Structure Of Temperate Forests Research Articles

Forest Management and Tree Species Diversity in a Temperate Forest of the Meseta Purhépecha, Michoacán

Objective: To evaluate how traditional forest management practices impact the diversity and structure of temperate forests in the Nuevo San Juan Parangaricutiro Indigenous Community (ICNSJP), with the goal of providing information on the sustainable management of these forests. Design/methodology/approach: Forest inventory data were collected and analyzed in stands treated with four thinning (A4) through the Silvicultural Development Method (SDM) and contrasted with stands that have not been intervened for more than 30 years (A0). Diversity indices and stand variables were used to statistically compare the effects of the treatments. Results: In total 20 species were recorded, 13 in A0 and 18 in A4. The true diversity (q1) recorded a value of 3.3±1.6 in A4 and 1.9±0.8 in A0, although this difference was not statistically significant. The species with highest importance value were Pinus douglasiana Martinez (30%) for A0 and P. pseudostrobus Lindl (27%) for A4. Limitations on study/implications: According to the SDM, the cutting cycle in A4 has not yet ended since the release and regeneration treatments are missing, therefore, monitoring is recommended to evaluate the effect of the SDM more comprehensively on diversity and structure in the forests of the ICNSJP. Findings/conclusions: Forest management in the ICNSJP has shown a positive effect in terms of species diversity and due to its commercial value, the development of P. pseudostrobus has been favored. In general, forest management has contributed to socioeconomic development by promoting species diversity, a key element for sustainable development.

Effect of silvicultural treatments on forest diversity and structure in temperate forests under management in Durango, Mexico

<p>The present study evaluated the effect of silvicultural treatments on the diversity and structure of species in temperate forest ecosystems in the Municipality of Pueblo Nuevo in the State of Durango, Mexico; it was carried out to know if forest use modifies the diversity, mixture of species, spatial distribution, and dimensional differentiation of individuals in these ecosystems. The evaluation was carried out by comparing 10 plots with management history, which were measured before the application of the treatment and five years later. The diversity indices of Shannon, Simpson and Margalef were compared, as well as indices of structure of mixture of species, spatial distribution, and dimensional differentiation. According to the silvicultural treatments applied, the values of the indices do not present significant differences in their evaluations (p> 0.05), which indicates that forest use does not modify the diversity and structure of species of the tree stratum of this plant community.</p>

Strata-dependent relationships among temperate forest structure, diversity, and growth rate along a local-scale environmental gradient

Exploring diversity-function relationships across overstory and understory strata is crucial for understanding ecological mechanisms, biodiversity conservation and forest management. In this study, we aimed to investigate the relationships among species diversity and stand structure, environmental factors, leaf area index (LAI), and the growth rate of overstory and understory strata in a mixed-broadleaf Korean Pine Forest in Northeast China. We performed structural equation models (SEMs) to evaluate the effects of environmental factors on overstory and understory species diversity, stand structure, and growth rate; the effects of overstory and understory species diversity and stand structure (total basal area, stem density, and diameter at the breast height variation) on the LAI and their respective growth rates; and the effect of overstory stratum on understory stratum species diversity, stand structure, and growth rate. Our results showed that species diversity determined the growth rate for overstory strata, while stem density was appropriate to determine understory growth rate. The integrative SEM accounted for 13, 13, 11, 8, and 7% of the variance in overstory species diversity, understory absolute growth rate, overstory absolute growth rate, understory stem density, and LAI, respectively. The diversity of overstory species had a positive direct influence on overstory growth but a negative direct effect on understory growth. Environmental factors (i.e., soil nutrients and soil moisture) positively influenced the understory growth rate but negatively influenced the overstory growth rate. Increasing understory stem density may increase the LAI; simultaneously, the LAI supported the understory growth rate. In natural forests, an arrangement between the overstory canopy and the availability of environmental resources is ideal for controlling species diversity and maximizing the productivity of both the overstory and understory strata.

Avian Diversity and Their Feeding Guild Structure in Temperate Forests of Garhwal Himalaya, Uttarakhand, India

The study on avian diversity and their feeding guild structure with relation to their habitat use in temperate forest of district Pauri Garhwal was carried out between April 2015 to March 2017. Lines transect and direct visual methods were used to record the bird species diversity, their feeding habit and habitats. Frequent surveys were made in the study area and birds were counted. During the study period, a total of 152 species of birds belonging to 9 order and 43 families were recorded. The highest diversity index was recorded at Kandoliya (H¯= 3.98±0.06) and Adwani was recorded with minimum diversity (H¯= 3.34±0.08). The average bird diversity index at all sites was recorded as (H¯= 3.57±0.11). Further, on the basis of their feeding guilds the recorded birds were categorized into the six major categories such as insectivore (55.92%), omnivore (13.81%), grainivores (5.92%), carnivore (9.21%), nectarivorous (1.31), frugivore (5.92%) and 7.91% species remained unidentified. The insectivore guild was dominant in all the guild structures.

Response of soil bacterial communities to organic carbon input under soil freeze-thaw in forest ecosystems

The soil microbial community controls the biogeochemical cycle of elements critical to plant growth. Different carbon input modes have different effects on soil carbon storage and the microbial community, but the effects of carbon input control on soil microbial diversity and community structure in temperate forests remain unclear. We used high-throughput 16SrRNA gene sequencing and ecological network analysis methods to analyze the soil bacterial community, symbiotic network, and key species of three different carbon input treatments (litter removal, root removal, litter and root removal) in temperate natural secondary forests during the freeze-thaw season and growing season. The results showed that the change in the carbon source input led to a change in the way in which soil bacteria used carbon, which was mainly manifested as follows: (1) The relative abundance of Acidobacteria, which was oligotrophic bacteria, significantly decreased in the sample plots where the root system was removed. (2) In the litter removal treatment, the abundance of bacteria with functions related to the absorption of CH4 decreased. (3) The correlation between the module characteristic genes in the bacterial network analysis and the physical and chemical properties of soil, CK modules were grouped separately, and the change in the correlation may also indicate the change in the way soil bacteria use carbon. Second, the influence of belowground roots on the soil bacterial community structure was more significant than that of aboveground litter. The root system had a greater influence on the soil bacterial community. Third, the decrease of organic carbon input reduced the stability of the soil bacterial network, and the proportion of positive connections in the bacterial network for litter removal and root treatment increased significantly, indicating that these bacterial communities had the same change trend as the fluctuation of the environment. Finally, the freeze-thaw season had a greater impact than the growing season on bacterial diversity, community structure, and function. The freeze-thaw process allowed the bacterial community to respond to root removal more significantly, and the structural changes were mainly due to changes in temperature, water content, dissolved organic carbon, and nitrate nitrogen.

The relationship between soil bacteria substrate utilisation patterns and the vegetation structure in temperate forests

The aim of the study was to explore the relationship between the functional diversity pattern of soil bacteria and the vegetation diversity and structure in temperate forests (Poland). Pine-dominated forests occur on soils with lower pH, fewer nutrient contents (P, Na, Mg, Mn and K) and higher C/N and C/P ratios than beech-dominated forests and mixed broadleaved forest with hornbeam and ash. Both forest type and soil horizon (O and A) strongly influenced bacterial catabolic activity and the number of substrates decayed on Biolog® ECO plates. Pine forest soil bacteria were less active and less functionally diverse than those in deciduous forest soils. The community-level physiological profiles (CLPPs) were dissimilar (one-way analysis of similarities) between pine and mixed deciduous forests, but only in the O soil horizon. Carboxylic acids primarily contributed to the average dissimilarity in CLPP between forests (the similarity percentage procedure); these substrates are preferentially used by pine forest soil bacteria. The canonical correspondence analysis indicated that soil pH, nitrogen and organic matter contents and plant diversity index $$H_{\text{plant}}^{\prime }$$ were related to bacterial CLPP in the O soil horizon. Only for the soil O horizon, the Mantel test showed a clear relationship between vegetation structure and bacterial CLPP.

Forest Management Type Influences Diversity and Community Composition of Soil Fungi across Temperate Forest Ecosystems.

Fungal communities have been shown to be highly sensitive toward shifts in plant diversity and species composition in forest ecosystems. However, little is known about the impact of forest management on fungal diversity and community composition of geographically separated sites. This study examined the effects of four different forest management types on soil fungal communities. These forest management types include age class forests of young managed beech (Fagus sylvatica L.), with beech stands age of approximately 30 years, age class beech stands with an age of approximately 70 years, unmanaged beech stands, and coniferous stands dominated by either pine (Pinus sylvestris L.) or spruce (Picea abies Karst.) which are located in three study sites across Germany. Soil were sampled from 48 study plots and we employed fungal ITS rDNA pyrotag sequencing to assess the soil fungal diversity and community structure. We found that forest management type significantly affects the Shannon diversity of soil fungi and a significant interaction effect of study site and forest management on the fungal operational taxonomic units richness. Consequently distinct fungal communities were detected in the three study sites and within the four forest management types, which were mainly related to the main tree species. Further analysis of the contribution of soil properties revealed that C/N ratio being the most important factor in all the three study sites whereas soil pH was significantly related to the fungal community in two study sites. Functional assignment of the fungal communities indicated that 38% of the observed communities were Ectomycorrhizal fungi (ECM) and their distribution is significantly influenced by the forest management. Soil pH and C/N ratio were found to be the main drivers of the ECM fungal community composition. Additional fungal community similarity analysis revealed the presence of study site and management type specific ECM genera. This study extends our knowledge on the impact of forest management type on general and ectomycorrhizal fungal diversity and community structure in temperate forests. High plasticity across management types but also study site specific spatial distribution revealed new insights in the ECM fungal distribution patterns.

Community composition, diversity and metabolic footprints of soil nematodes in differently-aged temperate forests

Soil nematode communities can provide important information about soil food web structure and function. However, how soil nematode communities and their metabolic footprints change over time in temperate forests is not well known. We examined the changes in the composition, diversity and metabolic footprints of soil nematode communities in three differently-aged (young, mid and old) forests of the Changbai Mountains, China. Carbon flows through different nematode trophic groups were also quantified based on nematode biomasses. The results showed that the highest abundance and diversity of total nematodes was found in the mid forest. Nematode communities were characterized by the replenishment in abundance but not the replacement of dominant genera. A low enrichment footprint in the young forest suggests a decline in available prey, while a high enrichment footprint in the mid forest indicates an increase in resource entry into soil food web. The relationship between the carbon flows of omnivores-predators and fungivores was stronger than that among other trophic groups. Our study shows that bottom-up effects of the vegetation, the soil environment and the connectedness of nematode trophic groups are all important driving forces for nematode community structure in temperate forests.

Conspecific negative density‐dependent mortality and the structure of temperate forests

Factors that control tree seedling dynamics are critical determinants of forest diversity. We examined the role of density‐dependent mortality and abiotic factors in the differential establishment and survival of tree seedlings at three, large, mapped forest plots in Indiana, Virginia, and Wisconsin, USA. We tested whether seedling densities and seedling survival are related to local biotic and abiotic factors with generalized linear mixed models. Spatial point pattern analyses were utilized to determine if the distribution patterns of seedlings and saplings are consistent with a pattern generated by negative density‐dependent mortality with respect to conspecific trees.Initial sampled seedling density for nearly a third of species showed a positive correlation with increasing conspecific basal area, indicating dispersal limitation, but few had any association with abiotic variables. By contrast, survival of seedlings over one year significantly declined with increasing conspecific basal area. Point pattern analyses indicated that nearly one‐third of tree species had significantly over‐dispersed point patterns of conspecific seedlings and saplings relative to adult densities; the majority of other species exhibited random spatial arrangements. Our results demonstrate that negative conspecific density‐dependent mortality of seedlings could generate the spatial patterns observed at later life stages. By differentially favoring seedlings of other species, this process may contribute to the maintenance of tree diversity in temperate forests, just as others have demonstrated for tropical forests.

Effects of single-tree selection harvesting on hymenopteran and saproxylic insect assemblages in the canopy and understory of northern temperate forests

Insects respond to changes in microhabitat caused by canopy disturbance, and thus can be used to examine the ecological impacts of harvesting. Single-tree selection harvesting is the most common silvicultural system used to emulate local small-scale natural disturbance and maintain uneven-aged forest structure in temperate forests. Here, we test for differences in richness, abundance, and composition of hymenopteran and saproxylic insect assemblages at four different taxon levels (selected insect orders; and all hymenopteran families, and braconid subfamilies and morphospecies) between the canopy and understory of unharvested and single-tree selection harvested sites in a northern temperate forest from central Canada. Harvesting had no effect on insect assemblage richness, composition or abundance at the three highest taxon levels (order, family and subfamily). Similarly, richness and abundance at the lowest-taxon level (braconid morphospecies) were similar, although composition differed slightly between unharvested and harvested stands. Insect assemblages were vertically stratified, with generally higher abundance (for Diptera, Hymenoptera, some hymenopteran families and braconid subfamilies) and richness (for braconid morphospecies) in the understory than the canopy. In particular, composition of the braconid morphospecies assemblage showed relatively low similarity between the understory and canopy. Single-tree selection harvesting appears to influence wood-associated insect taxa only subtly through small changes in community composition at the lowest taxon level, and thus is recommended as a conservative approach for managing these northern temperate forests.

Herb layer response to broadleaf tree species with different leaf litter quality and canopy structure in temperate forests

AbstractQuestion: How do broadleaf tree species affect humus characteristics, herb layer composition and species diversity through their leaf litter quality and canopy structure?Location: Mixed broadleaf forests in Brandenburg, NE Germany.Methods: We studied the herb and tree layer composition in 129 undisturbed stands using a 10‐degree cover‐abundance and percentage scale, respectively. The main floristic gradients were extracted by non‐metric multidimensional scaling. Effects of tree species on the herb layer were analysed with partial Spearman rank correlation. We assessed affinities for specific tree species using indicator species analysis.Results: Both beech and oak influenced herb layer composition mainly through their litter quality, which resulted in deep Ol and Of horizons, respectively. The less dense canopy of oak, in contrast to the dense beech canopy, enhanced species diversity in favour of indifferent herb species (species not closely tied to forests). Lime was correlated with a distinct floristic gradient, but a direct effect on the herb layer cannot be proven with the available data. Effects of hornbeam were less pronounced.Conclusions: The relationship between the tree and herb layer must be partly attributed to pH differences. However, tree species effects on humus characteristics and on light flux to the ground were largely responsible as well. The results suggest that tree species can influence herb layer composition and diversity, but the missing correlation with lime and hornbeam raise questions requiring further detailed investigation.

Rapid Inventory of the Ant Assemblage in a Temperate Hardwood Forest: Species Composition and Assessment of Sampling Methods

Ants are key indicators of ecological change, but few studies have investigated how ant assemblages respond to dramatic changes in vegetation structure in temperate forests. Pests and pathogens are causing widespread loss of dominant canopy tree species; ant species composition and abundance may be very sensitive to such losses. Before the experimental removal of red oak trees to simulate effects of sudden oak death and examine the long-term impact of oak loss at the Black Rock Forest (Cornwall, NY), we carried out a rapid assessment of the ant assemblage in a 10-ha experimental area. We also determined the efficacy in a northern temperate forest of five different collecting methods--pitfall traps, litter samples, tuna fish and cookie baits, and hand collection--routinely used to sample ants in tropical systems. A total of 33 species in 14 genera were collected and identified; the myrmecines, Aphaenogaster rudis and Myrmica punctiventris, and the formicine Formica neogagates were the most common and abundant species encountered. Ninety-four percent (31 of 33) of the species were collected by litter sampling and structured hand sampling together, and we conclude that, in combination, these two methods are sufficient to assess species richness and composition of ant assemblages in northern temperate forests. Using new, unbiased estimators, we project that 38-58 ant species are likely to occur at Black Rock Forest. Loss of oak from these forests may favor Camponotus species that nest in decomposing wood and open habitat specialists in the genus Lasius.