scholarly journals ARAUSIS: Sistema de simulação para manejo sustentável de florestas de Araucária

FLORESTA ◽  
1999 ◽  
Vol 29 (12) ◽  
Author(s):  
CARLOS ROBERTO SANQUETTA

Este artigo apresenta um modelo de simulação para o manejo sustentável de Florestas Naturais de Araucária. Para validar o modelo foram utilizados dados advindos de três parcelas permanentes de um hectare, instaladas em 1995 e remedidas anualmente, situadas na Estação Experimental de São João do Triunfo, Centro-Sul do estado do Paraná. Informações sobre taxas de recrutamento, crescimento em diâmetro e mortalidade foram empregadas para o estudo, considerando a população de árvores com DAP acima de 10 cm. O modelo de simulação fundamentou-se na metodologia de matriz de transição, a qual considera um vetor de freqüências por classe de DAP inicial., probabilidade de transição de uma classe para outra e mortalidade para cada classe de diâmetro. Dez classes foram empregadas no estudo, considerando duas populações distintas: todas as espécies em conjunto (floresta) e a araucária em separado. Simulações feitas com o modelo para avaliar efeitos de práticas de manejo na floresta. Os resultados obtidos na simulação, apesar de preliminares, indicaram que as práticas de manejo permitidas pelos órgãos ambientais precisam ser revistas. Cortes seletivos de baixa magnitude em pequenos fragmentos florestais, como os que são geralmente praticados e permitidos por lei, não favorecem a regeneração natural do pinheiro, a principal espécie dentro da estrutura da floresta. O simulador ARAUSIS, imitando o que ocorre na natureza, indicou que é necessária a existência de perturbações mais severas e abertura de grandes clareiras na floresta para promover a regeneração natural do pinheiro. ARAUSIS: simulation system for sustainable management of araucaria forests Abstract This article presents a simulation model for the sustainable management of Araucaria Natural Forests. To validate the model, data coming from three permanent plots of one hectare each were used. The plots were established in 1995 in the Experimental Station at São João do Triunfo, Paraná State, and have been remeasured annually since then to provide figures on recruitment rates, tree diameter growth and mortality for individuals over 10 cm DBH. The simulation model was based on the transition matrix method, which considers a vector of initial frequencies by DBH class, transition probabilities of a class for other, and mortality, as well. Ten classes were used in this study, considering two different populations: all the species together (forest) and araucaria in separate. Model simulations were carried out to evaluate effects of logging practices in the forest. The results from simulations, despite of being preliminary ones, indicated that the management practices allowed by the environmental official institution in Paraná need to be reviewed. Selective logging of low magnitude in small forest fragments, as those that are generally practiced and allowed by the law, do not favor the natural regeneration of araucaria, the main species occurring in the forest. ARAUSIS simulator, imitating what happens in the reality, indicated that is necessary the existence of more severe disturbances and large openings in the forest to promote the natural regeneration of araucaria.

2019 ◽  
Vol 48 (3) ◽  
pp. 417-425
Author(s):  
Md Khayrul Alam Bhuiyan ◽  
Md Akhter Hossain ◽  
Abdul Kadir Ibne Kamal ◽  
Mohammed Kamal Hossain ◽  
Mohammed Jashimuddin ◽  
...  

A study was conducted by using 5m × 5m sized 179 quadrates following multistage random sampling method for comparative regenerating tree species, quantitative structure, diversity, similarity and climate resilience in the degraded natural forests and plantations of Cox's Bazar North and South Forest Divisions. A total of 70 regenerating tree species were recorded representing maximum (47 species) from degraded natural forests followed by 43 species from 0.5 year 39 species from 1.5 year and 29 species from 2.5 year old plantations. Quantitative structure relating to ecological dominance indicated dominance of Acacia auriculiformis, Grewia nervosa and Lithocarpus elegans seedlings in the plantations whereas seedlings of Aporosa wallichii, Suregada multiflora and Grewia nervosa in degraded natural forests. The degraded natural forests possess higher natural regeneration potential as showed by different diversity indices. The dominance-based cluster analysis showed 2 major cluster of species under one of which multiple sub-clusters of species exists. Poor plant diversity and presence of regenerating exotic species in the plantations indicated poor climate resilience of forest ecosystem in terms of natural regeneration.


1999 ◽  
Vol 64 ◽  
Author(s):  
K. M. Tabari ◽  
N. Lust

Monitoring  of natural regeneration in a dense semi-natural mixed hardwood forest on the  base    of ash, beech, oak and sycamore occurred over 3 years in the Aelmoeseneie  experimental    forest, Belgium. 40 permanent plots (4 m x 5 m) were selected in three  various humus types,    located in an ash stand and in an oak - beech stand. In all plots abundance  and top height of all    broad leaved regenerated species were determined at the end of the growing  seasons 1995 and    1998. In addition, the seedlings which appeared in the plots during 1996  and 1997 were    identified and followed up.    This study proves that in the investigated sites natural regeneration is  drastically poor and    diversity is low, in particular where the humus layer is more acidic (mull  moder) and the litter    layer is thick. No regeneration phase older than the seedling stage (h <  40 cm) is developed on    the different humus types. On average, total number of seedlings in 1995  amounts to 38    units/are in the ash stand and to 63 units/are in the oak - beech stand.  Survival rate over a 3-    year period is 37% and 42% respectively in the ash and oak - beech stands.  Total ingrowth    during the growing seasons 1996 and 1997 is virtually poor, indicating 16  and 8 units/are    respectively in above mentioned stands. Survival rate of occurring  seedlings, as well as the ingrowth of new seedlings are notably different (P < 0.05) according to the soil conditions of the    ash stand. Generally, the low presence of seedlings and the lack of  regeneration older than the    seedling stage reveal that the regeneration development encounters with a  critical problem. The    continuation of this process would likely result in a progressive  succession by the invasive and    the unwanted tree species.


2017 ◽  
Vol 5 (2) ◽  
pp. 132-140 ◽  
Author(s):  
Kewat Sanjay Kumar ◽  

Mechanisms governing carbon stabilization in soils have received a great deal of attention in recent years due to their relevance in the global carbon cycle. Two thirds of the global terrestrial organic C stocks in ecosystems are stored in below ground components as terrestrial carbon pools in soils. Furthermore, mean residence time of soil organic carbon pools have slowest turnover rates in terrestrial ecosystems and thus there is vast potential to sequester atmospheric CO2 in soil ecosystems. Depending upon soil management practices it can be served as source or sink for atmospheric CO2. Sustainable management systems and practices such as conservation agriculture, agroforestry and application of biochar are emerging and promising tools for soil carbon sequestration. Increasing soil carbon storage in a system simultaneously improves the soil health by increase in infiltration rate, soil biota and fertility, nutrient cycling and decrease in soil erosion process, soil compaction and C emissions. Henceforth, it is vital to scientifically explore the mechanisms governing C flux in soils which is poorly understood in different ecosystems under anthropogenic interventions making soil as a potential sink for atmospheric CO2 to mitigate climate change. Henceforth, present paper aims to review basic mechanism governing carbon stabilization in soils and new practices and technological developments in agricultural and forest sciences for C sequestration in terrestrial soil ecosystems.


Author(s):  
Maximilian Axer ◽  
Sven Martens ◽  
Robert Schlicht ◽  
Sven Wagner

AbstractThe potential utilisation of natural regeneration of European beech (Fagus sylvatica L.) for forest conversion has received little attention to date. Ecological knowledge is necessary to understand and predict successful natural regeneration of beech. The objective of this study was to improve understanding of what drives the occurrence of beech regeneration and, once regeneration is present, what drives its density. In the study, we utilised a forest inventory dataset provided by Sachsenforst, the state forestry service of Saxony, Germany. The dataset was derived from 8725 permanent plots. Zero-altered negative binomial models (ZANB) with spatial random effects were used to analyse factors influencing occurrence and density simultaneously. The results provided by the spatial ZANB models revealed that the probability of the occurrence of beech regeneration is highly dependent on seed availability, i.e. dependent on source trees in close proximity to a plot. The probability of beech regeneration rises with the increasing diameter of a potential seed tree and decreases with increasing distance to the nearest potential seed source. The occurrence of regeneration is affected by overstorey composition and competition exerted by spruce regeneration. Where sites are affected by groundwater or temporary waterlogging, the impact on the occurrence of regeneration is negative. Although distance to the nearest potential seed source has an influence on occurrence, this variable exerts no influence on density. A high regeneration density arises in conjunction with a high beech basal area in the overstorey. Beech regeneration density, but not occurrence, is negatively affected by browsing intensity. These variables can be used to predict the occurrence and density of beech regeneration in space to a high level of precision. The established statistical tool can be used for decision-making when planning forest conversion using natural regeneration.


2019 ◽  
pp. 1-7

To understand how various factors influence phenological patterns like fruit production and the extent of phenological variability as survival strategy in different environments, fruit production of shea trees was studied in different agroclimatic zones (North Sudanian, South Sudanian and North Guinean) in Mali. Three sites were selected for this study and in each site; two stands (field and fallow) were concerned. For each stand, three “land use history or land management" i.e. new fields/fallows (1-5 years), medium (6-10 years) and old (10 years) were considered and permanent plots of 0.25 ha were established. 60 adult shea trees (DBH) ≥ 10 cm) were selected by site and monitored for fruit production assessment. The nested analysis of variance on the yield showed a significant site effect and significant effect of land use history within stand. However, stand effect within site was not significant. Factors like site and land management (land use history) appear to be determinant for fruit production of V. paradoxa. The site of Mperesso in the South Sudanian zone showed the highest fruit mean yield (11 kg/tree), significantly higher than the fruit mean yield observed at Daelan (7 kg/tree) in the North Sudanian zone and that observed at Nafégué (6 kg/tree) in the North Guinean zone. For field stand, old fields showed highest mean yield in all sites. For fallow stand, old fallows showed the lowest mean yield in most of cases. Different pattern was observed between field and fallow stands regarding the effect of land management. More fields are aged, more they influence positively fruit production whereas more fallows are aged, and more they influence negatively fruit production. This study highlighted the importance of land management practices and therefore, any domestication program to be successful should consider the potential effect of management practices.


2018 ◽  
Vol 19 (1) ◽  
pp. 163-171
Author(s):  
PRIJANTO PAMOENGKAS ◽  
ISKANDAR Z. SIREGAR ◽  
AJI NURALAM DWISUTONO

Pamoengkas P, Siregar IZ, Dwisutono AN. 2018. Stand structure and species composition of merbau in logged-over forest in Papua, Indonesia. Biodiversitas 19: 163-171. Single selective cutting is the most common form of timber extraction in natural forest in the tropics. Although, vast tracts natural forests are already logged-over, the effect of logging on the structure and species composition has been sparsely documented, especially for merbau (Intsia bijuga). Merbau is an excellent timber species and intensively harvested in Papua. The objective of this study was to analyze the structure and species composition of merbau in the several logged-over forests at different ages, i.e., 1, 5, 11, 16, 21 years old after selective logging and primary forest as the reference plot. The study was conducted in February 2016 at Sarmi District, Papua. The distributions of merbau in each plot varies but when they were compared with that in the primary forest that had reached 9.81%. Thus, the decrease of merbau trees in the plots of logged forest areas was not significant. Index of Diversity of all growth stages was high. In general, the number of merbau seedling regeneration in the study plots are above the average value standardized in Selective Cutting and Replanting System (TPTI) regulation. With regard to the condition of sapling regeneration, we concluded that selective logging might not provide enough growing space for regeneration of merbau. Providing appropriate growing space is one of the key factors to achieve adequate merbau natural regeneration.


2020 ◽  
Vol 12 (1) ◽  
pp. 412 ◽  
Author(s):  
Cloe X. Pérez-Valladares ◽  
Ana I. Moreno-Calles ◽  
Alejandro Casas ◽  
Selene Rangel-Landa ◽  
José Blancas ◽  
...  

Palm plants provide important benefits for rural communities around the world. Of the 95 native palm species in Mexico, Brahea dulcis (Soyate palm) has been tagged as an important resource for many Mesoamerican ethnical groups. Scientific and empirical knowledge concerning Soyate is thematically fragmented and disassociated, meaning that sound sustainable management is far from established. Research of over 20 years has permitted us to document ecological, cultural and geographical outcomes of B. dulcis; thus, the present paper aims at compiling all knowledge on Soyate to eventually guide its long-term management. It was conducted in two stages: firstly, it comprised a thorough review of previous studies on the management of B. dulcis in Mexico; secondly, we integrated unpublished outcomes obtained from fieldwork, including participatory ground-truth validation and semi-structured interviews obtained from local ethnic groups. Five factors guided our compilation effort: (i) biological and ecological information, (ii) cultural importance, (iii) economic triggers, (iv) traditional management, and (v) ecological and ecogeographical implications of Soyate palm management. The present paper confirms that B. dulcis is an important cultural resource whose utilization can be traced back over 10,000 years. The leaves of Soyate are the most useful part of the palm and were profusely used in the past for thatching roofs and weaving domestic and agricultural objects. Currently, however, palm-leaf weaving is primarily oriented toward satisfying economic needs. We depicted ten management practices aimed at favoring palm availability. Most of these management practices have enhanced sustainable palm leaf harvesting; however, these practices harbor spatial trends that turn highly diverse habitats into Soyate-dominated spaces. To conclude, we propose a framework to describe sound and sustainable Soyate management in the light of the current long-term Soyate–human relationship. It is here acknowledged that Soyate has played and continues to play a critical socioeconomic and cultural role for many ethnical groups in Central Mexico. Nonetheless, emerging challenges concerning the sustainability of the whole socioecological system at a landscape level are yet to be overcome.


1990 ◽  
Vol 14 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Donald G. Hodges ◽  
Frederick W. Cubbage

Abstract Private and public technical assistance foresters were surveyed in 12 southern states. Their management practices on southern forests are summarized by employment sector. Industrial foresters helped manage more acres per forester than consultants or state foresters. All foresters assisted more in planting trees than in preparing for natural regeneration. Industrial foresters favored clearcutting, consultants selective cuts, and state foresters a mix. Consultants performed much more natural regeneration than industrial or state foresters, who focused almost exclusively on artificial regeneration. Respondents also provided written opinion about current forest management and environmental issues, as well as suggestions for professional education. South. J. App. For. 14(1):44-48.


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