scholarly journals How much birch (Betula papyrifera) is too much for maximizing spruce (Picea glauca) growth: a case study in boreal spruce plantation forests

2012 ◽  
Vol 58 (No. 7) ◽  
pp. 314-327 ◽  
Author(s):  
C.D.B. Hawkins ◽  
A. Dhar ◽  
B.J. Rogers
Keyword(s):  
Picea Glauca ◽  
Management Strategies ◽  
Growth And Yield ◽  
Stem Volume ◽  
Growth Data ◽  
Mixed Species ◽  
Yield Model ◽  
Mixedwood Forests ◽  
Spruce Stands ◽  
The Impact

Interest in conifer-broadleaf mixedwood forests has greatly increased due to continuous demand for hardwood products and a shift towards more biological or ecosystem-based management. In British Columbia, more than 30% of the productive forest land is a conifer&ndash;broadleaf mixture and current forest regulations are more conifer biased rather than maintaining a mixed-species condition. The aim of this study was to examine the impact of paper birch on white spruce growth. Spruce growth data from 10 to 18 years old complex stands indicate that radial, height, and stem volume was not impacted by retaining up to 3,000 stems&middot;ha<sup>&ndash;1</sup> of birch. Similarly, growth and yield model projections suggest spruce-birch stands would be more productive up to a threshold birch density (3,000 stems&middot;ha<sup>&ndash;1</sup>) than pure spruce stands. At a 4% real interest rate, the removal of birch from these stands does not appear to be warranted as an investment. The results suggest that instead of encouraging uniform broadleaf removal across conifer plantations, mixed species management strategies could enhance the forest productivity, stand diversity and resilience. &nbsp;

scholarly journals Comprehensive yield model for plantation teak in Panama

Silva Fennica ◽  
2020 ◽  
Vol 54 (5) ◽  
Author(s):  
Petteri Seppänen ◽  
Antti Mäkinen
Keyword(s):  
Input Parameter ◽  
Large Diameter ◽  
Measurement Data ◽  
Growth And Yield ◽  
Tree Level ◽  
Stem Volume ◽  
Yield Model ◽  
Individual Tree ◽  
Support Tool ◽  
Volume Models

The purpose of this study was to prepare a comprehensive, computerized teak ( L.f) plantation yield model system that can be used to describe the forest dynamics, predict growth and yield and support forest planning and decision-making. Extensive individual tree and permanent sample plot data were used to develop tree-level volume models, taper curve models and stand-level yield models for teak plantations in Panama. Tree volume models were satisfactorily validated against independent measurement data and other published models. Tree height as input parameter improved the stem volume model marginally. Stand level yield models produced comparable harvest volumes with models published in the literature. Stand level volume product outputs were found like actual harvests with an exception that the models marginally underestimate the share of logs in very large diameter classes. The kind of comprehensive model developed in this study and implemented in an easy to use software package provides a very powerful decision support tool. Optimal forest management regimes can be found by simulating different planting densities, thinning regimes and final harvest ages. Forest practitioners can apply growth and yield models in the appropriate stand level inventory data and perform long term harvest scheduling at property level or even at an entire timberland portfolio level. Harvest schedules can be optimized using the applicable financial parameters (silviculture costs, harvesting costs, wood prices and discount rates) and constraints (market size and operational capacity).Tectona grandis

scholarly journals A Growth and Yield Model Incorporating Hardwood Competition for Natural Loblolly Pine Stands in the Georgia Piedmont

1999 ◽  
Vol 23 (3) ◽  
pp. 179-185 ◽  
Author(s):  
Stacey W. Martin ◽  
Graham H. Brister
Keyword(s):  
Loblolly Pine ◽  
Basal Area ◽  
Growth And Yield ◽  
Parameter Estimates ◽  
Yield Model ◽  
Pinus Taeda L ◽  
Projection Equations ◽  
Georgia Piedmont ◽  
The Impact ◽  
Over Time

Abstract Using 5 yr remeasurement data from even-aged natural loblolly pine (Pinus taeda L.) stands in the Georgia Piedmont, a system of growth equations was developed to project pine yield over time that accounts for hardwood competition. In this system, the increase in the proportion of hardwood basal area over time is estimated, then the projected pine basal area and trees per acre are adjusted inversely to account for this increase. The parameter estimates for this system ensure compatibility between volume prediction and projection equations and the proportion of hardwood basal area, pine basal area, dominant height, and trees per acre projection equations. The whole-stand growth and yield system developed here coupled with published merchantable yield equations allow for the evaluation of the impact of hardwoods on future stand yield and product distributions. The results indicate that the impact of hardwood competition on pine yield is substantial and occurs mainly as a reduction in sawtimber volume. South. J. Appl. For. 16(3):179-185.

scholarly journals To Blend or Not to Blend? A Framework for Nationwide Landsat–MODIS Data Selection for Crop Yield Prediction

2020 ◽  
Vol 12 (10) ◽  
pp. 1653
Author(s):  
Yang Chen ◽  
Tim R. McVicar ◽  
Randall J. Donohue ◽  
Nikhil Garg ◽  
François Waldner ◽  
...  
Keyword(s):  
Crop Yield ◽  
Temporal Frequency ◽  
Management Strategies ◽  
Crop Growth ◽  
Growth And Yield ◽  
Yield Prediction ◽  
Landsat Images ◽  
Yield Model ◽  
Pixel Resolution ◽  
Country Level

The onus for monitoring crop growth from space is its ability to be applied anytime and anywhere, to produce crop yield estimates that are consistent at both the subfield scale for farming management strategies and the country level for national crop yield assessment. Historically, the requirements for satellites to successfully monitor crop growth and yield differed depending on the extent of the area being monitored. Diverging imaging capabilities can be reconciled by blending images from high-temporal-frequency (HTF) and high-spatial-resolution (HSR) sensors to produce images that possess both HTF and HSR characteristics across large areas. We evaluated the relative performance of Moderate Resolution Imaging Spectroradiometer (MODIS), Landsat, and blended imagery for crop yield estimates (2009–2015) using a carbon-turnover yield model deployed across the Australian cropping area. Based on the fraction of missing Landsat observations, we further developed a parsimonious framework to inform when and where blending is beneficial for nationwide crop yield prediction at a finer scale (i.e., the 25-m pixel resolution). Landsat provided the best yield predictions when no observations were missing, which occurred in 17% of the cropping area of Australia. Blending was preferred when <42% of Landsat observations were missing, which occurred in 33% of the cropping area of Australia. MODIS produced a lower prediction error when ≥42% of the Landsat images were missing (~50% of the cropping area). By identifying when and where blending outperforms predictions from either Landsat or MODIS, the proposed framework enables more accurate monitoring of biophysical processes and yields, while keeping computational costs low.

Are mixtures of aspen and white spruce more productive than single species stands?

1999 ◽  
Vol 75 (3) ◽  
pp. 505-513 ◽  
Author(s):  
Rongzhou Man ◽  
Victor J. Lieffers
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
White Spruce ◽  
Single Species ◽  
Physical Separation ◽  
Soil Resource ◽  
Mixedwood Forests ◽  
Environmental Extremes ◽  
Spruce Stands ◽  
Boreal Mixedwoods

In boreal mixedwood forests, aspen (Populus tremuloides) and white spruce (Picea glauca) commonly grow in mixture. These species may avoid competition through differential shade tolerance, physical separation of canopies, phenological differences, successional separation, and differences in soil resource utilization. Aspen may also be able to positively affect the growth of white spruce by improving litter decomposition and nutrient cycling rates, controlling grass and shrub competition, ameliorating environmental extremes, and reducing pest attack. These positive relationships likely make mixed-species stands more productive than pure stands of the same species. The evidence regarding the productivity of pure versus mixed aspen/white spruce stands in natural unmanaged forests is examined in this paper. Key words: Tree mixture; productivity; boreal mixedwoods; aspen; white spruce

A compatible growth and yield model for the management of mixed tropical rain forest

2000 ◽  
Vol 30 (2) ◽  
pp. 311-323 ◽  
Author(s):  
James Atta-Boateng ◽  
John William Moser, Jr.
Keyword(s):  
Forest Management ◽  
Rain Forest ◽  
Sustainable Use ◽  
Rate Of Change ◽  
Growth And Yield ◽  
Timber Species ◽  
Yield Model ◽  
Financial Investment ◽  
The Impact ◽  
Growth And Yield Models

The lack of appropriate analytical tools to evaluate the impact of forest management policies has hindered the sustainable use of the rain forest. Decisions about the level of forest management and financial investment require accurate predictions of future forest yields. A technique, using hierarchical clustering and canonical discriminant procedures, was developed previously to pool 112 timber species with similar growth increment characteristics into seven groups suitable for the construction of growth and yield models. Compatible growth and yield models were developed for each group by the solution of a system of differential equations expressing the rate of change of ingrowth, mortality, and survival growth components within a forest stand. The solution provides the means to project the status of the timber stand at any future time given some predefined initial stand conditions. The models are useful for inventory updating, allowable annual cut calculations, and management planning for natural or managed stands. They also provide a means to test hypotheses concerning the influence of stand characteristics on increment and to project future product assortments.

scholarly journals PREVISÃO DA PRODUÇÃO DE MILHO SUBMETIDO A DIFERENTES NÍVEIS DE MANEJO DE IRRIGAÇÃO VIA MODELO DE SIMULAÇÃO

Irriga ◽  
1998 ◽  
Vol 3 (2) ◽  
pp. 36-47
Author(s):  
Marcia Xavier Peiter ◽  
Fazal Hussain Chaudhry
Keyword(s):  
Agricultural Production ◽  
Water Status ◽  
Irrigation Management ◽  
Management Strategies ◽  
Simulation Models ◽  
Growth And Yield ◽  
Corn Yield ◽  
Yield Model ◽  
Area Index ◽  
Plant Available Water

PREVISÃO DA PRODUÇÃO DE MILHO SUBMETIDO A DIFERENTES NÍVEIS DE MANEJO DE IRRIGAÇÃO VIA MODELO DE SIMULAÇÃO[1]  Marcia Xavier PeiterCurso de Engenharia Agrícola - Universidade Regional do Alto Uruguai e Missões - URI Campus Santiago - Tel.(055)251-1715 - Rua 20 de setembro, 2410 - Santiago, RSFazal Hussain ChaudhryDepartamento de Hidráulica e Saneamento - Escola de Engenharia de São Carlos - USPTel.(016)274-3444 - Av. Dr. Carlos Botelho, 1465 - São Carlos, SP  1 RESUMO O advento de modelos simuladores de crescimento e produção de culturas agrícolas vem permitir que as quantidades de água aplicadas e o momento de rega possam ser testados com significativas reduções de custo, tempo e mão-de-obra, além do que, a estimativa da produção não é influenciada por eventuais fatores externos, alheios ao tratamento aplicado. Desta forma, o presente trabalho tem como objetivo a avaliação, calibração e validação de um modelo de simulação de produção para a cultura do milho quando submetido a diferentes níveis de irrigação, a fim de disponibilizar uma ferramenta que permita a análise desta cultura com maior rapidez e redução de custos. Para a validação do modelo, a cultivar de milho Pioneer 3069 foi submetida a quatro níveis de manejo de irrigação com três repetições em um conjunto de lisímetros de drenagem. Procedeu-se as irrigações sempre que a fração de água disponível fosse igual ou inferior a 0,90; 0,75; 0,60 e 0,45. Através dos resultados obtido, pode-se concluir que o modelo de simulação apresenta uma aceitável estrutura de rotinas para previsão da produção de massa seca total de milho quando a cultura é submetida a diferentes níveis de manejo de rega. Desta forma, o modelo pode ser utilizado para a avaliação das conseqüências produtivas e econômicas de diferentes estratégias de irrigação. UNITERMOS: Simulação, milho, manejo de irrigação  PEITER, M.X., CHAUDHRY, F.H. Corn yield predicted when submitted to different irrigation management levels by simulation model  2 ABSTRACT The advent of simulation models for growth and yield of crops makes it possible to test the influence of irrigation depths and their timings on the economy of agricultural production. This paper calibrates and validates a corn yield model for different irrigation management strategies to obtain a tool for rapid analysis of crop response without having to conduct repeated experiments. Thus, the corn cultivar Pioneer 3069 was submitted to four irrigation management levels with three replications in a number of drainage lysimiters. Irrigations were applied when the plant available water reaches 0,90; 0,75; 0,60 and 0,45. The results show that the calibrated model has an acceptable conceptual structure of computational routines to predict corn dry matter when the crop is irrigated according to different management levels. It is concluded further that the model is capable of predicting correctly the temporal variation of the observed leaf area index and soil water status. KEY-WORDS: Simulation, corn, irrigation management 

Yield prediction for mixed species stands in boreal Ontario

2008 ◽  
Vol 84 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Margaret Penner
Keyword(s):  
Yield Curve ◽  
Growth Yield ◽  
Growth And Yield ◽  
Tree Level ◽  
Mixed Species ◽  
Management Planning ◽  
Average Growth ◽  
Forest Management Planning ◽  
Mixedwood Forests ◽  
Provincial Yield

Wood supply of the major industrial species groups (spruce–pine–fir [Picea–Pinus–Abies spp.] and poplar [Populus spp.]) in the boreal forest of Ontario is forecast to fall below demand in the relatively near future. This has lead to more interest in the growth and yield of mixedwood forests. Mixedwood stands are defined for forest management planning as stands in which 26% to 75% of the canopy is softwood. With an average growth rate one-third higher than the average for all forest types combined, mixed species stands have potential to mitigate some of the shortfalls. This paper reviews the history of yield curve development in Ontario and some of the current initiatives in mixedwood modeling. The Forestry Research Partnership, a partnership between Tembec, the Ontario Ministry of Natural Resources, the Canadian Forest Service, and the Canadian Ecology Centre, was formed in 1999. One of the first projects of the Partnership was to update the provincial yield curves. These updated curves provide good estimates of yield for mixedwoods on upland, drier sites but mixedwoods on moister sites need to be further stratified by leading species. Mid-rotation activities such as density regulation and partial harvesting in the selection or shelterwood silvicultural systems are generally tree-level activities. These are more compatible with tree-level models. Ontario is calibrating the Forest Vegetation Simulator (FVS) for use in Ontario and this shows particular promise in mixedwood modeling. Key words: mixedwood growth, yield tables, FVS

Relations entre des indicateurs de croissance du sapin baumier en début d'épidémie et sa vulnérabilité à la tordeuse des bourgeons de l'épinette

1995 ◽  
Vol 25 (8) ◽  
pp. 1292-1302 ◽  
Author(s):  
Denis Thibault ◽  
Jean Bégin ◽  
Louis Bélanger
Keyword(s):  
Management Strategies ◽  
Logistic Models ◽  
The State ◽  
Growth And Yield ◽  
Probability Models ◽  
Study Sites ◽  
The Individual ◽  
Linear Probability ◽  
Individual Trees ◽  
The Impact

Integrated pest management strategies for the spruce budworm (Choristoneurafumiferana (Clem.)) give high priority to preventive silvicultural treatments that increase the vigour of balsam fir stands to decrease their vulnerability. The aim of this study was to determine to which extent the survival probability of individual balsam firs (Abiesbalsamea L.), during the last budworm outbreak (1974–1986), was related to some growth rate indicators evaluated at the beginning of the outbreak. The study was carried out in two permanent study sites, established initially to follow the impact of precommercial thinnings on growth and yield in young boreal fir stands in eastern Quebec: the area of Lake Matapédia, thinned in 1968 and protected by chemical insecticides, and the area of Lake Huit-Milles, thinned in 1960 and not protected. Discriminant logistic models, based on tree diameters in 1976 and diameter growth rates between 1968 and 1976, were used to determine if it was possible to discriminate the state of the trees (living or dead) at the end of the outbreak. Using Dagnelie's transformation of the logistic model, we produced linear probability models that were called survival thresholds. In the protected study area (Lake Matapédia), the models correctly predicted the state of 81% of the individual trees in 1989 for the validation sample. In the unprotected stands (Lake Huit-Milles), we observed a higher position of the survival thresholds following higher defoliation levels. The relationship between tree growth indicators and tree vulnerability is stronger when defoliation levels are low to moderate, but is clearly weaker when defoliation is severe. At high levels of defoliation and without insecticide spraying programs, even vigourous trees become vulnerable.

Sign in / Sign up

Export Citation Format

Share Document