scholarly journals Economic optimization of the rotation age of stands

2016 ◽  
Vol 58 (4) ◽  
pp. 188-197 ◽  
Author(s):  
Lech Płotkowski ◽  
Stanisław Zając ◽  
Emilia Wysocka-Fijorek ◽  
Arkadiusz Gruchała ◽  
Jarosław Piekutin ◽  
...  
Keyword(s):  
Theoretical Background ◽  
Growth And Yield ◽  
Timber Production ◽  
Economic Optimization ◽  
Current Increase ◽  
Economic Relationships ◽  
Biological Growth ◽  
Total Inventory ◽  
Production Value ◽  
Rotation Age

Abstract The central task of this research was to choose the age at which stands of growing timber should be harvested. The choice governs how long each stand must continue to earn interest, and also governs the size of the total inventory that must be maintained to sustain the annual harvest. It is a problem that calls for analysis of biological as well as economic relationships over time, and has intrigued economists for more than two centuries. The paper presents the theoretical background and results of economic optimization of the rotation age of a single stand. It analyses the timber production function depending on rotation age, growth, cost and other characteristics of forest, as well as the costs of land. The prerequisite for achieving the economic optimum of the rotation age of a stand is to balance the current increase in the total timber production value (growth and yield) and the value of opportunity costs from delaying cutting till the next year. This paper demonstrates how this economically optimum rotation age can be calculated, and how it varies according to the biological growth and economic parameters of the forest.

scholarly journals Using the Wweibull function for prognosis of yield by diameter class in Eucalyptus urophylla stands

CERNE ◽  
2010 ◽  
Vol 16 (1) ◽  
pp. 94-104 ◽  
Author(s):  
Eder Pereira Miguel ◽  
Sebastião do Amaral Machado ◽  
Afonso Figueiredo Filho ◽  
Julio Eduardo Arce
Keyword(s):  
Wood Products ◽  
Growth And Yield ◽  
Coefficient Of Determination ◽  
Average Height ◽  
Eucalyptus Urophylla ◽  
Diameter Class ◽  
Percentile Method ◽  
Volumetric Model ◽  
Rotation Age ◽  
Stand Attributes

This study aimed to fit the Weibull probability density function to stand data so as to represent the distribution of number of trees by diameter class, and also to fit models representing stand attributes so as to project growth and yield by diameter class and also yield of multiple wood products at the relevant rotation age (7 years). Data were collected from Eucalyptus urophylla stands owned by Anglo Americana plc (CODEMIM), a company situated in the municipality of Niquelândia, Goiás state. Initially a 3P-Weibull probability function was fitted by the percentile method for the aggregate stand. Then models were fitted and selected of stand attributes using residuals plot, residual standard error (s yx) and coefficient of determination (R²) as selection criteria. The hypsometric model of Trorey was then used to derive the average height of possible diameter classes, and the taper model of degree 5 and volumetric model of Takata were used to check compatibility of generated volumes. Prognosticated results were consistent with local productivity when compared to previous inventories complied by the same company of stands within the same age group.

Measuring Wildfire Impacts: Method and Case Study

1987 ◽  
Vol 11 (3) ◽  
pp. 143-147
Author(s):  
W. L. Mills ◽  
S. D. Shnitzler ◽  
R. S. Meldahl
Keyword(s):  
Economic Impact ◽  
Cash Flow ◽  
Flow Model ◽  
Growth And Yield ◽  
Timber Production ◽  
Discounted Cash Flow ◽  
The Impact ◽  
Data Requirements

Abstract A discounted cash flow model called the Impact Appraisal Model (IAM) computes the economic impact due to a change in timber production caused by a wildfire. Data requirements for the IAM can be obtained using standard inventory procedures to estimate the pre- and post-fire stand conditionsneeded to initiate a growth and yield simulator. The model is demonstrated using five loblolly plantations that burned in 1980 and 1981. South. J. Appl. For. 11(3):143-147.

Croissance de sapinières à bouleau blanc boréales issues de coupe avec protection de la régénération

1992 ◽  
Vol 22 (11) ◽  
pp. 1701-1711 ◽  
Author(s):  
Lucie Bertrand ◽  
Louis Bélanger ◽  
Robert L. Beauregard
Keyword(s):  
Natural Regeneration ◽  
Basal Area ◽  
Balsam Fir ◽  
Growth And Yield ◽  
Permanent Plots ◽  
White Birch ◽  
Second Growth ◽  
Harvesting Method ◽  
Volume Production ◽  
Rotation Age

Models of compatible volume and basal area growth and yield covering a period of 10 to 45 years after harvesting were developed for second growth boreal stands of balsam fir (Abiesbalsamea (L.) Mill.). The 131 permanent plots used for the study were located near Matane, in the Gaspé Peninsula, and are part of the balsam fir–white birch ecoclimatic domain. These stands were harvested in 1934, 1944, and 1953, using a manual cut-and-bunch harvesting method that protected advance growth, and measures were taken in 1954, 1964, and 1978. The stands were moderately affected by spruce budworm outbreaks between 1950–1957 and 1975–1978. Years elapsed since release rather than total age was used as the temporal variable. Even though the characteristics of the coniferous natural regeneration were quite variable, total basal area explained an important part of growth variations of young fir stands by integrating both density and dimensions of the regeneration. Results show, within the limits of the observed densities (< 15 000 stems/ha, 10 years after harvesting), that stands with a higher basal area will have higher total and merchantable volumes at a given age; rotation age for maximum volume production will decrease correspondingly. Abundance of saplings in the initial natural regeneration can thus have an important impact on stand production and rotation age. In the case of nonoverdense young fir stands (< 15 000 stems/ha, 10 years after harvesting with no height growth impediment), the use of spacing treatments that significantly reduce total basal area could be questioned when pursuing maximum fiber production.

scholarly journals A Growth and Yield Model for Eucalyptus benthamii in the Southeastern United States

2019 ◽  
Author(s):  
Kevin B Hall ◽  
Jl Stape ◽  
Bronson P Bullock ◽  
Doug Frederick ◽  
Jeff Wright ◽  
...  
Keyword(s):  
United States ◽  
Cold Tolerance ◽  
Southeastern United States ◽  
Basal Area ◽  
Growth And Yield ◽  
Good Growth ◽  
Yield Model ◽  
Dominant Height ◽  
Growth And Yield Model ◽  
Rotation Age

Abstract In recent Eucalyptus cold-tolerance trials, E. benthamii has shown good growth rates as well as cold tolerance for USDA Plant Hardiness Zones 8 and 9. This study developed growth and yield models for E. benthamii in the southeastern United States. A network of 182 temporary sample plots of E. benthamii ranging in age from 1.5 to 13.3 years was established, and inventory data were collected. Site quality was determined by fitting a polymorphic site index curve, whereas a function for stand basal area based on age, dominant height, and site occupancy was fitted. Stand-level volume and dry-weight biomass prediction equations were fitted as a function of dominant height and basal area. Based on the growth and yield model results, mean annual increments ranged from 26.4 m3 ha–1 year–1 at rotation age 6 years on the best sites to 13.7 m3 ha–1 year–1 at rotation age 10 years on the poorest sites. This is the first published set of management-oriented models for land managers considering planting E. benthamii in the southeastern United States.

scholarly journals PROFITABILITY OF SUGAR BEET FOLIAR NUTRITION WITH SILICON

2019 ◽  
Vol XXI (1) ◽  
pp. 7-13 ◽  
Author(s):  
Arkadiusz Artyszak ◽  
Ewelina Klarzyńska ◽  
Magda Litwińczuk-Bis ◽  
Alicja Siuda
Keyword(s):  
Sugar Beet ◽  
Field Experiment ◽  
Foliar Application ◽  
Growth And Yield ◽  
Foliar Nutrition ◽  
Net Production ◽  
Growth Stimulator ◽  
Production Value ◽  
The Difference ◽  
Research Period

In the years 2015-2016 in Sahryń (50°41′ N, 23°47’ E) a field experiment, with the aim of assessing profitability of foliar nutrition of sugar beet with silicon, was carried out. The following products containing silicon were used in the experiment: Actisil, Herbagreen Z20 and Optysil. Each of them was applied once, twice and thrice. For each combination, the gross production value, the costs of foliar nutrition, the net production value and the profitability index were calculated. The total costs of silicon foliar application varied depending on the number of treatments and the applied product from 50 to 402 PLN/ha. The gross production value of sugar beet due to foliar nutrition with silicon increased by 1.3-22.9% for the research period, and the net production value by 5.5-19.0%. A large variation in the achieved financial results was observed in 2015, in which there were particularly unfavorable conditions for the growth and yield of sugar beet. In the more favorable year for growing sugar beet (2016), the difference was smaller. The largest increase in the gross and net production value of sugar beet was ensured by the double and triple application of Actisil fertilizer and the triple application of the Optysil growth stimulator. However, the largest profitability indicator (11.26) was characterized by a single Optysil growth stimulator application.

scholarly journals Modelling vegetation management treatments with the Tree and Stand Simulator

2008 ◽  
Vol 84 (1) ◽  
pp. 53-59 ◽  
Author(s):  
George J. Harper ◽  
Ken Polsson ◽  
Jim Goudie
Keyword(s):  
Pseudotsuga Menziesii ◽  
Vegetation Management ◽  
Growth And Yield ◽  
Picea Engelmannii ◽  
Annual Increment ◽  
Engelmann Spruce ◽  
Tree Survival ◽  
Treatment Data ◽  
Rotation Age ◽  
Mean Annual Increment

The Tree and Stand Simulator (TASS) has been used for over 20 years in British Columbia to generate yield tables for managed stands. In order to explore the impacts of weed control on site productivity we chose two vegetation management research trials where 10- to 15-year post-treatment data were available (Boston Bar and Mica research sites). Tree survival and height growth results were used to adjust the TASS input parameters to simulate the various brushing treatments. At the Boston Bar site, all vegetation reduction treatments shortened the Douglas-fir (Pseudotsuga menziesii var. glauca [Beissn.] Franco) physical rotation age by up to 10 years and culmination mean annual increment (cMAI) was increased 8% to 11% relative to the untreated control. At the Mica site, the glyphosate and all repeated manual cutting treatments resulted in a shortening of the Engelmann spruce (Picea engelmannii Parry) rotation age by seven years and increased cMAI by approximately 11% to12%. Key words: growth and yield modelling, vegetation management, Pseudotsuga menziesii, Picea engelmannii

Use of Prescribed Burning to Enhance Southern Pine Timber Production

1980 ◽  
Vol 4 (1) ◽  
pp. 15-18 ◽  
Author(s):  
A. Bigler Crow ◽  
Charles L. Shilling
Keyword(s):  
Environmental Effects ◽  
Prescribed Burning ◽  
Growth And Yield ◽  
Timber Production ◽  
Stand Development ◽  
Southern Pine ◽  
Development Control

Abstract Prescribed burning benefits pine timber production in many ways. It can facilitate regeneration and early stand development, control unwanted vegetation, reduce loss from certain diseases, thin overdense young stands, make working in an area easier and cheaper and, perhaps, encourage increased growth and yield. In most cases it enables the management objective to be achieved at reduced cost. As with any use of prescription fire, it must be carefully and skillfully applied to minimize loss and avoid adverse environmental effects.

scholarly journals Optimizing thinnings for timber production and carbon sequestration in planted teak (Tectona grandis L.f.) stands

2019 ◽  
Vol 28 (3) ◽  
pp. 3013
Author(s):  
María-Alejandra Quintero-Méndez ◽  
Mauricio Jerez-Rico
Keyword(s):  
Interest Rates ◽  
Net Present Value ◽  
Basal Area ◽  
Tectona Grandis ◽  
C Sequestration ◽  
Growth And Yield ◽  
Site Quality ◽  
Timber Production ◽  
Transport Costs ◽  
Yield Model

Aim of study: We developed an optimization model for determining thinning schedules in planted teak (Tectona grandis L.f.) stands that maximize the financial output in terms of soil expectation value (SEV) and net present value (NPV) considering a) the simultaneous optimization of timber production and carbon (C) sequestration and b) only for C sequestration.Area of study: Planted teak forests in the western alluvial plains of Venezuela.Material and methods: We integrated a stand growth and yield model with a constrained optimization model based on genetic algorithms (GA) for determining optimal thinning schedules (number, age, and removal intensity) that maximize SEV when simultaneously managing for timber production and C sequestration. The data came from permanent plots established in planted teak stands with remeasurements from 2 to 32 yr.-old. Plots differ in site quality, initial spacing, and thinning schedules. We obtained optimal thinning schedules for several scenarios combining site quality, initial spacing, interest rates, harvest and transport costs, as well as timber and C prices. The stand growth and yield model estimates timber products and C flows (storage and emissions) until most stored C is reemitted to the atmosphere.Main results: When considering simultaneously both, timber production and C sequestration, the scenario with the maximum SEV consisted of initial stand densities = 1,111 trees ha-1, site quality (SQ) I, harvest age 20 years, and four thinnings (ages 6, 10, 14, 17 with removal intensities 26 %, 28 %, 39 %, and 25 % of stand basal area respectively). For maximizing C sequestration only, the best schedule consisted of 1,600 trees ha-1, SQ I, harvest age 25 years, with no-thinning. A sensitivity analysis showed that optimal schedules and SEV were highly sensitive to changes in interest rates, growth rates, and timber prices.Research highlights:The management schedules favoring merchantable timber production are not the same that favor C sequestration.For planted teak, the objectives of maximizing timber production and carbon sequestration are in conflict because the thinning schedules that maximize financial gains from C sequestration reduce economic gains from timber and vice versa.With actual timber teak and market C prices, optimal NPVW is much larger than optimal NPVC.For C prices under 40 $US MgC optimizing simultaneously for timber production and C sequestration is the best option, as additional although sub-optimal revenues can be obtained from C payments.Lengthening the rotation, avoiding thinnings, or reducing their intensity increase carbon storage in planted teak, although, under the analyzed scenarios, after 120 yr. almost all carbon has been re-emitted to the atmosphere.Additional keywords: heuristics, genetic algorithms, operations research, forest management planning, stand level model, carbon stocks.Abbreviations used: C (Carbon); GA (genetic algorithm); NPVW, NPVC, NPVT (net present value from the cash flows of timber (wood), carbon, and total); SEV (Soil (land) expectation value); dbh (diameter at 1.3 m from the ground); G (stand basal area); Gp (potential site carrying capacity in terms of G); SQ (site quality); R (rotation, harvest age); A (age); I (thinning intensity); Vob, Vub (overbark, underbark volume); gr (basal area growth rate); r (interest rate); harvest and transport costs (Hc); Pc (C price). 

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