Natural Secondary Forest Research Articles

KERAGAMAN DAN KEMIRIPAN SPESIES BURUNG PADA TIGA TIPE HABITAT DI KAWASAN HUTAN DENGAN TUJUAN KHUSUS UNIVERSITAS LAMBUNG MANGKURAT (KHDTK ULM)

There are no publications on bird diversity in the Forest Area for Special Purpose, Lambung Mangkurat University (KHDTK ULM). This study aimed to analyze the diversity and similarity of bird species in the secondary natural forest, the plantation forest, and shrubs in the KHDTK ULM. Data related to diurnal birds was collected in these three habitat types. Researchers walked slowly following the transects (footpaths, inspection paths) that were already in each habitat type and recorded the name of the species and the number of individuals observed within 25 m between 06.30 - 10.00 and 15.00 - 18.00 in three replications. The data was processed to obtain diversity index of bird species (Shannon-Wienner index) and similarity index of species, as well as protection and conservation status according to LHK Regulation No. 106 of 2018 and its conservation according to IUCN. Twenty-eight species or 17 bird families were found in the area. Three of them are protected and most are categorized as least concern. The habitat types with species diversity index from highest to lowest are plantation forest, shrubs, and secondary natural forest. Based on the similarity index, the highest similarity of bird species occurs between secondary natural forest and shrub, while the lowest is between secondary natural forest and plantation forest.Keywords: diversity; forest are; habitat type; similarity; special purpose

Morphometry and size distribution of aggregates from a Typic Hapludult soil under natural secondary forest, implanted leguminous trees and degraded pasture in the Atlantic coast of Brazil

Revegetation of degraded land can in long-term improve the soil attributes compared to the initial condition. This study aimed to evaluate the efficiency of revegetation with leguminous trees to recover the structural quality of a Typic Hapludult soil. For this purpose, morphometric and size-classes distribution analyzes of soil aggregates were performed on soil samples collected from layers 0–0.10 m and 0.10–0.20 m depth. Three areas revegetated with leguminous trees 17 years earlier (Acacia auriculiformis, Mimosa caesalpiniifolia and Inga ssp.) and two reference areas (forest and pasture) were studied. The soil under leguminous trees showed larger aggregates than the soil under forest and pasture, with overall averages by grouping the former higher than those by grouping the latter around 31.6% for the weighted mean diameter and 47.6% for the geometric mean diameter. Aggregate morphometric variables obtained from image analysis were correlated to each other (such as circularity versus roundness, in all five size classes, with values ranging from R = 0.25⁎ to R = 0.72⁎⁎), and also to other soil physical and chemical attributes. As a general rule for all five aggregate size classes studied, both roundness and circularity increased with the increase in the aggregates diameter, the soil densification status, the soil richness in organic matter, the exchangeable cations content and the particle surface electronegativity. The aggregate morphometric variables of the two studied soil layers, analyzed by multivariate statistical tools, led to a consistent distinction between sites, grouping forests and pastures apart from the leguminous tree covers. Thus, it could be concluded that after 17 years of revegetation these leguminous trees changed the soil initially under pasture but in a divergent way in relation to the soil under forest.

Diversity of raptors at different habitat in Nature Reserve/Natural Tourism Park of Kawah Kamojang, Garut, West Java

The Nature Reserve/Natural Tourism Park of Kawah Kamojang has been fragmented and degraded by population growth and regional development, as well as disturbed by illegal logging and poaching. Accordingly, its function as conservation area has largely been decreased. This condition has created differences in the occurring habitat types, from natural forests to secondary natural forests, plantation forests, farmland and grassland. The presence of raptor as top predators can be used as one of indicators in the environmental changes. This study was conducted to determine the diversity and evenness index of eagle in relation to different habitats. The study was conducted in May 2019 using descriptive methods and sampling using the IPA method. The study found five species of raptor: Spilornis cheela, Ictinaetus malayensis, Nisaetus cirrhatus, Accipiter trivirgatus and Falco molluccensis. They spread separately in each habitat type. The habitat that has a highest diversity index value was secondary natural forest (H’ = 1,434) and the lowest was plantation forest (H’ = 0). In addition, the diversity index in plantation forest and grasslands had almost the same value, (H’ = 1,389 for farmland and H’ = 1,386 for grassland). The index value indicated that eagles were more dependent on the existence of natural forests. Eagles used forest habitats to hunt, perch and breed and used open areas (farmland and grassland) for hunting.

Multilevel Extraction of Vegetation Type Based on Airborne LiDAR Data

Precise determination of vegetation type is important in remote sensing of the ecological environment. Many studies have explored ecosystem structure on explicit spatial scales using specific remote sensing data, but few studies have considered vegetation information extraction at various landscape levels using LiDAR-derived raster layers. This study determined vegetation information based on LiDAR-derived canopy height model (CHM) and LiDAR-derived forest canopy coverage (FCC) from the typical natural secondary forest of Maoershan Experimental Forest Farm (Northeast China). Geographic object-based image analysis was adopted for all experiments. Optimal classification characteristics and thresholds were determined and classification rule sets established for vegetation type extraction at four levels: vegetation-not-vegetation, vegetation type, forest type, and canopy—canopy gap. We compared and analyzed the capability of LiDAR-derived raster layers extraction to describe vegetation features at these four levels. An area-based assessment method was used for accuracy verification. The research showed that physical information such as vegetation height and canopy density provided by LiDAR point cloud is effective for extracting vegetation characteristics and categories. Moreover, results showed that high-resolution LiDAR-derived raster layers could provide more detailed vegetation information. This study represents a reference for data selection and mapping strategies for hierarchical and multiscale vegetation type extraction.

The population characteristics of Lithocarpus polystachyus in natural secondary forests under different human disturbance intensity

In November 2018, the sample plot survey method was used to analyze the population characteristics of Lithocarpus polystachyus in the natural secondary forest with different disturbance intensity in Jianning, Fujian Province, and compile its population static life table. The results showed that the number of individuals in the population was small, but it was clustered. With the increase of interference intensity, the first and second age seedlings and young trees decreased. The population types affected by human disturbance are all lacking level V trees, and the population type belongs to primary population (N1); The undisturbed population lacks level I and II seedlings and young trees, but there are level V trees, and the population type belongs to medium decline population (S2). In general, all populations of L. polystachyus are unstable and belong to the transitional type. In the static life table, the mortality of level I and II seedlings and young trees is high, the survival rate has a small peak in level III and IV, and then the survival rate decreases rapidly, and the average life expectation of level II is the highest. It shows that artificial conservation measures and appropriate space re-lease are needed to maintain the stability of the population.

Larch or Mongolian pine? Effects of tree species on soil properties and microbial biomass with the consideration of afforestation time

Tree species and afforestation age can affect soil carbon (C) and nitrogen (N) sequestration as well as soil properties through different litter input and microbial activities. However, uncertainty remains because the responses vary under different climates and prior land uses. A site-specific study was conducted to investigate the dissimilarities in plant litter, soil properties, and soil microbial biomass and their influencing factors of different aged (22, 32, and 44 years) larch (Larix principis-rupprechtii) plantations and different aged (19, 30, and 43 years) Mongolian pine (Pinus sylvestris var. mongolica) plantations. In general, afforestation increased soil organic carbon (SOC), soil total nitrogen (STN), soil microbial biomass carbon (MBC), and soil microbial biomass nitrogen (MBN) contents compared with those of sparse grassland. However, there was still room for improvement in these variables compared with local natural secondary forest, which was dominated by white birch (Betula platyphylla, a deciduous broad-leaved tree species). Changes in STN, SOC, MBC, and MBN contents with afforestation age were almost insignificant in larch plantations, while significant increase can be found in STN (only in 10–20 cm soil layer), MBC and MBN in Mongolian pine plantations. The results indicated that larch was superior to Mongolian pine in soil C and N sequestration and soil fertility improvement at an early afforestation stage probably because of the higher C and N inputs from litter and higher N supply in the soil. There is an upper limit of carbon and nitrogen sequestration and soil fertility in the coniferous plantation, and mix planting of broad-leaved trees in coniferous forests may make up for this disadvantage. This study provided a reference for the selection of afforestation tree species in northern China and other areas with similar climatic conditions.

Effects of selective cutting on the distribution pattern and inter-specific association of arbor seedlings in Tilia amurensis secondary forest

The distribution pattern and interspecific associations of arbor seedlings were examined in two Tilia amurensis forest stands in Zhangguangcailing, with one without man-made interference (natural recovery secondary forest) and the other one being 20-year-old after selective cutting (selective cutting secondary forest). The results showed that the importance value of the seedlings of the soft broad-leaved (heliophile) and tolerant tree species was 7.9 and 64.5 in natural recovery secondary forest, and was 3.9 and 68.9 in selective cutting secondary forest, respectively. The spatial distribution pattern of arbor seedlings in natural recovery and selective cutting secondary forests showed clustered distribution at the scale of 0-18 m and 0-15 m, respectively. Most of tree species pairs were negatively correlated at large scale (14-45 m) in the natural recovery secondary forest, whereas tree species pairs at all the scales were mostly uncorrelated in the selective cutting secon-dary forest. Most of the tree pairs of T. amurensis seedlings (57%) with other tree species showed negatively correlation at large scale (31-45 m). In the natural recovery secondary forest, the proportion of negatively correlated tree pairs was higher than 60%. In selective cutting secondary forest, Acer mono seedlings were negatively correlated with other tree species at more scales (6-45 m). In the natural recovery secondary forest, the pairs of A. mono and other arbor seedlings were positively correlated at small scale (0-5 m), but not at large scale (31-45 m). Therefore, selective cutting accelerated the succession of the secondary forest of T. amurensis, which induced random distribution of the arbor seedlings at the large scale (31-45 m), promoted a more coordinated inter-specific relationship, and adjusted the spatial competition between T. amurensis seedlings. Both stands were under succession, and thus suitable artificial management should be carried out to promote tree regeneration and community restoration.

Positive tree diversity effect on fine root biomass: via density dependence rather than spatial root partitioning

The importance of species richness to ecosystem functioning and services is a central tenet of biological conservation. However, most of our theory and mechanistic understanding is based on diversity found aboveground. Our study sought to better understand the relationship between diversity and belowground function by studying root biomass across a plant diversity gradient. We collected soil cores from 91 plots with between 1 and 12 aboveground tree species in three natural secondary forests to measure fine root (≤ 2 mm in diameter) biomass. Molecular methods were used to identify the tree species of fine roots and to estimate fine root biomass for each species. This study tested whether the spatial root partitioning (species differ by belowground territory) and symmetric growth (the capacity to colonize nutrient‐rich hotspots) underpin the relationship between aboveground species richness and fine root biomass. All species preferred to grow in nutrient‐rich areas and symmetric growth could explain the positive relationship between aboveground species richness and fine root biomass. However, symmetric growth only appeared in the nutrient‐rich upper soil layer (0–10 cm). Structural equation modelling indicated that aboveground species richness and stand density significantly affected fine root biomass. Specifically, fine root biomass depended on the interaction between aboveground species richness and stand density, with fine root biomass increasing with species richness at lower stand density, but not at higher stand density. Overall, evidence for spatial (i.e. vertical) root partitioning was inconsistent; assumingly any roots growing into deeper unexplored soil layers were not sufficient contributors to the positive diversity–function relationship. Alternatively, density‐dependent biotic interactions affecting tree recruitment are an important driver affecting productivity in diverse subtropical forests but the usual root distribution patterns in line with the spatial root partitioning hypothesis are unrealistic in contexts where soil nutrients are heterogeneously distributed.

Species Diversity Characteristics of a Natural Pinus taiwanensis Community with Different Diameter Classes and Forest Densities

Pinus taiwanensis is a species endemic to China. This study selected four typical plots of Pinus taiwanensis in the natural secondary forest around Macheng City, in order to reveal the characteristics of and the relationships between different diameter classes (determined based on the diameter at breast height or DBH), forest densities and species diversity, as well as the similarities of species diversity of different plots within the community. The result showed that Pinus taiwanensis was the dominant species in the community. The ratio of Pinus taiwanensis trees of diameter class IV reached a peak of 19.46% of the total followed by diameter class VII at 18.92%. The study recorded 156 species of vascular plants from 130 genera of 71 families; Pinus taiwanensis was the dominant species in the community. When the forest density was 1200 trees ha–1 with the largest average diameter of DBH=36.779±4.444 cm, the diversity (Shannon index H'=1.6716) and the evenness (Pielou index E=0.6727) of the tree layer was the highest. When the forest density reached 1525 trees ha–1 with the lowest average diameter of DBH=18.957±5.141 cm, the richness (Dma=5.4308), the diversity (H'=2.9612) and the evenness (E=0.8985) of all shrub layers climbed to the maximum. When the forest density was 1325 trees ha–1, the richness (Dma=5.8132), the diversity (H'=3.0697) and the evenness (E=0.9025) of all herb layers peaked. In terms of vertical structure, the average diversity indexes were herb layer>shrub layer>tree layer. High canopy density weakened light intensity in the community, causing a reduction in the species diversities of herbs and shrubs. The average similarity coefficient between the sample plots was 0.3356, which was at the medium dissimilarity level. External disturbances and improper management were major contributors to the low species diversity of the community. The implementation of scientific management measures is urgently needed to optimize the forest structures of Pinus taiwanensis, create a benign community environment, and promote species diversities and establish a stable forest community structure.

Stabilities of soil organic carbon and carbon cycling genes are higher in natural secondary forests than in artificial plantations in southern China

AbstractOur understanding of how reforestation affects microbial carbon cycling genes remains limited, restricting our ability to evaluate reforestation methods. We hypothesized that natural reforestation produces soil organic carbon (SOC) with significantly more complex chemical composition and more diverse carbon cycling genes than artificial restoration. The SOC fractions and carbon cycling (primarily fixation and degradation) genes present in natural restoration/regrowth (natural secondary forests), and artificial restoration (Masson and slash pine plantations) were compared. The SOC in natural secondary forests was significantly more abundant and structurally more complex than that of Masson and slash pine plantations. The natural secondary forest soils contained significantly more abundant and diverse carbon cycling genes than plantations. Plant‐, soil‐, and nutrient‐associated factors explained 42.1% of the variation in microbial carbon cycling gene compositions. These factors included tree diversity, fine root surface area, litter stock, clay and silt, labile and recalcitrant organic carbon, available nitrogen and nitrate‐nitrogen contents. These factors affect the microbial carbon cycling gene diversity but not abundance in the natural secondary forest soils. These genes' abundance and diversity in the Masson and slash pine plantation soils were enriched by increasing litter stock and decreasing clay and silt contents; they were also enhanced by higher tree diversity, labile and recalcitrant organic carbon, available nitrogen, and nitrate‐nitrogen contents. These findings indicate that current reforestation methods affect carbon cycling genes, carbon cycling potential, and thus, biogeochemical carbon cycling processes. Natural restoration is better than artificial restoration in terms of organic carbon stability and cycling.

Effect of land uses on soil microbial community structures among different soil depths in northeastern China

Changes in land use affect the cycling and supply of soil nutrients, directly leading to changes in soil properties and the structure of soil microbial communities and altering the structure and function of terrestrial ecosystems. Previous studies have focused only on the response of soil microbial communities to changes in land use; however, the main drivers of changes in soil microbial community structure and abundance under different land uses and soil depths are still obscure. In this study, four types of land use (natural secondary forest, SF; larch plantation, LP; farmland, FL; and abandoned land, AL) in northeastern China were selected, and soil from the 0–5 cm, 5–10 cm and 10–20 cm layers was collected to evaluate the microbial communities by means of phospholipid fatty acid (PLFA) analysis. Due to land use history and soil legacy, land use had significant effects on soil organic carbon (C), nitrogen, and phosphorus, as well as on pH, bulk density, moisture, and phenolic compounds. The C content in SF was 40.7% higher than that in AL, and the total phenol (T-Ph) in SF was 39.6% lower than that in LP. Land use had a significant effect on total PLFAs, bacterial, fungal, actinomycetal and Gram-positive PLFA biomarkers. In topsoil, the total PLFAs and fungal communities were 55.62% and 240.51% higher than in AL, respectively. The cyclopropyl:monoenoic precursor fatty acids (cy:pre) PLFA biomarkers were higher in LP. The correlation between phenolic compounds and soil microbial community structure at every soil depth was stronger than the correlations between these structures and C, N, C/N and pH. Total phenol content promoted and inhibited the growth of various groups of microorganisms in the 0–5 cm and 5–10 cm soil layers, respectively. In summary, land use changed soil physicochemical properties in the conversion from SF to LP, FL and AL. These abiotic factors, especially phenolic compounds, regulated soil microbial community structure and abundance.

First Distribution Record of North Philippine Temple Pitviper (Tropidolaemus subannulatus Gray, 1842) on Cebu Island, Philippines

This paper presents the newly documented single specimen of the North Philippine temple pitviper (Tropidolaemus subannulatus), one of the venomous endemic snakes of the Philippines. The species has never been recorded in Cebu Island in the last two waves of survey in 1986 and 2016. The new record for Cebu Island on 13 Apr 2018 was a male juvenile T. subannulatus in a diverse forest over limestone in Mount Lantoy key biodiversity area (KBA), with an elevation of 648 m having geographic coordinates of 9.91395ºN and 123.51207ºE in Barangay Cansuje, Argao, Cebu, Philippines. The specimen was recorded in the permanent vegetation plot no. 1, established within the secondary natural forest, perching on the vines (Piper sp.). Some tree species found within the collection area were the following; Garcinia rubra, Ficus ampelas, Canarium asperum, Calophyllum blancoi, Gomphandra luzoniensis, and Goniothalamus almeri. The distance of occurrence from the ground is approximately 3 m. It seemed that the microhabitat characteristics of Mt. Lantoy KBA, particularly the forest over limestone in Barangay Cansuje, is favoring the survival of T. subannulatus.

Spatial Structure Evaluation of Natural Secondary Forest around Dongting Lake Based on Entropy Weight - Cloud Model

Li, X.; Zhang, G., and Li, J., 2020. Spatial structure evaluation of natural secondary forest around Dongting Lake based on entropy weight - cloud model. In: Yang, Y.; Mi, C.; Zhao, L., and Lam, S. (eds.), Global Topics and New Trends in Coastal Research: Port, Coastal and Ocean Engineering. Journal of Coastal Research, Special Issue No. 103, pp. 484–489. Coconut Creek (Florida), ISSN 0749-0208.In order to provide theoretical support for the formulation of optimized measures of stand spatial structure, 15 sample plots are set up in Daweishan Nature Reserve, Longhushan national forest farm in Yuanjiang City and Lutou national forest farm in Pingjiang County to analyze and evaluate the stand spatial structure of natural secondary forest around Dongting Lake. After determining the spatial structure unit of trees by Voronoi diagram, the five indicators including mingling degree, neighborhood comparison, openness comparison index, neighborhood pattern and angle competition index are segmented to correspond to the five grades of stand spatial structure divided by the combination of qualitative and quantitative methods. Then through the comprehensive assessment on stand spatial structure by entropy weight-cloud model, the fifteen plots are evaluated as grade III and grade IV, respectively accounting for two-thirds and one-thirds of all plots, which indicates that the reasonable stand spatial structure of natural secondary forest around Dongting Lake is above the average. As a new evaluation method of stand spatial structure, the entropy weight-cloud model has solved the issue of qualitative and quantitative conversion, and objectively calculate the weights of indicators, so as to enrich the evaluation methods of stand spatial structure, overcome the one-way evaluation by single indicator, improve the objectivity and scientificity of evaluation results, and provide theoretical basis for the scientific guidance of stand spatial structure optimization.

Studying the soil pore physical resistance and resilience of a shallow volcanic ash soil subjected to pure cyclic loading

In the last 250 years the Aquands (depth-limited and waterlogged-volcanic ash soils) in southern Chile were exposed to an intensive land use change inducing physical degradation of these fragile soils. The aim of this work was to evaluate the effect of cyclic loading on soil structural properties and the resilience capacity after simulating one event of soil waterlogging as usually occurs in the field. In undisturbed soil samples, collected from two horizons (2−5 cm, Hz1 [A1] and 20−23 cm, Hz2 [Bs1]) of a Duric Histic Placaquand under secondary native forest (sNF) and naturalized grassland (NG), the precompression stress (Pc), deformation and recovery indices derived from cyclic loading tests (20, 80 and 200 kPa) were determined. The air permeability (Ka) and soil volume changes were measured during the entire test. The land use change from sNF to NG increased the rigidity of the pore system due to plastic deformation. However, the cyclic loading provokes changes in the pore system (e.g. increase in bulk density as well as decrease in wide coarse pores, which finally induce a decrease in air permeability: 1.89 to -0.17 log μm2 and 1.03 to 0.37 log μm2 in Hz1 of aNF and NG, respectively) even at loads lower than Pc highlighting the fragility of the soils. As the applied load increases to levels higher than Pc, the plastic deformation induces an increase in pore water pressure and mechanical strength, affecting the pore network and in turn the air permeability of the soil. After one event of ten days of waterlogging conditions, the resilience capacity of the pore system was low. CT-images show that the soil under sNF recovered apart of the deformed porosity allowing an increase in Ka (0.55 ± 0.15 log μm2) after waterlogging conditions, however, no changes were identified for the soil under NG (final Ka = 0.57 ± 0.26 log μm2). Therefore, both land use change and increasing loads on these fragile soils imply the loss of their resilience capacity generating a further soil settlement.

Response of soil phosphorus fractions and fluxes to different vegetation restoration types in a subtropical mountain ecosystem

Soil phosphorus (P) improvement is one of the important aims of vegetation restoration. However, the effects of different vegetation restoration types on soil P cycling and the underlying mechanisms remain unclear. Together with vegetation structure and soil properties, we measured the soil P fractions and P transformation rates to evaluate the characteristics of ecologically relevant soil P fraction distributions and their dynamics for the most common vegetation restoration types in a subtropical mountain ecosystem (i.e., PF, Pinus forest; EF, Eucalyptus forest; SL, shrubland; and NSF, natural secondary forest). We found that water-extractable inorganic P (Pi), organic P (Po), and acid phosphatase activity (APA) were significantly higher in NSF than those in the other vegetation types (P < 0.01), together with the highest gross P mineralization rate (Pmin) and net P immobilization rate (Pimm), suggesting biological processes played a more important role in soil P cycling in the NSF. In contrast, the soil showed the lowest values of Pmin, Pimm, and APA in the EF compared to NSF and PF (P < 0.05), together with the highest P loss and the higher net P solubilization rate (Psol), indicating the greater importance of soil geochemical processes. Compared with the NSF and EF, geochemical and biological processes co-regulated soil P cycling in the PF and SL. However, the soil in the PF displayed higher P fluxes (Pmin, Pimm, Psol, and P loss) than those in the SL (P < 0.05), suggesting the soil had higher P flux magnitudes in the PF. Results of correlation analyses showed that the soil microbial community structure and activity played a more important role than plant community attributes and soil physicochemical properties in soil P fraction distribution and fluxes. In conclusion, soil P fraction distributions and their fluxes can be significantly influenced by vegetation restoration types. Land management strategies focusing on restoration of the soil microbial community may enhance soil P cycling and improve soil quality.

Seasonal variations in soil microbial communities under different land restoration types in a subtropical mountains region, Southwest China

Soil microbial community is an important indicator for understanding the effects of land restoration on soil quality and ecosystem development. Natural vegetation restoration types (shrubland and natural secondary forest) and plantation forests (Pinus forest and Eucalyptus forest) were selected to investigate the effects of land restoration models and seasons (dry and wet seasons) on soil microbial communities using phospholipid fatty acid analysis (PLFA). The results of two-way ANOVA and PERMANOVA test demonstrated that the land restoration type and season had significant effects on the concentrations of PLFA biomarkers. Significantly higher concentrations of all groups of PLFAs were found in natural secondary forest than in shrubland and plantation forests, suggesting that plant species-specific differences in quality and quantity of litters, root exudates and the soil properties influence the soil microbial community composition. Relative to the wet season, increases of biomasses of fungi, actinomycetes, AMF, and gram-positive bacteria in SL and NSF in the dry season were significant. The result of redundancy analysis showed that soil organic carbon and soil moisture significantly explained the variation in response of soil microbial communities to season and land restoration type in this region. Our finding indicates that heterogeneity of soil microbial response to time and vegetation must be considered in assessment of ecosystem functions and services under different land restoration types.

Microbial functional gene diversity in natural secondary forest Ultisols

The diversity and biogeography of functional genes at a regional scale remains unclear. We hypothesize that plant community composition, nutrient availability, and spatial distance are driving factors for the functional gene diversity of soil microorganisms at a regional scale. We also hypothesize that different functional genes have different responses to environment. Using functional gene arrays (GeoChip 3.0), we examined microbial diversity, and influencing factors in Ultisols in 11 natural secondary forest plots in southern China which contained 4073 functional genes averagely. Carbon and nitrogen cycle genes were more variable than genes involved in phosphorus utilization, organic remediation, and metal resistance, in similar trends with soil substrate availability. Genes involved in nitrification being more variable than other nitrogen cycling genes; phytase genes being more variable than polyphosphate kinase genes (ppk) and exopolyphosphatase genes (ppx); exoglucanase and endoglucanase genes being more variable than cellobiase genes; lignin peroxidase genes (lip) being more variable than manganese peroxidase genes (mnp). Approximately 41% of the variation in gene composition could be explained by fine root surface area, available nitrogen, and the largest spatial scale factor, with the former two environmental factors over influenced spatial distance. Both environmental factors (represented by nutrient availability) and spatial distance influenced microbial functional gene composition, while the influence of spatial distance worked through environmental factors in natural secondary forest in Ultisols within approximately 500 km, providing insights into microbial biogeography from a functional gene perspective.

Cacao agroforestry management systems effects on soil fungi diversity in the Peruvian Amazon

Abstract Cacao agroforestry system provides productive land use and preserves the best conditions for physical, chemical and biological properties of tropical soils in cocoa tropical region of the world. We evaluated the impact of changing a 30-year-old native secondary forest to two cacao agroforestry systems on soil fungal diversity. The cacao agroforestry systems adapted were: an improved natural agroforestry system (INAS) where trees without economic value were selectively removed to provide 50% shade; and an improved traditional agroforestry system (ITAS) where all native trees were cut and burnt in the location. In both systems, new economically valuable trees were planted. In these management systems, plots of 10 cacao genotypes and one plot with a spontaneous cacao hybrid were selected for soil sampling. In each plot, soil samples were randomly collected at 0–20 cm depth, immediately after the trees were planted (2004) and at the end of 2010; each sample was divided in two, one part for soil characterization by conventional chemical analytical methods and the other for soil fungal analysis using the plate dilution method. Soil fungi were identified by appropriate keys and grouped according to their functionality as potential biocontrol, plant pathogenic, facultative or saprophytic fungi; the structure of fungal communities was analyzed by population, richness and Shannon and Simpson indices. Fungal diversity varied significantly during the years of study, at all soil depths and under the agroforestry systems assessed. The fungal communities showed significant changes due to soil management influenced by INAS and ITAS, and mainly after burning of native vegetation in ITAS. Overall higher abundance of soil fungal communities were observed in ITAS than in INAS. In both systems, differential changes in soil physical and chemical properties under cacao also could have been a contributing factor in the fungal diversity and functional groups observed.

Optimizing Forest Spatial Structure with Neighborhood-Based Indices: Four Case Studies from Northeast China

The fine-scale spatial patterns of trees and their interactions are of paramount importance for controlling the structure and function of forest ecosystems; however, few management techniques can be employed to adjust the structural characteristics of uneven-aged mixed forests. This research provides an accurate, efficient, and impersonal comprehensive thinning index (P-index) for selecting candidate harvesting trees; the index was proposed by weighting the commonly used quantitative indices with respect to stand fine-scale structures, competition status, tree vigor, and tree stability. The applications of the proposed P-index in evaluating and simulating the process of thinning operations were examined using four 1-ha mapped plots with different forest types, namely, natural secondary forest, natural pine-broadleaved mixed forest, natural larch-birch mixed forest, and natural oak forest, which were widely distributed across the Heilongjiang Province in Northeast China. The results indicated that the proposed P-index could effectively affect the structural differentiations between different forest types and alternative thinning intensities. The marginal benefits of alternative thinning intensities on the integrated forest structure indicated that removing 10% of the trees from the plots might be the optimal thinning intensity from the perspective of optimizing stand structure, in which the P-index values could be increased by approximately 5%–11% for the four tested plots. The main conclusion from this paper was that the proposed P-index could be used as a quantitative tool to manage uneven-aged mixed forests.

The application of economics in the policy formulation to manage peat swamp forests as important ecosystems in climate change

Forest resources can provide benefits according to their capacity if there is an efficient resources allocation. Efficient allocation requires an assessment of value of benefits for the entire economy, not just financial benefits for business entities. Currently, degraded natural peat swamp forests within production forest areas are faced with the choice of being managed as natural forests, plantations forests or converted into plantations. Financial benefits are seen as more tangible and prominent benefits than economic benefits in policy formulation. This study aims to apply appropriate economic analysis methods to formulate policies for allocating forest resources efficiently. A comprehensive cost benefit analysis framework by internalizing environmental costs is used to formulate management policy of degraded natural peat swamp forest. This research is a case study in Sungai Merang-Sungai Ngirawan Peat Hydrological Unit (PHU). The results indicate that secondary peat swamp forests are more appropriately managed as secondary natural production forests rather than if it is managed as industrial plantations or converted to plantations. The use of a science framework in the practice of policy formulation is expected to support the sustainable forest development, especially in relation to climate change.