National Forest Research Articles

Induced drought in an Amazonian forest affects diversity but not foraging distance of generalist ants

Abstract Ongoing environmental change is forecast to lead to lower precipitation and concomitant species losses in tropical regions. These losses may affect generalist species that provide essential ecosystem services, such as controlling the rate at which nutrients become available for uptake by other organisms in tropical forests. Here, we use a long‐term (16 years) rainwater exclusion experiment in a primary Amazonian tropical rainforest (Caxiaunã National Forest, Northern Brazil) to test whether induced water stress (“drought”) affects the species richness of generalist ants, their abundance (i.e., nest density), and the distance at which they detect food resources (i.e., baits). The number of generalist ant species and colonies was reduced by 50% in the drought‐induced plot, and ant species composition differed between the control (typical moist forest) and drought‐induced plots. Although ants that nested in both control and drought plots had shorter estimated foraging distances than habitat specialists, the distance at which these colonies detected baits was not affected by drought. We conclude that the extremely high diversity of tropical forest ants may be able to buffer the detrimental effects of drought on the resource detection rates of generalist ants. Different generalist ant species were also functionally similar to wet‐forest species that cannot forage under drier conditions.

Restoring Soil Features and Biodiversity Indicators in Managed Forests to the Levels of Protected Forests: After One Silvicultural Rotation Period

This study examines the provision of ecosystem services in natural mixed broadleaf forests located in the Hyrcanian region of Iran. These services include habitat conservation, soil preservation, timber production, and carbon storage (C-stock). The forests are managed under three different silvicultural methods: shelterwood, selection cutting, and protection, allowing for a comparative analysis of their impact on these critical services. The time since the last cutting operation varied among the forest stands. In the shelterwood stand, 25 years had passed since the previous operation, while in the selection cutting stand, it had been 13 years. In contrast, the protected stand had remained untouched by logging for the past 40 years. This presents a valuable opportunity to assess the effects of the recovery period and evaluate the extent of ecosystem service restoration. Additionally, it allows for determining whether these services have reached the levels observed in a protected forest. The results show that habitat conservation, soil preservation, and carbon stock (C-stock) values ranked as follows: protection > selection cutting > shelterwood. In contrast, timber production values were highest under selection cutting, followed by shelterwood, and lowest in protected areas. Furthermore, the Stand Structural Complexity Index (SCI) was greatest in protected stands, with selection cutting and shelterwood-managed stands ranking second and third, respectively. Similarly, species diversity indices, the abundance of large-diameter trees, and the volume of deadwood followed this same trend. These findings highlight a trade-off in forest management practices. While selection cutting and shelterwood management simplify stand structure to enhance timber production and maximize economic returns, they also lead to a significant reduction in other critical forest ecosystem services. Our findings further revealed that, even decades after the cessation of forest operations, the ecological value of previously managed forests remains substantially lower than that of protected forests. Moreover, the results demonstrate that a single silvicultural rotation period is insufficient to fully restore the ecological value of managed forests, regardless of whether they were subjected to selection cutting or shelterwood management practices.

Ecosystem carbon stock variation along forest stand ages: insight from eastern coast mangrove ecosystem of India

BackgroundThe mangrove ecosystem has the highest carbon sink potential which significantly contributes to bringing carbon neutrality. Understanding the carbon stock dynamics along the age of forest stands in the mangrove forest ecosystem is of significance for managing the forests and their carbon accumulation. This study aimed to estimate the forest structural attributes, biomass and total ecosystem carbon stock (TECS) of old natural (age > 50 years) and young planted (age ~ 20 years) mangrove forest stands at Bichitrapur Mangrove Reserve Forest in eastern coast of India. We also attempted to understand the interrelationship of structural attributes, biomass and soil properties in the mangrove forests. To achieve the results, twenty random plots were established (size: 20 m × 25 m) and suitable allometric equations along with species-specific wood density values were used to estimate the biomass and carbon stock.ResultsAltogether, 29 plant species (18 exclusive and 11 associate species) were recorded. The mean total biomass (± SE) and soil organic carbon (at 30 cm depth) were 165.31 ± 20.89 t ha−1 and 40.20 ± 1.24 t C ha−1 for young stands, and 586.12 ± 56.74 t ha−1 and 49.68 ± 2.39 t C ha−1 for old stands, respectively. Among mangrove species, Avicennia marina contributed the highest vegetation biomass in both forest stands (59.72 t ha−1 and 262.28 t ha−1 in young and old stands, respectively), followed by Avicennia officinalis (35.05 t ha−1) and Sonneratia apetala (26.09 t ha−1) in young stand and Avicennia alba (169.28 t ha−1) and Avicennia officinalis (115.58 t ha−1) in old stand. The mean TECS was 235.62 ± 27.34 t C ha−1. The contribution of vegetation and soil to TECS was 63% and 37% in the young stand, whereas in the old stand it was 83% and 17%, respectively. The correlation analyses revealed that mean stand height (r = 0.87), basal area (r = 0.99), soil nitrogen (r = 0.76), potassium (r = 0.78), and carbon (r = 0.80) were significantly positively correlated with total biomass at p < 0.01.ConclusionsOur results demonstrate that old mangrove forest stands store substantially high carbon stock than young planted forest stands, implying the role of forest age in determining the carbon storage potential of mangrove ecosystems.

Evaluation of the Fixed Population of Zanthoxylum zanthoxyloides (lam.) Zepernick &amp; Timler Along the Climate Variation in Benin (West Africa)

Z. zanthoxyloïdes is a versatile plant that serves multiple purposes. Consequently, it faces significant user demand in Benin. The present investigation evaluated the abundance of this species and conducted an ecological analysis of the existing habitats that sustain its growth. The inventory of Z. zanthoxyloïdes was carried out in 120 square 50 m x 50 m plots on mega-transets in the Lama, Wari-Maro and N'Dali classified forests and fallows that surround them. The results show that adult individuals are almost absent in fallow land and are found in natural forests (P&lt; 0.05). As for juveniles, they are found in both natural forests and fallow.. The distributions of the diameter classes showed a good fit with the Weibull distribution .The density of Z. zanthoxyloïdes adult trees is greater in the Lama Classified Forest compared to the other two. The study reported that fallows currently contain more young individuals than natural forests. The confirmation of the species' vulnerability aligns with the previous report from the Benin Red List. Consequently, undertaking measures to support its natural rejuvenation becomes imperative in order to preserve the species for both current and future generations.

Forestry, from theory to practice: Central European ideas in native Patagonian forests in a context of climate change

Forestry, from theory to practice: Central European ideas in native Patagonian forests in a context of climate change

Changes in Soil Properties, Organic Carbon, and Nutrient Stocks After Land‐Use Change From Forests to Grasslands in Kumaun Himalaya, India

ABSTRACTLand‐use changes are anticipated to be a substantial contributor to global change climate, substantially causing significant modifications in soil characteristics. This study addressed the impact of land‐use change from native forests to grasslands on the soil physico‐chemical properties in entirely replicated grasslands of three different forest zones (Oak, Pine and Cypress) in temperate region of Kumaun Himalaya. A total of 162 soil samples (6 sites × 3 plots × 3 seasons × 3 depths = 162 samples) were randomly collected from each site in triplicates from depths. The soil texture, bulk density (bD), porosity, water holding capacity, soil moisture content, pH, organic carbon (SOC), total nitrogen (TN), available phosphorus (P) and available potassium (K) were determined at different depths in forest and grassland sites. Results showed that soil bD, pH, SOC, TN, P and K significantly (p &lt; 0.05) decreased with increasing depth. Moreover, conversion of forests into grassland reduced nutrient concentrations, physical qualities (bD and porosity), and pH levels. The decreasing trend of nutrient along the soil depth explains that the zone of nutrient accumulation is not well established in these grasslands because of the substantial leaching effect. Our findings indicate that conversion of natural forests into grasslands resulted in significant losses of SOC and TN stocks which can be attributed to the disturbance of natural forests. Therefore, while making land‐use change plans, the impact of these alterations on soil nutrients must be considered. These findings emphasize the value of establishing natural vegetation (forests) in these areas to retain nutrients and safeguard soil against runoff and erosion. However, anticipating the physico‐chemical impacts of land‐use alteration necessitates a better comprehension of its relations with other drivers of global change, such as changing climate and nitrogen deposition.

Engaging Sustainable Reforestation and Forest Protection in the Wallacea Line, Indonesia

The Wallacea region of Indonesia has high biodiversity and highly unique and endangered species. Its terrestrial ecosystems have unique flora and fauna found nowhere else. Nevertheless, the strategy for protecting and conserving the Wallacea ecosystem is like that in other parts of Indonesia, since it refers to the national forest and environmental regulations. The uniqueness of the Wallacea ecosystem does not reflect the extraordinary efforts of protecting and conserving the region’s pristine ecosystem. The continuing decline of the forestland and expansions of agricultural lands have indicated the need for a more fundamental and integrative approach to conserving and protecting the Wallacea ecosystem, particularly forestlands. We use the actor-centered power (ACP) approach or ideas and use the Wallacea Line to highlight how this idea is contested and confronted with the dynamics of complex societies and ecosystems. The ACP approach is the most widely used one in the implementation of the community forest (CF) program in Indonesia. The CF program is one of Indonesia’s community-based forest management schemes that empowers local communities to manage state forests sustainably. We chose two national parks established in the Wallacea region, Mutis on Timor Island and Matalawa on Sumba Island, to elaborate further on the development, conservation, and changes that occurred within that landscape. The ACP approach, in line with the spirit of the decentralization era, has mixed consequences for forest management and the biodiversity of the Wallacea region. Regarding the specific characteristics of the Wallacea region and lessons learned from the ACP approach implementation in the CF program, we then propose a sustainable model of reforestation and forest protection that applies the principle of “unity in diversity,” where all actors involved have space for the growth of creativity and positive contributions to sustainable forest protection.

Terrestrial isopods (Isopoda, Oniscidea) of Slovakia: an annotated checklist, new records, and bibliography

Woodlice (terrestrial isopods) represent an unmissable, often very numerous components of macrosaprophages inhabiting soil, rocky environments, rotting wood and subterranean habitats, as well as the dwellings of various organisms, including humans. The paper provides a comprehensive summary of the literature on woodlice in Slovakia, including a list of species with unpublished data on two exotic species first recorded in Slovakia. Research on Slovakian terrestrial isopods has been documented in 213 papers (from 1794 to 2024) and 25 theses. To date, 48 species from 14 families have been recorded in Slovakia. Of these, 30 species are autochthonous, while 18 species have been introduced into anthropogenic habitats, with eight species found exclusively in greenhouses. The list also includes an analysis of habitat preferences, bioindicator potential, and biogeographic comments. Notably, two species, Buddelundiella cataractae and Reductoniscus costulatus, are recorded in Slovakia for the first time. Carpathian elements are sparsely distributed within the mosaic of well-preserved natural forests. Hyloniscus mariae is likely the only surface-dwelling endemic species in the northern parts of the Carpathian range. Other species, such as Hyloniscus transsilvanicus, Trichoniscus carpaticus and Trachelipus difficilis, have a broader distribution within the Carpathians. Additionally, Mesoniscus graniger, Orthometopon planum and a few other taxa reach their northern distribution limits in Slovakia. Current research is predominantly focused on the fauna of subterranean habitats and urbanized landscapes.

Predicting ixodid tick distribution in Tamil Nadu domestic mammals using ensemble species distribution models

Abstract Background Tick borne diseases are re-emerging around the world, including India. Information about the occurrence of the tick vectors in different geographical locations is essential for controlling the diseases. Tick surveys have not been conducted in many parts of India and information on the current prevalence of tick vectors is not available in all states of India. Many studies have been carried out utilizing modelling methods to predict the distribution of tick species in other countries. The MaxEnt model is widely used for predicting tick species distribution using bioclimatic variables. Lyme disease vectors such as Ixodes sp., Amblyomma sp., and Dermacentor sp. are the most commonly predicted tick species. However, very few studies have been carried out to predict the distribution of tick species in India. Haemaphysalis spinigera, the primary Kyasanur Forest Disease vector, was predicted along the Western Ghats using the MaxEnt model. Rhipicephalus (Boophilus) microplus was predicted across India using the generalized linear model (GLM). Identifying the tick vectors in transmitting the infection through conventional survey and identification methods is cumbersome due to the less number of experienced persons available. Prediction of tick vectors of public health concern, including other tick species in different geographical regions of Tamil Nadu, India, is essential for the prevention and control of tick-borne disease in humans and domestic animals. The present study adopts the package ‘SSDM’ (stacked species distribution models) with R software containing ensemble species distribution models to predict the distribution of tick species using different available environmental and climatic data. Results The categorical variables such as land use and land cover (LULC), soil type, elevation, Bio1, Bio10, Bio15, Bio19 and Bio8 contributed more to modelling the distribution of tick species. MaxEnt, GLM, GBM and GAM are suitable models for predicting the tick species distribution in the present study. Among these models, MaxEnt is the most suitable model for predicting tick species distribution in Tamil Nadu, India. Conclusions Our results suggest that MaxEnt is a suitable model for predicting the distribution of tick species. Both environmental factors such as LULC, elevation and soil type and bioclimatic factors such as temperature and precipitation contribute significantly to predicting tick species distribution in domestic animals in Tamil Nadu. The SSDM package is very useful and user-friendly graphical user interface for modelling the distribution of tick species. However, the package can be further improved by using higher resolution raster variables in larger areas, which is not currently supported. The predicted elevation range of Ha. spinigera distribution could not be provided due to software limitations.

A Sentinel-2 machine learning dataset for tree species classification in Germany

Abstract. We present a machine learning dataset for tree species classification in Sentinel-2 satellite image time series of bottom-of-atmosphere reflectance. It is geared towards training classifiers but is less suitable for validating the resulting maps. The dataset is based on the German National Forest Inventory of 2012 as well as analysis-ready satellite imagery computed using the Framework for Operational Radiometric Correction for Environmental monitoring (FORCE) processing pipeline. From the National Forest Inventory data, we extracted the tree positions, filtered 387 775 trees in the upper canopy layer, and automatically extracted the corresponding bottom-of-atmosphere reflectance time series from Sentinel-2 L2A images. These time series are labeled with the corresponding tree species, which allows pixel-wise classification tasks. Furthermore, we provide auxiliary information such as the approximate tree position, the year of possible disturbance events, or the diameter at breast height. Temporally, the dataset spans the years from July 2015 to the end of October 2022, with approx. 75.3 million data points for trees of 48 species and 3 species groups as well as 13.8 million observations for non-tree backgrounds. Spatially, it covers the whole of Germany. The dataset is available at the following DOI (Freudenberg et al., 2024): https://doi.org/10.3220/DATA20240402122351-0.

Non-Timber Forest Products and Their Income Contributions to Rural Households in Kalu District, Northeast Ethiopia

Abstract Non-timber forest products (NTFPs) are crucial for rural livelihoods either for subsistence or income generation. However, the natural vegetation and forests in the study area have been degraded by human impacts leading to habitat loss. Therefore it is essential to study and document evidence about NTFPs and their value in the study area. The main aim of this study is to assess non-timber forest products and their income contributions in Kalu District, Northeast Ethiopia. Three Kebeles were purposively selected based on NTFP availability, household reliance on NTFP collection and time. A total of 149 sample household respondents were selected using simple random sampling methods from the three Kebeles (Ancharo, Keteteya, and Gedero) in proportionate allocations. Data were collected through key informant interviews, focus group discussions, direct observations and structured and semi-structured household interviews. The collected data were analyzed using descriptive statistics. The study identified six major types of NTFPs used by households, namely: energy sources (fuel-wood and charcoal), medicinal plants, household utensils, wild edibles, wild spices, and fodders. The most important NTFPs included honey, fuel wood, charcoal and others (household utensils, edible fruits), contributing 39 %, 31 %, 25 %, and 5 % of forest income, respectively. NTFPs contributed 13.3 % of the total annual household income in the study area. The findings of this study revealed that incomes derived from NTFPs in the study area were relatively low compared to other sources of income. Therefore, polices and strategies aimed at improving the well-being of the local people should pay attention to the contribution of NTFPs to their livelihoods.

Planted Forests in China Have Higher Drought Risk Than Natural Forests.

To improve the environment and mitigate climate change, China has implemented ambitious projects for natural forest protection and expanded planted forests. However, increased climate variability has led to more frequent and severe droughts, exacerbating the decline of these forests. The drought risk of planted forests is rarely assessed by considering both resistance and resilience, and comparative analyses between natural and planted forests are lacking. Here, we compared drought resistance and resilience in natural and planted forests across China using satellite observations from 2001 to 2020 to understand which forests were at higher risk of drought. The results showed that planted forests exhibited lower drought resistance and resilience compared to natural forests, particularly in subtropical broad-leaved evergreen forests and warm temperate deciduous broad-leaved forests. Moreover, drought resistance in planted forests significantly increased, while resilience decreased during 2011-2020 compared to 2001-2010, suggesting a shift in the strategies of planted forests to cope with drought stress. The higher drought risk in planted forests compared to natural forests was mainly attributed to lower forest canopy height and poorer soil nutrients, which limited resistance, and lower canopy height and severe drought characteristics (severity, duration, and frequency), which reduced resilience. These results underscore the higher potential risk of drought exposure in planted forests. To mitigate future drought impacts on planted forests under climate change, enhanced management strategies, including the preservation of natural forests and augmentation of structural diversity in planted forests, are imperative.

Factors Influencing Emergence Timing Patterns of Long-Tailed Bats in Exotic and Native Forest in New Zealand.

Understanding temporal behavioural patterns in animals can be crucial to their conservation management. Emergence timing in bats, that is, the decision on when to depart day-roosts for foraging, is one such example and is well studied in Northern Hemisphere bats. The emergence timing of New Zealand long-tailed bats (Chalinolobus tuberculatus) is not yet fully understood, including when and where they may be vulnerable to threats. We investigated factors influencing long-tailed bat emergence timing in the Kinleith Forest (exotic plantation, 38° S) and the Eglinton Valley (native beech forest, 45° S). We recorded emergence times during late pregnancy through post-lactation (October to March), to determine whether the month, temperature at sunset, tree density, cloud cover, presence of rain and the number of bats within a roost influenced emergence timing. Most long-tailed bats emerged after sunset in the Kinleith Forest, whilst 80% of first emerging bats departed before sunset in the Eglinton Valley where nights are much shorter in summer, reducing foraging time. Month, temperature at sunset, and roost population size were the most important predictors of emergence timing at both sites. Long-tailed bats in the Kinleith Forest also emerged earlier as tree density increased, a pattern potentially associated with predator defence. The factors influencing long-tailed bat emergence timing are likely context dependent, namely latitude and habitat structure, which has implications for roost protection protocols, timing of bat surveys and interpretation of bat acoustic monitoring data.

Relative fire-proneness of land cover types in the Brazilian Atlantic forest.

Fires are increasingly affecting tropical biomes, where landscape-fire interactions remain understudied. We investigate the fire-proneness-the likelihood of a land use or land cover (LULC) type burning more or less than expected based on availability-in the Brazilian Atlantic Forest (AF). This biodiversity hotspot is increasingly affected by fires due to human activities and climate change. Using a selection ratio-based approach, we analyzed fire-LULC interactions in 40,869 fires over a 35-year period (1987-2022) across various ecoregions in the AF. Our findings revealed that secondary forests, forest areas that have regrown after major disturbances, burned 61% more than expected by chance, whereas old-growth forests, native forests that have developed over very long periods, burned 57% less than expected, highlighting a nearly inverse relationship in their fire-proneness. Interestingly, our data indicate that pastures in the AF are less prone to fire than expected, despite being considered among the land uses that burn the most in Brazil. Other LULCs showed variable fire-proneness, with some differences between ecoregions. Over time, the fire-proneness of secondary forests decreased, likely due to forest aging and changes in land management practices. We emphasize the necessity for tailored fire management strategies that address the unique vulnerabilities of secondary forests, particularly in the context of ongoing restoration efforts aimed at increasing native forests. Effective measures, including the implementation of 'fire-smart management' practices and enhancing the perceived value of secondary forests among local communities, are crucial for mitigating fire risks. Integrating these strategies with incentive-based approaches can bolster fire prevention, ensuring the long-term success of restoration programs. Our study provides a framework for understanding fire-landscape dynamics in tropical forests and offers actionable insights for practitioners working to safeguard these biomes from the escalating threat of wildfires.

The Ural Owl as a Keystone Species in Interspecific Interactions Among Avian Predators—A Review

Ural owls are one of the largest owls in Europe, exhibiting known aggressive behaviour toward other raptors. They are known to interact with nearly all sympatric owls and many diurnal raptors. To summarise these interactions, a literature search was undertaken in the Web of Sciences and Scopus databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology as well principal books on owl biology. The search revealed 22 relevant publications that (along with the book data) described the Ural owl’s relations with seven owls and six diurnal raptor species. The Ural owl is subordinate only to the largest predators like golden eagles and eagles, although only its chicks are known to be killed. Contrary to that, the Ural owls shape the distribution of numerous other species, mostly by strong competition (e.g., forcing tawny owls to breed in suboptimal habitats) or by predation (killing smaller owls and diurnal raptors). Their occurrence could be also protective for some species like boreal owls thanks to the removal of intermediate predators. The relations of Ural owls with goshawks are interesting, which seem to live in some balance—temporal avoidance of activity with frequent co-occurrence. Thanks to their association with old-growth forests and their impact on other predators in their territories, Ural owls act as keystone species in mountainous and boreal forests in Europe. Considering this ecosystem service, Ural owls should be effectively protected e.g., by designing forest-management-free zones around their nesting sites.

Biogenic volatile organic compound (BVOC) emission profiles from native Atlantic Forest trees: Seasonal variation and atmospheric implications in southeastern Brazil

Biogenic volatile organic compound (BVOC) emission profiles from native Atlantic Forest trees: Seasonal variation and atmospheric implications in southeastern Brazil

Responses of insectivorous bats to different types of land-use in an endemic-rich island in Central West Africa

Land-use change underpins the ongoing biodiversity crisis. Although such impacts are particularly acute across endemic-rich oceanic islands, little is known for afro-tropical islands. Here we assessed insectivorous bat responses to different land-use types of the island of São Tomé, in Central West Africa. Since its human colonization in the mid-15th century, São Tomé lost over 70 % of its native habitat, mostly to shaded and oil palm plantations, agriculture, and urban areas, while part of that was abandoned allowing secondary forests to re-grow. Using passive acoustic monitoring, we surveyed insectivorous bats in 115 sites across each land-use type over one month. We then examined bat species richness and activity, and species-specific activity. Based on 5520 h of recordings, we obtained 19,744 bat passes from five of the six taxa known to occur on the island, three of which are endemics. Both species richness and activity were highest in the four non-forest land-use types, with activity further decreasing with altitude. Species-specific responses corresponded to foraging guild: the forest foragers Hipposideros ruber and Macronycteris thomensis showed higher activity in forests and shaded plantations, the activity of the open-space foragers Chaerephon spp. peaked in urban areas, while that of the edge forager Miniopterus newtoni was highest in oil palm plantations. The island's insectivorous bats are persisting despite land-use change, including island endemics. Maintaining the mosaic of land-use types, including native forests, is likely to help sustain insectivorous bat diversity in this tropical island.

A scale for evaluating the willingness of national forest farm to participate in forest carbon sink project.

In recent years, the development of Forest Carbon Sink Project (FCSP) has become a key focus within forestry sector. Despite this, decision-makers often lack reliable tools to assess forest owners' willingness to engage in this project. This study aims to develop, validate and evaluate a rational value perception scale as the tool to understand the willingness of forest manager. Based on the theoretical model we proposed, the Forest Carbon Sink Project Development Value Perception Scale (FORSCALE) was developed. The scale consists of two subscales, one is Perceived Benefit Subscale including three dimensions - economic, social, and ecological benefits, another is Perceived Risk Subscale comprising five dimensions - financial, performance, technical, time, and policy risks. Data were collected from 1014 employees across 95 major national forest farms of China. Both Exploratory Factor Analysis and Confirmatory Factor Analysis were employed to validate the multidimensional robustness of FORSCALE. The Multidimensional Graded Response Model in Item Response Theory (IRT) was applied for evaluating the rationality of FORSCALE. Our findings indicated that the scale exhibited a strong multidimensional structure and good model fit. Among the dimensions, ecological benefits, time, policy, and technology risks, were particularly salient to FCSP developers. IRT analysis revealed discrimination parameter ranging from 3.057 to 15.241 and thresholds parameter from -2.296 to 1.055, indicating that all 48 items of the scale possess high discrimination and reasonable thresholds. Additionally, all items demonstrated measurement accuracy that varied along the perceived attitude continuum, with better discrimination for participants holding neutral and negative latent attitudes. Finally, we made specific recommendations for item addition or deletion, and collapsing options to refine the scale. In conclusion, FORSCALE provides decision-makers with an effective tool for creating sound guidance schemes and can be widely utilized in future FCSP development practices.

Farmers’ perceptions of Terminalia brownii management in agroforestry Parklands and its impact on soil physicochemical properties in the South Ari District, Southern Ethiopia

Smallholder farmers in the South Ari District of southern Ethiopia retain natural forest remnants of Terminalia brownii trees in their crop fields. However, little is known about their perceptions of its management in crop fields and its impacts on soil properties. Therefore, we investigated farmers’ perceptions and the impacts of scattered Terminalia brownii trees on soil physicochemical properties. For this purpose, we collected household survey data from 80 farmers and 54 composite soil samples from four directions at three radial distances and two soil depths. A randomized complete block design was used with three independent random field replications for the treatments within factorial arrangements, including the three radial distances and two soil depths. Based on the survey data, 90% of the respondents manage scattered Terminalia brownii trees in their crop fields. Among them, 63% use pollarding, while 49% use pruning techniques to enhance the impact on crops grown beneath trees. Our results revealed that soil organic carbon, total nitrogen, plant-available potassium and phosphorus, and bulk density were significantly higher (P < 0.05) under the tree canopy. However, soil texture, pH, electrical conductivity, cation exchange capacity, and exchangeable bases depicted no significant differences between the tree canopy and open fields. Hence, retaining Terminalia brownii trees on the crop field is crucial for farmers to improve the soil physicochemical properties. However, sustained long-term studies are essential to gain a comprehensive understanding of the diverse functions of Terminalia brownii and its impact on microclimate dynamics and crop productivity.

Variability increased underneath growth enhancement of Mongolian pine natural forests in northeastern China in response to climate change

Clarifying tree growth variability in response to long-term climate change and short-term climate extremes is crucial for predicting future trends of forest performances. With climate change accompanied by more frequent climate extremes, tree mortality has been recently observed in the natural distribution areas of Mongolian pine (Pinus sylvestris var. mongolica), an important species used for afforestation in water-limited environments of northern China. However, the growth dynamics of the naturally grown pine trees and their associations with climate change are not well understood. We combined tree-ring and remote sensing approaches to investigate long-term growth performances and their responses to climate change from tree individual to landscape scales of Mongolian pine natural forests in a water-limited region in northeastern China. We found that the tree-ring width index (RWI) was highly correlated (r = 0.927, P < 0.0001) with satellite-derived normalized difference vegetation index (NDVI) during growing season (May-September) and both metrics consistently showed an obvious increasing trend in recent two decades, indicating enhancements of growth and their strong associations at both individual tree and landscape scales. However, long RWI time series also revealed obviously greater variations in radial growth (reflected by increased coefficient of variation) and lower resilience to potential disturbances (higher first-order antocorrelation) underneath such enhanced growth during the past two decades than earlier periods. RWI was found to be positively influenced by water-related climate factors (i.e., precipitation, relative humidity and drought index-SPEI) and negatively affected by temperature during growing season, which were further corroborated by similar relationship patterns between these climate variables and NDVI. Such impacts seemed to have strengthened over time, particularly at short time scales, which likely contribute to the increased growth variability with increasing climate extremes. Comprehensive examinations on growth performances of Mongolian pine natural forests through integrating multiple approaches imply that such forests would suffer from increasing growth instability and risks of die-off under climate change.