuations in the diameter increment were recorded in Norway maple (Acer platanoides L.) and the highest in beech in the temperature cycles of 7–15 years. Over the last 20 years, sessile oak [Quercus petraea (Matt.) Liebl.] showed an increase in radial growth by 7%, while other tree species reported a decrease with a maximum in beech (by −38%). The forest stands managed as high forest, characterized by a higher production potential and lower diversity, had slower dynamics when compared to coppice with standards and coppice.

How sensitive are epiphytic and epixylic cryptogams as indicators of forest naturalness? Testing bryophyte and lichen predictive power in stands under different management regimes in the Białowieża forest

The aim of this study was to test the sensitivity of epiphytic and epixylic bryophytes and lichens as indicators of forest naturalness, by comparing their diversity patterns with forest structural, compositional and historical features associated with different management/protection regimes and protection time spans. The study was carried out in the Białowieża Forest (Poland). Out of 1370 pre-existing inventory plots established all across the Polish part of the Białowieża Forest, we randomly selected 10 plots for each of the 18 plot aggregation groups resulting from the combination of 3 management/protection regimes and 6 habitat types, for an overall number of 180 plots. At each of them, we carried out bryophyte and lichen sampling on four substrates (coarse woody debris – CWD, standing dead trees, stumps, living trees). The management/protection regimes exemplifying the gradient of forest naturalness were: the 100 years-old Białowieża National Park (BNP), a set of more recently established nature reserves and managed forests. We tested differences in mean species richness values among management/protection regimes, protection time spans, habitat types and stand age classes by analysis of variance and calculated coefficients of correlation with 45 selected structural and compositional features of forest stands. Differences in species composition of epiphytic and epixilic bryophytes and lichens among management/protection regimes were tested by ordination methods. Lastly, we compared frequency of red-listed species and primeval forest relics among management/protection regimes. Species richness of lichens was significantly correlated with the degree of forest naturalness assessed by structural and historical features along the naturalness gradient, with the highest number of species recorded in BNP and the lower in managed stands, while bryophyte number did not exhibit a clear dependence on the management regimes. Relic species of primeval forests and red-listed species occurred with significantly higher frequency in protected areas than in managed forests for both lichens and bryophytes, with the highest frequency observed in BNP for lichens and in nature reserves for bryophytes. Volume of deadwood, particularly of CWD in advanced decays stage, species richness of undergrowth vascular plants, tree layer diversity, shrub cover and herb layer cover exhibited the strongest correlation with cryptogam species richness and cover on the various substrates. Response to light availability strongly differenciated bryophyte and lichens optimal niches. The results of this study clearly show that cryptogams, and lichens in particular, are indeed reliable ecological indicators of forest status, since they sensibly intercepted the environmental changes observable along the tested naturalness gradient.

Changes in diversity of protected scree and herb-rich beech forest ecosystems over 55 years

Abstract Species composition along with spatial and age structure are the main attributes of forest ecosystems. The diversity of scree forests and herb-rich beech forests was analyzed in the Broumovsko Protected Landscape Area, the Czech Republic. The paper objective was to evaluate forest structure and dynamics of species diversity of tree layer, natural regeneration and herb layer in the period 1961–2016. Scree forests were structurally, and species very rich forest stands, in herb-rich beech forests the stands were of medium richness. Studied stands managed by small-scale methods, in the past especially by coppicing and later by shelterwood and selection felling, have maintained high species biodiversity during the 55 years of observation. Substantially higher biodiversity was found out in scree forests compared to herb-rich beech forests. Based on the comparison of predominantly coppiced forest stand and stand of generative origin at sites of scree forests, coppice have maintained higher biodiversity than high forests. Species richness increased during the observation period, but species evenness had mostly decreasing tendency. Species heterogeneity in coppiced scree forests increased in tree layer and natural regeneration, but it decreased in herb layer; inverse dynamics was observed in the high forests. Changes in biodiversity dynamics were remarkable for coppice, while high forests showed relatively high level of stability. During study period herb population of light-demanding species and species characteristic for broadleaved forests decreased, while an increase in shade tolerant, moisture-demanding and nutrient-demanding species, especially nitrophilous species was confirmed. Moreover, occurrence of thermophilic plants increased, respectively cold-tolerant plant population decreased in relation to climate change.

Linkages between Phosphorus and Plant Diversity in Central European Forest Ecosystems—Complementarity or Competition?

The phosphorus nutrition status of European forests has decreased significantly in recent decades. For a deeper understanding of complementarity and competition in terms of P acquisition in temperate forests, we have analyzed α-diversity, organic layer and mineral soil P, P nutrition status, and different concepts of P use efficiency (PUE) in Fagus sylvatica L. (European beech) and Picea abies (L.) H. Karst. (Norway spruce). Using a subset of the Second National Soil Survey in Germany, we correlated available data on P in the organic layer and soil with α-diversity indices for beech and spruce forests overall and for individual vegetation layers (tree, shrub, herb, and moss layers). Moreover, we investigated α-diversity feedbacks on P nutrition status and PUE of both tree species. The overall diversity of both forest ecosystems was largely positively related to P content in the organic layer and soil, but there were differences among the vegetation layers. Diversity in the tree layer of both forest ecosystems was negatively related to the organic layer and soil P. By contrast, shrub diversity showed no correlation to P, while herb layer diversity was negatively related to P in the organic layer but positively to P in soil. A higher tree layer diversity was slightly related to increased P recycling efficiency (PPlant/Porganic layer) in European beech and P uptake efficiency (PPlant/Psoil) in Norway spruce. The diversity in the herb layer was negatively related to P recycling and uptake efficiency in European beech and slightly related to P uptake efficiency in Norway spruce. In spruce forests, overall and herb species richness led to significantly improved tree nutrition status. Our results confirm significant, non-universal relationships between P and diversity in temperate forests with variations among forest ecosystems, vegetation layers, and P in the organic layer or soil. In particular, tree species diversity may enhance complementarity and hence also P nutrition of dominant forest trees through higher PUE, whereas moss and herb layers seemed to show competitive relationships among each other in nutrient cycling.

Effects of the overstory on the diversity of the herb and shrub layers of Anatolian black pine forests

Understory plants are important components of forests because they are responsible for the majority of the vascular plant diversity of forest ecosystems. The richness and composition of understory communities are closely related to the tree layer diversity, structure and composition. The aim of this study was to examine the understory diversity of Anatolian black pine (Pinus nigra Arnold subsp. pallasiana (Lamb.) Holmboe)-dominated forests on the Kazdagi Mountains of West Turkey. To describe the overstory structure and composition in a numerically and quantitatively well-defined manner, cumulative abundance profiles (CAPs) of the tree species were used. The resemblance of the sampling plots was classified into five stand types assessing the CAP through the Fuzzy C-Means clustering method. A permutational multivariate analysis of variance (PERMANOVA) was performed to test the variance of the community ecological distance between the five stand types, and the results showed significant differences in these clusters. Many shade-tolerant plants were associated with the mixed stands of Anatolian black pine–Kazdagi fir. The composition of the herb and shrub layer could not be explained by the environmental variables but by differences in the overstory structure of the stands. Pure or nearly pure Anatolian Black pine stands were more diverse than mixed oak–Anatolian black pine and Kazdagi fir–Anatolian black pine stands. However, although dense and young pure Anatolian black pine stands had the most diverse plant species in the shrub layer, they were ranked third in terms of the herb layer diversity. The Anatolian black pine–Kazdagi fir mixed stands had the lowest herb and shrub layer diversity. These results allow us to comprehend the relationship between the overstory structure and composition, and the understory diversity. Understanding this relationship is important for the conservation of understory plant diversity in the management of forest ecosystems.

Relations between tree canopy composition and understorey vegetation in a European beech-sessile oak old growth forest in Western Romania

AbstractThe diversity relationship between tree and herb layer has often been investigated, but the results are contradictory. Moreover, few studies of deciduous European species have been conducted to date in natural or near-natural forests, while such studies in old-growth forest with considerable co-dominance of oak are missing.In one of the best preserved natural European beech-sessile oak forests (Runcu-Grosi Natural Reserve, Western Romania) we investigated whether there is a correlation between canopy-layer diversity and herb-layer diversity. Structural diversity, vegetation composition, ecological and functional traits were evaluated. Our results show that the herb-layer diversity is higher under canopy with greater tree-layer diversity, and the diversity of both layers depend on whether the overstorey is dominated by beech or sessile oak. Herb layers of plots with oak co-dominance showed higher indicator values for light and temperature, and a higher proportion of graminoides and shrub species. In contrast, herb-layer in beech plots is dominated by juvenile trees, mainly beech and competitive herb species. Oak plots are characterised by a generally more evenly distributed herb-layer composition. Species richness of herb-layer was higher under a diversely structured overstorey, which was mainly achieved when oak was present in the canopy, and correlated negatively with litter thickness, which was highest in beech plots. We conclude that the identity of the dominant canopy species is most important for herb layer species composition and diversity. Furthermore, the plots with oak occurrence in the overstorey even with weak proportion (around 20% of stand basal area) features a higher biodiversity of species in the understorey.

Structure and dynamics of spruce-beech-fir forests in Nature Reserves of the Orlické hory Mts. in relation to ungulate game

Abstract Knowledge of the structure and dynamics of near-natural mixed forests is a key factor for ecologically oriented management of forest ecosystems. The development of these model forests mostly takes place continually without any pronounced disturbances. Natural regeneration can be locally limited by ungulate browsing. The paper was focused on the structure and development of forest stands with emphasis on natural regeneration in relation to ungulates in Černý důl Nature Reserve and Trčkov National Nature Reserve situated in the Orlické hory Mts., Czech Republic. The case study was conducted in a spruce-beech-fir forest stand on four permanent research plots (PRP) of 0.25 ha in size. PRP are situated in the same stand and in comparable site and stand conditions, but two PRP has been protected against game by fencing since 1985-1989. The stand volume ranged from 478 to 565 m3 ha−1 in age 143 - 156 year. The results showed that the diversity of tree layer was higher by 19.8% (48.0% in species richness) in the stands protected by fence. In the phase of natural regeneration, the species composition, stand structure and number of recruits were poorer on unfenced PRP (7,990 recruits ha−1) compared to fenced PRP (13,160 recruits ha−1). Admixed silver fir and rowan were completely eliminated by browsing (to 94 - 100% of individuals). Growth analyses statistically confirmed that ungulates were a significant limiting factor for successful forest development (P < 0.001).

白云山自然保护区植物群落多样性分布格局研究

根据白云山自然保护区6个植物群落的样地调查资料，为研究白云山自然保护区植物群落物种多样性的空间分布格局，采用DCCA (detrended canonical correspondence analysis)排序法，从丰富度指数、物种多样性指数、均匀度指数、优势度指数等方面的关系进行了分析。结果表明：在调查样地区域内，乔木层多样性平均指数较低，为1.344，灌木层植物多样性平均指数为3.054，草本植物的多样性指数为2.753，高于乔木层的指数。乔木层丰富度平均指数较低，为2.734，灌木层植物丰富度平均指数为6.447，草本植物的丰富度指数为5.467。通过重要值分析得出华山松的各种指数均高于锐齿槲栎，华山松在调查的群落里占更大优势，更加适应样地内的生长环境，地带性植被总体上表现为向锐齿槲栎(Quercus aliena var. acuteserrata Maxim.)、华山松(Pinus armandii Franch.)林的方向更新。此外，乔木优势树种较为单一，可适当引入当地的其他树种，丰富样地内的物种丰富度，使林分组成更加健全。 According to Baiyun Mountain Nature Reserve, six plots of plant community survey data for the study of Baiyun Mountain Nature Reserve of plant species diversity spatial distribution pattern, using DCCA (detrended canonical correspondence analysis) sort, from the species richness index, relationships between species diversity index, evenness index, dominance index and other aspects were analyzed. Research suggests in the sample plots, the average tree layer diversity index was lower, which was 1.344, the average diversity index of shrub layer was 3.054, and the diversity index of herbaceous plants was 2.753, which was higher than that of QiaoMuceng. The average richness index of the tree layer was low, which was 2.734, and the average index of shrub layer was 6.447, and the richness index of herb was 5.467. Through the analysis of the important values, various index of Huashan pine is higher than the Quercus aliena var. acuteserrata, Huashan pine in the investigation of the community has a greater advantage, more adapted to the growth environment of the sample plots, zone of vegetation on the whole performance for updates to the direction of the Sharptooth oak (Quercus aliena var. acuteserrata Maxim.) Huashan pine (Pinus armandii Franch.). In addition, the dominant tree species is single, other tree species can appropriately be introduced into the local area, so that the species richness of the samples can be enriched, and the composition of the forest will be more perfect.

川中丘陵区柏木低效林改造模式植物多样性对土壤有机碳的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 川中丘陵区柏木低效林改造模式植物多样性对土壤有机碳的影响 DOI: 10.5846/stxb201307181913 作者: 作者单位: 四川农业大学林学院 长江上游林业生态工程四川省重点实验室 四川 雅安 625014,雅安市林业局,四川农业大学林学院 长江上游林业生态工程四川省重点实验室 四川 雅安 625014,四川农业大学林学院 长江上游林业生态工程四川省重点实验室 四川 雅安 625014,四川农业大学林学院 长江上游林业生态工程四川省重点实验室 四川 雅安 625014,四川农业大学林学院 长江上游林业生态工程四川省重点实验室 四川 雅安 625014 作者简介: 通讯作者: 中图分类号: 基金项目: 国家"十二五"科技支撑项目(2011BAC09B05);国家林业局中央财政林业科技推广示范(2010TK55);四川省科技支撑计划(2010NZ0049)共同资助 Effects of plant diversity on soil organic carbon under different reconstructing patterns in low efficiency stands of cuprssus funebris in the hilly region of central Sichuan Author: Affiliation: College of Forestry,Sichuan Agricultural University,Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province,Ya’an,Forestry Bureau of Ya'an,College of Forestry,Sichuan Agricultural University,Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province,Ya’an,College of Forestry,Sichuan Agricultural University,Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province,Ya’an,College of Forestry,Sichuan Agricultural University,Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province,Ya’an,College of Forestry,Sichuan Agricultural University,Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province,Ya’an Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以川中丘陵区柏木低效林改造10a后的4种模式:纯杂交竹模式(Bambusa pervariabilis × Dendrocalamopsis daii)(CZ)、柏木(Cupressus funebris Endl.)+桤木(Alnus cremastogyne Burk.)+杂交竹模式(BZQ)、柏木+麻栎(Quercus acutissima Carruth)模式(BL)、柏木+杂交竹模式(BZ)为研究对象,纯柏(CB)为对照,对土壤有机碳含量、碳密度和土壤活性有机碳(土壤易氧化碳、水溶性碳和微生物量碳)含量及植物多样性进行了研究。结果表明:(1)随着土层深度的增加,土壤有机碳含量、碳密度及其组分均下降,其中土壤有机碳含量下降幅度最大,易氧化碳含量下降幅度最小;0-10 cm土壤有机碳密度占整个取样剖面的45.7%-64.4%,具有明显的表聚性。(2)不同模式0-40 cm土层土壤有机碳含量、碳密度和土壤易氧化碳、水溶性碳和微生物量碳含量均为BZQ > BZ > CB > BL > CZ,差异均达到显著水平(P < 0.05)。几种模式中,BZQ与CB相比,土壤有机碳含量、碳密度、土壤易氧化碳、水溶性碳和微生物量碳含量增幅分别为37.8%、33.5%、36.6%、52.5%和23.2%,表明BZQ模式在提高土壤有机碳方面作用最明显。(3)植物Simpson优势度指数、Shannon-Wiener多样性指数、Pielou均匀度指数和丰富度指数大致表现为BZQ > BZ > CB > BL > CZ;相关分析表明,土壤有机碳、碳密度、易氧化碳、水溶性碳和微生物量碳与灌木层和草本层的植物多样性指数均呈显著正相关,而与乔木层植物多样性不相关。 Abstract:The soil organic carbon (SOC) pool is an important component of global carbon stock, It could play a huge impact on global terrestrial carbon cycling, eco-system construction and material recycling due to its slight changes. Plant diversity could influence the temperature, humidity, microorganisms and litter of forest floor, and then affect the reserves of SOC. The hilly region in central Sichuan province is a critical part of ecological barriers in the upper reaches of the Yangtze River, and the low efficiency stands of Cuprssus funebris grow in these areas are the main forest types. Our objectives were (1) to explore the characteristics of SOC in the low efficiency stands of Cuprssus funebris which have been reconstructed for 10 years, (2) to quantify the relationships between SOC and plant diversity of the tree layers, the shrub layers and the herb layers.The planting patterns of Bambusa pervariabilis×Dendrocalamopsis daii (CZ), Cupressus funebris Endl.+Bambusa pervariabilis×Alnus cremastogyne Burk.+ Alnus cremastogyne Burk. (BZQ), Cupressus funebris Endl.+Quercus acutissima Carruth (BL), Cupressus funebris Endl.+Bambusa pervariabilis× Dendrocalamopsis daii (BZ) were reconstructed in 2002. CZ pattern was reconstructed on the planting spacing of 4 m×4 m after clear cutting, and the other patterns were reconstructed by interplanting after intermediate cutting. In 2012, 3 sample plots were set in each pattern to study SOC content, SOC density, easily-oxidized carbon (EOC), water-soluble organic carbon (WSOC), soil microbial biomass carbon (SMBC) and plant diversity. The results were found as follows: (1) The contents of SOC and its components were decreased with increasing soil depth, with the maximal drop of SOC and the minimum drop of EOC; SOC density in topsoil (0-10 cm) accounted for 45.7% to 64.4% of the whole sampling profile, exhibiting obvious surface accumulation. (2) SOC content, SOC density, EOC, WSOC and SMBC content in 0-40 cm were in the order of BZQ > BZ > CB > BL > CZ, with significant differences (P < 0.05). Compared with CB, the increase rates of SOC content, SOC density, EOC, WSOC and SMBC content were 37.8%, 33.5%, 36.6%, 52.5% and 23.2%, respectively, and BZQ revealed the most obvious effect on SOC. (3) The index of species dominance, species diversity, species evenness and species richness were roughly arranged as BZQ > BZ > CB > BL > CZ. There were significant positive correlation between SOC content, SOC density, EOC, WSOC and SMBC content and the plant diversity of shrub and herbaceous layers, while the correlation were not significant between SOC and its components and the plant diversity of tree layer. It indicated that the effects of the diversity of herbaceous and shrub layers on SOC were more obvious than those of the other tree layers. The most obvious influence on the improvement of SOC content was BZQ pattern, and thus this pattern was proposed to promote. Due to the vegetational transformation in the studied region is still in its initial stage, vegetation succession will continue and in a unstable state, therefore, it will be more meaningful to provide a theoretical basis for the transformation of low efficiency stands of Cupressus funebris. 参考文献 相似文献 引证文献

When beech strikes back: How strict nature conservation reduces herb-layer diversity and productivity in Central European deciduous forests

Current nature conservation policy is going to alter the tree-layer composition of many Central European deciduous forests. As a consequence of ceasing silvicultural management, the competitive ecosystem engineer European beech (Fagus sylvatica L.) will spread and the proportion of secondary tree species will considerably decrease. Thus, changes can also be expected in herb-layer diversity, productivity and composition. To predict these changes, we analysed relationships between tree- and herb-layer diversity and composition along tree-diversity gradients in the Central German woodland areas of the Hainich National Park (unmanaged) and the Göttinger Wald (managed by close-to-nature forestry).The flora of both study areas was dominated by typical forest species. In the Hainich, the herb-layer vegetation in beech-dominated stands was less diverse compared to stands richer in canopy species. Herb-layer productivity was also lower in beech-dominated stands. In the Göttinger Wald, herb-layer diversity and productivity were not related to tree-layer diversity and beech proportion, instead to the light transmissibility of the canopy layer. The different results can be explained by logging effects in the Göttinger Wald, which promoted the light factor as significant for herb-layer diversity and productivity. In the consistently darker stands of the Hainich, soil variables, particularly influenced by the ecosystem engineer beech, were decisive. Areas of high canopy diversity in the Hainich result from former management practices and can, in the future, be expected to decrease with the spread of beech.We conclude that forest management cessation will result in decreasing herb-layer diversity and productivity in many Central European deciduous woodlands, especially in landscapes where historical management practices led to unnaturally low proportions of beech. The short-term consequence of management cessation is a loss of herb-layer diversity due to reduced light availability; in the long-term, herb-layer diversity is expected to decrease due to the expansion of beech.If the key aim of nature conservation policy is to preserve and develop the typical diversity of near-natural beech forests, then a complete cessation of forest management can be advised. However, if the typical forest herb diversity of the semi-natural, century-old cultural landscape is to be maintained, close-to-nature forestry management is necessary.

A continental comparison indicates long-term effects of forest management on understory diversity in coniferous forests1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.

Promotion of species diversity has become a major goal in forestry. This requires an understanding of the impacts of management disturbance on species diversity relative to natural drivers such as climatic or edaphic conditions on the relevant temporal scales, i.e., centuries. We examined the effects of long-term management disturbance on understory plant diversity in coniferous forests by comparing structure types (ages since disturbance) between regions with comparable abiotic settings but contrasting management history, i.e., management for centuries in central Europe versus the first logging in primary forests in western Canada. We systematically sampled three age classes after disturbance and compared their alpha diversity and species composition. The structure types (age classes) showed similar differences in alpha diversity in both landscapes, while the response of species compositions differed between the two. Fewer late-successional specialists occurred in the European landscape. Within the setting of our study, the structure types, which reflect the time since major forest management disturbance, affected understory species richness and composition at least as strongly as environmental conditions such as climate, soil, and tree layer diversity across the broad altitudinal gradients that we sampled. Our results suggest that forest management affects the diversity of coniferous forests, with management for centuries disadvantaging late-successional specialists. Furthermore, it appears that human action is becoming the major determinant of diversity of coniferous forests, emphasizing the need for sustainable management schemes.

Lack of tree layer control on herb layer characteristics in a subtropical forest, China

Question: Knowledge of the interaction between understorey herb and overstorey tree layer diversity is mostly restricted to temperate forests. How do tree layer diversity and environmental variables affect herb layer attributes in subtropical forests and do these relationships change in the course of succession? Do abundance and diversity of woody saplings within the herb layer shift during succession?

Tree diversity and environmental context predict herb species richness and cover in Germany's largest connected deciduous forest

Abstract In temperate deciduous forests, the herb layer contributes most to total vascular plant species richness. The diversity of the tree layer can influence herb layer diversity by modifying resource availability and environmental conditions relevant to herb layer plants. Here, we explore the relationship between tree layer diversity and herb layer species richness and cover. Also, we address the question how different environmental factors that are potentially modified by the tree layer influence herb layer characteristics. Our study area is located in the Hainich National Park, one of the largest continuous stretches of broad-leaved deciduous forest in Central Europe. We recorded herb and tree layer composition on 79 plots selected along a tree diversity gradient ranging from two to nine tree species. In addition, canopy cover, soil pH, mass of the humus layer, soil C:N ratio, soil moisture and distance to the forest edge were determined. We used generalized least square models to analyse effects of tree diversity, environmental variables, and spatial plot positions on herb layer species richness and cover. Species richness and cover of the herb layer increased with increasing tree diversity. In addition, both species richness and cover showed a negative response to increasing canopy cover and mass of the humus layer. Herb layer species richness was also positively related to increasing soil pH and the distance to the forest edge. The proportion of forbs increased with increasing tree diversity, whereas the proportion of tree saplings decreased and the proportion of graminoids was not affected. The proportion of true forest species increased with increasing canopy cover. We conclude that forest stands with a high tree diversity feature a more diverse herb layer and a higher herb cover. Furthermore, the environmental variables humus layer mass, light availability and pH also strongly affect herb layer species richness and cover.

Beziehungen zwischen Baum- und Krautschicht in Buchenmischwäldern | Relations between tree and herb layer in mixed beech forests

Tree layer composition is a crucial factor for the stability and diversity of forest ecosystems, and many factors such as nutrient availability or the light regime are influenced by trees and their species-specific properties. The occurrence and abundance of herbs as indicators for site characteristics are likely to be related to the variability in tree layer diversity and changes in environmental variables. To test this hypothesis, the effect of tree layer composition on herb layer diversity was studied in mixed deciduous beech (Fagus sylvatica) forest reserves on the Swiss Plateau. Applying a transect design we recorded tree and herbaceous species composition and measured key top soil properties and light availability in seven forest reserves. Tree layer diversity did not affect herb layer diversity at the study sites. However, a species-specific influence of trees on the herb layer was evident: a high proportion of beech had a negative effect on herb layer diversity, and the presence of ash (Fraxinus excelsior) was correlated with a thick A h horizon and high soil pH, which enhanced herb layer diversity. Spruce (Picea abies) and pine (Pinus sylvestris) were related to a thick forest floor (litter) layer, which negatively affected herb layer diversity.

Structure and composition of the seed bank in monospecific and tree species-rich temperate broad-leaved forests

How tree species diversity affects ecosystem functioning is a topic of intensive research. This study compares monospecific and species-rich broad-leaved forests under similar bedrock and climate conditions for the size and composition of their seed bank. We tested the hypotheses that (i) the actual herb-layer vegetation has an only weak influence on the composition of the seed bank, (ii) the species diversity of the seed bank increases with tree-layer diversity, and (iii) tree species forming a more persistent litter layer reduce the number of germinating seeds. The number of seeds and their species composition were investigated in soil cores taken from three soil depths (0–5, 5–10 and 10–20 cm; n = 4, with each 6 sub-samples) in 9 study plots differing in tree species diversity (3 monospecific Fagus plots, 3 plots with Fagus, Fraxinus and Tilia, and 3 plots with Fagus, Fraxinus, Tilia, Carpinus and Acer). Tree species diversity had a much stronger influence on the size and composition of the seed bank than herb-layer diversity or composition, the latter revealing only a low similarity to the corresponding seed bank. The number and species diversity of emerging seedlings decreased significantly with the amount of acidifying Fagus litter, but increased with litter mass of Tilia and other trees with nutrient-rich, rapidly decomposing litter. We conclude that tree species diversity does not influence the seed bank through effects on herb-layer composition, but mostly through differential disturbance histories of the stands and litter quality effects on germination and soil chemistry. From the contrasting effects of Fagus and Tilia leaf litter, it appears that effects of tree species identity are more relevant than influences of tree species diversity itself.

Herb-layer diversity in deciduous forests: Raised by tree richness or beaten by beech?

Where natural production capacity permits, modern silvicultural management in Central Europe frequently aims at the development of mixed broadleaved stands, instead of pure European beech ( Fagus sylvatica) stands. It is crucial to study the effects of these tree-layer diversity variations on herb-layer vegetation, since herb-layer vegetation contributes significantly to ecosystem functioning in forests. In Hainich National Park (Thuringia, Germany), we conducted observational research in deciduous stands to investigate whether herb-layer diversity was related to canopy-layer diversity, and to ascertain possible causal mechanisms. We found that herb-layer vegetation of deciduous forest stands rich in canopy species appeared to be more diverse than herb-layer vegetation of beech-dominated stands. We surmise that herbaceous understorey diversity was indirectly influenced by canopy tree species through the medium of the altered environmental factors soil pH and litter layer thickness. Apparently, lower beech proportion had a more profound effect than the number of secondary tree species. There were no correlations between herb-layer diversity and light transmissibility of the canopy layer, indicating that the light factor was not crucial for herb-layer diversity. At least for the Hainich research sites, our results indicated that small-scale light and soil heterogeneity is insignificant for herb-layer diversity. We found several herb-layer species whose occurrence was particularly correlated with tree-layer diversity and environmental factors. Remarkably, all species positively correlated with soil pH were important for the phytosociological classification of the research sites. Beech-dominated research sites showed high tree-layer volumes, whereas research sites with high tree-layer diversity tended to feature lower tree-layer volumes. These findings could be the result of differing former silvicultural systems and varying soil clay contents affecting tree species composition. In contrast, herb-layer biomass was positively correlated with tree-layer diversity. Herb-layer productivity might be promoted in more diverse research sites by increased nutrient supply and base saturation. It is also possible that greater beech proportion interfered with herb-layer productivity. However, herb-layer biomass was also positively correlated with herb-layer diversity. Hence, our study hints that positive diversity-functioning relationships might occur in the herb-layer of the deciduous forest under investigation.

Relations between selected geomorphology features and tree species diversity of forest ecosystems and interpolation on a regional level

The presented paper analyses the relations between four features of geomorphology, i.e. aspect, slope, elevation and type of terrain, and tree layer diversity of forest ecosystems. The forest stand diversity is quantified by nine species diversity indices (N0, R1, R2, H′, N1, N2, E1, E3, E5). The data used in this study come from the regional forest inventory of the Forest School Enterprise, Technical University Zvolen, Slovakia. Within this inventory, 26 permanent tracts were established in the systematic grid of 2×2 km, whereby a total of 120 sample plots were created on which 1,728 trees were measured. Analyses showed that species diversity is closely related only to elevation. However, the relationships of the individual species diversity indices to elevation are loose since the correlation coefficients do not exceed values of 0.30–0.40. The second part of this work presents spatial interpolation of species diversity degrees on a regional level using geostatistical methods. For this regionalisation, we used an indicator kriging. The final kriging map was found to be a suitable tool for the interpretation of tree species diversity over the investigated area.

Flora and ecological characteristics of rare plant communities on the southern slope of Shennongjia Mountain

According to the investigation of sampling area of 6800 m2 on the south slope of Shennongjia Mountain, there were 126 vascular plant species, belonging to 108 genera and 64 families, in the investigated rare plant communities, of which 9 rare plant species were recorded, accounting for 27.3% of the total rare plants. The communities were about 30 m in height and were divided into three layers as tree layer, shrub layer, and herb layer. The flora of the communities had obvious temperate character. Phanerophytes (accounted for 65.9%), Mesophyllous (62.7%), Papyraceous (84.1%), simple leaf (83.3%), un-entire leaf (69.8%) were dominant in life form, leaf size class, leaf texture, leaf form, and leaf margin respectively. According to important value of species, the communities were divided into three types asDavidia involucrata+Litsea pungens community,Cercidiphyllum japanicum +Padus wilsonii community, andPadus wilsonii+Acer mono community. The indexes of species diversity of tree layer had little difference among communities and evenness was high. The results indicated that the communities had complex structure and relative stability.