Forest Transition Research Articles

The ‘gift of the new world’: Retelling the trajectories of black Locust in France

This article provides a detailed account of the shifting places of the black Locust tree (Robinia pseudoacacia) in France, from its introduction as a North American exotic in the early seventeenth century to the present. Three phases or moments are identified, articulating material and discursive dimensions of the trajectory of the tree — and of the spaces where it became prominent: exhortation, instrumentalization and marginalization. Due to a long introduction timeline and unmatched levels of expectations for versatility, the intertwined social-ecological dynamics of black Locust are marked by several reframings and rediscoveries. As such, a geohistorical focus on French ‘acacia’ landscapes offers an original window on the political economies of past and ongoing regional forest transitions of Western Europe.

Present and prospects for multi-aged silviculture in Chilean temperate forests: Targeting secondary forests in transition and partially harvested old-growth forests

Valdivian Temperate Rainforests in Chile have a global conservation value, but nowadays many correspond to secondary forests following regeneration in agricultural and burned lands, and to high-graded old-growth due to mismanagement, especially at mid to low elevations. Perspectives for increasing old-growth attributes in these productive forests through silviculture are high considering the diverse demands of ecosystem services and the high timber value of tree species. In the Llancahue experimental forest (40°S Lat) we implemented three ecological silviculture approaches: variable-density thinning in a Nothofagus dombeyi secondary forest (NDS), irregular shelterwood in a mature N. dombeyi forest (NDM), and single-tree selection cutting in a partially harvested old-growth forest (OG). Based upon an old-growth index (OGI) that includes density, basal area (BA), BA of the trees >80 cm in diameter, ba of shade-tolerant species, and the Gini coefficient, and aims to estimate how close a given forest is to a typical old-growth forest, these forests had a 22, 22, and 62% OGI before management. The OGI remained similar or declined following management, but 7–10 years after management it increased in NDS and NDM and declined in the OG (significant changes only in NDM and OG). We discuss these results considering that managed forests should target for an OGI ≈70% rather than maximum values. These managed forests contribute to halt degradation, mitigate climate change (carbon stores in the forest and in timber), and may have greater adaptive capacity to disturbances. We discuss perspectives for the potential scale-up of implementing these approaches.

A phenology- and trend-based approach for accurate mapping of sea-level driven coastal forest retreat

The rapid replacement of upland forest by encroaching marshland is a striking manifestation of global sea-level rise (SLR). Timely and high-resolution information on the location and extent of transition forest (the ecotone between upland forest and marsh where tree mortality due to seawater intrusion begins) is fundamental to understanding the processes and patterns of SLR-driven landscape reorganization. Despite its significance, accurate characterization of salt-impacted transition forest remains challenging due to the complexity of coastal environments, scarcity of ground-truth data, and the lack of effective mapping algorithms. Here we use the full archive of Landsat images between 1984 and 2021 to investigate the spectral, temporal, and phenological characteristics of transition forest, and develop a robust framework for monitoring coastal vegetation shifts in the mid-Atlantic U.S., a global SLR hotspot. We found that transition forest exhibits strong negative NDVI trends and a deviation of land surface phenology from marsh and upland forest that distinguishes itself from surrounding vegetation. By integrating temporal trends and land surface phenology, our results demonstrate superior discrimination between marsh and coastal forests to existing map products (e.g. NOAA Coastal Change Analysis Program, National Land Cover Database) that allows a reliable identification of the coastal treeline. We applied the approach to map regional land cover in 1985, 2000 and 2020 (overall classification accuracy >92%) and found that the area of coastal forest decreased by 22.0% from 1985 to 2020, the majority of which transitioned to marshland (92.3%, 5.3 × 103 ha). Based upon fine-scale patterns of coastal transgression, we created a practical workflow for spatially explicit quantification of forest retreat rates. Concurrent with rising sea level, coastal forests migrated upslope from 0.63 (± 0.27) m above sea level in 1985 to 0.78 (± 0.32) m above sea level in 2020, and horizontal forest retreat rates accelerated from 3.1 (range of 0–36) m yr−1 during 1985–2000 to 4.7 (0–55) m yr−1 during 2001–2020. As SLR continues to accelerate, our study may serve as a scalable solution for consistent tracking of coastal landscape evolution that is urgently needed for sustainable forest and wetland management.

From woodfuel to industrial wood: A socio-metabolic reading of the forest transition in Spain (1860–2010)

After centuries of deforestation, many, mostly industrialized countries have recently been experiencing net increases in forest area and biomass stocks, a phenomenon described as ‘Forest Transition’. In this article, we analyse the Spanish forest transition over the last 150 years from a socio-metabolic perspective. We provide the first estimation on forest surface, wood production and biomass stocks and we relate these changes to the socio-metabolic transformations of Spain's economy. Between 1860 and 1950, within a context of organic metabolism and growing population pressure, the stock of forest biomass decreased by 25.3%, falling to its lowest level in c. 1950. By conducting a decomposition analysis, we show that deforestation (i.e., declining forest area) explains 33.7% of the decrease in stock, while the reduction of biomass density accounts for 66.3%. Since 1950, and coinciding with the industrial socio-metabolic transition, forest biomass stocks multiplied by a factor of 2.5. Cropland intensification, the outsourcing of land use to third countries and agricultural policy encouraged the expansion of forest areas. Nevertheless, the substitution of firewood with fossil fuels was the main explanatory factor of the stock increase, since it enabled a dramatic decline in wood appropriation and the consequent increase in biomass density.

Contrasting strategies of nutrient demand and use between savanna and forest ecosystems in a neotropical transition zone

Abstract. The total demand for and uptake of nutrients by vegetation is rarely quantified or compared across vegetation types. Here, we describe different nutrient use and allocation strategies in neotropical savanna (cerrado) and transitional forest (cerradão) tree communities composed of different species, report leaf nutrient resorption and calculate ecosystem-level nutrient use efficiency. We couple net primary productivity (NPP) estimates with nutrient stoichiometry to quantify nutrient demand and nutrient flows at the whole-stand scale for different components of vegetation biomass. Species from the two vegetation communities showed similar mean nutrient concentrations and nutrient resorption efficiency, except for wood P concentration that was fourfold higher in cerrado than cerradão species. The cerradão showed higher canopy NPP, while fine roots and wood NPP were similar for the two vegetation types. Nutrient requirement in the two vegetation types was dominated by the demands of the canopy, with canopy resorption generally contributing more than 50 % of the total canopy demand for nutrients, while less than 35 % of N, P, K, Ca and Mg were allocated to wood or fine roots. Proportionally, cerrado showed higher nutrient demand from fine roots (over 35 % of the total nutrient demand) and for the wood component (over 13 % of the total nutrient demand), while ∼ 60 %–70 % of the cerradão nutrient demand was allocated to the canopy. The proportional difference in nutrient allocation to the different biomass components suggests cerrado species allocate less nutrients to a given fine root biomass, but more nutrients to a given wood biomass. Our findings suggest that cerradão species are more limited in P and K than cerrado species, inducing higher resorption to compensate for low uptake. Moreover, we found that N uptake for cerradão was higher with lower N use efficiency, i.e. the amount of production per nutrient unit, leading higher N demand compared to the cerrado. This difference in nutrient dynamics explains how similar soils and the same climate dominated by savanna vegetation can also support forest-like formations. Tree species composition is likely the major factor regulating nutrient use, limiting vegetation transitions and influencing nutrient demand at landscape scales.

Basic ecology of ant gardens in a dry-premontane transitional forest

Introduction: Ant gardens are ant nests located at different heights on trees on which vascular epiphytic plants that have been transported and sown by ants have germinated. Although this mutualistic relationship has been studied in humid tropical ecosystems, information on other tropical and Colombian ecosystems is scarce. Objective: To characterize the spatial distribution, formation process, diversity, demography, and phenology of Ant gardens in a secondary dry premontane transitional forest in Colombia. Methods: We estimated the spatial distribution and formation process of ant gardens. Phenological and demographic monitoring of epiphytes plants of ant gardens was performed. The monitoring of the ant gardens was done in transects, every 15 days. Results: The ant gardens showed an aggregated distribution pattern relative to water bodies. The garden-forming ant species was identified as Azteca ulei. Ten species of epiphytes plants and 13 species of phorophytes trees related to ant gardens were identified. The behavior of A. ulei favored the formation and maintenance of the ant gardens. A positive relationship was found between epiphyte richness and ant garden size. Some epiphytes presented a bimodal phenological pattern. The demographic pattern of epiphytes suggests that in the dry season, the number of established seedlings is reduced, which reduces the number of adults that remain in ant gardens. Conclusions: Ant gardens are the microhabitat that allows the germination, establishment, and reproduction of diverse epiphytes in the studied dry-premontane transitional forest.

Structure and dynamics of co-dominant species in different succession stages of natural forests in Daxing'an Mountains, China

Affected by the disturbance of forest fire and logging, the primary forest in Daxing'an Mountains gradually degenerates into secondary forest. In this study, we established 16 plots in each of three typical forests, including natural Betula platyphylla pure forest (pioneer stage), natural B. platyphylla and Larix gmelinii mixed forest (transition stage) and natural L. gmelinii pure forest (top stage). The methods of population age and tree height structure, static life table, survival analysis, dynamic index and time series prediction were used to quantitatively analyze the dynamics of dominant species (B. platyphylla and L. gmelinii) and all the arbors, aiming to provide scientific basis for the restoration and development of natural L. gmelinii forest. The results showed that the abundance of young co-dominant species and total arbors in each stage was large, and that all population had strong self-renewal potential. With the progress of succession, the abundance of B. platyphylla in each age class gradually decreased, whereas that of L. gmelinii gradually increased. The mortality and disappearance rates of total arbors and B. platyphylla in the transition stage and L. gmelinii in the pioneer stage gradually increased with the increases of age class, and the survival curve was Deevey-Ⅰ type. The survival analysis results showed that the population was stable in the early stage, increased in the middle stage, and declined in the later stage. In other stages, the mortality rates fluctuated slightly, the survival curves were Deevey-Ⅱ type, and the population increased in the early stage, declined in the middle stage, and stable in the later stage. The co-dominant species and total arbors were growing in the three succession stages, among which B. platyphylla in the pioneer stage, L. gmelinii and total arbors in the top stage showed the lowest sensitivity to the environment. The results of time series prediction showed that the co-dominant species and total arbors in each stage would increase in the future. During forest succession, it was necessary to strengthen the protection of seedlings and young trees, thin the forest with large coverage, and take appropriate measures to ensure population renewal.

Spatiotemporal pattern of global forest change over the past 60 years and the forest transition theory

Forest ecosystems play an indispensable role in addressing various pressing sustainability and social-ecological challenges such as climate change and biodiversity loss. However, global forest loss has been, and still is today, an important issue. Here, based on spatially explicit data, we show that over the past 60 years (1960–2019), the global forest area has declined by 81.7 million ha (i.e. 10% more than the size of the entire Borneo island), with forest loss (437.3 million ha) outweighing forest gain (355.6 million ha). With this forest decline and the population increase (4.68 billion) over the period, the global forest per capita has decreased by over 60%, from 1.4 ha in 1960 to 0.5 ha in 2019. The spatiotemporal pattern of forest change supports the forest transition theory, with forest losses occurring primarily in the lower income countries in the tropics and forest gains in the higher income countries in the extratropics. Furthermore, economic growth has a stronger association with net forest gain than with net forest loss. Our results highlight the need to strengthen the support given to lower income countries, especially in the tropics, to help improve their capacity to minimize or end their forest losses. To help address the displacement of forest losses to the lower income countries in the tropics, higher income nations need to reduce their dependence on imported tropical forest products.

Distribution of Molecular Weight of Humic Substances Isolated from Soils of Tallgrass Temperate Rainforests (Chernevaya Taiga)

The boreal forests of Russia are one of the largest forest areas on the planet. As a result of climate change, the rate of carbon sequestration and stabilization of organic matter are important indicators of environmental conservation. To understand mechanisms of stabilization and the structure of soil organic carbon, the molecular-weight (MW) distribution of humic acids (HAs) in soils of the central deciduous-forest zone of boreal forests (Chernevaya taiga, transitional ecotone forest, coniferous forest) was studied. Analysis of the MW distribution of HAs was conducted using size-exclusion chromatography. This approach allowed us to obtain the distribution of high-, medium-, and low-molecular fractions of HAs. It has been revealed that the content of the low-MW fraction prevails over the content of the medium- and high-MW fractions of HAs, which indicates the process of stabilization in soil organic matter. The accumulation of low-molecular-weight fraction occurs with the aromaticity increase in HAs, which indicates that HAs with a relatively high proportion of aromatic fragments have smaller hydrodynamic radius and a lower MW. It has been statistically substantiated that the low-molecular-weight fraction correlates with the content of aromatic compounds and carboxyl structural fragments of HAs, which indicates the resistance of the soil organic matter of Chernevaya taiga to biodegradation.

Medium- and large-sized mammals from Estação Biológica Fiocruz Mata Atlântica, Rio de Janeiro, south-eastern Brazil.

The Pedra Branca Forest is in a highly urbanised region of the central portion of Rio de Janeiro City and comprises the largest urban forest in the world (> 12,000 ha). The local flora and fauna are protected by three conservation units and the Estação Biológica Fiocruz Mata Atlântica (EFMA), which comprises 462 hectares on the east side of the remnant. The local biodiversity is still little known compared to other Atlantic Forest remnants from the Rio de Janeiro State. Here, we provide results of a survey of medium- and large-sized terrestrial mammals from the EFMA. In addition, we analysed the distribution of this fauna along three habitat types defined as Peridomicile, Transitional Forest and Forest Core. Sampling was performed from 2017 to 2020 and comprised a camera-trap survey, interviews with residents and local workers and occasional records. Results include occurrence records for 16 autochthonous and one allochthonous (Callithrix sp.) wild mammals, which are distributed into 14 families and seven orders, in addition to the presence of free-ranging domestic dogs and cats. Four species are in some category of threat of extinction at national or global levels. Amongst them, Leontopithecusrosalia (first record for the Rio de Janeiro City in more than a century) and Leopardusguttulus are classified as Vulnerable by IUCN. Most wild native species were registered in the three habitat types, but with differences in the frequency of records. Our results indicate that the presence of domestic dogs and cats influenced the species composition in each area, with Nasuanasua, Dasyproctaleporina and Didelphisaurita less frequent in places where domestic dogs and cats are more frequent. This is the first systematic effort to understand the occurrence and distribution of mid- and large-sized mammals in the Pedra Branca Forest.

Lidar-Based Aboveground Biomass Estimations for the Maya Archaeological Site of Yaxnohcah, Campeche, Mexico

This study aims to provide a technique applied to archaeology to estimate lidar-based aboveground biomass (AGB) in contemporary tropical forests surrounding archaeological sites. Accurate AGB estimations are important to serve as a baseline to evaluate the wood resources that the ancient Maya could have used for the development of their cities. A lidar processing model is proposed to study the contemporary forest surrounding the Yaxnohcah archaeological site. As tropical forests are highly diverse environments where species are not uniformly distributed, it was necessary to consider the variation within the forest to obtain accurate AGB. Four vegetation communities were defined from a supervised classification of a Sentinel-2 satellite image. A stratified sample was then selected for the field survey that comprised 73 transects of 500 m2 each. To estimate the transect AGB, we used an allometric equation that requires diameter, height, and wood density measurements for identified species. Linear-derived models provided the relationship between field data with lidar statistics for each vegetation type. Predicted average AGB values agreed with those obtained in the field. However, they significantly differed between vegetation types, averaging 83 Mg/ha for lowland forest, 178 for transition forest, and 215 for upland forest communities. From those results, we created a map with wall-to-wall AGB estimates following the distribution of vegetation classes that could complement archaeological research of past land use. Vegetation classification also helped determine that there is a spatial relationship between vegetation communities and the distribution of archaeological settlement features for the ancient city of Yaxnohcah.

Implications of Trade and Trade Adjustment on Forest Transition in Africa and Asia: Based on FMOLS and DOLS Approaches

Implications of Trade and Trade Adjustment on Forest Transition in Africa and Asia: Based on FMOLS and DOLS Approaches

Models of deforestation for setting reference levels in the context of REDD: A case study in the Peruvian Amazon

One of the main elements in the mechanisms proposed by REDD+ , is to pay countries (and then the users and/or forest owners, depending on each type of project), for real reductions in deforestation and the resulting GHG emissions, as well as to ensure other benefits, such as technical assistance and qualification, among others. To be able to estimate the emission reductions, it is necessary to establish a Reference Level either through different forms of a historical average or in the form of a BAU or “Business as Usual” scenario. In this sense, current proposals set the Reference Levels equal to historical deforestation, which apply another political logic to the predictions made by the Forest Transition (FT) theory. According to this theory, when using a simple historical extrapolation, it is possible that: “countries with a lot of forest and little deforestation”, lose in the initial stages of forest transition, while “countries with little forest and a lot of deforestation”, win in the later stages of the FT. Our study shows how the predictions of FT and other socio-economic variables can be incorporated into predictive models (historical trend), by including the forest area as an explanatory variable. Sub-national data from the 15 departments with forest cover in the Peruvian Amazon are used to develop 6 optional deforestation models for comparative purposes. It is observed that the most important predictive variable to explain current deforestation is historical deforestation. In the same way, it is observed that when applying and implementing econometric models with different variables, there are projections very close to the results of spatially explicit models for Peru (models that include spatial data for distance to roads, elevation, slope, distance to populated centers, among others). The variation of results is only 3–4%, so it can be concluded that the projections based on the historical trend considering the forest transition of each region and other socio-economic variables, are very good estimators of the deforestation expected in the future and are adequate to define the possible reductions by deforestation and degradation in the Peruvian Amazon or other areas with similar conditions.

Phytosociology and the timber potential of transitional ecosystems from forested campinarana to dense forest in the south of Roraima, Brazil

Transitional forest ecosystems in the south of the state of Roraima show great heterogeneity of tree species and represent different volumes of timber stock in projects of vegetation suppression requiring Deforestation Licences (DL). The aim of this study was to evaluate the phytosociology and standing timber volume in ecosystems of Submontane Dense Ombrophilous Forest (Ds) and transitional Campinarana/Ombrophilous Forest (LOt1 and LOt2) in the district of Rorainópolis, Roraima. The DL were issued and authorised from 2011 to 2016 by the State Foundation for the Environment and Water Resources of Roraima (FEMARH) and the Brazilian Institute of the Environment and Renewable Natural Resources (IBAMA). A total of 9,391 timber-yielding trees were analysed, with a DBH ≥ 45 cm in 646.5 hectares; these belonged to 21 botanical families, 73 species and 8 taxa identified at the genus level. Diversity and evenness were greater in Ds (H’ = 3.34; J = 0.82) compared to LOt (H’ = 1.92 to 2.20; J = 0.55). The floristic similarity was greater between Ds and LOt2, of different forest typologies, showing that transitional environments can be complex in terms of floristic composition and diversity. However, the larger volumes of timber stock in LOt1 and LOt2 compared to Ds may be related not only to natural processes, but also to the influence of deforestation and illegal selective logging in the surrounding area. There is a strong need for studies on transitional forest ecosystems in the Amazon, due to the complexity of the ecological relationships, the influence of environmental gradients, and anthropogenic factors.

Plant Parasitic Nematodes Associated with Okra in the Forest Savanna Transition and Semi-Deciduous Forest Agro-Ecologies of Ghana

Okra is an important vegetable crop in Ghana. Plant-parasitic nematodes infect okra, reducing the quality and quantity of fresh immature and dry fruits. This study was carried out to determine diversity, density and distribution of plant parasitic nematodes attacking okra in the Forest savanna transition and Semi-deciduous forest agro-ecologies of Ghana. In each agro-ecology, soils from okra rhizosphere were sampled from 15 farms for plant-parasitic nematodes assessment. Nematodes were extracted using the modified Baermann nematodes extraction method. Six nematode genera were identified; Meloidogyne, Pratylenchus, Xiphinema, Helicotylenchus, Rotylenchulus and Scutellonema. Meloidogyne occurred with 64.9% relative abundance and 100% frequency. Rotylenchulus, Pratylenchus, and Helicotylencus nematodes also occurred with 100% frequency. Xiphinema were the least abundant (0.05%) and the least frequent (15%). The findings have shown that a large number of nematodes exist on okra plants and therefore there is the need for educational campaigns to be stepped up by Agricultural Extension Services of the Ministry of Food and Agriculture on plant parasitic nematode infections in okra production.

Regional sustainability transition through forest-based bioeconomy? Development actors' perspectives on related policies, power, and justice

Forests and forest-based bioeconomy have central roles in the contemporary sustainability transition. However, the transition towards a bioeconomy is loaded with tensions regarding economic growth, ecological integrity, and social justice. These tensions reproduce varying transition discourses. Political actors at the level of the European Union (EU) and nation states take part in the processes creating the discourses and aim to govern the forest bioeconomy-based transition in certain directions viewed as favourable.The transition tensions are strongly felt in regions that are rich with forest resources but poor in terms of economic and political power, called ‘forest peripheries’. In this study, we explored how the forest bioeconomy discourses are downscaled in the development of the forest peripheries in East and North Finland. We examined the ways in which the regional development actors interpret prevailing forest-related policies and reproduce or challenge associated forest discourse(s). The focus was on the linkages between the macro-policies and the regional development, uncertainties that relate to the practical implementation and realisation of the policies, and the conflicts and power relations between the policies, practices, and the actors behind them. As a research strategy, we used embedded triangulation, where the interviews of development actors as initial data were contrasted with policy documents as the supportive data.For the analysis, we used the critical discourse analysis.From the policy documents, we identified the ‘You can have it all (if you close your eyes)’ discourse as the most hegemonic discourse, which aims to merge all the sides under the sustainable forest bioeconomy that favours the biomass regime. From the interviews, we identified three interlinked regional forest bioeconomy discourses: 1) ‘You can have it all is possible’, 2) ‘You can have it all is dependent on many ifs’, and 3) ‘You can have it all runs into conflicts’. The first discourse reproduced the hegemonic discourse, power relations appeared to be vertically unproblematic, and relatively manifested just transition for the forest peripheries. The second discourse produced an alternative discourse, which displayed more dependencies on the qualities of economic actors under the biotech regime. Power relations appeared to be more horizontal and complex, with a random just transition. The third discourse manifested tensions between the ideological aspirations of the policies and the practical reality in the forest peripheries. Conflicts arise from disharmonies between policy implementation and regional needs, cultural clashes, and misrecognition of the regional perspectives. The discourse reflected skewed power relations in vertical and horizontal manners. The transition appeared to be unjust in many ways because the external benefits seemed to be regarded over the regional ones.

Pigeonpea (Cajanus cajan) and white yam (Dioscorea rotundata) cropping system: Improved resource use and productivity in Ghana

Yam production along the West African yam belt is challenged with deteriorating soil fertility and unavailability of stakes, resulting in decreased yam productivity, and farmers' livelihood. This study evaluated resource use and yam productivity in pigeonpea-yam cropping systems in Ghana's forest and forest-savannah transition zones from 2017 through 2019 cropping seasons. Pigeonpea was established either in an alley or as a border during the 2017 cropping season, while yam was cultivated in 2018 and 2019. A split-plot design of cropping system (yam planted in alleys of pigeonpea—PA; yam planted with pigeonpea as a border—PB and sole yam) as main-plot treatments and chemical fertilizer (0–0–0; 23–23–30; 45–45–60 N-P2O5-K2O kg ha−1) as subplot treatments were used for the study. Productivity data on pigeonpea and yam were collected. The results revealed significantly higher leafy biomass and correspondent higher N content and N due to fixation in PA fields than PB fields in both locations and seasons. The presence of the pigeonpea and its biomass resulted in a significant suppression of ridge erosion and weeds, while soil moisture and nutrients improved, resulting in increased yam tuber productivity than in sole yam production. Further, planting yam with pigeonpea and half (23–23–30 N-P2O5-K2O kg ha−1) the recommended fertilizer rate significantly improved tuber yield and productivity than planting sole yam with full recommended fertilizer level in both locations and seasons. Promoting and adopting the pigeonpea-yam cropping system could sustain soil fertility, provide readily available stakes to address the constraint of deforestation and land degradation associated with yam production.

Detection and Quantification of Forest-Agriculture Ecotones Caused by Returning Farmland to Forest Program Using Unmanned Aircraft Imagery

The ‘Returning Farmland to Forest Program’ (RFFP) in China has become an essential factor in land cover changes and forest transition, especially in terms of the ecological processes between two adjacent ecosystems. However, accurately delineating ecotones is still a big challenge for vegetation and landscape ecologists. Acquiring high spatial resolution imagery from a small, unmanned aircraft system (UAS) provides new opportunities for studying ecotones at a small scale. This study aims to extract forest-agriculture ecotones by RGB ultrahigh-resolution images from a small UAS and quantify the small biotopes in 3D space. To achieve these objectives, a canopy height model (CHM) is constructed based on a UAS-photogrammetric-derived point cloud, which is derived from the digital surface model (DSM) minus the digital terrain model (DTM). Afterward, according to the difference of plant community height between abandoned farmland ecosystem and forest ecosystem, the ecotones are delineated. A landscape pattern identified with ecotones and other small biotopes at the fine scale. Furthermore, we assess the accuracy of the ecotones’ delineation based on the transects method with the previous situ work we carried out and quantify the landscape structure using common landscape metrics to describe its spatial and geometric characteristics. Through transect-based analysis at three transects, the overall accuracy of the width of UAS-derived delineation is greater than 70%, and the detection accuracy for the occurrence location is 100%. Finally, we conclude that ecotones extraction from UAS images would also provide the possibility to gain a comprehensive understanding of the entire ecological process of agricultural abandoned land restoration through continuous investigation and monitoring.

Synthesis of palaeoecological data from the Polish Lowlands suggests heterogeneous patterns of old-growth forest loss after the Migration Period

Human impact on Central European forests dates back thousands of years. In this study we reanalyzed 36 published pollen data sets with robust chronologies from Polish Lowlands to determine the patterns of large-scale forest decline after the Migration Period (fourth to sixth century CE). The study revealed substantial heterogeneity in the old-growth forest decline patterns. Using new high-resolution studies, we could better understand the timing of this transition related to increasing economic development. After the Migration Period, forest expansion continued until the seventh to ninth centuries cal. CE, when the dawn of Slavic culture resulted in large-scale forest decline, especially in north-western and north-central Poland. Later, forest decline was recorded mainly in north-eastern Poland and was related to Prussian settlements, including activities associated with the Teutonic Order, as well as with new settlements from the fourteenth century. The composite picture shows a varied spatio-temporal forest loss and transition towards the present-day, human activity dominated landscapes. However, some sites, such as in north-eastern Poland, are characterized by a less abrupt critical transition. The pristine nature of the oak-hornbeam forest had already been destroyed in Early Medieval times (eighth to ninth centuries cal. CE) and the potential for recovery was largely lost. Our study has confirmed previous assumptions that the decline of hornbeam across the Polish Lowlands may be an early indicator of local settlement processes, preceding severe forest loss, and establishment of permanent agriculture.

Copiotrophic Bacterial Traits Increase With Burn Severity One Year After a Wildfire

Wildfire and burn severity influence soil microbial communities during post-fire recovery. If post-fire differences in microbial communities affect soil carbon (C) pool dynamics, altered microbial communities could influence the transition of forests from C sources to C sinks during ecosystem recovery. For example, fire may change the abundance of copiotrophic and oligotrophic bacteria, influencing the kinetic rates of soil C pools due to differences in C-acquisition strategies and nutrient requirements. We assessed differences in soil bacterial communities and soil C pool kinetics 1 year after a wildfire in a mixed-conifer forest in northern California, United States. We determined whether differences in bacterial communities and soil C pools were related to copiotrophic versus oligotrophic life history strategies. Specifically, we assessed bacterial community oligotrophy versus copiotrophy based on phyla relative abundances and predicted 16S gene copy numbers. We then determined whether these life-histories were correlated with C pool kinetic rates. We further determined whether C degradation metabolic pathways predicted using PICRUSt2 were related to C pool kinetics. We found that copiotrophic bacteria exhibited greater abundance in burned areas than unburned areas, evidenced by increases in 16S rRNA gene copy number and by taxonomic classifications. Furthermore, the abundance of predicted metabolic pathways associated with fast-cycling C compounds increased with severity, including carbohydrate, alcohol, and amine degradation pathways, suggesting increased copiotrophic metabolic strategies. In contrast, the abundance of metabolic pathways of slow-cycling aromatic C compounds did not change, indicating oligotrophic metabolic strategies did not increase. The kinetic rate of the active C pool was positively related to the copiotrophic metabolic pathway of alcohol degradation, and negatively related to oligotrophic pathways like aromatic compound degradation. The links between C pool kinetics and phylum-level life-strategy classifications were ambiguous. Overall, our results suggest that metabolic life-strategies are related to soil C pool kinetics and could have short- and long-term impacts on soil C persistence during post-fire recovery. In the short-term, increased copiotrophy could increase soil C effluxviarapid cycling of labile C pools. However, over the longer-term lower prevalence of oligotrophic strategies could allow aromatic compounds associated with pyrogenic C to accumulate, increasing stable soil C stocks.