National Forest Research Articles

Exploring environmental and climate features associated with yellow fever across space and time in the Brazilian Atlantic Forest biome.

The Atlantic Forest Biome (AFB) creates an ideal environment for the proliferation of vector mosquitoes, such as Haemagogus and Sabethes species, which transmit the Yellow Fever virus (YFV) to both human and non-human primates (NHP) (particularly Alouatta sp. and Callithrix sp.). From 2016 to 2020, 748 fatal cases of YF in humans and 1,763 in NHPs were reported in this biome, following several years free from the disease. This underscores the imminent risk posed by the YFV. In this study, we examined the spatiotemporal distribution patterns of YF cases in both NHPs and humans across the entire AFB during the outbreak period, using a generalized linear mixed regression model (GLMM) at the municipal level. Our analysis examined factors associated with the spread of YFV, including environmental characteristics, climate conditions, human vaccination coverage, and the presence of two additional YFV-affected NHP species. The occurrence of epizootics has been directly associated with natural forest formations and the presence of species within the Callithrix genus. Additionally, epizootics have been shown to be directly associated with human prevalence. Furthermore, human prevalence showed an inverse correlation with urban areas, temporary croplands, and savannah and grassland areas. Further analyses using Moran's Index to incorporate the neighborhoods of municipalities with cases in each studied host revealed additional variables, such as altitude, which showed a positive correlation. Additionally, the occurrence of the disease in both hosts exhibited a spatio-temporal distribution pattern. To effectively mitigate the spread of the virus, it is necessary to proactively expand vaccination coverage, refine NHP surveillance strategies, and enhance entomological surveillance in both natural and modified environments.

Forest Restoration Thinning Has Minimal Impacts on Surface Soil Carbon in a Second-Growth Temperate Rainforest

Forest restoration thinning may accelerate the development of structural complexity toward old-growth conditions faster than a natural forest, yet associated changes in forest carbon (C) are poorly understood. Old-growth forests are characterized by high levels of sequestered C in aboveground biomass and soil C pools, yet active management has well-recognized negative impacts on stored C. Effects of forest restoration thinning on forest C can be determined using longitudinal measurements and modeling based on stand conditions and tree growth. At Ellsworth Creek Preserve in Southwest Washington, forest restoration efforts in a second-growth temperate rainforest have been monitored using permanent plots since 2007. Here, we compare repeat measurements from 2020, modeled forest C, and measurements of O-horizon C pools from 2022 to determine C impacts of silvicultural treatments for old-growth restoration. We found good general agreement between empirical measurements and models of forest C using the Forest Vegetation Simulator (FVS). However, treatment alone was not a strong indicator for C conditions; rather, forest age and age–treatment interactions better predicted soil C responses to restoration treatments. These data may indicate that “light” forest restoration thinning can accelerate old-growth development with minimal effects on soil carbon—a win-win conservation strategy for old-growth forests and the climate.

Community Involvement in Participatory Forest Monitoring around Kibale National Park of Western Uganda

A study on Participatory Forest Monitoring (PFM) and Natural Forest Restoration (NFR) was carried out in the communities residing around the Kibale National Park (KNP), Uganda. The research was conducted from June to August 2024 among 394 respondents, adopting a cross-sectional research design to explore mechanisms for scaling up Participatory Forest Monitoring. The results revealed that participation in PFM improved income at the household level directly addressing household needs especially income for school fees and other needs by 79.9% (r=0.799, P<0.05). Enhancing PFM activities and practices, the Uganda Wildlife Authority Forest Absorbing Carbon Emission (UWA-FACE) project is encouraged to consider electric fencing as an addition to existing PFM benefits (23.40%), increase the remuneration of a daily wage for PFM recipients (28.6%) and PFM could consider compensating farmers who lose livelihoods (29.9%). The findings indicated that PFM can effectively restore natural forests in the study area and enhance income and community livelihoods. There is a need to invest more funds in PFM activities.

Developing an integrative management plan for urban and peri-urban forests: A case study of Ljubljana, Slovenia

Many cities worldwide have adopted management strategies for urban forests, typically focusing on forest parks, street trees and park trees. However, planning that concentrates on natural urban forest areas remains scarce. This study introduces an advanced planning framework for the integrative management of natural urban forests and applies it to Ljubljana's urban forests (2151 ha). The framework consists of an initiation phase and a six-step planning procedure. Through a comprehensive process lasting 20 months, with strong stakeholder involvement and political support, we developed a strategic plan for Ljubljana’s entire urban forest area and an operational plan for a specific block within this area. The approach employs the integrative management of forest stands within or near the city, incorporating harmonised activities in silviculture, recreation, protection, harvesting and communication. This planning method aims to bridge the gap between traditional forest management planning and urban green infrastructure planning.

Characterizing long-term tree species dynamics in Canada’s forested ecosystems using annual time series remote sensing data

Mapping tree species and changes in species distribution over time enables monitoring of successional dynamics and linking of realized species distributions to regional, climatic, and disturbance processes. Such knowledge is valuable for informing forest management activities regarding the role of climate change and various types of forest disturbances on tree species distributions and successional processes. In this study, we used time-series Landsat imagery to produce annual maps of dominant tree species (n = 37 tree species classes) from 1984 to 2022 at a 30-m spatial resolution for the 650 Mha of Canada’s forested ecosystems. The classification approach was based on spectral, geographic, climatic, and topographic descriptive metrics and was independently calibrated and validated with data from Canada’s National Forest Inventory. Preliminary results were informed by disturbance events and post-processed to ensure consistency of the annual species maps. Assessment of the resulting annual species maps using independent validation data resulted in an overall accuracy of 86.1 % ± 0.14 % (95 %-confidence interval). Over the study period, Canada’s treed area increased from 335 to 359 Mha. The area dominated by conifers increased in absolute terms but decreased in relative terms (from 86 % to 84.9 %), especially in western ecozones where wildfire is the main agent of disturbance. The area dominated by black spruce (Picea mariana), the most common tree species in Canada, remained stable, but its relative area decreased by 4.6 %. The area dominated by balsam fir (Abies balsamea, 1.5 %), trembling aspen (Populus tremuloides, 0.9 %), jack pine (0.5 %), and sugar maple (Acer saccharum, 0.4 %) increased. In burned areas, the prevalence of black spruce (74.7 %) and jack pine (Pinus banksiana, 14.6 %) was greater than their prevalence in Canada’s forested ecosystems overall (58.7 % and 3.8 %, respectively), while trembling aspen (2.4 % vs. 10 %) and subalpine fir (1.1 % vs. 4.6 %; Abies lasiocarpa) were underrepresented in burned areas. The area dominated by black spruce was underrepresented in harvested areas (46.8 % vs. 58.7 %) whereas balsam fir (6.9 % vs. 3 %), Engelmann spruce (5.5 % vs. 2 %; Picea engelmannii), red spruce (1.8 % vs. 0.4 %; Picea rubens), lodgepole pine (11.2 % vs. 5.6 %; Pinus contorta), Douglas-fir (2.7 % vs. 1.3 %; Pseudotsuga menziesii), and western hemlock (4.8 % vs. 2 %; Tsuga heterophylla) were found to be overrepresented. Both post-fire and post-harvest dynamics indicated a general trend of regeneration to the same pre-disturbance tree species, with post-harvest landscapes exhibiting a greater variety of different dominant tree species. These results provide valuable information for sustainable forest management and can inform conservation strategies by helping to better understand the short- and long-term effects of forest disturbances on species presence and distribution.

Spatial Analysis of Regional Planning Related to Moratorium Right to Cultivate (Plantation) in Indonesia

Indonesia is a country that is blessed by Allah Swt with a very large expanse of space and territory and is located on the equator surrounded by the sea. This is a natural resource that is very rarely owned by other countries, where the sun shines every year with high humidity. These resources are controlled by the state and used as much as possible for the welfare of the community. One of the related natural resources is plants that can grow well in the area. Oil palm is a plant originating from West Africa that is very suitable for growing in the equatorial area. Currently, Indonesia is the largest producer of palm oil in the world. The greatest utilization of this blessing are for the welfare of the community and based on sustainable Regional Spatial Planning. On its implementation the Regional Spatial Planning has been divided according to its function and sustainability. This condition is contrary to the current government policy, where the government has implemented a moratorium policy on new business use rights for the Plantation sector. The regulation was Presidential Instruction (Inpres) Number 8 of 2018. The purpose of the Moratorium is to control the deforestation of Primary Forests and also improve the Governance of Oil Palm Plantations. In its implementation, there are indeed successes and weaknesses. Successes are mainly in holding back the rate of deforestation or forest encroachment. The weakness is that in terms of Regional Spatial Planning, there should still be many areas that can be used for developing plantation land, especially unproductive and non-forest areas. So that the ideals of improving the welfare of the community can be truly realized.

Resource availability enhances positive tree functional diversity effects on carbon and nitrogen accrual in natural forests

Forests harbor extensive biodiversity and act as a strong global carbon and nitrogen sink. Although enhancing tree diversity has been shown to mitigate climate change by sequestering more carbon and nitrogen in biomass and soils in manipulative experiments, it is still unknown how varying environmental gradients, such as gradients in resource availability, mediate the effects of tree diversity on carbon and nitrogen accrual in natural forests. Here, we use Canada’s National Forest Inventory data to explore how the relationships between tree diversity and the accumulation of carbon and nitrogen in tree biomass and soils vary with resource availability and environmental stressors in natural forests. We find that the positive relationship between tree functional diversity (rather than species richness) and the accumulation of carbon in tree biomass strengthens with increasing light and soil nutrient availability. Moreover, the positive relationship between tree functional diversity and the accumulation of carbon and nitrogen in both organic and mineral soil horizons is more pronounced at sites with greater water and nutrient availabilities. Our results highlight that conserving and promoting functionally diverse forests in resource-rich environments could play a greater role than in resource-poor environments in enhancing carbon and nitrogen sequestration in Canada’s forests.

Tradeoffs between Stand Volume and Understory Vegetation Diversity in Quercus wutaishanica Forests under Climate Change

Natural forests play a crucial role in providing various ecosystem services, including timber production and biodiversity conservation. However, climate change and anthropogenic factors pose a severe threat to competing forest ecosystem services functions. Therefore, to optimize and sustainably utilize competing forest services, tradeoffs are often necessary. This study was conducted in Northwest China to explore tradeoffs aimed at improving the quality of Quercus wutaishanica Mayr natural forests under climate change conditions, focusing on stand volume, timber production, and understory vegetation diversity conservation. Data from 77 field surveys were used to construct a coupled model for stand growth, stand structure, and site conditions. Changes in understory vegetation species number (UVSN) with crown cover were quantified. These models and relationships can be used as tools to estimate tradeoffs. As stand density increased, single-tree volume decreased, whereas timber volume increased. UVSN increased and then decreased with increasing crown cover and was able to maintain a relative maximum at 0.5–0.65. Under the current climatic conditions, the optimum stand densities corresponding to 30, 40, 50, and 60 years were 1390, 1153, 1042, and 871 trees/ha, respectively, to maintain a high UVSN and adequate stand volume. When mean annual temperature rose, stand densities could be reduced to maintain high-quality timber. Although only two major services were considered, the tradeoffs presented in this study can inform future research to improve the quality of natural forests.

The cost of operational complexity: A causal assessment of pre-fire mitigation and wildfire suppression

Pre-fire mitigation efforts that include the installation and maintenance of fuel breaks are integral to wildfire suppression in Southern California. Fuel breaks alter fire behavior and assist in fire suppression at strategic locations on the landscape. However, the combined effectiveness of fuel breaks and wildfire suppression is not well studied. Using daily firefighting personnel to proxy the quantity and diversity of potential fire suppression operations (i.e., operational complexity), we examined 15 wildfires from 2017 to 2020 in the Los Padres, Angeles, San Bernardino, and Cleveland National Forests to assess how weather and site-specific fuel break characteristics influenced wildfire containment when leveraged during suppression operations. After removing effects of fuel treatments, wildfire and aerial firefighting, we estimated that expanding fuel break width in grass-dominant systems from 10 to 100 m increased the average success rate against a heading fire from 31 % to 41 %. Likewise, recently cleared fuel breaks had higher success rates compared to poorly maintained fuel breaks in both grass (25 % to 45 %) and shrub systems (20 % to 45 %). Combined, grass and shrub systems exhibited an estimated success rate of 80 % under mild weather conditions (20th percentile) and 19 % under severe weather (80th percentile). Other significant determinants included forb and grass production, adjacent tree canopy cover and terrain. Consistent with complexity theory and previous suppression effectiveness research, our analysis showed signs of suppression effectiveness declining as firefighter personnel increased. Future work could better account for the role of suppression with improved data on firefighting resource types, actions, locations, and timing.

Anthropogenic effects and ecosystem services of tropical highland forests in Ethiopia

Despite the significant direct and indirect benefits that forests, particularly tropical highland forests, provide to local communities, they are facing severe degradation primarily due to population growth and rapid land-use changes. This has made it difficult for policymakers to effectively manage these forests due to a lack of comprehensive current forest research data. Therefore, the primary objective of this study was to examine the anthropogenic impacts on forest ecosystems and the ecosystem services (11ecosystem services,ESs) they provide, as well as to understand local perspectives on management of natural forests. For collecting disturbance indicators and other environmental data, 12 transect lines by 150 meter interval between each of the two consecutive parallel transects and 40 quadrats (20 m x 20 m size each) by 100 m interval were laid out in 145 ha total forest land size of the five study sites of three districts. However, for questionnaire-based data, 266 respondents were participated. As revealed in the results, the majority of households (about 78 %) relied on mixed farming and had ≤ 1 ha of land with 5.6 average family size. Besides, 74.3 % of the households used forest products for cooking food and getting energy to their homes due to little or no electricity, or other energy sources in rural communities. Nearly 85 % of the households also obtained timber from natural forests. Tree cutting, grazing, cultivation, and fires were the major anthropogenic factors leading to deforestation and loss of ecosystem services and biodiversity of the studied forest ecosystems. Disturbance assessment indicated that almost all forest patches, excluding one in the eastern subregion of the study area, were severely impacted. This suggests a widespread degradation of Ethiopia's forests. However, various ESs, mainly regulating and habitat services, followed by provisioning ones, were delivered from these sites. Hence, soil erosion controlling, flood protecting, and soil fertility regulating services were some of the most services provided by the forests. Likewise, being shelter and nursery sites for biota were the other most important habitat service. The raw materials including grass for fodder, medicinal plants, timber, fuel wood, and water for livestock watering and domestic uses were the major provisioning services provided. Thus, more than 93 % of the households had a great interest for the protection and continuity of the present forest patches in the future. Briefly, despite being heavily degraded due to anthropogenic factors, these natural forests still provided various ecological, social, and economic services to the local people; thereby the people were interested in protecting and conserving them. Thus, for restoring degraded forest areas of the zone, community-based participatory conservation strategies were recommended.

Stem CH4 emissions from the reclaimed forests: magnitude, drivers, and contribution

BackgroundTrees in natural forests are a major contributor to atmospheric methane (CH4), yet these emissions have never been investigated in reclaimed forests. Our study aimed to assess the magnitude, seasonality, drivers, and contributions of tree CH4 emissions to ecosystem CH4 flux in the reclaimed forests. We measured CH4 emissions from different emission pathways, including the stems of trees (Populus euramericana, Metasequoia glyptostroboides, and Camphora officinarum), shoots of herbs (Carex breviculmis and Carex dispalata), and soils in the two reclaimed forests with reclamation periods of 12 and 5 years. We identified factors controlling seasonal tree CH4 emissions and measured tree morphological variables (diameter at breast height, wood density, and lenticel density) to determine species differences in emissions.ResultsCH4 emissions from trees in the 12-year-old reclaimed forest were significantly higher than those in the 5-year-old forest. Seasonal variations in tree CH4 emissions were primarily driven by growth stage and soil parameters, including soil CH4 flux, temperature, and moisture.ConclusionIn the reclaimed forests, tree-mediated CH4 emissions could be an important contributor to ecosystem CH4 flux, with contributions varying by season. As these forests mature and become ecologically restored, they may significantly impact regional and global CH4 emissions.

Wild pigs influence tropical forest soil microbial communities in a forest-agriculture mosaic landscape

Edge effects, the altered abiotic and biotic conditions on the borders of natural areas, have rarely been linked to altered soil biota, which shape ecosystem processes including carbon storage, biogeochemical cycling, and plant performance. Here, we investigated if increased wildlife populations (their increase mediated by foraging in nearby oil palm plantations) affect soil biota when they move between plantations and natural habitats. We used a 22-year fenced exclusion experiment in a primary rain forest in Peninsular Malaysia. We found that the presence of wildlife (mainly native pigs; Sus scrofa) was associated with greater bacterial diversity, an altered bacterial community composition, and indications of a reduced abundance of symbiotic ectomycorrhizal fungi. There were only minor effects of pigs on soil chemistry or microclimate, so we suggest that changes in soil communities are driven by pigs’ leaf litter removal and alterations to plant composition. Our study highlights that indirect effects from agriculture can be induced by wildlife more than1 km into protected areas and this could have important repercussions for ecosystem processes and plant-soil feedbacks.

Generic and Specific Models for Volume Estimation in Forest and Savanna Phytophysiognomies in Brazilian Cerrado.

The Cerrado has high plant and vertebrate diversity and is an important biome for conserving species and provisioning ecosystem services. Volume equations in this biome are scarce because of their size and physiognomic diversity. This study was conducted to develop specific volumetric models for the phytophysiognomies Gallery Forest, Dry Forest, Forest Savannah, and Savannah Woodland, a generic model and a model for Cerrado forest formation. Twelve 10 m × 10 m (100 m²) (National Forest Inventory) plots were used for each phytophysiognomy at different sites (regions) of the Federal District (FD) where trees had a diameter at breast height (DBH; 1.30 m) ≥5 cm in forest formations and a diameter at base height (Db; 0.30 m) ≥5 cm in savanna formations. Their diameters and heights were measured, they were cut and cubed, and the volume of each tree was obtained according to the Smalian methodology. Linear and nonlinear models were adjusted. Criteria for the selection of models were determined using correlation coefficients, the standard error of the estimates, and a graphical analysis of the residues. They were later validated by the chi-square test. The resultant models indicated that fit by specific phytophysiognomy was ideal; however, the generic and forest formation models exhibited similar performance to specific models and could be used in extensive areas of the Cerrado, where they represent a high potential for generalization. To further increase our understanding, similar research is recommended for the development of specific and generic models of the total volume in Cerrado areas.

Habitat requirements of a critically endangered Ninox hawk‐owl: implications for island‐wide restoration

Small, isolated populations can be especially sensitive to poor habitat conditions due to their limited capacity to adapt or disperse. Management of such populations, with an objective to implement the most effective strategies, is a conservation priority. The Norfolk Island morepork (Ninox novaeseelandiae undulata) is a Critically Endangered hawk‐owl endemic to Norfolk Island with an estimated population of 25 individuals. This species faces compounding threats from habitat degradation and loss, as well as inbreeding depression. It presents an exemplar for the development of habitat management strategies for top‐order predators in small, isolated systems. We paired fine‐scale light detection and ranging‐derived habitat variables with tracking data to quantify habitat suitability and the relative importance of environmental variables. Maximum entropy modeling indicated vegetation patch size and canopy height were important habitat variables, with moreporks more likely to be found in larger patches and canopy heights above 7 m. Morepork presence was not strongly influenced by the type of wooded vegetation; rather, the species appears to be a generalist occupier of forested areas. We demonstrate that suitable habitat during the breeding season is currently constrained, with coverage limited to one‐third (34%) of the island and an estimated carrying capacity of 36 morepork pairs. Restoration of native forest in cleared areas adjacent to existing wooded patches, with a specific goal to increase patch size, was the optimized management strategy to increase in situ carrying capacity. This study has demonstrated how habitat suitability modeling can inform targeted habitat restoration to enhance threatened species recovery.

Influence of isolation on the resilience of tank bromeliad ecosystems to drought in a Neotropical rainforest

AbstractLittle is known of how Neotropical freshwater ecosystems will respond to future climate scenarios. In Neotropical rainforests, a substantial fraction of the freshwater available to the aquatic fauna is found within phytotelmata, plant-held waters that form aquatic islands in a terrestrial matrix. We hypothesized that phytotelmata in close proximity have higher resilience capacity to severe drought than the isolated ones, under the assumption that immigration from nearby sources promotes faster recovery. We used rainshelters to emulate an extreme drought (67 days without rainfall) in tank-forming bromeliads arranged in patches of 1, 3 or 6 plants in a primary forest of French Guiana. Habitat size was a stronger determinant of invertebrate species richness and biomass per bromeliad than patch size. Larger bromeliad patches attenuated the adverse effect of drought on the biomass of predators, probably because short-range migration within dense patches allowed individuals to find moist refuges. However, the recovery of aquatic communities and ecosystem functions was mostly supported by in situ resistance, and a rescue effect of immigration was weak. Whilst environmental management plans tend to focus on dense networks of connected water bodies, our study shows that efforts should not omit the isolated ones.

TREE SPECIES AND MACROFAUNA INFLUENCE ON SOIL AGGREGATES AND CARBON IN EASTERN DEMOCRATIC REPUBLIC OF CONGO

<p><strong>Background</strong>. Soil aggregates represent a major indicator of soil fertility as they are important components of soil C protection. However, in the Democratic Republic of Congo, the choice of tree species being integrated into crop farms influence the type of soil macrofauna beneath these agroforestry trees with effect on soil aggregates and carbon fractions. <strong>Objective</strong>. To assess the combined effect of diverse tree species alongside earthworms and termites on soil aggregation and soil organic C. <strong>Methodology</strong>. Soil samples were collected from five agroforestry systems comprising <em>Eucalyptus saligna,</em> <em>Grevillea robusta</em> and <em>Ficus benghalensis</em> (an indigenous tree) woodlots, an agricultural farm (beans) and a natural forest in four different locations. Soil aggregates and soil organic C were analysed in the laboratory following standard procedures. The analyses of variance and correlations were carried out using R programming software. <strong>Results</strong>. A significantly higher proportion of large macroaggregates was recorded in soil under natural forest (13.1 %) whereas microaggregates were significantly low in soils under natural forest. For all the categories of aggregate-associated C, natural forest recorded the highest values while beans had the lowest values. The same trends were observed for labile C with 22.9 g kg<sup>-1</sup> in soil under natural forest and 9.7 g kg<sup>-1</sup> in soil under beans. <strong>Implication</strong>. The high levels of soil aggregates as well as carbon fractions recovered from natural forest clearly show the significance of a well-diversified tree-based farm. <strong>Conclusion</strong>. Therefore, it is advisable to consider a large diversification of tree species on farms to sustain and maintain a better soil quality.</p>

Large-scale inventory in natural forests with mobile LiDAR point clouds

Large-scale forest inventory at the individual tree level is critical for natural resource management decision making. Terrestrial Laser Scanning (TLS) has been used for individual tree level inventory at plot scale However, due to the inflexibility of TLS and the complex scene of natural forests, it is still challenging to localize and measure every tree at large scale. In this paper, we present a framework to conduct large-scale natural forest inventory at the individual tree level by taking advantage of deep learning models and Mobile Laser Scanning (MLS) systems. First, a deep learning model, ForestSPG, was developed to perform large-scale semantic segmentation on MLS LiDAR data in natural forests. Then, the forest segmentation results were used for individual stem mapping. Finally, Diameter at Breast Height (DBH) was measured for each individual stem. Two natural forests mapped with backpack and Unmanned Aerial Vehicle (UAV) LiDAR systems were tested. The results showed that the proposed ForestSPG is able to segment large-scale forest LiDAR data into multiple ecologically meaningful classes. The proposed framework was able to localize and measure all 5838 stems at individual tree level in a 20 ha natural forest in less than 20 min using UAV LiDAR. DBH measurement results on trees’ DBH larger than 38.1 cm (15 in) showed that backpack LiDAR was able to achieve 1.82 cm of Root Mean Square Error (RMSE) and UAV LiDAR was able to achieve 3.13 cm of RMSE. The proposed framework can not only segment complex forest components with LiDAR data from different platforms but also demonstrate good performance on stem mapping and DBH measurement. Our research provides and automatic and scalable solution for large-scale natural forest inventory at individual tree level, which can be the basis for large-scale estimation of wood volume and biomass.

Regeneration of secondary forest following anthropogenic disturbance from 1985 to 2021 for Amazonas, Brazil.

Following old-growth forest loss and subsequent land abandonment, secondary forest grows throughout the Amazon biome. For Amazonas, agricultural colonization was unsuccessful in many regions, leading to the regeneration of secondary forest and carbon storage under favorable climate conditions. Herein, the extent of regeneration in Amazonas and its timescale are investigated, including a granular analysis of its 62 municipalities, based on the MapBiomas dataset from 1985 to 2021. By 2021, 10,495 km2 of secondary forest had grown, corresponding to 28% of the lost old-growth forest. After normalization for algorithmic differences, this estimate was 17%-38% lower than prior studies for Amazonas that used earlier versions of the MapBiomas dataset, indicating increased accuracy in landcover assignments for more current versions of the dataset. For the northeastern microregion, representing the 15 municipalities of economic and population dominance in Amazonas, the growth of secondary forest varied from 3.0% to 9.8% of the total land area. For the southern microregion, constituting seven municipalities adjacent to large-scale deforestation of Mato Grosso and Rondônia, regeneration of secondary forest constituted 0.4%-1.2% of the land area. For the remaining interior municipalities, the regeneration was 0.0%-1.9%. Among the municipalities, the median regeneration interval, corresponding to the duration between the loss of old-growth forest and the appearance of secondary forest, ranged from 2 to 7 years. The median regeneration intervals of the interior, northeastern, and southern microregions were 3, 4, and 5 years, respectively. Even as the secular trend of deforestation continues in the Amazon biome and encroaches into the southern border of Amazonas state, the results herein indicate a possible resiliency toward secondary forest for undisturbed land on a timescale of several years, at least for mixed pasture-forest landscapes of kilometer-scale heterogeneity and assuming that a favorable climate persists for regeneration even as global change occurs.

Towards data-driven tropical forest restoration: Uncovering spatial variation, interactions and historical management effects on nutrients along soil depth gradients

Data scarcity hinders global conservation initiatives, and there is a pressing demand for spatially detailed soil and species data to restore human-altered tropical forests. We, therefore, aimed to generate foundational soil environment and habitat suitability data and high-resolution soil maps to aid restoration efforts in a critical ecosystem of the threatened Indo-Burma Biodiversity Hotspot region, i.e., Tarap Hill Reserve (THR) in Bangladesh. Using multiple soil depths and vegetation data, we answered three major questions. (QI) How do spatial distribution and the relationships between soil physicochemical properties (i.e., pH, sand, silt, and clay percentages, organic carbon, and nutrients – N, P, K, Ca, Mg, Fe, and Zn) vary from surface to deeper soils (top 1 m)? (QII) How do different forest management interventions, i.e., old-growth forests (OGF), mixed plantations (MXP), and mono-specific plantations (MOP), influence soil properties, nutrients, and carbon in different soil depths? (QIII) Which spatial interpolation methods are best suited for making more accurate soil property predictions at different depths? Our analyses reveal decreasing availability of critical nutrients like N, P, Mg, and Fe from surface to subsurface soils, while pH, soil organic carbon, and clay content increased with depth. Several soil properties showed significant interactions, although the strength of the interactions changed from surface to deeper soils. Besides, forest management interventions significantly influenced soil functionality by having higher nutrient availability and soil organic carbon in OGF than MXP and MOP. Predictive performances of the deterministic and geostatistical interpolation methods varied for different soil properties in different soil depths, and soil maps revealed substantial heterogeneity in the distribution of soil properties across space and along depths. This study represents a pioneering step in data-driven tropical forest restoration, and our novel findings and high-resolution soil maps could guide future studies focusing on species habitat preferences, restoration ecology, and spatial conservation planning in the Indo-Burma Biodiversity Hotspot region and elsewhere in the tropics.

Assessing Land-Cover Changes in the Natural Park ‘Fragas do Eume’ over the Last 25 Years: Insights from Remote Sensing and Machine Learning

The ‘Fragas do Eume’ Natural Park includes one of the best-preserved Atlantic forests in Europe. These forests are part of the Natura 2000 Network. This scientific study focuses on analysing land-cover changes in the ‘Fragas do Eume’ Natural Park (NW Spain) over a 25-year period, from 1997 to 2022, using machine learning techniques for the classification of satellite images. Several image processing operations were carried out to correct radiometry, followed by supervised classification techniques with previously defined training areas. Five multispectral indices were used to improve classification accuracy, and their correlation was evaluated. Land-cover changes were analysed, with special attention to the transitions between eucalyptus plantations and native deciduous forests. A significant increase in eucalyptus plantations (48.2%) (Eucalyptus globulus Labill.) was observed, while native deciduous forests experienced a decrease in their extent (17.6%). This transformation of the landscape affected not only these two habitats, but also cropland and scrubland areas, both of which increased. Our results suggest that the lack of effective conservation policies and the economic interest of fast-growing tree plantations could explain the loss of native deciduous forests. The results highlight the need to implement pro-active and sustainable management measures to protect these natural forest ecosystems in the ‘Fragas do Eume’ Natural Park.