Natural Forest Stands Research Articles

The space occupation and use by tree crowns explain variations of individual growth rates in an old-growth temperate forest in Japan

Relative growth rates (RGR), i.e., growth rates per unit biomass (ΔM/M, where M is plant mass and ΔM is the change in M over a period of time), reflect growth strategies of plant species. Partitioning of RGR to net assimilation rate (ΔM/leaf area) and leaf area ratio (leaf area/M) provides further insights into allocation strategies. To apply this analytical approach to large canopy tree species, we used crown area (Ac) as a proxy for leaf area to understand variations of RGR partitioned to space use efficiency (SUE, ΔM/Ac) and space occupation efficiency (SOE, Ac/M). With UAV imagery, we measured Ac of 226 co-occurring individuals of 14 canopy tree species in a 1-ha stand in a temperate old-growth mixed-forest in Japan, and analyzed how RGR was related to SUE and SOE. The results show that deciduous species exhibited higher SOE and lower SUE compared to evergreen species, even though their RGR values largely overlapped. Late successional species tended to have higher RGR through higher SUE than early-to-middle successional species. We also analyzed the relationship of absolute growth rates (AGR) with several functional traits including DBH (diameter at breast height), Ac, leaf- and stem traits. Both Ac and DBH were strong determinants of AGR across species. Low specific leaf area (SLA, leaf area per unit leaf mass) and high wood density positively contributed to AGR across species, offering long-term growth advantages for old-growth natural forest. The analytical framework introduced in this study may be useful to elucidate the variation of tree growth strategies of canopy trees in natural forest stands.

Comparison of spatial dispersion of epigeic fauna between alluvial forests in an agrarian and Dunajské luhy protected landscape area, southern Slovakia

Abstract The spatial distribution of the epigeic fauna of floodplain ecosystems (willow-poplar floodplain forest, regenerated poplar forest), in the conditions of the natural environment of the Dunajské luhy Protected Landscape Area (PLA, hereinafter) and agrarian landscape was studied. The Dunajské luhy PLA, hereinafter (Slovak Republic) is the part of the system of protected areas of the European Union. During the three years 2020–2022, 24,169 individuals belonging to 19 taxa at 6 locations using the pitfall traps method were recorded. Through spatial modeling, the preference of most taxa for floodplain forests located in the Dunajské luhy PLA was found. We also observed a significant difference in number of individuals of epigeic fauna in floodplain forests betvween Dunajské luhy PLA area and agrarian landscape during all three years 2020 (p = 0.0070), 2021 (p = 0.0077) and 2022 (p = 0.04624). Thus, agroecosystems in the neighborhood of alluvial forests had a negative impact on the taxonomic diversity and abundance of epigeic fauna. In order to maintain a balance between the production of food, wood and the preservation of natural forest stands, it is important to optimally allocate areas and set up their management. For example, by creating forest islands in agricultural crops, to increase the epigeic fauna.

Spatial distribution of soil organic carbon and macronutrients in the deep soil across a chronosequence of tea agroforestry

Due to the rapid growth of the tea industry, the tea plantation area has steadily increased worldwide. In some regions, croplands and natural forests have been converted into tea plantations causing habitat fragmentation, reducing landscape connectivity and loss of biodiversity. On the other hand, ancient tea forests, rustic tea and tea agroforestry have been shown to support higher native biodiversity. However, there is a dearth of information on the potential of tea agroforestry systems (TAFS) to store soil organic carbon (SOC) and nutrients in deeper soil layers. For the first time, here we provide estimates of concentrations and stocks of SOC and available nitrogen (N), phosphorus (P) and potassium (K) in deep soils in a chronosequence of tea agroforestry and adjacent natural forest stands. The concentrations of SOC, available N, P and K steadily decreased with soil depth across all the chronosequence of TAFS and natural forest stands. The SOC stocks in the 0–500 cm soil depth varied from 174.5 Mg C/ha in 20 years old TAFS to 213.2 Mg C/ha in 60 years old TAFS and 311 Mg C/ha in natural forest stands. Based on the empirical data, we propose the following predictive models for estimation of deep SOC concentrations (Y): Y=0.55+14.67e-0.013D in TAFS and Y=1.04+31.53e-0.014D in natural forests. The highest available N stocks were found in 60 years old TAFS (181.7 kg ha−1) while the available P and K stocks were highest in the forest soils (22.42 kg ha−1 and 56.86 kg ha−1). As in SOC, clay content and the SOC: clay ratios declined with soil depth in all the land uses studied. The SOC: clay ratios indicated a good soil structure in the study sites. It is concluded that TAFS store 39–46 % the SOC stocks and over 50 % of the available N, P and K stocks in the 100–500 cm soil depths. The predictive models developed here could be used for estimating deep soil SOC stocks after validation with independent datasets.

Potential implications of shortened rotation length for forest birds, bryophytes, lichens and vascular plants: An example from southern Swedish production forests

The rotation lengths of intensively managed production forests may be altered to achieve a variety of goals, with correspondingly implications for biodiversity. Here we consider the potential implications of shortened rotation times for biodiversity in planted monocultures of the two most common production tree species in Sweden, Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). To do so we surveyed bird, bryophyte, epiphytic lichen and vascular plant diversity in 80 and 55-year-old stands; stand ages which approximate present-day and potential future rotation lengths in this region respectively. We found clear differences in the species communities of the 55 compared to the 80-year-old stands for both understory species and epiphytes, but not for birds. Nevertheless, bird species richness was still highest in the 80-year-old Norway spruce dominated stands. Dead wood amount was also highest the 80-year-old Norway spruce stands. Highest species richness of epiphytic lichens was found in 80-year-old Scots pine stands. However, 55-year-old Scots pine stands had a higher understory species richness and diversity than the older Scots pine stands, including a larger number of open land species. The 80-year-old forest stands examined may be considered old with respect to production forest rotation lengths in Sweden but are relatively young when comparing stand ages of unmanaged natural forest stands. Nevertheless, our results indicate that shortening the rotation time of Scots pine and Norway spruce, in this part of Sweden from 80 to 55 years, could have important consequences for forest biodiversity. These consequences are primarily inferred from the likely implications from shortened rotations for lichens community composition and diversity in both Norway spruce and Scots pine stands, as well as impacts on understory plant species in Norway spruce stands.

The Stability of Trees Species in Terms of Height-Diameter Ratio and the Relationship of Stand Quantitative Characteristics in Natural Forest Stands (Case Study: Arasbaran Forest)

The Stability of Trees Species in Terms of Height-Diameter Ratio and the Relationship of Stand Quantitative Characteristics in Natural Forest Stands (Case Study: Arasbaran Forest)

Эффективность рубок ухода в лиственно-еловых насаждениях в северной подзоне европейской части России

Research on permanent sample plots (Arkhangelsk, Northern district forestry, Obozerskoye forestry) in birch and spruce stands with an understory layer of spruce was carried out. The sample plots were established since 1966 and differed in the intensity of thinning. The results were analyzed by correlating them with the data of 6 previously conducted surveys (in 1966, 1974, 1986, 2001, 2010, 2020) for permanent sample plots 1K and 2RU and 5 surveys (1974, 1986, 2001, 2010, 2020) for permanent sample plot 19. In the absence of maintenance in young stands aged 20-30 years (permanent sample plot 1K), further growth of spruce was inhibited, competition between trees increased, and growth tension increased. Birch had a biophysical impact on spruce. Carrying out thinning of various intensities made it possible to form the most productive forest stand on the permanent sample plot 2RU. The total stand stock here is maximum - 435 m3/ha, the average heights for the whole growth period is also maximum. In terms of stock, spruce prevails, however, it is still located in the understory forest level, but will eventually enter the canopy forest level. According to the results of the study, three stages of stand formation were identified. The first stage, the stage of emergence, is characterized by the predominance of birch and spruce over the area, spruce regeneration lasting 15–25 years. In the process of passing this stage, favorable conditions for spruce settlement and its survival are created. The second stage is accompanied by deterioration of spruce growth conditions, as the birch layer differentiation and birch growth are intensively going on. The duration of the stage is 70–90 years. As a result, a new mixed biogeocenosis is formed. The final third stage lasts until the formation of a pure spruce forest. Thinning in natural young forest stands should be considered as a measure providing reliable restoration of forests with coniferous species with costs and labor much less than in case of full artificial reforestation. For citation: Surina E.A., Minin N.S. Efficiency of Thinning in Deciduous-Spruce Forest Stands in the Northern Taiga Forest Region of the European Part of the Russian Federation. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 103–114. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-103-114

Potential of carbon sequestration enhancement through intensive silvicultural techniques using Shorea leprosula plantation in Central Kalimantan, Indonesia

Abstract. Iskandar M, Siregar IZ, Krisnawati H. 2023. Potential of carbon sequestration enhancement through intensive silvicultural techniques using Shorea leprosula plantation in Central Kalimantan, Indonesia. Biodiversitas 24: 4699-4713. Various sectors are involved in achieving Indonesia’s Enhanced Nationally Determined Contribution (NDC), including Forestry and Other Land Uses (FOLU) sector. Sustainable Forest Management (SFM) implementation by forest concessionaires (PBPHs) enormously contributes to land-based mitigation activities, primarily at the local level. One of the SFM activities is forest enrichment with Intensive Silvicultural (SILIN) technique using Shorea leprosula Miq. to enhance carbon stock and sequestration. This study was conducted in PT Sarmiento Parakantja Timber (PT Sarpatim) in Central Kalimantan (Indonesia) and used the measurement data from 32 purposive sampling plots. Each plot was 40m × 40m in size, constructed under three different SILIN patterns (conventional strip, effective strip, and gap) as well as natural forest stands. This study found that SILIN gap pattern had higher carbon stock and sequestration potential, compared to the natural forest (reference) stands, and reached a net sink condition after 30 years. For the stands of SILIN conventional and effective strip patterns, the carbon stocks were lower than the reference stand, even when the vegetation aged 30 years. PBPHs applying SILIN technique as part of the SFM and the mitigation actions demonstrate an enhanced carbon stock and sequestration. This effort supports Indonesia’s Enhanced NDC target and FOLU Net Sink 2030.

Efficient use of timber resources in Mexico: Historical development and current challenges

The use and consumption of wood has always captured the attention of forest researchers, mainly from the point of view of forest management and the sustainable processing of raw materials. For this reason, the wood industry has not only been concerned with the maintenance of forests, but also with efficient processing. The objective was to identify, analyse and discuss the main elements that influence the efficient use of natural timber resources at a global, regional and local level, providing a historical and current perspective of the industrial forestry sector in Mexico. Historically, the wood industries worldwide have been concerned with applying intensive silvicultural treatments in native and artificial forest stands, in search of satisfying the demand of a growing market. In this context, industries evolved as processes needed to be more efficient. Therefore, efforts were made to reduce and take advantage of forest residues, at the same time various historical events generated additional needs. At present, the integration of silviculture and forest transformation allow to increase and improve the quality of the products generated. Through the application of intensive silvicultural treatments, products of a single species are obtained. However, it is possible to direct production to a specific market as the forest mass develops. For its part, selective treatments in uneven-aged forests maintain a constant production of diverse products for different specialized markets. In Mexico, it is imperative to analyse and generate innovative or competitive products derived from wood to improve the efficiency of forest harvesting.

Soil fungal diversity of birch plantations on former agricultural land resembles naturally regenerated birch stands on agricultural and forest land

Short-rotation forestry on former agricultural soils is a novel silvicultural system for producing woody biomass and mitigating climate change through CO2 uptake. However, tree plantations are often criticized for their low biodiversity and are sometimes referred to as “green deserts”. We hypothesize that regarding biodiversity, the spontaneous natural regeneration of birch on former agricultural lands may be preferable to plantations. In this study, we compared soil fungal diversity and composition of fast-growing silver birch (Betula pendula Roth) plantations on former agricultural lands (n = 11) with naturally regenerated birch stands on former agricultural lands (n = 11) and native forest birch stands (n = 11) at the age of 21–28 years in hemiboreal Estonia. PacBio third-generation sequencing was carried out to analyse fungal species richness and composition in the soil samples. Sequencing of the fungal ITS region from 33 birch stand soil samples yielded 2830 fungal OTUs. We found that the total fungal species richness, per sample species richness, Shannon diversity index, and Pielou's evenness index did not differ significantly between the studied stand types. However, fungal community composition of both plantations and naturally regenerated stands on former agricultural lands differed significantly from the native forest stands, indicating that previous land use (agriculture vs. forest) had a stronger effect on fungal assemblages than the used regeneration method (planting vs. natural regeneration). The relative abundance of ectomycorrhizal and arbuscular mycorrhizal fungi was higher, and the relative abundance of saprotrophic fungi was lower in plantations than in native birch dominated forest stands. Soil chemical properties were found to be weak explanatory variables for describing soil fungal richness and composition. We identified historical surrounding forest cover, stand age, stand distance from a native forest, and soil Mg content as the factors significantly affecting soil fungal communities. These results indicate that fast-growing birch plantations established on former agricultural soils or naturally regenerated stands on such soils in the Northern Europe region harbour soil fungal diversity levels similar to those of same-aged native birch forests.

Is the Current Forest Management to the Northernmost Population of Cordulegaster heros (Anisoptera: Cordulegastridae) in Central Europe (Czech Republic) Threatening?

Cordulegaster heros is included in the EN category on the IUCN Red List for the territory of the Czech Republic, where it inhabits an area of approximately 100 km2. All of the localities are located in the forest complex in Chřiby hills, and all of the forests fall into the category of management forests. Most of the forest stands have a high and very high degree of naturalness; they are natural forest stands. The predominant management units are Nutrient sites in middle elevations (78.2% of the area) and Oligotrophic sites in middle elevations (2.1% of the area), with stand types of Fagus sylvatica representing 92.5% of the area, and forest stand types of Quercus sp. representing 5.7% of the area. The wider alluvia in forest streams are classified as being in management unit alder and ash sites on waterlogged and floodplain soils (1.1%), with the forest stand type of Alnus glutinosa. The forest stands are restored by regeneration under shelterwood (97.8% of the area). The waterlogged alluvia, if a separate management unit is established for them, are restored by a regeneration by strip method. Realistically, seven factors were recorded in C. heros habitats, but they mostly have only point effects. Within forestry management, the factors of logging directly in the habitats and the subsequent transport of harvested timber in the habitat were recorded. The most intrusive effects were found on tractor logging roads, where fine soil washes into the stream and causes prolonged turbidity. Of the water management structures in the study area, logging roads with bridges and culverts are constructed, stream banks are reinforced with longitudinal walls at points, and stone steps in the channels are constructed only sporadically. The current forest management system can be described as a nature-friendly system, and therefore, it fully ensures the conditions for the survival of the C. heros population in the Czech Republic.

Nutritional Assessment and Comparison of the Composition of Oil Extracted from Argan Nuts Collected from a Plantation and Two Natural Forest Stands of ARGAN Trees

Argan oil (AO), extracted from the argan tree’s fruits, is principally composed of mono-unsaturated fatty acids, polyphenols, tocopherols, and sterols. This unique chemical composition is likely to be responsible for its beneficial effects. The argan tree (Argania spinosa) grows endemically in the southwest of Morocco. This study aimed to evaluate the chemical composition of three types of argan oil from three geographical locations: argan oil extracted from argan nuts collected from a plantation (Casablanca, AOC) and two forest stands of argan trees growing naturally in their native environment of the south-west of Morocco ((regions of Essaouira (AOE) and Taroudant (AOT)). The composition of the three oils corresponds to the known composition of argan oil in terms of fatty acids and unsaponifiable fraction. The chemical analyses revealed that the argan oil extracted from the plantations (AOC) is significantly richer in linoleic acid, linolenic acid, and tocopherols compared to the oil from the two natural stands (AOE and AOT) of argan trees. These results suggest that it is possible to facilitate an assisted migration of the argan tree outside its natural area into sites exposed to sea spray without affecting the quality of its argan oil.

Ecological Aspects of the Analysis of the Age Structure of the Stand of the National Park “Buzuluksky Bor”

The forests of the steppe Trans-Urals cover a small area and are represented to a greater degree by island forests, birch outlier and inundable poplar forests. However, it is difficult to overestimate their bioecological, habitat forming, soil-fixing, protective and recreational functions. Currently, due to various forest growth conditions and forestry operations, in natural and artificial forest stands, there are processes of shrinking of the stand, epiphytoxics of the stand with harmful insects and fungal diseases, an increase in the proportion of overmature stands, which worsen the general condition of the forest, lead to the development of outbreaks of diseases and create an inflammability. The tree plantations Buzuluksky Bor National Park are exposed to periodic droughts, high temperatures in spring and summer, fires in large areas, diseases, as well as continuous logging carried out in the past, which leads to a change in the structure of the stand. The article provides a history of the bor formation, which in the process of its formation was undergone serai change, the influence of various both positive and negative factors, which can be attributed to an anthropogenous factor. An analytical analysis of the changes in the forest fund of the national park Buzuluksky Bor National Park because of the use of logging of the main use and the impact of the pyrogenic factor is given. Changes in the area of plantings of individual species by years of forest management are also presented. The optimal age structure is determined, the value of the normative distribution of the areas of plantings for each kind of wood is calculated. Conservation and restoration of forest territories of the steppe zone, in particular Buzuluksky Bor National Park, the productive capacity of tree plantations, continuing of protective functions, as well as biodiversity and their contribution to global ecological processes are currently the task of prime importance and criterion for sustainable management of forest resources.

Short-term effects of retention forestry on the diversity of root-associated ectomycorrhizal fungi in Sakhalin fir plantations, Hokkaido, Japan

We have examined the effects of dispersed and aggregated retention on the diversity of root-associated ectomycorrhizal fungi (EcMf) in Sakhalin fir (Abies sachalinensis) plantations, 4 years after logging. Roots of Sakhalin fir seedlings and the adjacent broadleaved or Sakhalin fir trees were sampled in broadleaved dispersed retention sites (10, 50, or 100 trees/ha), conifer aggregated retention sites (a single 60 × 60 m square patch of Sakhalin fir trees per site), clear-cut sites, unharvested Sakhalin fir plantations, and natural broadleaved forest stands. The EcMf on the roots were grouped into operational taxonomic units based on the similarity of the internal transcribed spacer sequences within the nuclear ribosomal DNA. Clear-cutting significantly reduced the species richness and diversity of the EcMf and altered the species composition when compared with the unharvested Sakhalin fir plantations and natural broadleaved forests. In contrast, both the aggregated and dispersed retention sites maintained higher levels of EcMf diversity, as well as different EcMf communities when compared with the clear-cut sites. Aggregated retention was effective at conserving EcMf diversity at the unharvested Sakhalin fir plantations, but the effects were limited within retained patches. Broadleaved dispersed retention did not retain the EcMf communities that were present prior to logging even at high retention levels, but they could retain unique EcMf communities, which differed between the Sakhalin fir plantations, natural broadleaved forests, and clear-cut sites. The species richness and diversity values for some of the dispersed retention sites were comparable to the values for the unharvested Sakhalin fir plantations and tended to be greater than the values for the aggregated retention sites. The results indicate that dispersed retention could be an effective strategy by which to preserve a larger number of EcMf species and unique EcMf communities in logged conifer plantations, although the positive effects were likely limited spatially within the rooting zones of the retained broadleaved trees. Finally, naturally regenerating Sakhalin fir seedlings were found to share a large amount of their EcMf with adjacent broadleaved retention trees, indicating that multi-host EcMf of retained trees largely contribute to ectomycorrhizal colonization of the surrounding regenerated seedlings in the logged areas. Our findings demonstrated that both dispersed and aggregated retention methods could be used to mitigate the impacts of logging on EcMf diversity in Sakhalin fir plantations, in Japan, and that there were large differences in the effects among the different retention methods.

Estimating Carbon Stocks and Biomass Expansion Factors of Urban Greening Trees Using Terrestrial Laser Scanning

Urban forest carbon sequestration represents an important component of the global forest carbon pool; however, accurate measurements are limited by the inability of existing field stand models to match the specificity of urban greening species. Herein, canopy volume, carbon stock, and the biomass expansion factor (BEF) of 30 Koelreuteria paniculate trees were measured based on terrestrial laser scanning (TLS) and compared to the results of existing wood volume and carbon stock model measurements. The findings revealed that (1) TLS point cloud data were highly reproducible and accurate (root mean square error of tree height and diameter at breast height were ±0.35 m and ±0.33 cm, respectively). (2) Owing to human interference and cluttered urban environments, the BEF of urban greening tree species fluctuated irregularly, considerably different from that of natural forest stands. (3) Leaf carbon stocks were influenced by the size of the voxel. (4) Different tree measurement factors maintained variable degrees of influence on BEF (height under branch, volume of thick branch, crown width, and projected areas of tree-crown produced correlation coefficients of −0.64, 0.54, 0.45, and 0.43, respectively). Accordingly, the carbon stock and BEF of urban greening tree species can be accurately calculated via TLS without damage.

Functional trait space and redundancy of plant communities decrease toward cold temperature at high altitudes in Southwest China.

Plant communities in mountainous areas shift gradually as climatic conditions change with altitude. How trait structure in multivariate space adapts to these varying climates in natural forest stands is unclear. Studying the multivariate functional trait structure and redundancy of tree communities along altitude gradients is crucial to understanding how temperature change affects natural forest stands. In this study, the leaf area, specific leaf area, leaf carbon, nitrogen, and phosphorous content from 1,590 trees were collected and used to construct the functional trait space of 12 plant communities at altitudes ranging from 800 m to 3,800 m across three mountains. Hypervolume overlap was calculated to quantify species trait redundancy per community. First, hypervolumes of species exclusion and full species set were calculated, respectively. Second, the overlap between these two volumes was calculated to obtain hypervolume overlap. Results showed that the functional trait space significantly increased with mean annual temperature toward lower altitudes within and across three mountains, whereas species trait redundancy had different patterns between mountains. Thus, warming can widen functional trait space and alter the redundancy in plant communities. The inconsistent patterns of redundancy between mountains suggest that warming exerts varying influences on different ecosystems. Identification of climate-vulnerable ecosystems is important in the face of global warming.

Assessment of Drought-Tolerant Provenances of Austria’s Indigenous Tree Species

(1) Background: Forestry will have to react to climate change because many tree species suffer. Mitigation can be realized either by planting non-native trees from regions with high climatic stress or by utilizing native tree provenances already adapted to stressful environments. Non-native trees have often generated problems in the past due to uncontrolled invasiveness. The use of native trees pre-adapted to the prospective climatic conditions is far less risky for the respective ecosystems. We offer a tool for selecting ecotypes of native trees as provenances for future forestry. (2) Methods: We propose the selection of tree species native to Middle Europe from a database of vegetation relevés of ± natural forest stands. By calculating the mean ecological indicator values of stands from their vegetation, cover sites can be elected that can provide seeds of provenances well adapted to future climatic conditions. (3) Results: By selecting the 10% partition of the most extreme stands of European tree species, seeds can be sampled and propagated for re-cultivating forests fit for future climate. (4) Conclusions: One can expect ecotypes of tree species that grow well on dry sites, since generations have faced evolutionary selection, for survival under stressful environments. This approach helps to avoid ecological risks of non-native trees.

Hypotheses and lessons from a native moth outbreak in a low‐diversity, tropical rainforest

AbstractOutbreaks of defoliating insects in low‐diversity tropical forests occur infrequently but provide valuable insights about outbreak ecology in temperate environments and in general. We investigated an extensive outbreak of the endemic koa moth (Scotorythra paludicola), which defoliated endemic koa trees (Acacia koa) over a third of their range on Hawai‘i Island during 2013 and 2014. At Hakalau Forest National Wildlife Refuge, we observed the dynamics of the outbreak and its effects on host trees, nutrient cycling, and insectivorous consumers in reforestation stands of densely planted koa and in natural forest stands of mixed koa and ‘ōhi‘a (Metrosideros polymorpha). Contrary to predictions of the resource concentration hypothesis, caterpillar biomass and defoliation severity were greater in the natural forest sites, where koa density was relatively low. Caterpillars preferentially consumed the most palatable koa foliage type (phyllodes), and koa initially refoliated with the least palatable foliage type (true leaves). Lightly defoliated small trees refoliated more quickly than did heavily defoliated ones but the opposite was true for large trees, which also produced a greater proportion of phyllodes. Mortality was greatest for heavily defoliated small koa. Caterpillar frass caused larger increases in soil nitrogen (N) than phosphorus (P) availability, with the greatest N increases in fine‐textured soils. Foliar N increased in alien grasses under koa canopies compared to grasses away from koa and to native woody understory species. Bird activity was influenced by ‘ōhi‘a flower abundance and the severity of koa defoliation; birds switched to outbreaking caterpillar prey, and they gained weight during the outbreak. Bat foraging times decreased during the outbreak, apparently because they became satiated quickly each night. Parasitoid wasps increased with caterpillar abundance but had little influence on outbreak dynamics. Reducing alien grass cover and increasing tree diversity would likely reduce the impacts of insect outbreaks and similar perturbations to native forests.

Coffee plantations can strongly sequester soil organic carbon at high altitudes in Brazil

Context Soil organic carbon (SOC) affects all soil-based environmental services, and can be readily depleted upon cultivation. SOC concentrations are often higher in mountains than in lowlands due to lower temperatures slowing microbial activity and organic decomposition. However, the effects of altitudinal differences on SOC changes upon cultivation are mostly unknown. Aims We posed the question: when cultivated, are high-SOC mountain soils more likely to be depleted or are more stable under lower temperatures? Methods We assessed SOC concentrations and stocks (to a 40 cm depth) under comparable native forest and coffee (Coffea arabica L.) stands, both at two different altitudes (940 and 1260 m a.s.l.) along a mountain range in Brazil. The two soils were Inceptisols with similar 11° slope, and under native forests showed strong acidity, low fertility and cation exchange capacity. Key results Mean SOC concentrations under forests were relatively high, varying between 4.3% (0–5 cm depth) and 1.05% (20–40 cm depth) and were not significantly affected by altitude. The effects of cultivation varied with altitude: at 940 m, SOC concentrations decreased under coffee at the 0–5 cm depth, but increased below 10 cm depth at 1260 m, when compared to the native forest control. Conclusions SOC stocks under native forest and coffee stands were similar at 940 m, but the SOC stock under coffee stands at 1260 m increased by ca. 30 Mg ha−1. Implications These results are a promising indication that well-managed coffee stands can preserve or sequester SOC in higher altitudes, thus suggesting tropical mountain range soils are not highly susceptible to SOC losses upon conversion to perennial crops.

Genome survey sequencing of Ailanthus altissima and identification of simple sequence repeat (SSR) markers

Abstract Ailanthus altissima is a deciduous tree native to China and introduced to other parts of the world as an ornamental plant. It exhibits resistance to both abiotic and biotic stress factors and has various pharmacological effects and strong allelopathy, generating significant research interests. However, the genome sequence of this species has not been reported, limiting its research development. The purpose of the study was to determine the genome size and characteristics of A. altissima to conduct its genomic survey. Next-generation sequencing and K-mer analysis were employed to measure the genome size of A. altissima. Overall, a total of 61.93 Gb high-quality clean data were acquired, representing approximately 64.09× coverage of the A. altissima genome. The genomic characteristics of A. altissima include a genome size of 966.38 Mbp, a heterozygosis rate of 0.78 %, and a repeat rate of 41.22 %. A total of 735,179 genomic SSRs markers were identified based on genome survey sequences. Alignment analysis showed that A. altissima was closely related to Citrus sinensis and Leitneria florida-na. This study provides basic information for future whole-genomic sequencing of A. altissima. This will facilitate a knowledge of the population structure, genetic diversity, long distance-gene transfer, and pollen-based gene flow analyses of A. altissima populations from its known distribution ranges in China, focusing on planted and natural forest stands.

Forest and Plantation Soil Microbiomes Differ in Their Capacity to Suppress Feedback Between Geosmithia morbida and Rhizosphere Pathogens of Juglans nigra Seedlings

Thousand cankers disease (TCD) is hypothesized to have a greater impact on eastern black walnut (Juglans nigra) in urban forests and plantations compared with natural forest stands. Along with other factors such as resource availability, the phytobiome could partly account for observed differences in disease severity across management regimes. We investigated the extent to which J. nigra-associated soil microbiomes from plantations and natural forests modulate (i) the amount of necrosis caused by Geosmithia morbida in 1-year-old seedlings, and (ii) relative abundance of rhizosphere endophytes and opportunistic pathogens Fusarium and Rhizoctonia in response to aboveground inoculation with G. morbida. Our results suggest that the microbiome from natural forest soil in central Indiana suppresses Fusarium spp. and is indirectly suppressive of G. morbida. Natural forest soil had a greater ability to reduce the size of necrotic area caused by G. morbida compared with steam-treated soil. Inoculating stems of seedlings with G. morbida induced a shift in fungal community composition in the rhizosphere, including Fusarium and Rhizoctonia spp.; however, the direction and magnitude of the shift depended on whether seedlings were amended with forest, plantation, or steam-treated soil. In a companion experiment, necrotic area in G. morbida-inoculated seedlings was twice as high in seedlings grown from seeds that were treated with Fusarium solani relative to those grown from seed treated with water. Our findings support the hypothesis that TCD severity can be modulated by host-mediated feedback between above- and belowground pathogens, as well as by microbial interactions in the rhizosphere.