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 ◽  
...  

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.

2018 ◽  
Vol 34 (6) ◽  
pp. 364-377 ◽  
Author(s):  
Sarai Sánchez-Silva ◽  
Bernardus H.J. De Jong ◽  
Deb R. Aryal ◽  
Esperanza Huerta-Lwanga ◽  
Jorge Mendoza-Vega

Abstract:Trends in structural and chemical leaf traits along a chronosequence of semi-evergreen tropical forest and their correlation with litter production and decomposition and associated carbon (C) and nitrogen (N) fluxes were assessed. Leaves of 15 dominant species in each plot were collected to measure leaf area, specific leaf area (SLA), C and N concentration and C:N ratio. Litterfall was measured and litter decomposition experiments were set up in 16 experimental plots in a chronosequence of secondary and mature forest. All five leaf traits combined discriminated the secondary forests from mature forest. SLA, N and C:N were significantly correlated to litter decomposition rates. Litter decomposition was significantly slower in mature forest compared with secondary forests. The N concentration of litter was lowest during the dry season, when litterfall was highest. N concentration in fresh leaves was higher than in litter, indicating that N is re-absorbed before leaf abscission. Leaf dynamics and associated nutrient cycling differ significantly between secondary forests and mature forest. Ecosystem-level leaf structural and chemical traits are good predictors of the stage of the forest and explain well the differences in decomposition rates between secondary and primary forests.


Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 720 ◽  
Author(s):  
Tian Zhang ◽  
Xibin Dong ◽  
Huiwen Guan ◽  
Yuan Meng ◽  
Jiafu Ruan ◽  
...  

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.


Human Ecology ◽  
2021 ◽  
Author(s):  
Adam Pain ◽  
Kristina Marquardt ◽  
Dil Khatri

AbstractWe provide an analytical contrast of the dynamics of secondary forest regeneration in Nepal and Peru framed by a set of common themes: land access, boundaries, territories, and rights, seemingly more secure in Nepal than Peru; processes of agrarian change and their consequences for forest-agriculture interactions and the role of secondary forest in the landscape, more marked in Peru, where San Martín is experiencing apparent agricultural intensification, than in Nepal; and finally processes of social differentiation that have consequences for different social groups, livelihood construction and their engagement with trees, common to both countries. These themes address the broader issue of the necessary conditions for secondary forest regeneration and the extent to which the rights and livelihood benefits of those actively managing it are secured.


2021 ◽  
Author(s):  
Shanshan Song ◽  
Xiaokang Hu ◽  
Jiangling Zhu ◽  
Tianli Zheng ◽  
Fan Zhang ◽  
...  

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 817
Author(s):  
Marina Palmero-Iniesta ◽  
Josep Maria Espelta ◽  
Mario Padial-Iglesias ◽  
Òscar Gonzàlez-Guerrero ◽  
Lluís Pesquer ◽  
...  

Farmland abandonment has been a widespread land-use change in the Iberian Peninsula since the second half of the 20th century, leading to the establishment of secondary forests across the region. In this study, we aimed to address changes in the recent (1985–2014) emergence patterns of these forests and examine how environmental factors affected their growth by considering differences in leaf-habit types. We used a combination of Landsat-derived land-cover maps and aboveground biomass (AGB) maps from the European Space Agency to assess the secondary forest establishment and growth, respectively, in the study region. We also obtained a set of topographic, climatic and landscape variables from diverse GIS layers and used them for determining changes over time in the environmental drivers of forest establishment and AGB using general linear models. The results highlight that secondary forest cover was still increasing in the Iberian Peninsula at a rate above the European average. Yet, they also indicate a directional change in the emergence of secondary forests towards lower and less steep regions with higher water availability (mean rainfall and SPEI) and less forest cover but are subjected to greater drought events. In addition, these environmental factors differentially affect the growth of forests with different leaf-habit types: i.e., needleleaf secondary forests being less favoured by high temperature and precipitation, and broadleaf deciduous forests being most negatively affected by drought. Finally, these spatial patterns of forest emergence and the contrasting responses of forest leaf-habits to environmental factors explained the major development of broadleaf evergreen compared to broadleaf deciduous forests and, especially, needleleaf secondary forests. These results will improve the knowledge of forest dynamics that have occurred in the Iberian Peninsula in recent decades and provide an essential tool for understanding the potential effects of climate warming on secondary forest growth.


2020 ◽  
Vol 3 (1) ◽  
pp. 25
Author(s):  
David Candel-Pérez ◽  
J. Bosco Imbert ◽  
Maitane Unzu ◽  
Juan A. Blanco

The promotion of mixed forests represents an adaptation strategy in forest management to cope with climate change. The mixing of tree species with complementary ecological traits may modify forest functioning regarding productivity, stability, or resilience against disturbances. Litter decomposition is an important process for global carbon and nutrient cycles in terrestrial ecosystems, also affecting the functionality and sustainability of forests. Decomposition of mixed-leaf litters has become an active research area because it mimics the natural state of leaf litters in most forests. Thus, it is important to understand the factors controlling decomposition rates and nutrient cycles in mixed stands. In this study, we conducted a litter decomposition experiment in a Scots pine and European beech mixed forest in the province of Navarre (north of Spain). The effects of forest management (i.e., different thinning intensities), leaf litter types, and tree canopy on mass loss and chemical composition in such decomposing litter were analysed over a period of three years. Higher decomposition rates were observed in leaf litter mixtures, suggesting the existence of positive synergies between both pine and beech litter types. Moreover, a decomposition process was favoured under mixed-tree canopy patches. Regarding thinning treatments significant differences on decomposition rates disappeared at the end of the study period. Time influenced the nutrient concentration after the leaf litter incubation, with significant differences in the chemical composition between the different types of leaf litter. Higher Ca and Mg concentrations were found in beech litter types than in pine ones. An increase in certain nutrients throughout the decomposition process was observed due to immobilization by microorganisms (e.g., Mg in all leaf litter types, K only in beech leaves, P in thinned plots and under mixed canopy). Evaluating the overall response in mixed-leaf litters and the contribution of single species is necessary for understanding the litter decomposition and nutrient processes in mixed-forest ecosystems.


2002 ◽  
Vol 46 (1) ◽  
Author(s):  
Dietrich Schmidt-Vogt

AbstractManagement of secondary tropical forests: a new perspective for sustainable use of forests in Asia. The decline of primary forests in the tropics is leading to a reassessment of the role secondary forests might play within the context of tropical forest management. Recent research has shown that secondary forests in the tropics can be both rich in species and complex in terms of stand structure. There is, moreover, a growing recognition of the importance of secondary forests for traditional subsistence economies in the tropics and of their economic potential for land use systems in the future. Management of secondary forests in Asia as an alternative to the extraction of timber from primary forests but also as one among other options to intensify traditional land use systems has a potential for the future especially because of the existence of vast tracts of valuable secondary forest cover, and because of the store of traditional knowledge that can still be found in tropical Asia.


2009 ◽  
Vol 69 (3) ◽  
pp. 795-804 ◽  
Author(s):  
JAL. Pontes ◽  
RC. Pontes ◽  
CFD. Rocha

We studied and compared parameters of the snake community of the Serra do Mendanha, Rio de Janeiro State, southeastern Brazil (22º 48'-22º 51' S and 43º 31'-43º 28' W), such as: abundance distribution, richness, species diversity and biomass, between forested areas, areas under regeneration and agriculture areas (banana plantations); to obtain information about the natural history and facilitate the development of future research. For capturing the snakes we used: pitfall traps, drift-fences and visual search (diurnal and nocturnal) along four transects for each habitat. The captured snakes were measured with a tape and caliper, weighed with dynamometers and sexed with the use of a catheter. The animals marked (with ventral scales cut) were released for posterior recapture. One individual per species was fixed and deposited at the Museu Nacional, Rio de Janeiro. We undertook an effort of 840 man/hour, and captured a total of 207 snakes belonging to 25 species (Colubridae 80.2%, Elapidae 12.6%, Viperidae 6.3% and Boidae 0.9%). The most abundant were: Liophis miliaris (n = 33), Micrurus corallinus and Chironius fuscus (both with n = 26); the least abundant: Elapomorphus quinquelineatus, Siphlophis compressus and Tropidodryas serra (all with n = 1). The species that contributed the greatest biomass were Spilotes pullatus (7,925 g), Chironius laevicollis (4,694 g), Liophis miliaris (3,675 g) and Pseustes sulphureus (3,050 g); those that contributed the lowest biomass were: Siphlophis compressus, Tropidodryas serra (both with 4 g) and Elapomorphus quinquelineatus (3 g). We found significant differences between the sampled habitats at the Serra do Mendanha (undisturbed forest, secondary forest and banana plantations). The results showed that a great reduction in the abundance, richness, diversity and biomass of the snakes occurs when the native forest is replaced by banana plantations.


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