Pub Date : 2024-04-10DOI: 10.1093/forestscience/39.1.137
J. D. Nelson, D. Errico
A methodology for approximating and incorporating spatial harvesting constraints into forest-level, aspatial models is presented. First, operational cut block scheduling methods based on map-coloring theory are used to sample the number of passes and the percentage of area-per-pass that can be harvested without violating adjacency and exclusion period constraints for a given set of harvesting guidelines. These results are defined as spatial approximation rules, and they are subsequently used to control harvest rates within a spatial approximation model. In test cases, the multiple-pass harvesting technique used in the spatial approximation model appears to closely estimate actual cut block schedules. Two major advantages of the spatial approximation technique are: (1) the onerous task of designing and scheduling cut blocks for an entire forest is not necessary, and (2) policy analysis is enhanced because the spatial approximation rules can be quickly altered to reflect different harvesting guidelines. Model calibration and optimization of harvest timings are identified as areas requiring further research. FOR. SCI. 39(1):137-151.
{"title":"Multiple-Pass Harvesting and Spatial Constraints: An Old Technique Applied to a New Problem","authors":"J. D. Nelson, D. Errico","doi":"10.1093/forestscience/39.1.137","DOIUrl":"https://doi.org/10.1093/forestscience/39.1.137","url":null,"abstract":"A methodology for approximating and incorporating spatial harvesting constraints into forest-level, aspatial models is presented. First, operational cut block scheduling methods based on map-coloring theory are used to sample the number of passes and the percentage of area-per-pass that can be harvested without violating adjacency and exclusion period constraints for a given set of harvesting guidelines. These results are defined as spatial approximation rules, and they are subsequently used to control harvest rates within a spatial approximation model. In test cases, the multiple-pass harvesting technique used in the spatial approximation model appears to closely estimate actual cut block schedules. Two major advantages of the spatial approximation technique are: (1) the onerous task of designing and scheduling cut blocks for an entire forest is not necessary, and (2) policy analysis is enhanced because the spatial approximation rules can be quickly altered to reflect different harvesting guidelines. Model calibration and optimization of harvest timings are identified as areas requiring further research. FOR. SCI. 39(1):137-151.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"22 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/35.2.569
R. F. Walker, D. C. West, S. B. McLaughlin, C. C. Amundsen
The effects of Pisolithus tinctorius ectomycorrhizae on survival, growth, xylem pressure potential, and nutrient uptake of loblolly pine on a southern Appalachian coal surface mine were examined. One-year-old bareroot seedlings artificially inoculated with P. tinctorius and control seedlings with Thelephora terrestris ectomycorrhizae were outplanted on a surface-mined site in Tennessee. The site had previously been contoured and hydroseeded with a mixture of herbaceous ground cover species. A soil fertility variable was imposed in the study by broadcast fertilization at outplanting of one-half of the plots of each mycorrhizal treatment at the rate of 336 kg/ha NPK. After 7 years, survival and growth of trees previously inoculated with P. tinctorius were significantly improved relative to control trees. Fertilization elicited a significant reduction in survival and a negligible growth response in trees of both mycorrhizal treatments due primarily to its stimulation of competing herbaceous species. During the third growing season, xylem pressure potential of seedlings with P. tinctorius ectomycorrhizae was significantly less negative than that of control seedlings during a prolonged period of moisture stress. Analyses of foliar samples collected during the third growing season revealed that seedlings infected by P. tinctorius had more NO3 and less Zn in their needles than control seedlings. The results of this study provide evidence that the benefits afforded loblolly pine on surface mines by P. tinctorius ectomycorrhizae include enhanced absorption of water as well as increased uptake of nutrients, and these benefits are not compromised by the presence of competing herbaceous species. For. Sci. 35(2):569-581.
{"title":"Growth, Xylem Pressure Potential, and Nutrient Absorption of Loblolly Pine on a Reclaimed Surface Mine as Affected by an Induced Pisolithus tinctorius Infection","authors":"R. F. Walker, D. C. West, S. B. McLaughlin, C. C. Amundsen","doi":"10.1093/forestscience/35.2.569","DOIUrl":"https://doi.org/10.1093/forestscience/35.2.569","url":null,"abstract":"The effects of Pisolithus tinctorius ectomycorrhizae on survival, growth, xylem pressure potential, and nutrient uptake of loblolly pine on a southern Appalachian coal surface mine were examined. One-year-old bareroot seedlings artificially inoculated with P. tinctorius and control seedlings with Thelephora terrestris ectomycorrhizae were outplanted on a surface-mined site in Tennessee. The site had previously been contoured and hydroseeded with a mixture of herbaceous ground cover species. A soil fertility variable was imposed in the study by broadcast fertilization at outplanting of one-half of the plots of each mycorrhizal treatment at the rate of 336 kg/ha NPK. After 7 years, survival and growth of trees previously inoculated with P. tinctorius were significantly improved relative to control trees. Fertilization elicited a significant reduction in survival and a negligible growth response in trees of both mycorrhizal treatments due primarily to its stimulation of competing herbaceous species. During the third growing season, xylem pressure potential of seedlings with P. tinctorius ectomycorrhizae was significantly less negative than that of control seedlings during a prolonged period of moisture stress. Analyses of foliar samples collected during the third growing season revealed that seedlings infected by P. tinctorius had more NO3 and less Zn in their needles than control seedlings. The results of this study provide evidence that the benefits afforded loblolly pine on surface mines by P. tinctorius ectomycorrhizae include enhanced absorption of water as well as increased uptake of nutrients, and these benefits are not compromised by the presence of competing herbaceous species. For. Sci. 35(2):569-581.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"122 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/40.2.341
Bijan Payandeh, Yonghe Wang
A new base-age invariant site index model was developed based on the constrained version of the Chapman-Richards function. It was compared with that of Goelz and Burk's (1992) in terms of relative accuracy and average bias across a range of potential base ages. The data format for fitting the above models was also simplified. Comparing the models on a set of white spruce (Picea glauca [Moench] Voss) stem analysis data indicated that the choice of predictor age influences the models' accuracy and bias. Except for very young ages, the new model performed as well as that Goelz and Burk's (1992) model in relative accuracy. For. Sci. 40(2):341-348.
{"title":"Relative Accuracy of a New Base-Age Invariant Site Index Model","authors":"Bijan Payandeh, Yonghe Wang","doi":"10.1093/forestscience/40.2.341","DOIUrl":"https://doi.org/10.1093/forestscience/40.2.341","url":null,"abstract":"A new base-age invariant site index model was developed based on the constrained version of the Chapman-Richards function. It was compared with that of Goelz and Burk's (1992) in terms of relative accuracy and average bias across a range of potential base ages. The data format for fitting the above models was also simplified. Comparing the models on a set of white spruce (Picea glauca [Moench] Voss) stem analysis data indicated that the choice of predictor age influences the models' accuracy and bias. Except for very young ages, the new model performed as well as that Goelz and Burk's (1992) model in relative accuracy. For. Sci. 40(2):341-348.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"24 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/51.1.64
François Rollin, Joseph Buongiorno, Mo Zhou, Jean-Luc Peyron
A deterministic matrix growth model of uneven-aged stands of fir, spruce, and hardwood trees was extended to recognize random shocks. The results showed that the expected basal area of hardwoods, mainly beech, was substantially higher in the long run than that predicted by the deterministic model. A parallel stochastic model of prices was also developed from past data. It showed that real prices had no trend but that they were autocorrelated over time. The stochastic stand and price models were simulated simultaneously to obtain the probabilities of transition between stand and market states. This transition probability matrix was used in Markov decision-process models to calculate the best decision in each possible stand and market state. The policies examined included maximizing net present value, or expected tree diversity, production, or annual returns, subject to constraints on net present value, expected tree diversity, and basal area. A general mathematical programming method is presented to optimize economic or ecological objective functions subject to multiple constraints with or without time discounting. In the French Jura context, the solutions suggested that high net present value could be obtained while maintaining the average basal area near its current level, and keeping a high level of tree diversity. Accounting for risk called for more intense harvesting to raise revenues, and it led to stands that were much more diverse than suggested by deterministic solutions. FOR. SCI. 51(1):64–75.
{"title":"Management of Mixed-Species, Uneven-Aged Forests in the French Jura: From Stochastic Growth and Price Models to Decision Tables","authors":"François Rollin, Joseph Buongiorno, Mo Zhou, Jean-Luc Peyron","doi":"10.1093/forestscience/51.1.64","DOIUrl":"https://doi.org/10.1093/forestscience/51.1.64","url":null,"abstract":"A deterministic matrix growth model of uneven-aged stands of fir, spruce, and hardwood trees was extended to recognize random shocks. The results showed that the expected basal area of hardwoods, mainly beech, was substantially higher in the long run than that predicted by the deterministic model. A parallel stochastic model of prices was also developed from past data. It showed that real prices had no trend but that they were autocorrelated over time. The stochastic stand and price models were simulated simultaneously to obtain the probabilities of transition between stand and market states. This transition probability matrix was used in Markov decision-process models to calculate the best decision in each possible stand and market state. The policies examined included maximizing net present value, or expected tree diversity, production, or annual returns, subject to constraints on net present value, expected tree diversity, and basal area. A general mathematical programming method is presented to optimize economic or ecological objective functions subject to multiple constraints with or without time discounting. In the French Jura context, the solutions suggested that high net present value could be obtained while maintaining the average basal area near its current level, and keeping a high level of tree diversity. Accounting for risk called for more intense harvesting to raise revenues, and it led to stands that were much more diverse than suggested by deterministic solutions. FOR. SCI. 51(1):64–75.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"2013 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/54.4.442
Alastair J. McNaughton, David Ryan
Consider a forest containing units of various sizes for which a maximum clearfell area has been specified along with an associated green-up time period. For such an application it is customary to use adjacency constraints to produce a harvesting plan. These constraints control the availability for harvest of specific units relative to the harvesting of certain adjacent units. However, such constraints are difficult to formulate and often precipitate major difficulties in the implementation of the solution algorithm. A new concept, a nuclear set, is introduced. This concept allows the unit-specific aspects of the problem to be analyzed in an insightful manner. Any adjacency violation can be detected in relation to these nuclear sets. Suitable adjacency branches can be implemented to remove these violations. The form of these branches derives from the same nuclear sets. A remarkably small number of these branches are required to obtain a feasible solution. These ideas are incorporated into a column generation and constraint generation model. This new forest harvesting model solves the clearfell area restriction problem in an exact sense. Results are included for numerical trials involving simulated data representing moderately sized applications with a planning horizon of up to one rotation. The output from these trials suggests that this algorithm is suitable for large commercial applications. Several applications of 1,600 units are solved over 25 time periods with multiple green-up.
{"title":"Adjacency Branches Used To Optimize Forest Harvesting Subject to Area Restrictions on Clearfell","authors":"Alastair J. McNaughton, David Ryan","doi":"10.1093/forestscience/54.4.442","DOIUrl":"https://doi.org/10.1093/forestscience/54.4.442","url":null,"abstract":"Consider a forest containing units of various sizes for which a maximum clearfell area has been specified along with an associated green-up time period. For such an application it is customary to use adjacency constraints to produce a harvesting plan. These constraints control the availability for harvest of specific units relative to the harvesting of certain adjacent units. However, such constraints are difficult to formulate and often precipitate major difficulties in the implementation of the solution algorithm. A new concept, a nuclear set, is introduced. This concept allows the unit-specific aspects of the problem to be analyzed in an insightful manner. Any adjacency violation can be detected in relation to these nuclear sets. Suitable adjacency branches can be implemented to remove these violations. The form of these branches derives from the same nuclear sets. A remarkably small number of these branches are required to obtain a feasible solution. These ideas are incorporated into a column generation and constraint generation model. This new forest harvesting model solves the clearfell area restriction problem in an exact sense. Results are included for numerical trials involving simulated data representing moderately sized applications with a planning horizon of up to one rotation. The output from these trials suggests that this algorithm is suitable for large commercial applications. Several applications of 1,600 units are solved over 25 time periods with multiple green-up.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"249 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/41.2.268
Charles P.-A. Bourque, David A. Daugharty, Robert B. B. Dickison, Paul A. Arp
A semi-empirical model designed to stimulate seasonal and midsummer albedo of a northern tolerant hardwood stand following clearcutting was developed from field determinations conducted in west-central New Brunswick. In this model, changes in albedo are related to (1) vegetative regrowth (spreading of newly developing foliage over the cut area); (2) the gradual addition of vegetation layers within the forest canopy; and (3) seasonal variations from bud burst to fall. The field data indicated that (1) cutting reduced the albedo; (2) foliage regrowth rapidly increased the albedo to a maximum similar to that of a continuous single leaf layer within a few years after the cutting operation; (3) deepening of the canopy gradually decreased the albedo after its initial peak; and (4) albedo values were highest in early summer, except in the first year after the cutting operation. For. Sci. 41(2):268-277.
{"title":"Changes in Albedo of a Northern Hardwood Forest Following Clearcutting","authors":"Charles P.-A. Bourque, David A. Daugharty, Robert B. B. Dickison, Paul A. Arp","doi":"10.1093/forestscience/41.2.268","DOIUrl":"https://doi.org/10.1093/forestscience/41.2.268","url":null,"abstract":"A semi-empirical model designed to stimulate seasonal and midsummer albedo of a northern tolerant hardwood stand following clearcutting was developed from field determinations conducted in west-central New Brunswick. In this model, changes in albedo are related to (1) vegetative regrowth (spreading of newly developing foliage over the cut area); (2) the gradual addition of vegetation layers within the forest canopy; and (3) seasonal variations from bud burst to fall. The field data indicated that (1) cutting reduced the albedo; (2) foliage regrowth rapidly increased the albedo to a maximum similar to that of a continuous single leaf layer within a few years after the cutting operation; (3) deepening of the canopy gradually decreased the albedo after its initial peak; and (4) albedo values were highest in early summer, except in the first year after the cutting operation. For. Sci. 41(2):268-277.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"16 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/44.3.390
W. Thomas Adams, Jinghua Zuo, Jarbas Y. Shimizu, John C. Tappeiner
Genetic implications of natural and artificial regeneration following three regeneration methods (group selection, shelterwood, and clearcut) were investigated in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) using genetic markers (17 allozyme loci). In general, harvesting followed by either natural or artificial regeneration resulted in offspring populations little altered from those in the previous generation. Cutting the smallest trees to form shelterwoods, however, resulted in the removal of rare, presumably deleterious, alleles, such that slightly fewer alleles per locus were observed among residual trees (2.76) and natural regeneration (2.75) than found in uncut (control) stands (2.86). Thus, although the shelterwood regime appears quite compatible with gene conservation, it would be best to leave parent trees of a range of sizes in shelterwoods designated as gene conservation reserves, in order to maximize the number of alleles (regardless of current adaptive value) in naturally regenerated offspring. Seedling stocks used for artificial regeneration in clearcut, shelterwood, and group selection stands (7 total) had significantly greater levels of genetic diversity, on average, than found in natural regeneration. This is probably because the seeds used in artificial seedling stocks came from many wild stands and thus, sampled more diversity than found in single populations. For. Sci. 44(3): 390-396.
{"title":"Impact of Alternative Regeneration Methods on Genetic Diversity in Coastal Douglas-Fir","authors":"W. Thomas Adams, Jinghua Zuo, Jarbas Y. Shimizu, John C. Tappeiner","doi":"10.1093/forestscience/44.3.390","DOIUrl":"https://doi.org/10.1093/forestscience/44.3.390","url":null,"abstract":"Genetic implications of natural and artificial regeneration following three regeneration methods (group selection, shelterwood, and clearcut) were investigated in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) using genetic markers (17 allozyme loci). In general, harvesting followed by either natural or artificial regeneration resulted in offspring populations little altered from those in the previous generation. Cutting the smallest trees to form shelterwoods, however, resulted in the removal of rare, presumably deleterious, alleles, such that slightly fewer alleles per locus were observed among residual trees (2.76) and natural regeneration (2.75) than found in uncut (control) stands (2.86). Thus, although the shelterwood regime appears quite compatible with gene conservation, it would be best to leave parent trees of a range of sizes in shelterwoods designated as gene conservation reserves, in order to maximize the number of alleles (regardless of current adaptive value) in naturally regenerated offspring. Seedling stocks used for artificial regeneration in clearcut, shelterwood, and group selection stands (7 total) had significantly greater levels of genetic diversity, on average, than found in natural regeneration. This is probably because the seeds used in artificial seedling stocks came from many wild stands and thus, sampled more diversity than found in single populations. For. Sci. 44(3): 390-396.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"34 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/50.2.139
Wiktor Adamowicz, Peter Boxall, Michel Haener, Yaoqi Zhang, Donna Dosman, Juanita Marois
Assessing the impacts of forest harvesting activities on Aboriginal people and incorporating these considerations into forest management plans is one of the challenges facing Canadian forest managers. In this study, we model hunting behavior using stated and revealed preference data on subsistence use of wildlife resources. We use this framework to assess the impacts of forest management changes on Aboriginal people in northwestern Saskatchewan. Innovative approaches to data collection are employed to address challenges in obtaining data in these contexts. The econometric analysis combines the stated and revealed preference information to account for limitations in the revealed preference data. Monetary measures of welfare are examined, but we also assess resource compensation and zoning as mechanisms for addressing the impact of forest harvesting on subsistence wildlife use. The results also demonstrate the use of geographic information system information in linking forest management and Aboriginal resource use. FOR. SCI. 50(2):139–152.
{"title":"An Assessment of the Impacts of Forest Management on Aboriginal Hunters: Evidence from Stated and Revealed Preference Data","authors":"Wiktor Adamowicz, Peter Boxall, Michel Haener, Yaoqi Zhang, Donna Dosman, Juanita Marois","doi":"10.1093/forestscience/50.2.139","DOIUrl":"https://doi.org/10.1093/forestscience/50.2.139","url":null,"abstract":"Assessing the impacts of forest harvesting activities on Aboriginal people and incorporating these considerations into forest management plans is one of the challenges facing Canadian forest managers. In this study, we model hunting behavior using stated and revealed preference data on subsistence use of wildlife resources. We use this framework to assess the impacts of forest management changes on Aboriginal people in northwestern Saskatchewan. Innovative approaches to data collection are employed to address challenges in obtaining data in these contexts. The econometric analysis combines the stated and revealed preference information to account for limitations in the revealed preference data. Monetary measures of welfare are examined, but we also assess resource compensation and zoning as mechanisms for addressing the impact of forest harvesting on subsistence wildlife use. The results also demonstrate the use of geographic information system information in linking forest management and Aboriginal resource use. FOR. SCI. 50(2):139–152.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"28 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/52.2.173
Thomas Nord-Larsen
In base-age specific methodologies, assessment of base age and site index may be a problem when developing site curves from repeated measurements on permanent sample plot data. In most cases, such data will not contain measurements at any base age that is common for all the sample plots, and some sort of interpolation or even extrapolation would have to be applied to address this issue. Base-age invariant methodologies pose the desirable property of estimating the curves without prior arbitrary assumptions about values of the site indices. Presented here is the development of such base-age invariant site index curves for European beech (Fagus sylvatica L.) in Denmark, fitted to permanent sample plot data. The developed polymorphic dynamic site equations with variable asymptotes are based on the generalized algebraic difference approach, and the parameters of the model were estimated with correction for first-order serial correlation.
{"title":"Developing Dynamic Site Index Curves for European Beech (Fagus sylvatica L.) in Denmark","authors":"Thomas Nord-Larsen","doi":"10.1093/forestscience/52.2.173","DOIUrl":"https://doi.org/10.1093/forestscience/52.2.173","url":null,"abstract":"In base-age specific methodologies, assessment of base age and site index may be a problem when developing site curves from repeated measurements on permanent sample plot data. In most cases, such data will not contain measurements at any base age that is common for all the sample plots, and some sort of interpolation or even extrapolation would have to be applied to address this issue. Base-age invariant methodologies pose the desirable property of estimating the curves without prior arbitrary assumptions about values of the site indices. Presented here is the development of such base-age invariant site index curves for European beech (Fagus sylvatica L.) in Denmark, fitted to permanent sample plot data. The developed polymorphic dynamic site equations with variable asymptotes are based on the generalized algebraic difference approach, and the parameters of the model were estimated with correction for first-order serial correlation.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"56 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1093/forestscience/52.4.381
Qing Xiang, Runsheng Yin
To examine the effects of global economic integration, public policy, and other factors on US softwood lumber trade, a demand and supply system for both exports and imports is estimated with panel data sets. We find that the combined impact of trading price and exchange rate before 2003 has made foreign lumber products much cheaper than those manufactured domestically. Furthermore, domestic economic conditions and production capacity strongly affect the exports and imports of both the United States and its trade partners. Also, the US federal harvest reduction policy and the Asian financial crisis influenced both export and import markets. All of these suggest the need for more integrated market analysis and strategic business thinking.
{"title":"Impact of Globalization and Policy Change on United States Softwood Lumber Trade","authors":"Qing Xiang, Runsheng Yin","doi":"10.1093/forestscience/52.4.381","DOIUrl":"https://doi.org/10.1093/forestscience/52.4.381","url":null,"abstract":"To examine the effects of global economic integration, public policy, and other factors on US softwood lumber trade, a demand and supply system for both exports and imports is estimated with panel data sets. We find that the combined impact of trading price and exchange rate before 2003 has made foreign lumber products much cheaper than those manufactured domestically. Furthermore, domestic economic conditions and production capacity strongly affect the exports and imports of both the United States and its trade partners. Also, the US federal harvest reduction policy and the Asian financial crisis influenced both export and import markets. All of these suggest the need for more integrated market analysis and strategic business thinking.","PeriodicalId":12749,"journal":{"name":"Forest Science","volume":"198 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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