Optimization of irregular-grid cellular automata and application in risk management of wind damage in forest planning

2010 ◽  
Vol 40 (6) ◽  
pp. 1064-1075 ◽  
Author(s):  
Hongcheng Zeng ◽  
Timo Pukkala ◽  
Heli Peltola ◽  
Seppo Kellomäki
Keyword(s):  
Cellular Automata ◽  
Damage Model ◽  
Timber Harvesting ◽  
Forest Growth ◽  
Wind Damage ◽  
Growth And Yield ◽  
Planning Problem ◽  
Risk Minimization ◽  
Yield Model ◽  
Forest Management Planning

This study demonstrated how cellular automata, using irregular grids, can be used to minimize the risk of wind damage in forest management planning. The development of a forest in central Finland was simulated for a 30-year period with three subplanning periods. A forest growth and yield model in association with a mechanistic wind damage model was applied to simulate forest growth and to calculate the length of stand edges at risk. Irregular cellular automata were utilized to optimize the harvest schedules for reducing the risk and maintaining a sustainable harvest level. The cellular automata produced rational results, i.e., new clearcuts were often placed next to open gaps, thereby, reducing the amount of vulnerable stand edges. The algorithms of the cellular automata rapidly converged and optimized the harvest schedules in an efficient way, especially when risk minimization was the only objective. In a planning problem that included even-flow timber harvesting objectives (harvest level equal to the total timber growth), the targets were almost achieved. Although the cellular automaton had slightly larger deviations of harvesting from the targets compared with other tested heuristic approaches (simulated annealing, tabu search, and genetic algorithms), it had the best performance when minimizing the expected wind damage.

scholarly journals Stand-Level Components of a Growth and Yield Model for Nothofagus Mixed Forests from Southern Chile

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 810
Author(s):  
Sebastian Palmas ◽  
Paulo C. Moreno ◽  
Wendel P. Cropper ◽  
Alicia Ortega ◽  
Salvador A. Gezan
Keyword(s):  
Forest Type ◽  
Geographical Area ◽  
Basal Area ◽  
Forest Growth ◽  
Model Systems ◽  
Growth And Yield ◽  
Permanent Plots ◽  
Stand Age ◽  
Yield Model ◽  
Mixed Forests

Reliable information on stand dynamics and development is needed to improve management decisions on mixed forests, and essential tools for this purpose are forest growth and yield (G&Y) models. In this study, stand-level G&Y models were built for cohorts within the natural mixed second-growth Nothofagus-dominated forests in Chile. All currently available (but limited) data, consisting of a series of stratified temporary and permanent plots established in the complete range of this forest type, were used to fit and validate these models. Linear and nonlinear models were considered, where dominant stand age, number of trees, and the proportion of basal area of Nothofagus species resulted in significant predictors to project future values of stand basal area for the different cohorts (with R2 > 0.51 for the validation datasets). Mortality was successfully modeled (R2 = 0.79), based on a small set of permanent plots, using the concept of self-thinning with a proposed model defined by the idea that, as stands get closer to a maximum density, they experience higher levels of mortality. The evaluation of these models indicated that they adequately represent the current understanding of dynamics of basal area and mortality of Nothofagus and companion species in these forests. These are the first models fitted over a large geographical area that consider the dynamics of these mixed forests. It is suggested that the proposed models should constitute the main components of future implementations of G&Y model systems.

A simple growth and yield model for assessing changes in standing volume across Canada’s forests

2009 ◽  
Vol 85 (1) ◽  
pp. 57-64 ◽  
Author(s):  
C -H. Ung ◽  
P Y Bernier ◽  
X J Guo ◽  
M -C. Lambert
Keyword(s):  
Predictive Power ◽  
Robust Regression ◽  
Forest Growth ◽  
Growth Potential ◽  
Growth And Yield ◽  
Stand Age ◽  
Yield Model ◽  
Wood Volume ◽  
National Model ◽  
Growth And Yield Models

We have adjusted two growth and yield models to temporary sample plots from across Canada, and used climate variables in lieu of phytometric indices such as site index to represent, in part, the site-level variability in growth potential. Comparison of predicted increments in plot-level height, basal area and merchantable wood volume to increments of these variables measured in permanent sample plots shows a moderate to poor predictive ability. Comparison with the performance of four operational growth and yield models from different provinces across Canada shows comparable predictive power of this new model versus that of the provincial models. Based on these results, we suggest that the simplification of regional growth and yield models may be achieved without further loss of predictive power, and that the large error in the prediction of growth increment is mostly associated with the use of temporary sample plots which, by definition, contain little information on stand dynamics. We also suggest that, because of the empirical nature of these growth and yield models, the scale of application should determine the appropriate scale of the model. National estimates of forest growth are therefore less likely to be biased if obtained from a national model only than if obtained from a combination of regional models, where those exist, gap-filled with estimates from a national model. Key words: yield model, merchantable wood volume, stand age, climatic variables, simultaneous regression, robust regression

Growth and yield of tropical moist forest for forest planning: an inquiry through modeling

2003 ◽  
Vol 33 (3) ◽  
pp. 521-535 ◽  
Author(s):  
R Glauner ◽  
T Ditzer ◽  
A Huth
Keyword(s):  
Timber Harvesting ◽  
Forest Growth ◽  
Growth And Yield ◽  
Forest Reserve ◽  
Dipterocarp Forest ◽  
Management Standards ◽  
Moist Forest ◽  
Undisturbed Forest ◽  
Lowland Dipterocarp Forest ◽  
Diameter Outside Bark

For the forest growth and yield calculations presented here, the process-based model FORMIX was applied in combination with a geographic information system. The study was carried out for the 55 084 ha of the Deramakot Forest Reserve, which consists of heavily logged and degraded lowland dipterocarp forest. FORMIX was used to assess forest development with and without timber harvesting. Three scenarios were compared: undisturbed forest growth and two reduced-impact timber harvesting scenarios ("textbook" and "borderline"). The latter differ in the number of seed trees retained after harvesting. The simulations reveal that timber harvesting is feasible, although stands are presently degraded. Achievable harvesting levels differ widely from 200 to 10 000 m3·year–1 for the next 40 years for the textbook and borderline scenario, respectively. A future increase up to 80 000 m3·year–1 is possible if all silvicultural and management standards are strictly observed. An analysis of stand development reveals that the portion of commercial dipterocarps decreases with time, while the portion of pioneer and understorey species increases. Future stands do not contain as many trees >60 cm DBH (diameter outside bark at 1.3 m height above ground), whereas they contain more trees in lower diameter classes, ensuring adequate potential for future harvests.

Hotchkiss River Mixedwood Timber Harvesting Study

1999 ◽  
Vol 75 (3) ◽  
pp. 435-438 ◽  
Author(s):  
D. A. MacIsaac ◽  
S. Lux ◽  
D. Sidders ◽  
I. Edwards
Keyword(s):  
Technology Transfer ◽  
Populus Tremuloides ◽  
Forest Products ◽  
White Spruce ◽  
Timber Harvesting ◽  
Forest Service ◽  
Wind Damage ◽  
Growth And Yield ◽  
Research Network ◽  
Ecosystem Research

The Hotchkiss River Mixedwood Timber Harvesting Study is a cooperative project involving Canadian Forest Service, Daishowa-Marubeni International Ltd., Manning Diversified Forest Products Ltd., the Forest Engineering Research Institute of Canada and Alberta Land and Forest Service aimed at developing new approaches to natural regeneration and harvesting systems for western Canada's boreal mixedwood forests, at a site near the Hotchkiss River in northwestern Alberta. The study used conventional harvesting equipment to test eleven harvesting and silvicultural systems designed to protect and minimize wind damage to immature white spruce residuals and encourage vigorous hardwood regeneration following harvest of the aspen overstory. Research areas include wind damage, wind firmness and growth response of the immature white spruce, effects of harvesting disturbance and timing on soil properties, conifer and hardwood regeneration after harvest, efficiency of equipment and harvesting costs, modelling of wind flow and long-term growth and yield. Already in its sixth year, the project has a planned 20year series of harvests and surveys. Technology transfer is an important component of this study for delivery and promotion of research results on behalf of the proponents and all related research collaborators. Products include demonstration maps and field guides, self-guided tour trails with interpretive signage and field tours (including active operations) as required. Hotchkiss River has also been designated a Forest Ecosystem Research Network (FERN) site. Key words: silviculture systems, white spruce, Picea glauca, aspen, Populus tremuloides, understory protection, harvesting, Alberta, boreal mixedwoods, technology transfer

Variance propagation in growth and yield projections

1986 ◽  
Vol 16 (6) ◽  
pp. 1196-1200 ◽  
Author(s):  
H. T. Mowrer ◽  
W. E. Frayer
Keyword(s):  
Forest Growth ◽  
Growth And Yield ◽  
Yield Model ◽  
Estimation Errors ◽  
Bias Assessment ◽  
Substantial Error ◽  
Growth And Yield Model ◽  
Growth Projection ◽  
Variance Estimates ◽  
Assessment Procedures

This paper reports the results of a study on the propagated variance associated with stand estimates in a forest growth and yield model. A cumulative variance as a result of input measurement and regression estimation errors is propagated in a growth and yield model using the method of statistical differentials. To provide an assessment of relative performance, these variance estimates are compared with a Monte Carlo simulation estimate of propagated error for increasing levels of sampling intensity. The method of statistical differentials is used to estimate the propagated variance through five 10-year growth projections. The results indicate growth projection estimates may have substantial error components that are not readily apparent from model calibration statistics or bias assessment procedures.

Accounting for climate change in a forest planning stochastic optimization model

2016 ◽  
Vol 46 (9) ◽  
pp. 1111-1121 ◽  
Author(s):  
Jordi Garcia-Gonzalo ◽  
Cristóbal Pais ◽  
Joanna Bachmatiuk ◽  
Andrés Weintraub
Keyword(s):  
Climate Change ◽  
Forest Harvesting ◽  
Forest Growth ◽  
Growth And Yield ◽  
Forest Planning ◽  
Planning Problem ◽  
Climate Scenarios ◽  
Present Value ◽  
Eucalyptus Forest ◽  
Climate Change Uncertainty

An approach is proposed for incorporating the variations in timber growth and yield due to climate change uncertainty into the forest harvesting decision process. A range of possible climate scenarios are transformed by a forest growth and yield model into tree growth scenarios, which in turn are integrated into a multistage stochastic model that determines the timber cut in each future period so as to maximize net present value over the planning horizon. For comparison purposes, a deterministic model using a single average climate scenario is also developed. The performance of the deterministic and stochastic formulations are tested in a case study of a medium-term forest planning problem for a Eucalyptus forest in Portugal where climate change is expected to severely impact production in the coming years. Experiments conducted using 32 climate scenarios demonstrate the stochastic model’s superior results in terms of present value, particularly in cases of relatively high minimum timber demand. The model should therefore be useful in supporting forest planners’ decisions under climate uncertainty.

scholarly journals Validation of empirical yield curves for natural-origin stands in boreal Ontario

2008 ◽  
Vol 84 (5) ◽  
pp. 704-717 ◽  
Author(s):  
Margaret Penner ◽  
Murray Woods ◽  
John Parton ◽  
Al Stinson
Keyword(s):  
Yield Curve ◽  
Growth And Yield ◽  
Research Partnership ◽  
Yield Model ◽  
Yield Curves ◽  
Wood Supply ◽  
Permanent Sample Plots ◽  
Forest Management Planning ◽  
Forestry Research ◽  
Initial Work

In Ontario, yield tables for forest management planning have remained relatively unchanged since initial work in the 1950s that was based on a limited number of temporary sample plots. In 2000, the Forestry Research Partnership accelerated work on the Benchmark Yield Curve Project (initiated several years earlier by the Ontario Ministry of Natural Resources, OMNR) to update these tables. The resulting yield curves incorporated data from more than 3000 permanent sample plots (PSPs) maintained in Ontario as well as PSPs from neighbouring and ecologically similar jurisdictions. Two stratifications were considered: OMNR’s Northeast Region standard forest units and leading species. The 10 forest units considered cover the major commercial species in the boreal forest in Ontario. Equations were fit to the data to predict the growth and yield by stratum. The equations were validated against independently collected data and compared to predictions from the current wood supply yield curves in Ontario: Plonski’s yield tables, modified Plonski, and northeast regional curves. Results of the validation showed that, with the exception of the MW2 and SF1 forest units, the new yield curves generally had less bias for gross total volume than Plonski and modified Plonski. Results for net merchantable volume were consistent with those for gross merchantable volume. The MW2 and SF1 forest units are more mixed in terms of species type, species light tolerance, and age. A leading species approach resulted in better predictions and is recommended for these forest units. Key words: wood supply, benchmark yield curves, mixedwood yield, yield model, Forestry Research Partnership

Biomass and productivity of the woody strata of forested bogs in northern Minnesota

1985 ◽  
Vol 63 (12) ◽  
pp. 2416-2424 ◽  
Author(s):  
D. F. Grigal ◽  
C. G. Buttleman ◽  
L. K. Kernik
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Nutrient Status ◽  
Forest Growth ◽  
Growth And Yield ◽  
Aboveground Net Primary Productivity ◽  
Yield Model ◽  
Raised Bogs ◽  
Aboveground Productivity ◽  
Aboveground Production

Biomass and net primary productivity of three forested perched and three forested raised ombrotrophic bogs were determined and compared. The tree stratum was dominated by Picea mariana (Mill.) B.S.P. and the low shrub stratum by Ledum groenlandicum Oeder and Chamaedaphne calyculata (L.) Moench. Based on a modified forest growth and yield model (STEMS), aboveground living biomass of the tree stratum on the perched bogs was declining by about 0.5 t ha−1 year−1 from a base of 100.7 t ha−1, and on the raised bogs it was increasing by 0.2 t ha−1 year−1 on a base of 31.0 t ha−1. Net primary productivity of that stratum was 3.1 and l.0 t ha−1 year−1 on the perched and raised bogs, respectively. Low shrub aboveground productivity, equal to mortality, was 0.4 and 2.0 t ha−1 year−1 on the perched and raised bogs, respectively. This was about 40% of the standing biomass of shrubs in both bog types. Aboveground net primary productivity of woody strata was 3.5 and 3.0 t ha−1 year−1 on the perched and raised bogs, respectively. These data are comparable to earlier estimates of Sphagnum production on the same bogs: 3.8 t ha−1 year−1 on perched bogs and 3.2 t ha−1 year−1 on raised bogs. Vascular herbs contributed an additional 0.2 t ha−1 year−1 to aboveground production on the perched bogs and 0.1 t ha−1 year−1 on the raised bogs. The higher productivity of perched bogs is probably related to slightly higher nutrient status related to their landscape position. The total productivity of all strata of these ombrotrophic sites approaches that of upland sites in the same region.

A Blind Spot in the Use of the Weibull Function for Modeling Diameter Distributions

2020 ◽  
Author(s):  
Adrian Norman Goodwin
Keyword(s):  
Lower Bound ◽  
Blind Spot ◽  
Forest Growth ◽  
Growth And Yield ◽  
Diameter Distribution ◽  
Absolute Difference ◽  
Weibull Function ◽  
Distribution Models ◽  
Difference Statistic ◽  
Diameter Distributions

Abstract Diameter distribution models based on probability density functions are integral to many forest growth and yield systems, where they are used to estimate product volumes within diameter classes. The three-parameter Weibull function with a constrained nonnegative lower bound is commonly used because of its flexibility and ease of fitting. This study compared Weibull and reverse Weibull functions with and without a lower bound constraint and left-hand truncation, across three large unthinned plantation cohorts in which 81% of plots had negatively skewed diameter distributions. Near-optimal lower bounds for the unconstrained Weibull function were negative for negatively skewed data, and the left-truncated Weibull using these bounds was 14.2% more accurate than the constrained Weibull, based on the Kolmogorov-Smirnov statistic. The truncated reverse Weibull fit dominant tree distributions 23.7% more accurately than the constrained Weibull, based on a mean absolute difference statistic. This work indicates that a blind spot may have developed in plantation growth modeling systems deploying constrained Weibull functions, and that left-truncation of unconstrained functions could substantially improve model accuracy for negatively skewed distributions.

Sign in / Sign up

Export Citation Format

Share Document