Forest Restoration Research Articles

Increased policy ambition is needed to avoid the effects of climate change and reach carbon removal targets in Portugal

The Paris Agreement’s goal of limiting global warming hinges on forest carbon sequestration as a key in several national strategies. However, Portugal’s rising forest fire occurrences threaten its ability to meet ambitious 2030 and 2050 carbon sequestration targets. Considering fire and forest trends, this study aims to quantify whether Portugal can reach its carbon sequestration ambitions as stated in its 2030 and 2050 targets. We tested three national forest scenario extensions of the global Shared Socioeconomic Pathways (SSPs) and Shared Policy Assumptions (SPAs) based on a dynamic model, simulating forest area and carbon sequestration related to future fire risk and policies of fire management, forest management, restoration of burnt areas, and climate change adaptation. The model projects a rapidly decreasing forest area under existing Portuguese policies (PT-SSP3), a slow decline under moderate policy improvements (PT-SSP2), and an almost stable forest area under long-term sustainable policy developments (PT-SSP1). In PT-SSP3, carbon sequestration will be reduced to 60% by 2050 compared to 2015, while it declines to about 85% and 90% under PT-SSP2 and PT-SSP1, respectively. It is still plausible to reach Portugal’s 2030 sequestration obligations under the EU’s Paris Agreement target under all three scenarios, while the Portuguese GHG neutrality target is not reached in the presented scenarios. Our four introduced policy areas (increasing focus on fire and forest management, forest restoration, and climate change adaptation of forest stands) must be supplemented by other policy strategies, such as reforestation.

Forest Bird Populations at the Big Island National Wildlife Refuge Complex, Hawai'i

Abstract Endemic Hawaiian forest birds have experienced dramatic population declines. The Big Island National Wildlife Refuge Complex (Refuge Complex) was established for the conservation of endangered forest birds and their habitats. Surveys have been conducted at two units of the Refuge Complex to monitor forest bird populations and their response to management actions. We analyzed survey data from 1987 to 2019 at the Hakalau Forest Unit (HFU) and from 1995 to 2019 at the Kona Forest Unit (KFU). We analyzed three strata at HFU: open-forest, closed-forest, and afforested-pasture, and two strata at KFU: upper (>1,524 m elevation) and lower (<1,524 m). In all years, ‘i‘iwi Vestiaria coccinea, ‘apapane Himatione sanguinea, and Hawai'i ‘amakihi Chlorodrepanis virens virens were the most abundant species at HFU. Three endangered forest bird species, Hawai'i ‘ākepa Loxops coccineus, ‘alawī Loxops mana (also known as Hawai'i creeper) and ‘akiapōlā‘au Hemignathus wilsoni, had much lower densities. The most abundant species at KFU was ‘apapane, followed by Hawai'i ‘amakihi at much lower densities. We found a continuation of several trends observed in previous analyses at HFU up to 2012, with most species’ trends upward in afforested-pasture stratum, stable in the open-forest stratum, and downward in the closed-forest stratum. However, more species were showing downward trends in all three strata during the most recent decade. Results were mixed at KFU, with most species’ trends downward in the upper stratum and upward in the lower stratum. Populations of endangered species were either locally extirpated at KFU or in numbers too low to reliably estimate population abundance. The Refuge Complex is important for conservation of forest birds on Hawai'i Island. Our results show that HFU supports the majority of three endangered forest bird species. Threats to forest birds at the Refuge Complex appear to be having a negative impact. These threats include habitat loss, disease, feral ungulates, and nonnative predators. Continuing and enhancing management actions, such as forest restoration and removal of invasive species, could help mitigate these impacts and allow the Refuge Complex to remain a key site for forest bird conservation in Hawai'i.

The conservation value of forests can be predicted at the scale of 1 hectare

To conserve biodiversity, it is imperative to maintain and restore sufficient amounts of functional habitat networks. Therefore, the location of the remaining forests with natural structures and processes over landscapes and large regions is a key objective. Here we integrated machine learning (Random Forest) and open landscape data to scan all forest landscapes in Sweden with a 1 ha spatial resolution with respect to the relative likelihood of hosting High Conservation Value Forests. Using independent spatial stand- and plot-level validation data, we confirmed that our predictions correctly represent different levels of forest naturalness, from degraded to those with high and associated biodiversity conservation values. Given ambitious national and international conservation objectives and increasingly intensive forestry, our model and the resulting wall-to-wall mapping fill an urgent gap for assessing the achievement of evidence-based conservation targets, spatial planning, and designing forest landscape restoration.

Upscaling marine forest restoration: challenges, solutions and recommendations from the Green Gravel Action Group

IntroductionTo counteract the rapid loss of marine forests globally and meet international commitments of the UN Decade on Ecosystem Restoration and the Convention on Biological Diversity ‘30 by 30’ targets, there is an urgent need to enhance our capacity for macroalgal restoration. The Green Gravel Action Group (GGAG) is a global network of 67 members that are working on the restoration of a diverse range of macroalgal forests and it aims to facilitate knowledge exchange to fast-track innovation and implementation of outplanting approaches worldwide. MethodsHere, we overview 25 projects conducted by members of the group that are focused on testing and developing techniques for macroalgal restoration. Based on these projects, we summarise the major challenges associated with scaling up the area of marine forests restored. ResultsWe identify several critical challenges that currently impede more widespread rollout of effective large-scale macroalgal restoration worldwide: 1) funding and capacity limitations, 2) difficulties arising from conditions at restoration sites, 3) technical barriers, and 4) challenges at the restoration-policy interface. DiscussionDespite these challenges, there has been substantial progress, with an increasing number of efforts, community engagement and momentum towards scaling up activities in recent years. Drawing on the collective expertise of the GGAG, we outline key recommendations for the scaling up of restoration efforts to match the goals of international commitments. These include the establishment of novel pathways to fund macroalgal restoration activities, building skills and capacity, harnessing emerging innovations in mobile hatchery and seeding technologies, and the development of the scientific and governance frameworks necessary to implement and monitor macroalgal restoration projects at scale.

Impact of Deforestation on Regional Climate Patterns in Japan

Purpose: To aim of the study was to analyze impact of deforestation on regional climate patterns.
 Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries.
 Findings: Research on the impact of deforestation in Japan reveals significant alterations in regional climate patterns. Deforested areas experience changes in precipitation, often leading to decreased rainfall and potential drought conditions. Additionally, deforestation contributes to higher temperatures, exacerbating the urban heat island effect and altering local weather dynamics. Modifications in atmospheric circulation patterns further compound these effects, potentially increasing the frequency of extreme weather events.
 Unique Contribution to Theory, Practice and Policy: Theory of land surface-atmosphere interaction, bio geophysical feedback hypothesis & theory of atmospheric circulation changes may be used to anchor future studies on impact of deforestation on regional climate patterns. Implement sustainable land management practices and reforestation initiatives to mitigate the adverse effects of deforestation on regional climate patterns. Enact and enforce policies that promote sustainable forestry practices, including forest protection, sustainable logging, and forest restoration measures.

Effectiveness of Billion Trees Tsunami Afforestation Projects in restoration of forests in Pakistan

AbstractThe history of forest cover dynamics in Pakistan reveals an unsatisfactory environmental situation. In the past 5 decades, particularly during the period between 1990 and 2010, the country lost an average of 41,100 hectares of green cover with a deforestation rate of 1.6% per year. The factors behind that this high deforestation rate is numerous including socio-economic transformation after the major political change during the 1970s in the mountainous areas of Pakistan, demographic changes, accessibility improvements, and land use changes. Several social forestry campaigns have been launched over time to cope with this socioecological and environmental issue. However, most of them have not been very effective due to certain shortcomings. This study aims to evaluate the effectiveness of the most recent and history’s biggest forest restoration program initiated by the government of the Khyber Pakhtunkhwa Province called the Billion Trees Tsunami Afforestation Project (BTTAP). This project was announced in 2013 when a new political party, Pakistan Tehreek-e-Insaf, came into power. The study is focused on one of the main forest hubs of the country in the Hindukush Mountains spanning five districts. Forest cover in this study area decreased from 20 to 2% between 1990 and 2010. After the launch of the BTTAP, the forest cover increased considerably from 2 to 35% by the year 2021. This growth was achieved through planting new trees, banning forest cutting, practicing surveillance, and enhancing community participation. If the project continues and the protection measures are not suspended, it can play a historical role in forest restoration.

Pathways to enhance the efficiency of forestry ecological conservation and restoration: empirical evidence from Heilongjiang Province, China

This paper proposes a theoretical framework for assessing ecological protection and restoration from the perspective of ecological efficiency. We applied the super-efficiency Slack-based measure model to examine the social and economic impacts of ecological resource consumption transformation in Heilongjiang Province, China. Additionally, a convergence analysis was used to evaluate and test the impact of the standard deviation ellipse method on regional sustainability. The results indicated that the land use structure was unstable; the conversion rate of resource consumption was low; and the average Ecological efficiency was only 0.343 in terms of the land use structure. Funds for forest ecological restoration have a significant impact on the effectiveness of ecological resource transformation. Implementing the Chinese ecological restoration project improves the ecological efficiency level of the communities. The center of gravity of ecological efficiency moved greatly in the years when forestry investment increased. Technological transfer and diffusion, experience imitation in environmental regulation, and eventually convergent steady-state levels of the ecological efficiency of different regions are necessary to improve the economic and social development level of regions with low environmental quality efforts should be made to reduce resource consumption intensity, increase fund utilization efficiency, and form a comprehensive and systematic system of ecological environment governance through reasonable enhancement of regional environmental regulations, increased investment in technological advancement, and funds for ecological protection and restoration.

Zásoby uhlíku v lesních půdách a lesní hospodářství – review

The article summarizes and discusses studies focused on the carbon stock in forest soils and the way it is affected by forestry operations with a focus on the Central European (Czech) region. In general, the methods enhancing forests´ vitality and stability are more important than the procedures aimed at carbon sequestration only, as the major risk for carbon stock in forest soils is represented by large-scale disturbances. Important factors that will influence the mitigation potential include the change of tree species composition, as the majority of forests in the Czech Republic is still represented by Norway spruce or Scots pine even-aged monocultures. Careful practices of logging and forest restoration are recommended, with minimal opening of the crown layer. The use of clear-cuts should be reserved mainly for afforestation of light-demanding tree species. Care should be taken of sustainable nutrients content in forest soils, as the soil quality plays substantial role in the future forest vitality, productivity and resilience. Forest protection and all measures preventing large-scale forest disturbances are of key importance for carbon sequestration.

Alterations in Hydrological Responses under Changing Climate and Land Use/Land Cover across Contrasting Agroecological Environments: A Case Study on the Chemoga Watershed in the Upper Blue Nile Basin, Ethiopia

We analyzed hydrological responses to changing climate and land use/land cover (LULC) for the past (1985–2020) and future (2021–2080) in the Chemoga watershed of the Upper Blue Nile Basin. The watershed comprises four agroecological environments: Moist Kolla, Moist Weyna Dega, Moist Dega, and Wet Wurch. Past and projected LULC changes under business-as-usual (BAU) and land conservation (LC) scenarios were utilized. Climate projections from 2021 to 2080, under two Shared Socioeconomic Pathways (SSP2-4.5 and SSP5-8.5), were downscaled from Global Climate Models. Utilizing the Soil and Water Analysis Tool, we assessed impacts on mean annual surface runoff (SR) and evapotranspiration (ET). Maximum and minimum temperatures increased significantly in the past and future climate scenarios, with a significant rainfall increase observed under SSP5-8.5. Historical trends revealed a 16.6% increase in SR and 7% in ET from 1983–2002 to 2003–2020. Under BAU LULC with the SSP2-4.5 (SSP5-8.5) climate scenario, SR increased by 24% (26.1%) and ET by 3.1% (4.4%) from 2003–2020 to 2021–2050, followed by a subsequent SR rise of 13.7% (14.0%) and ET increase of 6.0% (5.7%) from 2021–2050 to 2051–2080. Conversely, the LC LULC with SSP2-4.5 (SSP5-8.5) resulted in a 5.3% (4.2%) SR decrease and ET increase of 9.7% (11.3%) from 2003–2020 to 2021–2050 and a further SR decrease of 1% (0.7%) and 6.1% (6.9%) ET increase from 2021–2050 to 2051–2080. The Moist Kolla agroecology experienced the highest SR increase due to vegetation clearances for commercial farming. Meanwhile, the LC scenario indicated substantial decreases in SR and marginal increases in ET in the Moist Weyna Dega agroecology due to forest restoration on steep slopes. Overall, SR showed greater sensitivity to LULC changes, while ET was more responsive to climate changes. The results emphasize considering diverse agroecological contexts for effective water resource management under changing climate and LULC scenarios.

Collective Córregos Da Tiririca- Restoration of Riparian Forest in a Stream Contributor of Itaipu Lagoon – Niterói- RJ- Brazil

The lake system Itaipu-Piratininga in Niterói at north from the Guanabara Bay is drained by a set of streams. As a result of urban expansion at oceanic region of the city those streams became dirty and polluted. In a time-scale of twenty-five years after studies on water biodiversity, the lake system became eutrophized, with shallow waters. One way to recover the health of the ecossystem is to restore the freshwater rivers draining the system. The present study proposes to inform the experience of agroforestry restoration of the riparian forest in a tributary of Itaipu lake as well as bring an evaluation of local biodiversity – arboreal plants, terrestrial and aquatic vertebrates. After the inventory made, there followed the agroforestry planting of riparian forest by the organized civil society through the collective Córregos da Tiririca [streams at Tiririca mountains]. The technique employed for restoration is related, as corresponds to an adaptation of the principles of syntropic agriculture to the reality of an urban stream.

Green deserts, but not always: A global synthesis of native woody species regeneration under tropical tree monocultures.

Tree monocultures constitute an increasing fraction of the global tree cover and are the dominant tree-growing strategy of forest landscape restoration commitments. Their advantages to produce timber are well known, but their value for biodiversity is highly controversial and context dependent. Therefore, understanding whether, and in which conditions, they can harbor native species regeneration is crucial. Here, we conducted meta-analyses based on a global survey of the literature and on a database created with local, unpublished studies throughout Brazil to evaluate the regeneration potential of native species under tree monocultures and the way management influences this regeneration. Native woody species regeneration under tree monocultures harbors a substantial fraction of the diversity (on average 40% and 68% in the global and Brazilian surveys, respectively) and abundance (on average 25% and 60% in the global and Brazilian surveys, respectively) of regeneration observed in natural forests. Plantations with longer rotation lengths, composed of native tree species, and located adjacent to forest remnants harbor more species. Pine plantations harbor more native individuals than eucalypt plantations, and the abundance of regenerating trees is higher in sites with higher mean temperatures. Species-area curves revealed that the number of woody species under pine and eucalypt plantations in Brazil is 606 and 598 species, respectively, over an aggregated sampled area of ca. 12 ha. We highlight that the understory of tree monocultures can harbor a considerable diversity of regenerating native species at the landscape and regional scales, but this diversity strongly depends on management. Long-rotation length and favorable location are key factors for woody regeneration success under tropical tree monocultures. Therefore, tree monocultures can play a role in forest landscape restoration and conservation, but only if they are planned and managed for achieving this purpose.

Prescribed fire placement matters more than increasing frequency and extent in a simulated Pacific Northwest landscape

AbstractPrescribed fire has been increasingly promoted to reduce wildfire risk and restore fire‐adapted ecosystems. Yet, the complexities of forest ecosystem dynamics in response to disturbances, climate change, and drought stress, combined with myriad social and policy barriers, have inhibited widespread implementation. Using the forest succession model LANDIS‐II, we investigated the likely impacts of increasing prescribed fire frequency and extent on wildfire severity and forest carbon storage at local and landscape scales. Specifically, we ask how much prescribed fire is required to maintain carbon storage and reduce the severity and extent of wildfires under divergent climate change scenarios? We simulated four prescribed fire scenarios (no prescribed fire, business‐as‐usual, moderate increase, and large increase) in the Siskiyou Mountains of northwest California and southwest Oregon. At the local site scale, prescribed fires lowered the severity of projected wildfires and maintained approximately the same level of ecosystem carbon storage when reapplied at a ~15‐year return interval for 50‐year simulations. Increased frequency and extent of prescribed fire decreased the likelihood of aboveground carbon combustion during wildfire events. However, at the landscape scale, prescribed fire did not decrease the projected severity and extent of wildfire, even when large increases (up to 10× the current levels) of prescribed fire were simulated. Prescribed fire was most effective at reducing wildfire severity under a climate change scenario with increased temperature and precipitation and on sites with north‐facing aspects and slopes greater than 30°. Our findings suggest that placement matters more than frequency and extent to estimate the effects of prescribed fire, and that prescribed fire alone would not be sufficient to reduce the risk of wildfire and promote carbon sequestration at regional scales in the Siskiyou Mountains. To improve feasibility, we propose targeting areas of high concern or value to decrease the risk of high‐severity fire and contribute to meeting climate mitigation and adaptation goals. Our results support strategic and targeted landscape prioritization of fire treatments to reduce wildfire severity and increase the pace and scale of forest restoration in areas of social and ecological importance, highlighting the challenges of using prescribed fire to lower wildfire risk.

Spicing up oak forest restoration: a preliminary report of the protective use of chili peppers in direct seeding of acorns

Direct sowing of acorns is a technique for oak forest restoration, however, high seed predation by mammals can occur and cost‐effective alternatives to protect acorns are therefore required. The present study evaluated the protection provided by chili peppers (Capsicum annuum and Capsicum pubescens) to acorns of Quercus germana, an endangered endemic oak tree of the cloud forests. Greenhouse and field experiments were established to evaluate the effect of chili peppers on acorn removal, germination, and seedling emergence. These processes were related to the prevalent microhabitat characteristics where the acorns were introduced, and the fauna that consumed chili peppers and acorns was identified using camera traps. In the greenhouse trial, more seedlings emerged from acorns covered by fruits of C. pubescens (65.71 ± 8.14) and C. annuum (57.14 ± 8.49%) compared to unprotected acorns (31.43 ± 7.96%). Contrary to expectation, acorn removal in the field was greater using C. pubescens than the unprotected acorns, particularly in microsites with lower tree cover and higher grass dominance. Acorn removal was similar to chili pepper treatments. These results are explained by the camera trap records, which showed bird species consuming Capsicum fruits, thus exposing the acorns to subsequent removal and/or consumption by rodents. The studied Capsicum fruits had no negative effect on acorn germination and seedling emergence under greenhouse conditions, and future practices could, therefore, involve the use of different techniques to prevent the discovery of chili peppers by birds; for example, using green chili peppers for camouflage, or hiding them under litter or herbaceous vegetation.

Suitability assessment for forest landscape restoration based on species diversity conservation

Forest landscape fragmentation poses a significant challenge to the conservation of species diversity. Evaluating the suitability of forest landscape restoration (FLR) becomes essential as it promotes effective management of forest resources and protects species diversity. This study focused on deploying and testing a suitability evaluation framework system for FLR in the Saihanba area of Hebei, China. The framework system incorporated factors such as land cover type, landscape structure, soil quality, and topography. Using the matter-element model, the study evaluated the restoration suitability and identified priority restoration areas. The results revealed that land cover type and landscape structure were the primary factors influencing FLR in the study area. The suitable area for FLR in the study area was about 519.20 km2, accounting for 55.55% of the total area. The area of moderate, marginal, and unsuitable restoration accounted for 17.30%, 23.96%, and 3.18% of the study area, respectively. The suitable restoration areas predominantly consisted of natural secondary forest characterized by large patch areas, short distances between patches, and complex patch shapes. In the study area, the objective of FLR should be protect large and complex shaped patches of natural secondary forests for better conservation of species diversity. The FLR suitability evaluation conducted in this study provide a valuable guidance for promoting species-diversity conservation and restoration of forest ecosystems at the landscape scale in the study area and other similar regions.

Assessment of Temperate Deciduous Forest Communities and Structures after Restoration through the Multi-Reference Ecosystems Framework

The reference forest serves as a model for forest ecosystem restoration and can be employed to assess the vegetation of the Restored Forest, thereby confirming the success of restoration. When evaluating restoration, employing multireference forests is advantageous for discerning gradual changes in Restored Forests. However, in previous studies, their utilization has been limited to comparisons with individual ecosystems. Therefore, this study investigates the status of Restored Forests in previously damaged areas and their resemblance to reference forests across four forest types, namely Climax Forest (CF), Secondary Forest (SF), Restored Forest (RF), and Planted Forest (PF). Reference forests, serving as model targets for restoration, include CF and SF, while RF and PF represent the restoration forests. Six target sites within two temperate deciduous forests (Quercus acutissima and Quercus variabilis) were selected, and a comparative analysis of species diversity, dominance, and evenness was conducted. This study revealed that the dominant species in the top canopy of restoration forests mirrored those in reference forests, with Q. variabilis and Q. acutissima being prevalent. A similarity index of over 60% and a high correlation of 0.987 were observed in the top canopy layer between the reference and restored ecosystems (CF-RF/SF-PF). These findings enhance our understanding of the current status of Restored Forests and advocate for the utilization of multiple reference forests for successful restoration efforts.

Meta-analysis shows the impacts of ecological restoration on greenhouse gas emissions

International initiatives set ambitious targets for ecological restoration, which is considered a promising greenhouse gas mitigation strategy. Here, we conduct a meta-analysis to quantify the impacts of ecological restoration on greenhouse gas emissions using a dataset compiled from 253 articles. Our findings reveal that forest and grassland restoration increase CH4 uptake by 90.0% and 30.8%, respectively, mainly due to changes in soil properties. Conversely, wetland restoration increases CH4 emissions by 544.4%, primarily attributable to elevated water table depth. Forest and grassland restoration have no significant effect on N2O emissions, while wetland restoration reduces N2O emissions by 68.6%. Wetland restoration enhances net CO2 uptake, and the transition from net CO2 sources to net sinks takes approximately 4 years following restoration. The net ecosystem CO2 exchange of the restored forests decreases with restoration age, and the transition from net CO2 sources to net sinks takes about 3-5 years for afforestation and reforestation sites, and 6-13 years for clear-cutting and post-fire sites. Overall, forest, grassland and wetland restoration decrease the global warming potentials by 327.7%, 157.7% and 62.0% compared with their paired control ecosystems, respectively. Our findings suggest that afforestation, reforestation, rewetting drained wetlands, and restoring degraded grasslands through grazing exclusion, reducing grazing intensity, or converting croplands to grasslands can effectively mitigate greenhouse gas emissions.

Utilizing symbiotic relationships and assisted migration in restoration to cope with multiple stressors, and the legacy of invasive species

IntroductionClimate change has increased the need for forest restoration, but low planting success and limited availability of planting materials hamper these efforts. Invasive plants and their soil legacies can further reduce restoration success. Thus, strategies that optimize restoration are crucial. Assisted migration and inoculation with native microbial symbiont communities have great potential to increase restoration success. However, assisted migrants can still show reduced survival compared to local provenances depending on transfer distance. Inoculation with mycorrhizal fungi, effective if well-matched to plants and site conditions, can have neutral to negative results with poor pairings. Few studies have examined the interaction between these two strategies in realistic field environments where native plants experience the combined effects of soil legacies left by invasive plants and the drought conditions that result from a warming, drying climate.MethodsWe planted two ecotypes (local climate and warmer climate) of Populus fremontii (Fremont cottonwoods), in soils with and without legacies of invasion by Tamarix spp. (tamarisk), and with and without addition of native mycorrhizal fungi and other soil biota from the warmer climate.ResultsFour main results emerged. 1) First year survival in soil legacies left behind after tamarisk invasion and removal was less than one tenth of survival in soil without a tamarisk legacy. 2) Actively restoring soil communities after tamarisk removal tripled first year cottonwood survival for both ecotypes, but only improved survival of the warmer, assisted migrant ecotype trees in year two. 3) Actively restoring soil communities in areas without a tamarisk history reduced first year survival for both ecotypes, but improved survival of the warmer, assisted migrant ecotype trees in year two. 4) By the second year, inoculated assisted migrants survived at five times the rate of inoculated trees from the local ecotype.DiscussionResults emphasize the detrimental effects of soil legacies left after tamarisk invasion and removal, the efficacy of assisted migration and restoring soil communities alongside plants, and the need to thoughtfully optimize pairings between plants, fungi, and site conditions.

Standardization of Quick Seed Viability Protocol for Pinus roxburghii Sarg. Using Tetrazolium Assay

Chir pine (Pinus roxburghii) is one of the important tree species among five indigenous pine species of the Himalayan region and is widely distributed throughout the Himalaya. It is used as a commercial timber, fuel wood and pulpwood and also provide resin for various utilities. For the ecological, silvicultural and economical significance, the regeneration of this species is required for restoration and conservation purposes. Before seed sowing in nursery, there is need to know the actual seed vigour and quality of seeds. Therefore, the present experiment was conducted at Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh of India to standardized a quick seed viability testing protocol using tetrazolium (TZ) and confirmed with laboratory seed germination testing. The tetrazolium test and germination test were conducted with 100 seeds in 4 replications in CRD design as per the procedure devised by ISTA and analyzed with OPSTAT statistical software. After pre-moistening, chir pine seeds were cut longitudinally into two parts away from the radicle end to expose the embryo. The seeds of the species stained with 0.5, 1.0, 1.5 and 2.0 % solution of TZ and incubated at 25, 30 and 35 °C temperature in the darkness for 12, 24 and 36 hours. The result of TZ test showed that the seeds of chir pine soaked in 0.5 % tetrazolium solution at 25 °C temperature for 24 hours found to be the best one for the seed vigour and seed quality testing. For predicting the accurate seed viability, RMS (root mean square) method was used and recognized six staining seed categories distinguished 1 to 6. Seed category 1 denoted as viable seeds and category 6 as non-viable seeds. Result showed that the topographical staining categories 1, 2 and 3 provided least root mean square value and recommended these as viable seed categories for TZ seed viability test. Furthermore, it is also compared with laboratory seed germination test to standardize the seed viability protocol and result in line with the conformity. Overall, the results of the present study fulfilled all the gaps and criteria of quick seed viability testing in chir pine species and standardized protocol could be used for future seed vigour testing within a short period of time for the forest restoration and conservation purpose.

Decoupled response of microbial taxa and functions to nutrients: The role of stoichiometry in plantations

The resource quantity and elemental stoichiometry play pivotal roles in shaping belowground biodiversity. However, a significant knowledge gap remains regarding the influence of different plant communities established through monoculture plantations on soil fungi and bacteria's taxonomic and functional dynamics. This study aimed to elucidate the mechanisms underlying the regulation and adaptation of microbial communities at the taxonomic and functional levels in response to communities formed over 34 years through monoculture plantations of coniferous species (Japanese larch, Armand pine, and Chinese pine), deciduous forest species (Katsura), and natural shrubland species (Asian hazel and Liaotung oak) in the temperate climate. The taxonomic and functional classifications of fungi and bacteria were examined for the mineral topsoil (0–10 cm) using MiSeq-sequencing and annotation tools of microorganisms (FAPROTAX and Funguild). Soil bacterial (6.52 ± 0.15) and fungal (4.46 ± 0.12) OTUs' diversity and richness (5.83*103±100 and 1.12*103±46.4, respectively) were higher in the Katsura plantation compared to Armand pine and Chinese pine. This difference was attributed to low soil DOC/OP (24) and DON/OP (11) ratios in the Katsura, indicating that phosphorus availability increased microbial community diversity. The Chinese pine plantation exhibited low functional diversity (3.34 ± 0.04) and richness (45.2 ± 0.41) in bacterial and fungal communities (diversity 3.16 ± 0.15 and richness 56.8 ± 3.13), which could be attributed to the high C/N ratio (25) of litter. These findings suggested that ecological stoichiometry, such as of enzyme, litter C/N, soil DOC/DOP, and DON/DOP ratios, was a sign of the decoupling of soil microorganisms at the genetic and functional levels to land restoration by plantations. It was found that the stoichiometric ratios of plant biomass served as indicators of microbial functions, whereas the stoichiometric ratios of available nutrients in soil regulated microbial genetic diversity. Therefore, nutrient stoichiometry could serve as a strong predictor of microbial diversity and composition during forest restoration.

Restoring Subtropical Forests: Alleviating P Limitation and Introducing C Limitation Using Evergreen Broad-Leaved Tree Species

Determining which species to utilize for the artificial restoration of subtropical secondary forests has become a focal point in forestry and ecology. To compare the effects of the subtropical secondary forest artificial restoration model on soil microbial nutrient acquisition and limitation, we examined secondary forests (CKs), evergreen coniferous forests (GCPs), evergreen coniferous mixed broad-leaved forests (GCBMs), evergreen mixed broad-leaved forests (GBMs), and natural deciduous broad-leaved mixed forests (DBMs) as research subjects. Among them, GCPs, GCBMs, and GBMs were dominated by the species of the early, middle, and climax stages of subtropical forest succession, respectively. The activities and stoichiometry of β-1,4-glucosidase (BG), β-1,4-N-acetylglucosaminidase (NAG), leucine aminopeptidase (LAP), and acid phosphatase (ACP) in the topsoil were analyzed. The results showed that the forest type significantly affects the activities of BG and LAP rather than NAG or ACP. The BG activity in DBMs was the lowest, while the LAP activity in CKs was significantly higher than that in plantations. Furthermore, the nutrient limitation of microbes was quantitatively analyzed by using the vector analysis of enzyme stoichiometry. The soil microbes in the study area were co-limited by C and P, and the nutrient limitation was in the order of C > P > N. Among the forests, the enzyme stoichiometric ratios in GCPs and DBMs were closest to 1:1:1. From CKs to GBMs, the microbial C limitation was increased, while the P limitation was decreased. The C limitation in DBMs was slightly lower than that in CKs. Overall, the P limitation in evergreen plantations was less than that in CKs. The soil bulk density, C/P, and N/P significantly influenced enzyme activities and stoichiometry. These results suggest that the artificial restoration of subtropical forests using evergreen species alleviated P limitation, while using deciduous broad-leaved species offered potential for alleviating microbial C limitation. Compared with evergreen broad-leaved species, employing pioneer and mid-successional or deciduous broad-leaved species can better achieve balanced microbial nutrient requirements.