Pub Date : 2019-03-03DOI: 10.33494/NZJFS492019X26X
D. Panagiotidis, Azadeh Abdollahnejad, P. Surový, Karel Kuželka
Background: High-resolution images from unmanned aerial vehicles (UAVs) can be used to describe the state of forests at regular time periods in a cost-effective manner. The purpose of this study was to assess the performance of a line template matching algorithm, the Hough transformation, for detecting fallen logs from UAV-based high-resolution RGB images. The suggested methodology does not aim to replace any known aerial method for log detection, rather it is more oriented to the detection of fallen logs in open forest stands with a high percentage of log visibility and straightness. Methods: This study describes a line template matching algorithm that can be used for the detection of fallen logs in an automated process. The detection technique was based on object-based image analysis, using both pixel-based and shape descriptors. To determine the actual number of fallen logs, and to compare with the ones predicted by the algorithm, manual visual assessment was used based on six high-resolution orthorectified images. To evaluate if a line matched, we used a voting scheme. The total number of detected fallen logs compared with the actual number of fallen logs based on several accuracy metrics. To evaluate predictive models we tested the cross-validation mean error. Finally, to test how close our results were to chance, we used the Cohen`s Kappa coefficient. Results: The detection algorithm found 136 linear objects, of which 92 of them were detected as fallen logs. From the 92 detected fallen logs, 86 were correctly predicted by the algorithm and 24 were falsely detected as fallen logs. The calculated amount of observed agreement was equal to 0.78, whereas the expected agreement by chance was 0.61. Finally, the kappa statistic was 0.44. Conclusions: Our methodology had high reliability for detecting fallen logs based on total user‘s accuracy (94.9%), whereas a Kappa of 0.44 indicated there was good agreement between the observed and predicted values. Also, the cross-validation analysis denoted the efficiency of the proposed method with an average error of 16%.
{"title":"Detection of fallen logs from high-resolution UAV images","authors":"D. Panagiotidis, Azadeh Abdollahnejad, P. Surový, Karel Kuželka","doi":"10.33494/NZJFS492019X26X","DOIUrl":"https://doi.org/10.33494/NZJFS492019X26X","url":null,"abstract":"Background: High-resolution images from unmanned aerial vehicles (UAVs) can be used to describe the state of forests at regular time periods in a cost-effective manner. The purpose of this study was to assess the performance of a line template matching algorithm, the Hough transformation, for detecting fallen logs from UAV-based high-resolution RGB images. The suggested methodology does not aim to replace any known aerial method for log detection, rather it is more oriented to the detection of fallen logs in open forest stands with a high percentage of log visibility and straightness. \u0000Methods: This study describes a line template matching algorithm that can be used for the detection of fallen logs in an automated process. The detection technique was based on object-based image analysis, using both pixel-based and shape descriptors. To determine the actual number of fallen logs, and to compare with the ones predicted by the algorithm, manual visual assessment was used based on six high-resolution orthorectified images. To evaluate if a line matched, we used a voting scheme. The total number of detected fallen logs compared with the actual number of fallen logs based on several accuracy metrics. To evaluate predictive models we tested the cross-validation mean error. Finally, to test how close our results were to chance, we used the Cohen`s Kappa coefficient. \u0000Results: The detection algorithm found 136 linear objects, of which 92 of them were detected as fallen logs. From the 92 detected fallen logs, 86 were correctly predicted by the algorithm and 24 were falsely detected as fallen logs. The calculated amount of observed agreement was equal to 0.78, whereas the expected agreement by chance was 0.61. Finally, the kappa statistic was 0.44. \u0000Conclusions: Our methodology had high reliability for detecting fallen logs based on total user‘s accuracy (94.9%), whereas a Kappa of 0.44 indicated there was good agreement between the observed and predicted values. Also, the cross-validation analysis denoted the efficiency of the proposed method with an average error of 16%.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2019-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44585022","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 : 2019-02-19DOI: 10.33494/NZJFS492019X24X
E. Mason
Background: A study was undertaken of 51 stand inventories to compare two alternative mean top height (MTH) calculation methods prevalent in New Zealand, and to evaluate the consequences of creating height versus diameter at breast height (H-D) curves at a stand-level during inventories as opposed to fitting H-D curves at a plot-level. Methods: The dataset was separated into two groups; one with plots having less than 6 heights measured and one with more than 5 heights measured. MTH was calculated using all possible combinations of the two calculation methods and with H-D curves either at a stand-level or a plot-level. Graphs were prepared to compare the 4 alternative MTH estimation techniques for all plots. In addition standard deviations of MTH between plots were calculated within stands, and then these were compared for different MTH calculation methods using interleaved histograms and with a mixed effects analysis of variance. Results: Results showed that the two MTH calculation methods were almost identical so long as H-D curves were fitted at a plot-level, but they differed substantially when curves were fitted at a stand-level. In addition, fitting H-D curves at a stand-level reduced independence of samples, resulting in substantial decreases in estimated standard deviations in MTH within samples, thereby artificially reducing confidence intervals around sample estimates. Conclusions: Inventory estimates of MTH were found to depend on calculation method, and so a standard definition is required. In addition, H-D curves fitted at a stand level undermined the assumption that sampling units were independent, and thereby reduced estimated variation between plots by up to 69%, depending on MTH calculation method. Forest inventory procedures in New Zealand’s forest plantations should be redesigned to enable accurate definition of confidence intervals around sample estimates, and to facilitate the use of inventories for estimating variation in productivity across landscapes.
{"title":"Influences of mean top height definition and sampling method on errors of estimates in New Zealand’s forest plantations","authors":"E. Mason","doi":"10.33494/NZJFS492019X24X","DOIUrl":"https://doi.org/10.33494/NZJFS492019X24X","url":null,"abstract":"Background: A study was undertaken of 51 stand inventories to compare two alternative mean top height (MTH) calculation methods prevalent in New Zealand, and to evaluate the consequences of creating height versus diameter at breast height (H-D) curves at a stand-level during inventories as opposed to fitting H-D curves at a plot-level. \u0000Methods: The dataset was separated into two groups; one with plots having less than 6 heights measured and one with more than 5 heights measured. MTH was calculated using all possible combinations of the two calculation methods and with H-D curves either at a stand-level or a plot-level. Graphs were prepared to compare the 4 alternative MTH estimation techniques for all plots. In addition standard deviations of MTH between plots were calculated within stands, and then these were compared for different MTH calculation methods using interleaved histograms and with a mixed effects analysis of variance. \u0000Results: Results showed that the two MTH calculation methods were almost identical so long as H-D curves were fitted at a plot-level, but they differed substantially when curves were fitted at a stand-level. In addition, fitting H-D curves at a stand-level reduced independence of samples, resulting in substantial decreases in estimated standard deviations in MTH within samples, thereby artificially reducing confidence intervals around sample estimates. \u0000Conclusions: Inventory estimates of MTH were found to depend on calculation method, and so a standard definition is required. In addition, H-D curves fitted at a stand level undermined the assumption that sampling units were independent, and thereby reduced estimated variation between plots by up to 69%, depending on MTH calculation method. Forest inventory procedures in New Zealand’s forest plantations should be redesigned to enable accurate definition of confidence intervals around sample estimates, and to facilitate the use of inventories for estimating variation in productivity across landscapes.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45479388","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 : 2018-12-01DOI: 10.1186/s40490-018-0119-5
P. Beets, L. Garrett
{"title":"Carbon fraction of Pinus radiata biomass components within New Zealand","authors":"P. Beets, L. Garrett","doi":"10.1186/s40490-018-0119-5","DOIUrl":"https://doi.org/10.1186/s40490-018-0119-5","url":null,"abstract":"","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":"48 1","pages":"1-8"},"PeriodicalIF":1.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40490-018-0119-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41731485","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 : 2018-12-01DOI: 10.1186/s40490-018-0122-x
A. Saini, S. Hegde, H. Hegde, S. Kholkute, Subarna Roy
{"title":"Assessment of genetic diversity of Saraca asoca (Roxb.) De Wilde: a commercially important, but endangered, forest tree species in Western Ghats, India","authors":"A. Saini, S. Hegde, H. Hegde, S. Kholkute, Subarna Roy","doi":"10.1186/s40490-018-0122-x","DOIUrl":"https://doi.org/10.1186/s40490-018-0122-x","url":null,"abstract":"","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":"48 1","pages":"1-12"},"PeriodicalIF":1.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40490-018-0122-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48737147","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 : 2018-12-01DOI: 10.1186/s40490-018-0118-6
Gayatri Mishra, D. Collings, C. Altaner
{"title":"Cell organelles and fluorescence of parenchyma cells in Eucalyptus bosistoana sapwood and heartwood investigated by microscopy","authors":"Gayatri Mishra, D. Collings, C. Altaner","doi":"10.1186/s40490-018-0118-6","DOIUrl":"https://doi.org/10.1186/s40490-018-0118-6","url":null,"abstract":"","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":" ","pages":"1-10"},"PeriodicalIF":1.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40490-018-0118-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44568597","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 : 2018-12-01DOI: 10.1186/s40490-018-0109-7
Fei Guo, C. Altaner
{"title":"Properties of rotary peeled veneer and laminated veneer lumber (LVL) from New Zealand grown Eucalyptus globoidea","authors":"Fei Guo, C. Altaner","doi":"10.1186/s40490-018-0109-7","DOIUrl":"https://doi.org/10.1186/s40490-018-0109-7","url":null,"abstract":"","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":" ","pages":"1-10"},"PeriodicalIF":1.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40490-018-0109-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44648847","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 : 2018-12-01DOI: 10.1186/s40490-018-0120-z
P. Salehi Shanjani, H. Javadi, Leila Rasoulzadeh, Mahmoud Amirkhani
{"title":"Evaluation of genetic differentiation among healthy and infected Buxus hyrcana with boxwood blight using RAPD and ISSR markers","authors":"P. Salehi Shanjani, H. Javadi, Leila Rasoulzadeh, Mahmoud Amirkhani","doi":"10.1186/s40490-018-0120-z","DOIUrl":"https://doi.org/10.1186/s40490-018-0120-z","url":null,"abstract":"","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":"48 1","pages":"1-10"},"PeriodicalIF":1.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40490-018-0120-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42279250","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 : 2018-12-01DOI: 10.1186/s40490-018-0125-7
P. Beets, M. Kimberley, G. R. Oliver, S. H. Pearce, J. D. Graham, D. Henley, D. Meason
{"title":"Plantation species-specific adjustment functions for the Forest Carbon Predictor in New Zealand","authors":"P. Beets, M. Kimberley, G. R. Oliver, S. H. Pearce, J. D. Graham, D. Henley, D. Meason","doi":"10.1186/s40490-018-0125-7","DOIUrl":"https://doi.org/10.1186/s40490-018-0125-7","url":null,"abstract":"","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":"48 1","pages":"1-17"},"PeriodicalIF":1.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40490-018-0125-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45281005","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 : 2018-12-01DOI: 10.1186/s40490-018-0123-9
Tomasz Hycza, K. Stereńczak, R. Bałazy
{"title":"Potential use of hyperspectral data to classify forest tree species","authors":"Tomasz Hycza, K. Stereńczak, R. Bałazy","doi":"10.1186/s40490-018-0123-9","DOIUrl":"https://doi.org/10.1186/s40490-018-0123-9","url":null,"abstract":"","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":"48 1","pages":"1-13"},"PeriodicalIF":1.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40490-018-0123-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44907771","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 : 2018-12-01DOI: 10.1186/s40490-018-0124-8
Lindani Z. Mavimbela, E. Sieben, Ş. Procheş
{"title":"Invasive alien plant species, fragmentation and scale effects on urban forest community composition in Durban, South Africa","authors":"Lindani Z. Mavimbela, E. Sieben, Ş. Procheş","doi":"10.1186/s40490-018-0124-8","DOIUrl":"https://doi.org/10.1186/s40490-018-0124-8","url":null,"abstract":"","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":"48 1","pages":"1-14"},"PeriodicalIF":1.5,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40490-018-0124-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43629525","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：