scholarly journals Computer Corner: Forester's Yield Curve Designer Software

1998 ◽  
Vol 15 (1) ◽  
pp. 23-27 ◽  
Author(s):  
David A. MacLean ◽  
Kevin B. Porter ◽  
Jeff Kerr
Keyword(s):  
Yield Curve ◽  
Growth Models ◽  
Management Plan ◽  
Free Software ◽  
Easy Access ◽  
Stand Growth ◽  
Data Formats ◽  
Volume Yield ◽  
Permanent Sample Plot ◽  
Development And Validation

Abstract The Forester's Yield Curve Designer(FYCD) software is aimed at helping forest management planners and field foresters in the development and validation of timber volume yield curves. It uses a mouse-driven graphical user interface that facilitates the import and display of results from stand growth models, the comparison of potential curves with permanent sample plot data, and the creation of new curves by drawing, adjusting, and combining curves. FYCD addresses the problem of getting management plan volume yield curve information out to field foresters for validation against available data and experience, and facilitating feedback from the forester to the planner. FYCD also increases the usability of valuable data from permanent and temporary sample plots by allowing easy access and display. This paper describes the primary functionality of FYCD, the data formats used, and how to obtain this free software from the Canadian Forest Service. North. J. Appl. For. 15(1):23-27.

Innovation Diffusion and New Product Growth Models in Marketing

1979 ◽  
Vol 43 (4) ◽  
pp. 55-68 ◽  
Author(s):  
Vijay Mahajan ◽  
Eitan Muller
Keyword(s):  
Innovation Diffusion ◽  
State Of The Art ◽  
Growth Models ◽  
New Product ◽  
Diffusion Models ◽  
The State ◽  
Development And Validation ◽  
Further Development

This paper assesses the state-of-the-art of the diffusion models of new product acceptance. A number of issues related to the further development and validation of these models are discussed.

scholarly journals The Application of Fractional Calculus in Chinese Economic Growth Models

Mathematics ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 665 ◽  
Author(s):  
Hao Ming ◽  
JinRong Wang ◽  
Michal Fečkan
Keyword(s):  
Fractional Order ◽  
Growth Models ◽  
Free Software ◽  
Statistical Computing ◽  
Order Model ◽  
Software Environment ◽  
R Software ◽  
Fractional Order Calculus ◽  
Economic Growth Models ◽  
Bic Criterion

In this paper, we apply Caputo-type fractional order calculus to simulate China’s gross domestic product (GDP) growth based on R software, which is a free software environment for statistical computing and graphics. Moreover, we compare the results for the fractional model with the integer order model. In addition, we show the importance of variables according to the BIC criterion. The study shows that Caputo fractional order calculus can produce a better model and perform more accurately in predicting the GDP values from 2012–2016.

It’s a Snap! An Inquiry-Based, Snapping Shrimp Bioacoustics Activity

2013 ◽  
Vol 75 (7) ◽  
pp. 470-475 ◽  
Author(s):  
Bradley K. Fox ◽  
Kelvin D. Gorospe ◽  
Roxanne D. Haverkort-Yeh ◽  
Malia Ana J. Rivera
Keyword(s):  
Experimental Data ◽  
Interdisciplinary Research ◽  
Scientific Inquiry ◽  
Animal Communication ◽  
Research Field ◽  
Free Software ◽  
Easy Access ◽  
Behavior Changes ◽  
Biology Teachers ◽  
Snapping Shrimp

This bioacoustics activity combines concepts in invertebrate taxonomy, animal communication, and acoustical physics while providing a unique opportunity for physics and biology teachers to collaborate and introduce their students to an exciting, interdisciplinary research field. Here, we propose a lab- and field-based activity that uses hydrophones to explore how shrimp snapping behavior changes in response to different stimuli and introduces students to the process of scientific inquiry. Using free software, students use spectrograms to visualize and analyze their experimental data. Furthermore, we propose potential modifications to the lab for classrooms without easy access to marine environments or snapping shrimp.

scholarly journals Forest Stand Growth Models: What For?

1985 ◽  
Vol 61 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Stephen J. Titus ◽  
Robert T. Morton
Keyword(s):  
Growth Models ◽  
Forest Stand ◽  
Growth And Yield ◽  
Effective Management ◽  
Management Planning ◽  
Computing Power ◽  
Stand Growth ◽  
The Future ◽  
Decision Making Processes ◽  
Growth And Yield Models

Until very recently foresters have relied on infrequent inventories to provide static descriptions of large forest areas for management planning. With the quantum increases in computing power, the massing of forestry data, and the increasing pressure for effective management planning, it is becoming necessary to view the forest as dynamic, and subject to manipulation for management purposes. Prediction of changes to forest structure and yield must be made to update old data and project stands into the future. This paper reviews the current sources of literature on growth and yield, discusses basic types and components of growth models, and gives some examples of important uses for growth and yield models. The future will see increased use of computers for analysis of forestry data including even more sophisticated growth and yield models linked to both inventory and decision making processes.

scholarly journals Pertumbuhan Riap Diameter Pohon Bakau Kurap (Rhizophora Mucronata) Di Lampung Mangrove Center

2016 ◽  
Vol 4 (3) ◽  
pp. 97 ◽  
Author(s):  
Robbi Angger Kesuma ◽  
Asihing Kustanti ◽  
Rudi Hilmanto
Keyword(s):  
Time Series ◽  
Key Words ◽  
Growth Models ◽  
Permanent Plots ◽  
Rhizophora Mucronata ◽  
Estimation Model ◽  
Control Block ◽  
Stand Growth ◽  
Diameter Increment ◽  
Increment Growth

Bakau kurap (R. mucronata) is a true mangrove.  The height of this mangrove could reach 27 m and rarely exceed 30 m.  The diameter trunk of this mangrove could reach 70 cm.  R. mucronata stands was found in Lampung Mangrove Center (LMC), it was located in Margasari Village district Labuhan Maringgai, East Lampung Regency.  The purposes of this study were to determine the diameter increment, growth models and stand growth past of R. mucronata at LMC.  The research was conducted on July to August 2015.  The method used measurement of diameter time series for three years (2013, 2014, and 2015) on circle form permanent plots with a radius 7 m of length are divided into three thinning blocks (A, B, and C). Block C was the control block or block that was not thinned and large thinning in blocks A and B, respectively 54.5% and 41.7%.  The results indicated that the biggest diameter increment of three block  at the age of 22nd years = 0.467 cm year-1. The estimation model of stand diameter (D) and diameter increment (MAI-d) based on the age of stand (X) could be formulated as follows: 1) Blok A D = 8,996 X0,021; MAI-d = 0,451 X0,035, 2) Blok B D = 8,215 X0,124; MAI-d = 0,412 X0,039, 3) Blok C D = 7,159 X0,074; MAI-d = 0,359 X(-0,012). Forecasting growth stands diameter R. mucronata age of 32nd years on the blocks A, B and C in a row were 10,280cm, 9,463cm, and 7,796cm while the diameter increment were 0,467cm, 0,430cm, and 0,354cm. Key words : Diameter increment, forecasting, Lampung Mangrove Center, Rhizophora mucronata

scholarly journals Stand growth model using volume increment/basal area ratios

2008 ◽  
Vol 54 (No. 3) ◽  
pp. 102-108 ◽  
Author(s):  
J. Martínez Pastur G ◽  
M. Cellini J ◽  
V. Lencinas M ◽  
L. Peri P
Keyword(s):  
Simple Model ◽  
Growth Models ◽  
Basal Area ◽  
Site Quality ◽  
Stand Age ◽  
Full Density ◽  
Nothofagus Pumilio ◽  
Stand Growth ◽  
Mean Error ◽  
Volume Increment

Estimation of stand growth is crucial for forest planning. Estimations were usually done using fixed values, and recently growth equations have been used. An alternative is through stand growth models. The objective was to develop a simple model for<I> Nothofagus pumilio</I> stands with full density along site quality and age gradients. The sample was obtained from 125 stands. Data on forest structure and samples for tree-ring measurement were taken in all trees to estimate growths using biometric models previously developed. The growth values of each plot during the last twenty years were calculated to fit the model, using the ratio of total volume increment/basal area as an independent variable. The developed model gives a ratio between stand volume increment and basal area (m/year) in relation to the site quality and stand age. The statistics (<I>r</I><sup>2</sup> = 0.819, mean error = 0.019, absolute mean error = 0.033), residual analysis and biological performance were satisfactory. The obtained stand growths varied between 1 and 20 m<sup>3</sup>/ha/year. This simple model allowed to estimate growth values at a stand level from easy field measurements from forest inventories.

Sensitivity of management planning model outcomes to yield curve inputs

2008 ◽  
Vol 84 (4) ◽  
pp. 575-581 ◽  
Author(s):  
Elizabeth McGarrigle ◽  
Evelyn W Richards ◽  
John A Kershaw Jr. ◽  
Thom A Erdle
Keyword(s):  
New Brunswick ◽  
Yield Curve ◽  
Growth Models ◽  
Average Yield ◽  
Yield Curves ◽  
Management Planning ◽  
Curve Type ◽  
Planning Models ◽  
Level Of Aggregation ◽  
Crown Lands

We investigated calendar- and age-based average yield curves used in management planning for Crown lands in New Brunswick. These yield curves are derived from the same data and growth models, but are averaged differently. We found that even-flow and non-declining harvest volumes generated by strategic planning models are sensitive to the yield curve type used as input. Strategic harvest volumes per five-year period varied as much as 30% when yield curve type used was changed. Key to this change was the coarsely aggregated stratification required by calendar-based yield curves. Level of aggregation affected whether model constraints could be met, and changed model outputs. Key words: strategic management planning, yield curves

scholarly journals Modelling the Sustainability of Forest Production and Yield for a Changing and Uncertain Future

1990 ◽  
Vol 66 (3) ◽  
pp. 271-280 ◽  
Author(s):  
J. P. Kimmins
Keyword(s):  
Forest Management ◽  
Management Practices ◽  
Environmental Changes ◽  
Growth Models ◽  
Forest Growth ◽  
Growth And Yield ◽  
Calibration Data ◽  
Stand Growth ◽  
The World ◽  
Ecosystem Level

The expected growth of the human population to about 11 billion sometime within the next rotation of most northern temperate forest crops will put greatly increased and varied demands on today's forested lands. Development of the timber resources on those lands that remain dedicated to timber production must be demonstrably sustainable if forest management is to help arrest rather than aggravate the continuing deterioration of the global environment, and if managed forests are to be a carbon sink rather than a carbon source with respect to the global "green-house effect". Unfortunately, the experience-based models traditionally used by foresters cannot make accurate predictions of future forest growth, yield, and carbon balance for the altered growing conditions that are expected to accompany this increase in human numbers. These tools are therefore unsuitable as a means of assessing the sustainability of site productivity under current or anticipated future forest management practices and the expected future soil, climate, and biotic conditions. It is time for foresters around the world to confront this issue and to develop and use more ecologically-sensitive, ecosystem-level stand growth and yield models.Knowledge-based, process-simulation stand growth models have many theoretical advantages, and are the only way of predicting future forest growth and carbon budgets on a particular site in the absence of accurate data on the past growth of forests on that site. However, such models have generally had significant practical limitations as an alternative to traditional forest yield models. They have either been too simple, or, if sufficiently complex, have had unacceptably large calibration data requirements, which has limited their portability. This has restricted most process-based simulation models to research and educational applications.An alternative approach which combines both the experience-based and the knowledge-based approaches offers a more practical alternative. The combination of "historical bioassay" and process-based modelling approaches into "hybrid simulation" stand models can provide a means by which to rank the most probable outcomes and the sustainability of alternative stand-level management strategies under a variety of possible future growing conditions.The accuracy of most forest management and forest economics models ultimately depends on the accuracy of stand-level growth models. As the world experiences increasing problems of air pollution (acid rain and the greenhouse effect), soil degradation, and deforestation, there is an urgent need for foresters to use ecosystem-level growth models that are sensitive to human-induced and naturally caused environmental changes. Use of such models is a necessary prerequisite to good stewardship of forest land and our legacy to future generations.

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