Business Feasibility of Intensive Vaname Shrimp (Litopenaeus vannamei) with Non-Partial System

Shrimp farming with a non-partial harvest system is a cultivation concept to obtain optimal production harvest. The purpose of this study was to determine the business feasibility status of vaname shrimp (L. vannamei) cultivation with a non-partial harvesting system in terms of the ecological and financial aspects from aquaculture. The research method used in this study is a survey research method with data collection techniques based on purposive sampling. The results showed, this non-partial system is ecologically very feasible, because the conditions of the average daily water quality parameter values (DO, pH, temperature, salinity) during the aquaculture period are still above the water quality standard threshold for intensive aquaculture. The business financial feasibility analysis resulted in a profit of IDR 441,307,102,-, BEP Unit 2,062 Kg, BEP Sales IDR 119,995,253,-, R/C of 1.71, Return on Investment of 47.69%, and Payback Period of 2.7 years. Meanwhile based on investment analysis, the Net Present Value of IDR 34,136,139,245,-, Net B/C 11.61, and Internal Rate of Return 37.23%. So, it can be denied, that based on ecological aspects and economic multiplication of aquaculture systems like this can be categorized as very feasible and profitable to be globally developed.

Partial Harvest in Paludified Black Spruce Stand: Short-Term Effects on Water Table and Variation in Stem Diameter

The boreal forest is considered to be a low productivity forest due to its cold climate and poorly drained soils promoting paludification. These factors create conditions favouring accumulation of undecomposed organic matter, which causes declining growth rates of forest stands, ultimately converting mature stands into peatlands. Under these conditions, careful logging is conducted during winter, which minimizes soil disturbance in northwestern Quebec boreal forest. This results in water table rise, increased light availability and paludification. Our main objective was to evaluate the short-term effect of partial harvesting as an alternative method to careful logging in winter to mitigate water table rise on black spruce (Picea mariana [Mill.] B.S.P.) stands. We quantified tree stem diameter variation and daily variation in water table depth in mature spruce stands before and after partial harvest (basal area reduction of 40%) and girdling (same basal area reduction with delayed mortality) during 2016 and 2017 growing seasons. Water table variation prior to and following silvicultural treatments did not differ one year after treatment. Daily stem diameter variation in black spruce did not differ between treatments and control. Furthermore, temperature exerted a positive effect on variation in water table and on stem diameter. These results suggest that partial harvest could be more effective than clearcutting to mitigate negative effects of a high water table while limiting paludification.

Development of Redwood Regeneration after Conifer Partial Harvest and Hardwood Management

Harvesting of commercial conifer species from conifer-hardwood mixtures can leave residual stands dominated by hardwoods. Removing unwanted hardwoods by cutting or herbicide makes growing space available to residual trees and regeneration and can restore conifer dominance. Forest managers of north coastal California need guidance on how such treatments affect subsequent growth of planted redwoods (Sequoia sempervirens [D. Don.] Endl.) or natural regeneration, as well as proliferation of undesirable species. Our observational study reconstructed growth of 108 regenerating redwoods in 26 treated stands. Residual stand density was the main driver of height and diameter growth in the new cohort of redwoods, irrespective of whether hardwoods were cut or received herbicide frill treatment (prevents resprouting). At lower residual stand densities, there were higher densities of natural regeneration (ingrowth) of conifers and hardwoods, which affected diameter at breast height (dbh) growth of regenerating redwoods. After heavier cutting of hardwoods, this ingrowth comprised a greater proportion of unwanted hardwood regeneration. Therefore, frill treatment is recommended when the objective of management is to reduce hardwood stocking and regeneration. Combining partial harvesting of conifers with cutting or frill treatment of hardwood is another option that reduces stand density to promote height and dbh growth of regenerating redwoods. Study Implications Redwood is a valuable commercial species in California Coast Range forests, but its regeneration often competes with unwanted hardwoods. The most influential solution is reducing stand density. Treatment choice is less influential, giving managers some flexibility. For example, stand density can be reduced by cutting a mix of conifers and hardwoods, or by herbicide frill treatment of hardwoods to release conifers, or some combination of these two treatments. After cutting, hardwoods resprout, leading to higher hardwood densities in the understory and slightly slower regeneration of redwood. Conversely, herbicide frill treatment promotes conifer dominance by removing hardwood trees and regeneration.

Forest Productivity Enhancement and Compensatory Growth: A Review and Synthesis

This review and synthesis article attempts to integrate observations from forestry to contemporary development in related biological research fields to explore the issue of forest productivity enhancement and its contributions in mitigating the wood supply shortage now facing the forest sector. Compensatory growth has been clearly demonstrated in the long-term precommercial thinning and fertilization trial near the Shawnigan Lake, British Columbia, Canada. This phenomenon appears similar to many observations from other biological fields. The concept of compensatory growth can be applied to forest productivity enhancement through overcompensation, by taking advantage of theories and methods developed in other compensatory growth research. Modeling technology provides an alternative approach in elucidating the mechanisms of overcompensation, which could reveal whether the Shawnigan Lake case could be generalized to other tree species and regions. A new mitigation strategy for dealing with issues related to wood supply shortage could be formed through searching for and creating conditions promoting overcompensation. A forest growth model that is state dependent could provide a way of investigating the effect of partial harvest on forest growth trajectories and stand dynamics. Results from such a study could provide cost-effective decision support tools to practitioners.

Growth and Graduation of Vannamei Shell Life (Litopenaeus Vannamei) with Feeding Tray (ANCO) System in AV 8 Lim Shrimp Organization (LSO) in Sumbawa District

Vannamei shrimp species look for lunch and dinner. These properties need to be known related to the amount of feed and frequency of feeding to be given. Because wasted feed is expensive and can reduce water quality, optimizing feeding practices is an important issue in shrimp culture management. The use of some ANCOs is intended to monitor feed consumption and estimate feed adjustments. So it is necessary to conduct research on the growth and graduation of vannamei shrimp (Litopenaeus Vannamei) with the feeding tray (ANCO) system in Av 8 Lim Shrimp Organization (LSO) in Sumbawa Regency. The method used in this research is descriptive method, namely research based on reality and the facts of the situation as it is. The results showed that the amount of feed every week or sampling is always different, this is because the amount of feed adjusted to the addition of shrimp growth every sampling. Addition and reduction of feeding is adjusted to the results of checking feed consumption on ANCO, adding the amount of feeding is done if when checking ANCO there is no feed left. Reduction in the number of gifts is done if when checking ANCO still left feed. In the 8th sampling the amount of feed decreased to 38 kg, this was due to the first partial harvest. In the 10th sampling is the lowest amount of feeding which is 30 kg, this is due to the second partial harvest, but in the 11th sampling the number of feeding again increased so that the shrimp could grow to its maximum potential during panentotal.

Modelling the Effects of Changes in Forest Cover and Climate on Hydrology of Headwater Catchments in South-Central Chile

This study analyses the changes in the runoff of forested experimental catchments in south-central Chile, to determine to what extent observed trends can be attributed to effects of intensive forestry and/or climate change. For this, we applied the distributed TETIS® model to eight catchments (7.1−413.6 ha) representative of the land uses and forestry activities in this geographical area. Rainfall and runoff data collected between 2008 and 2015 were used for modelling calibration and validation. Simulation of three land uses (current cover, partial harvest and native forest) and 25 combinations of climatic scenarios (percentage increases or decreases of up to 20% of rainfall and evapotranspiration relative to the no-change scenario applied to input series) were used in each calibration. We found that changes in land use and climate had contrasting effects on runoff. Smaller catchments affected by the driest climatic scenarios experienced higher runoff when the forest cover was lower than under full forest cover (plantations or native forests). In contrast, larger catchments under all climatic scenarios yielded higher runoff below the full forest cover than under partial harvest and native forest. This suggests that runoff can be influenced, to a great extent, by rainfall decrease and evapotranspiration increase, with the model predicting up to a 60% decrease in runoff yield for the dry’s climatic scenario. This study proves to be relevant to inform ongoing discussions related to forest management in Chile, and is intended to minimize the impact of forest cover on runoff yield under uncertain climatic scenarios.

Manajemen Pakan dan Analisis Usaha Budidaya Udang Vaname (Litopanaeus vannamei ) pada Lokasi yang Berbeda di Kabupaten Bangkalan dan Kabupaten Sidoarjo

Asian white shrimp or can be called vannamei shrimp has the Latin name Litopenaeus vannamei has native habitat in coastal waters and American sea waters. This research was carried out in September 2018 in the Asian white shrimp farming business unit Tanjung Putih Village Sepulu District Bangkalan District and in Penatar Sewu Village Tanggulangin District Sidoarjo Regency. This study population used 3 pond plots in Asian white shrimp culture in Tanjung Putih Village, Sepulu District, Bangkalan District and in Penatar Sewu Village Tanggulangin District Sidoarjo Regency. Sample size is determined from the amount of shrimp fry capacity stocked. The sampling technique was carried out by researchers by following activities in the field, census and visiting respondents directly on the farm or in the farmer's group home to obtain the information and data needed. The results showed that the best feed management was obtained the best results on the 4 sample ponds in Sidoarjo with an average final weight growth rate of 9.73 grams at the first partial harvest, 83% Feed Efficiency, and a 90% survival rate. As for the lowest feed management results obtained in sample ponds 1 Bangkalan with a yield of 6.98% growth, feed efficiency by 71% and survival rate of 86%. As for the results of the analysis of vannamei shrimp aquaculture business at different locations in Bangkalan and Sidoarjo districts, it was concluded that the best Production BEP was obtained in Sidoarjo's 4 sample ponds, amounting to 1427 kg. The best R / C ratio and Payback period is the average sample obtained in Sidoarjo. The conclusion of the best feed management and business analysis results is on the sidoajo sample ponds, the sidoarjo sample shows decent and efficient results.

Importance of considering the growth response after partial harvesting and economic risk of discounted net revenues when optimizing uneven-aged forest management

Because of the very high complexity of modern optimization models based on single trees, uncertainties are often disregarded. In this study, we present a modelling approach that allows partial harvesting but is still simple enough to consider risk. Our modelling approach investigates whether the inclusion of timber price uncertainty influences the harvesting schedule. The model considers positive growth response to the density reduction that follows harvesting. Testing the impact of uncertainty, we define the discounted net revenues of each harvest operation as random variables. We compare harvest scheduling both with and without the inclusion of uncertainty. We first model growth response based on a partial-harvest schedule, without integrating uncertainty from timber price fluctuations. The results show that harvesting tree cohorts at different times is financially optimal. We run the same model again, including the risk of timber price fluctuations. The inclusion of risk leads to slightly greater differences in recommended harvest timings. Because of the small difference observed, we conclude that it is unlikely that risk arising from fluctuating timber prices would strongly affect the results for more complex forest economic models concerning the optimal harvest schedules.