scholarly journals Effect of Thinning on the Spatial Structure of a Larix gmelinii Rupr. Secondary Forest in the Greater Khingan Mountains

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 720 ◽  
Author(s):  
Tian Zhang ◽  
Xibin Dong ◽  
Huiwen Guan ◽  
Yuan Meng ◽  
Jiafu Ruan ◽  
...  
Keyword(s):  
Spatial Structure ◽  
Comprehensive Evaluation ◽  
Secondary Forest ◽  
Stand Density ◽  
Distribution Patterns ◽  
Horizontal Distribution ◽  
Middle Level ◽  
Secondary Forests ◽  
Thinning Intensity ◽  
The Impact

Thinning is an important way to adjust and optimize the spatial structure of forests. The study of its impacts support a better understanding of the succession process of secondary forests after interference. To study the changes in forest spatial structure under different thinning intensities and stand densities, we considered five thinning intensities including unthinned (0%), low (3.4%, 6.2%, 12.5%), medium (16.8%, 20.9%, 25.5%), high (34.4%, 40.0%, 47.9%), and extra-high (50.6%, 59.9%, 67.3%) intensity. In addition, three different stand densities for each degree of thinning intensity. The results showed that the most horizontal distribution patterns after thinning were uniform distribution and near-uniform random distribution. Most of the trees were not mixed while several were mixed to an above medium degree. The effect on dominance of thinning was not significant and the overall plots were in the middle level. The tree density was in the sparse status. Competitive pressure on the reference tree was reduced. Thinning intensity and stand density affected stand spatial structure to different degrees. There were no obvious pattern under different thinning intensities and it was optimal at approximately 1600 trees/ha. As thinning intensity increased, the impact tended to decrease first and then increase under certain stand density. The improvement was greatest when thinning intensity was low. By analyzing the stand’s spatial structure after thinning, the unreasonableness of the stand’s spatial structure can be found, which provides the basis for optimizing management measures. We used the AHP-entropy to weigh the importance of each spatial structure parameter and we proposed a comprehensive distance evaluation index based on the optimal value obtained in order to perform a comprehensive evaluation of a forest’s spatial structure.

scholarly journals Unraveling the effects of environmental drivers and spatial structure on benthic species distribution patterns in Eurasian-Arctic seas (Barents, Kara and Laptev Seas)

Polar Biology ◽  
2020 ◽  
Vol 43 (11) ◽  
pp. 1693-1705
Author(s):  
Miriam L. S. Hansen ◽  
Dieter Piepenburg ◽  
Dmitrii Pantiukhin ◽  
Casper Kraan
Keyword(s):  
Environmental Factors ◽  
Spatial Structure ◽  
Large Scale ◽  
Environmental Changes ◽  
Spatial Scales ◽  
Distribution Patterns ◽  
Environmental Drivers ◽  
Arctic Seas ◽  
Faunal Distribution ◽  
The Impact

Abstract In times of accelerating climate change, species are challenged to respond to rapidly shifting environmental settings. Yet, faunal distribution and composition are still scarcely known for remote and little explored seas, where observations are limited in number and mostly refer to local scales. Here, we present the first comprehensive study on Eurasian-Arctic macrobenthos that aims to unravel the relative influence of distinct spatial scales and environmental factors in determining their large-scale distribution and composition patterns. To consider the spatial structure of benthic distribution patterns in response to environmental forcing, we applied Moran’s eigenvector mapping (MEM) on a large dataset of 341 samples from the Barents, Kara and Laptev Seas taken between 1991 and 2014, with a total of 403 macrobenthic taxa (species or genera) that were present in ≥ 10 samples. MEM analysis revealed three spatial scales describing patterns within or beyond single seas (broad: ≥ 400 km, meso: 100–400 km, and small: ≤ 100 km). Each scale is associated with a characteristic benthic fauna and environmental drivers (broad: apparent oxygen utilization and phosphate, meso: distance-to-shoreline and temperature, small: organic carbon flux and distance-to-shoreline). Our results suggest that different environmental factors determine the variation of Eurasian-Arctic benthic community composition within the spatial scales considered and highlight the importance of considering the diverse spatial structure of species communities in marine ecosystems. This multiple-scale approach facilitates an enhanced understanding of the impact of climate-driven environmental changes that is necessary for developing appropriate management strategies for the conservation and sustainable utilization of Arctic marine systems.

Quantifying the spatial patterns of Secondary Forest carbon sequestration potential in the Brazilian Amazon

2021 ◽  
Author(s):  
Viola Heinrich ◽  
Ricardo Dalagnol ◽  
Henrique Cassol ◽  
Thais Rosan ◽  
Catherine Torres de Almeida ◽  
...  
Keyword(s):  
Secondary Forest ◽  
Brazilian Amazon ◽  
Paris Agreement ◽  
Forest Carbon ◽  
Secondary Forests ◽  
North West ◽  
North East ◽  
The North ◽  
Forest Regrowth ◽  
The Impact

<p>Overall, global forests are expected to contribute about a quarter of pledged mitigation under the Paris Agreement, by limiting deforestation and by encouraging forest regrowth.</p><p>Secondary Forests in the Neo-tropics have a large climate mitigation potential, given their ability to sequester carbon up to 20 times faster than old-growth forests. However, this rate does not account for the spatial patterns in secondary forest regrowth influenced by regional and local-scale environmental and anthropogenic disturbance drivers.</p><p>Secondary Forests in the Brazilian Amazon are expected to play a key role in achieving the goals of the Paris Agreement, however, the Amazon is a large and geographically complex region such that regrowth rates are not uniform across the biome.</p><p>To understand the impact of key drivers we used a multi-satellite data approach with the aim of understanding the spatial variations in secondary forest regrowth in the Brazilian Amazon. We mapped secondary forest area and age using a land-use-land-cover dataset – MapBiomas – and, combined with the European Space Agency Aboveground Carbon dataset, constructed regional regrowth curves for the year 2017.</p><p>We found large variations in the regrowth rates across the Brazilian Amazon due to large-scale environmental drivers such as rainfall and shortwave-radiation. Regrowth rates are similar to previous pan-Amazonian estimates in the North-West (3 ±1.0 MgC ha<sup>-1</sup> yr<sup>-1</sup>), which are double than those in the North-East Amazon (1.3 ±0.3 MgC ha<sup>-1</sup> yr<sup>-1</sup>). The impact of anthropogenic disturbances, namely fire and repeated deforestation prior to the most recent regrowth only reduces the regrowth by 20% in the North-West (2.4 ±0.8 MgC ha<sup>-1</sup> yr<sup>-1</sup>) compared to 55% in the North-East (0.8 ±0.8 MgC ha<sup>-1</sup> yr<sup>-1</sup>). Overall, secondary forest carbon stock of 294 TgC in the year 2017, could have been 8% higher with avoided fires and repeat deforestation.<strong> </strong>We found that the 2017 area of secondary forest, which occupies only ~4% of the Brazilian Amazon biome, can contribute significantly (~5.5%) to Brazil’s net emissions reduction targets, accumulating ~19.0 TgC yr<sup>-1</sup>until 2030 if the current area of secondary forest is maintained (13.8 Mha). However,this value reduces rapidly to less than 1% if only secondary forests older than 20 years are preserved (2.2 Mha).</p><p>Preserving the remaining old-growth forest carbon stock and implementing legal mechanisms to protect and expand secondary forest areas are key to realising the potential of secondary forest as a nature-based climate change mitigation solution.</p>

scholarly journals Implementation of Silvopastoral Systems under Nutrient Cycling in Secondary Vegetation in the Amazon

2018 ◽  
Vol 10 (4) ◽  
pp. 124
Author(s):  
Perlon Maia dos Santos ◽  
Antonio Clementino dos Santos ◽  
Durval Nolasco das Neves Neto ◽  
Wallace Henrique de Oliveira ◽  
Luciano Fernandes Sousa ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Leaf Litter ◽  
Secondary Forest ◽  
Integrated Systems ◽  
Native Forest ◽  
Panicum Maximum ◽  
Secondary Forests ◽  
Silvopastoral Systems ◽  
Decomposition Rates ◽  
Thinning Intensity

Silvopastoral systems can be implemented in idle secondary forests; however, they may affect nutrient cycling in these ecosystems. This farming practice using babassu palms (Attalea speciosa Mart.) and Mombasa grass (Panicum maximum Jacq.) has been little studied, and the nutrient cycling occurred during this practice is yet unknown. The goal of this paper was to detect the leaf litter accumulation, decomposition, and nutrient release occurring in silvopastoral systems in a babassu secondary forest, and compared the results with those of a native forest and of a pasture grown under full sunlight. The data relating to deposition, chemical composition, decomposition, and macronutrient release of leaf litter and pasture litter were evaluated by multivariate analyses. The results showed that forest thinning reduced leaf litter deposition and overall nutrient cycling but had no effect on decomposition rates. Conversely, the presence of grass in the understory promoted increased overall nutrient cycling rates. The cycling in integrated systems occurs more similar to that of forests than that of monocultures. The greater the thinning intensity the more similar the cycling will be relative to that occurring in pastures and in monocultures. The nutrients Ca, Mg, and N were the most affected by thinning. Moreover, the presence of grass in integrated systems provided an increased N and Mg cycling, whereas the thinning reduced Ca cycling. K showed the highest release and return ratio to the soil. Lastly, leaf litter from pasture areas showed higher contents of nutrients, decomposition rates, as well as an enhanced nutrient cycling capacity.

scholarly journals Quantifying immediate carbon emissions from El Niño-mediated wildfires in humid tropical forests

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170312 ◽  
Author(s):  
Kieran Withey ◽  
Erika Berenguer ◽  
Alessandro Ferraz Palmeira ◽  
Fernando D. B. Espírito-Santo ◽  
Gareth D. Lennox ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Carbon Emissions ◽  
El Niño ◽  
Secondary Forest ◽  
El Nino ◽  
Fire Intensity ◽  
Secondary Forests ◽  
Study Region ◽  
Fire Emissions ◽  
The Impact

Wildfires produce substantial CO 2 emissions in the humid tropics during El Niño-mediated extreme droughts, and these emissions are expected to increase in coming decades. Immediate carbon emissions from uncontrolled wildfires in human-modified tropical forests can be considerable owing to high necromass fuel loads. Yet, data on necromass combustion during wildfires are severely lacking. Here, we evaluated necromass carbon stocks before and after the 2015–2016 El Niño in Amazonian forests distributed along a gradient of prior human disturbance. We then used Landsat-derived burn scars to extrapolate regional immediate wildfire CO 2 emissions during the 2015–2016 El Niño. Before the El Niño, necromass stocks varied significantly with respect to prior disturbance and were largest in undisturbed primary forests (30.2 ± 2.1 Mg ha −1 , mean ± s.e.) and smallest in secondary forests (15.6 ± 3.0 Mg ha −1 ). However, neither prior disturbance nor our proxy of fire intensity (median char height) explained necromass losses due to wildfires. In our 6.5 million hectare (6.5 Mha) study region, almost 1 Mha of primary (disturbed and undisturbed) and 20 000 ha of secondary forest burned during the 2015–2016 El Niño. Covering less than 0.2% of Brazilian Amazonia, these wildfires resulted in expected immediate CO 2 emissions of approximately 30 Tg, three to four times greater than comparable estimates from global fire emissions databases. Uncontrolled understorey wildfires in humid tropical forests during extreme droughts are a large and poorly quantified source of CO 2 emissions. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals Species richness, forest types and regeneration of Schima in the subtropical forest ecosystem of Yunnan, southwestern China

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Cindy Q. Tang ◽  
Peng-Bin Han ◽  
Shuaifeng Li ◽  
Li-Qin Shen ◽  
Diao-Shun Huang ◽  
...  
Keyword(s):  
Species Richness ◽  
Forest Canopy ◽  
Stand Structure ◽  
Secondary Forest ◽  
Distribution Patterns ◽  
Natural Disturbances ◽  
Secondary Forests ◽  
Forest Types ◽  
Regeneration Dynamics ◽  
Successional Forests

Abstract Background Schima genus of Theaceae is confined to subtropics and tropics of South, East and Southeast Asia. Thirteen species of Schima are distributed in subtropical China. Many of them appear as dominant canopy species in the subtropical forests. To date, Schima species richness distribution patterns of China have remained unknown. Meanwhile, there has been a longtime debate as to whether forests dominated by Schima species are early or late successional forests. We aim to clarify Schima species richness patterns and these species’ roles in the forest succession and regeneration dynamics of the subtropical ecosystem in Yunnan Province, China. Method We mapped Schima species richness distribution patterns in China. Based on 71 vegetation plots, we analyzed forest characteristics, population structure, and regeneration dynamics of Schima species in Yunnan. Results Yunnan was found to harbor the greatest richness and the highest rarity-weighted richness of Schima species in the subtropical regions of China. We classified five primary and six secondary forest types containing Schima species as one of dominants. Yunnan had the high floristic diversity and varying stand structure of forests containing Schima species. The Schima species studied generally had a sporadic regeneration type and a long life-span. Four species (Schima argentea, Schima villosa, Schima sinensis, Schima sericans) were shade-intolerant. But three species (Schima noronhae, Schima khasiana and Schima wallichii) were considered as bi-modal type species having shade-intolerant and shade-tolerant traits. Schima noronhae was seen to be a top dominant in late successional forests, while S. wallichii was found as a top-dominant in early or middle or late successional forests. S. khasiana, Schima villosa, Schima sinensis usually appeared as a top dominant in early or middle successional secondary forests, though they also presented as a second dominant in late-successional forests. Schima argentea and Schima sericans dominated only in the early or middle/seral successional forests. Schima species’ regeneration establishment depended mainly on forest canopy gap formation through moderate human and natural disturbances. Conclusions Yunnan has high species richness and rarity-weighted richness of Schima. Both moderate human and natural disturbances have provided regeneration niches for Schima species. Some of the Schima species studied as a second dominant (rare as the top-dominant) present in the late-successional forests. Some of them are more often as the top-dominant in early or middle successional forests, where as time goes by the dominance of Schima species would be replaced by their associated dominant taxa such as Castanopsis species.

Differences in dung beetle activity at western gorilla defecation sites in south-east Cameroon: implications for establishment of Uapaca spp. seedlings

2015 ◽  
Vol 31 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Charles-Albert Petre ◽  
Marie-Hélène Zinque ◽  
Nikki Tagg ◽  
Roseline-Claire Beudels-Jamar ◽  
Barbara Haurez ◽  
...  
Keyword(s):  
Secondary Forest ◽  
Seedling Emergence ◽  
Dung Beetle ◽  
Dung Beetles ◽  
Burial Depth ◽  
Secondary Forests ◽  
Beetle Assemblages ◽  
Sleeping Sites ◽  
Seed Deposition ◽  
The Impact

Abstract:For endozoochorous seed dispersal systems, the extant dung beetle assemblage at seed deposition sites may influence site suitability as burial activity may change the probability that seeds germinate and seedlings establish. This study tested if the different conditions of the two main seed-deposition habitats of a western lowland gorilla population of south-east Cameroon (sleeping sites and old secondary forest) influenced dung beetle assemblages and consequently the seed relocation patterns. In March 2012, in both habitats, burial patterns (proportion and depth) were described in eight stations based on two 300-g experimental faeces with known number of Uapaca spp. seeds (N = 75) left for 48 h, and beetle assemblages were described based on one 48h-dung-baited pitfall trapping session in five of these stations. To assess the impact of burial pattern on seedling emergence, Uapaca seedling emergence trials were performed in a nursery (75 seeds per depth treatment). Assemblage at sleeping sites had a higher species richness (non-significant) and was significantly more abundant than in old secondary forests. Conversely, significantly more seeds were buried in old secondary forests than sleeping sites and at significantly greater depths (mean: 14.9 cm vs. 8.7 cm). As trials suggested that burial depth ≥7 cm prevented Uapaca seedling emergence, dung beetles are assumed to induce seed loss more strongly in old secondary forests than sleeping sites (20.5% vs. 6.7% of initial seed crop). The demonstration that dung beetles may exert a negative influence on seed fate overall, and that the degree to which this occurs may vary depending on habitat, highlights the complexity in determining the suitability of deposition sites for recruitment.

Tropical secondary forests

1990 ◽  
Vol 6 (1) ◽  
pp. 1-32 ◽  
Author(s):  
Sandra Brown ◽  
Ariel E. Lugo
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Net Primary Productivity ◽  
Secondary Forest ◽  
Ground Vegetation ◽  
Litter Production ◽  
Secondary Forests ◽  
Forest Lands ◽  
The Tropics ◽  
The Impact

ABSTRACTThe literature on tropical secondary forests, defined as those resulting from human disturbance (e.g. logged forests and forest fallows), is reviewed to address questions related to their extent, rates of formation, ecological characteristics, values and uses to humans, and potential for management. Secondary forests are extensive in the tropics, accounting for about 40% of the total forest area and their rates of formation are about 9 million ha yr−1. Geographical differences in the extent, rates of formation and types of forest being converted exist.Secondary forests appear to accumulate woody plant species at a relatively rapid rate but the mechanisms involved are complex and no clear pattern emerged. Compared to mature forests, the structure of secondary forest vegetation is simple, although age, climate and soil type are modifying factors. Biomass accumulates rapidly in secondary forests, up to 100 t ha−1 during the first 15 yr or so, but history of disturbance may modify this trend. Like biomass, high rates of litter production are established relatively quickly, up to 12–13 t ha−1 yr−1 by age 12–15 yr. And, in younger secondary forests (< 20 yr), litter production is a higher fraction of the net primary productivity than stemwood biomass production. More organic matter is pro duced and transferred to the soil in younger secondary forests than is stored in above-ground vegetation. The impact of this on soil organic matter is significant and explains why the recovery of organic matter in the soil under secondary forests is relatively fast (50 yr or so). Nutrients are accumulated rapidly in secondary vegetation, and are returned quickly by litterfall and decomposition for uptake by roots.We propose a model of the gains and losses, yields and costs, and benefits and tradeoffs to people from the current land-use changes occurring in the tropics. When the conversion of forest lands to secondary forests and agriculture is too fast or land-use stages are skipped, society loses goods and services. To avoid such a loss, we advocate management of tropical forest lands within a landscape perspective, a possibility in the tropics because land tenures and development projects are often large.

scholarly journals Urban Spatial Structure in Barcelona (1902–2011): Immigration, Spatial Segregation and New Centrality Governance

2020 ◽  
Author(s):  
Miquel-Àngel Garcia-López ◽  
Rosella Nicolini ◽  
José Luis Roig Sabaté
Keyword(s):  
Population Density ◽  
Spatial Structure ◽  
Density Distribution ◽  
Population Distribution ◽  
Research Question ◽  
Central Business District ◽  
Distribution Patterns ◽  
Urban Spatial Structure ◽  
The Impact ◽  
Over Time

AbstractThis paper investigates the impact of the city’s urban spatial structure in shaping population density distribution over time. This research question is relevant in Barcelona because urban population grew at a sustained pace in various decades due to intense immigration inflows. When the urban spatial structure fails to behave as the backbone of population density distribution, population distribution can suffer from polarization problems. We conduct our empirical study using an urban monocentric framework, tracking the different spatial distribution patterns of the overall population and a few selected urban communities in light of the degree of attractiveness of the central business district (CBD). To this end, we construct an original database by each district in Barcelona from 1902 to 2011 and perform an econometric analysis. Our results reveal that the urban spatial structure continued to be a crucial determinant over time for shaping the overall population distribution in Barcelona and in almost all selected communities. However, its importance fluctuated over time, bottoming out in the 1950s–1960s, and whose resurgence was mostly driven by the political initiative to create a new centrality in the urban periphery. This policy reinforced the attractiveness of the CBD, resulting in the de-facto avoidance of urban polarization.

AFRICA’S RENAISSANCE AND POTENTIAL IN THE LEATHER SECTOR WITH REFLECTION TO THE GLOBAL PERFORMANCE

2015 ◽  
Vol 2 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Mwinyihija M.
Keyword(s):  
Value Chain ◽  
Small And Medium Enterprises ◽  
Middle Level ◽  
Individual Member ◽  
Socioeconomic Indicators ◽  
Value Add ◽  
Medium Enterprises ◽  
The Impact ◽  
Productivity And Competitiveness ◽  
Critical Aspects

Africa’s renaissance is inevitable and rapidly emerging as a reality in tandem with the continent’s continued exploration of its natural resources in a more sustained way than previously done. Currently, the clarion call is to value add, avoid plundering and involve its population through the SME’s to adapt modern methods of entrepreneurship. During the study, critical aspects that are envisaged to trigger the growth and development of Africa, included the entry of major countries of the continent into the global emerging markets such as MINT (Mexico, Indonesia, Nigeria and Turkey) and BRICS (Brazil, Russia, India, China and South Africa). For the leather sector, certain socioeconomic indicators such as the youthful participation in the value chain, ownership status, literacy levels and acquired experiences are all contributing to a vibrant sector. It was observed that these indicators if well aligned with individual member states of African Union Commission and structured than productivity and competitiveness of leather products will be attained. As such, ease of either foreign direct investment, local recapitalization and development of the SME’s could become feasible. Indeed, with the emergence of over 300 million youth at middle level income level is construed to start building on the impact of the continents purchasing power. Therefore, Africa needs to respond by address on development of ICT, develop affordable financial support to provide stimulus packages to SME’s (Small and Medium Enterprises) to transform, improve on inter and intra trade to optimize on unexplored synergies and enhance mobility of persons with in Africa as preamble to Africa’s renaissance.

Perception of Professionals towards Effectiveness of Human Resource Information System

2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Bharti Motwani
Keyword(s):  
Information System ◽  
Human Resource ◽  
Training Programme ◽  
Middle Level ◽  
Human Beings ◽  
Human Resource Information System ◽  
Resource Information ◽  
Future Challenges ◽  
Operational Decision Making ◽  
The Impact

Organizations are facing stiff market and other external pulls and pushes, thus HR will become vital source for managing future challenges. HRIS is an information system that makes use of computers to monitor, control, and influence the movement of human beings from the time they indicate their intention to join an organization till the time they separate from it. The purpose of the HRIS is to provide service, in the form of accurate and timely information, to the clients of the system. As there are a variety of potential users of HR information, it may be used for strategic, tactical, and operational decision making (e.g., to plan for needed professionals in a merger), to avoid litigation (e.g., to identify discrimination problems in hiring), to evaluate programmes, policies, or practices (e.g., to evaluate the effectiveness of a training programme), and/or to support daily operations (e.g., to help managers monitor time and attendance of their professionals). However, in order to maximize HRIS success, researchers and practitioners have to know more about its underlying drivers. The study is undertaken looking to the importance of HRIS in the organizations. The paper identifies the factors of HRIS as perceived by professional users. This study is also an attempt to study the impact of designation on identified factors of Human Resource Information System (HRIS). The results of this research will increase researchers comprehension on difference in factors that influence effectiveness of senior and middle-level professionals.

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