L. Korhonen, J. Repola, Tomi Karjalainen, P. Packalen, M. Maltamo
Airborne laser scanning (ALS) data is nowadays often available for forest inventory purposes, but adequate field data for constructing new forest attribute models for each area may be lacking. Thus there is a need to study the transferability of existing ALS-based models among different inventory areas. The objective of our study was to apply ALS-based mixed models to estimate the diameter, height and crown base height of individual sawlog sized Scots pines ( L.) at three different inventory sites in eastern Finland. Different ALS sensors and acquisition parameters were used at each site. Multivariate mixed-effects models were fitted at one site and the models were validated at two independent test sites. Validation was carried out by applying the fixed parts of the mixed models as such, and by calibrating them using 1â3 sample trees per plot. The results showed that the relative RMSEs of the predictions were 1.2â6.5 percent points larger at the test sites compared to the training site. Systematic errors of 2.4â6.2 percent points also emerged at the test sites. However, both the RMSEs and the systematic errors decreased with calibration. The results showed that mixed-effects models of individual tree attributes can be successfully transferred and calibrated to other ALS inventory areas in a level of accuracy that appears suitable for practical applications.Pinus sylvestris
{"title":"Transferability and calibration of airborne laser scanning based mixed-effects models to estimate the attributes of sawlog-sized Scots pines","authors":"L. Korhonen, J. Repola, Tomi Karjalainen, P. Packalen, M. Maltamo","doi":"10.14214/SF.10179","DOIUrl":"https://doi.org/10.14214/SF.10179","url":null,"abstract":"Airborne laser scanning (ALS) data is nowadays often available for forest inventory purposes, but adequate field data for constructing new forest attribute models for each area may be lacking. Thus there is a need to study the transferability of existing ALS-based models among different inventory areas. The objective of our study was to apply ALS-based mixed models to estimate the diameter, height and crown base height of individual sawlog sized Scots pines ( L.) at three different inventory sites in eastern Finland. Different ALS sensors and acquisition parameters were used at each site. Multivariate mixed-effects models were fitted at one site and the models were validated at two independent test sites. Validation was carried out by applying the fixed parts of the mixed models as such, and by calibrating them using 1â3 sample trees per plot. The results showed that the relative RMSEs of the predictions were 1.2â6.5 percent points larger at the test sites compared to the training site. Systematic errors of 2.4â6.2 percent points also emerged at the test sites. However, both the RMSEs and the systematic errors decreased with calibration. The results showed that mixed-effects models of individual tree attributes can be successfully transferred and calibrated to other ALS inventory areas in a level of accuracy that appears suitable for practical applications.Pinus sylvestris","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Claudie-Maude Canuel, N. Thiffault, Michael K. Hoepting, James C. G. Farrell
The Green River precommercial thinning (PCT) trial was established between 1959â1961 in New Brunswick (Canada) within natural balsam fir ( (L.) Mill.)-dominated stands. Three silviculture scenarios differing only by the increasing nominal spacings of PCT treatments (1.2 m, 1.8 m, 2.4 m) were compared to an unthinned control within randomized replicates that were clearcut harvested in 2008 and treated with herbicide in 2011. During the fourth post-harvest growing season, we assessed regeneration, competing vegetation and coarse woody debris (CWD; differentiated between large woody debris and slash) to assess the legacy effects of PCT on regeneration of next rotation stands. Our results confirmed that silviculture scenarios including PCT significantly increased conifer stocking in treated plots compared to control conditions, but only in the 1.8 m nominal spacing. Considering that treated and untreated stands were fully stocked, we conclude that PCT using the spacing gradient tested has no legacy effect on the regeneration of next rotation natural balsam fir stands. Given the known sensitivity of balsam fir to future climate conditions in this region, we suggest that future treatments should promote tree species diversity to support ecosystem resilience to climate change by favouring more warm-adapted species, such as some hardwoods.Abies balsamea
绿河商业前间伐(PCT)试验于1959 - ~ 1961年在加拿大新不伦瑞克省的天然香脂冷杉(L.)中建立。机控制站。将三种仅因PCT处理的标称间距(1.2 m, 1.8 m, 2.4 m)增加而不同的造林方案与2008年采伐后使用除草剂的随机重复中未稀释的对照进行了比较。在收获后的第四个生长季节，我们评估了更新、竞争植被和粗木屑(CWD;以评估PCT对下一个轮作林分再生的遗留影响。我们的研究结果证实，与对照相比，包括PCT在内的造林方案显著增加了处理样地的针叶树蓄积量，但仅在名义间距1.8 m范围内。考虑到处理过的林分和未处理过的林分均有充足的库存，我们得出结论，采用所测试的间距梯度的PCT对下一次轮作天然香脂冷杉林分的更新没有遗留效应。鉴于该地区香脂冷杉对未来气候条件的敏感性，我们建议未来的处理应促进树种多样性，以支持生态系统对气候变化的适应能力，如一些硬木。冷杉属balsamea
{"title":"Legacy effects of precommercial thinning on the natural regeneration of next rotation balsam fir stands in eastern Canada","authors":"Claudie-Maude Canuel, N. Thiffault, Michael K. Hoepting, James C. G. Farrell","doi":"10.14214/sf.10209","DOIUrl":"https://doi.org/10.14214/sf.10209","url":null,"abstract":"The Green River precommercial thinning (PCT) trial was established between 1959â1961 in New Brunswick (Canada) within natural balsam fir ( (L.) Mill.)-dominated stands. Three silviculture scenarios differing only by the increasing nominal spacings of PCT treatments (1.2 m, 1.8 m, 2.4 m) were compared to an unthinned control within randomized replicates that were clearcut harvested in 2008 and treated with herbicide in 2011. During the fourth post-harvest growing season, we assessed regeneration, competing vegetation and coarse woody debris (CWD; differentiated between large woody debris and slash) to assess the legacy effects of PCT on regeneration of next rotation stands. Our results confirmed that silviculture scenarios including PCT significantly increased conifer stocking in treated plots compared to control conditions, but only in the 1.8 m nominal spacing. Considering that treated and untreated stands were fully stocked, we conclude that PCT using the spacing gradient tested has no legacy effect on the regeneration of next rotation natural balsam fir stands. Given the known sensitivity of balsam fir to future climate conditions in this region, we suggest that future treatments should promote tree species diversity to support ecosystem resilience to climate change by favouring more warm-adapted species, such as some hardwoods.Abies balsamea","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"117 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The stoniness index of forest soil describes the stone content in the upper soil layer at depths of 20â30 centimeters. This index is not available in any existing map databases, and traditional measurements for the stoniness of the soil have always necessitated laborious soil-penetration methods. Knowledge of the stone content of a forest site could be of use in a variety of forestry operations. This paper presents a novel approach to obtaining automatic measurements of soil stoniness during an excavator-based mounding operation. The excavator was equipped with only a low-cost inertial measurement unit and a satellite navigation receiver. Using the data from these sensors and manually conducted soil stoniness measurements, supervised machine learning methods were utilized to build a model that is capable of predicting the stoniness class of a given mounding location. This study compares different classifiers and feature selection methods to find the most promising solution for this learning problem. The discussion includes a proposition for a meaningful measurement resolution of the soilâs stoniness, and a practical method for evaluating the variability of the stone content of the soil. The results indicate that it is possible to predict the soil stoniness class with 70% accuracy using only the inertial and location measurements.
{"title":"Classifying soil stoniness based on the excavator boom vibration data in mounding operations","authors":"Lari Melander, R. Ritala, Markus Strandström","doi":"10.14214/sf.10068","DOIUrl":"https://doi.org/10.14214/sf.10068","url":null,"abstract":"The stoniness index of forest soil describes the stone content in the upper soil layer at depths of 20â30 centimeters. This index is not available in any existing map databases, and traditional measurements for the stoniness of the soil have always necessitated laborious soil-penetration methods. Knowledge of the stone content of a forest site could be of use in a variety of forestry operations. This paper presents a novel approach to obtaining automatic measurements of soil stoniness during an excavator-based mounding operation. The excavator was equipped with only a low-cost inertial measurement unit and a satellite navigation receiver. Using the data from these sensors and manually conducted soil stoniness measurements, supervised machine learning methods were utilized to build a model that is capable of predicting the stoniness class of a given mounding location. This study compares different classifiers and feature selection methods to find the most promising solution for this learning problem. The discussion includes a proposition for a meaningful measurement resolution of the soilâs stoniness, and a practical method for evaluating the variability of the stone content of the soil. The results indicate that it is possible to predict the soil stoniness class with 70% accuracy using only the inertial and location measurements.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66766822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite the influence of cavities on the survival and distribution of cavity-dependent fauna, the variation in the density and characteristics of tree cavities across different habitat types in tropical forests is unknown. In this study, we surveyed 26â312 living trees from 376 species and compared cavity density and characteristics (height, size, type, and orientation) across five habitat types (valley, low-slope, high-slope, high-gully, and high-plateau) in a 20-hectare tropical rainforest in southwest China. From a total of 2047 cavities, we found that cavity density was mainly driven by habitat rather than tree species richness or diameter at breast height (DBH), and the characteristics of cavities were not uniformly distributed across habitats. Cavities were significantly more abundant in high- and low-slope than high-plateau habitats. Compared with other habitats, more âbutt hollowâ cavity types were found in high-slope habitat and they occurred at a lower tree height, whereas more âcrackâ cavities were found in low-slope habitat and they had a narrower entrance diameter. Although the mean orientation of cavities faced towards the northeast, cavity orientation varied significantly across habitat types. Our results indicate that certain types of cavities are concentrated in specific habitat types, which can provide avenues for forest management and biodiversity conservation. We highlight the importance of habitat heterogeneity in providing resources for cavity nesters.
{"title":"Do tree cavity density and characteristics vary across topographical habitats in the tropics? A case study from Xishuangbanna, southwest China","authors":"Jun-yan Liu, Junfeng Tang, Si‐Chong Chen, Wenbao Ma, Zheng Zheng, T. Dong","doi":"10.14214/SF.10019","DOIUrl":"https://doi.org/10.14214/SF.10019","url":null,"abstract":"Despite the influence of cavities on the survival and distribution of cavity-dependent fauna, the variation in the density and characteristics of tree cavities across different habitat types in tropical forests is unknown. In this study, we surveyed 26â312 living trees from 376 species and compared cavity density and characteristics (height, size, type, and orientation) across five habitat types (valley, low-slope, high-slope, high-gully, and high-plateau) in a 20-hectare tropical rainforest in southwest China. From a total of 2047 cavities, we found that cavity density was mainly driven by habitat rather than tree species richness or diameter at breast height (DBH), and the characteristics of cavities were not uniformly distributed across habitats. Cavities were significantly more abundant in high- and low-slope than high-plateau habitats. Compared with other habitats, more âbutt hollowâ cavity types were found in high-slope habitat and they occurred at a lower tree height, whereas more âcrackâ cavities were found in low-slope habitat and they had a narrower entrance diameter. Although the mean orientation of cavities faced towards the northeast, cavity orientation varied significantly across habitat types. Our results indicate that certain types of cavities are concentrated in specific habitat types, which can provide avenues for forest management and biodiversity conservation. We highlight the importance of habitat heterogeneity in providing resources for cavity nesters.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66766982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is commonly accepted that the period of early-spring xylem sap exudation marks a stage during which a positive pressure builds inside the tree trunks. This state changes when leaves appear, initiating water transport within the trunk. It is unknown, however, how the wood anatomical structure and its mechanical resistance influences the sap. We present the results of research on the relationship between exudation of sap from Roth trees from the interior of a forest stand and from its edge, and the anatomical structure of the trunk wood and its bending strength. During the period between March 21 and April 18, we performed five sets of measurements of sap exudation from trees at the edge of the stand and from the forest interior. The resulting radial wood samples were tested for bending strength using a fractometer. We tested the sap for electrolytic conductivity and sugars content. For the anatomical analysis of the wood, we determined the number of vessels per 1 mm, average vessel lumen area and potential conductivity index. We found that the trees along the edge of the stand exude more sap, but it is less concentrated than the sap from the trees from the interior. Bending strength perpendicular to wood fibres is higher in the trees from the stand edge and in the western side of the trunk, where the number of vessels per 1 mm2 and conductivity index are smaller. Seemingly, this is the result of western winds, which are dominant in Poland.Betula pendula2
{"title":"Birch sap exudation: influence of tree position in a forest stand on birch sap production, trunk wood anatomy and radial bending strength","authors":"U. Zajączkowska, K. Kaczmarczyk, Janusz Liana","doi":"10.14214/sf.10048","DOIUrl":"https://doi.org/10.14214/sf.10048","url":null,"abstract":"It is commonly accepted that the period of early-spring xylem sap exudation marks a stage during which a positive pressure builds inside the tree trunks. This state changes when leaves appear, initiating water transport within the trunk. It is unknown, however, how the wood anatomical structure and its mechanical resistance influences the sap. We present the results of research on the relationship between exudation of sap from Roth trees from the interior of a forest stand and from its edge, and the anatomical structure of the trunk wood and its bending strength. During the period between March 21 and April 18, we performed five sets of measurements of sap exudation from trees at the edge of the stand and from the forest interior. The resulting radial wood samples were tested for bending strength using a fractometer. We tested the sap for electrolytic conductivity and sugars content. For the anatomical analysis of the wood, we determined the number of vessels per 1 mm, average vessel lumen area and potential conductivity index. We found that the trees along the edge of the stand exude more sap, but it is less concentrated than the sap from the trees from the interior. Bending strength perpendicular to wood fibres is higher in the trees from the stand edge and in the western side of the trunk, where the number of vessels per 1 mm2 and conductivity index are smaller. Seemingly, this is the result of western winds, which are dominant in Poland.Betula pendula2","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Crane work is the most time-consuming work element in forwarding. Hence, assist systems like boom-tip control are of interest. The first commercially available boom-tip control for forwarders was introduced in 2013. In this study we analysed whether replacing conventional boom control (CBC) with John Deereâs version of boom-tip control (named Intelligent Boom Control, IBC), increases crane-work productivity. We used data automatically gathered from 10 final-felling stands, covering typical logging conditions for southern, central and northern Sweden. Two John Deere 1510E and two John Deere 1910G forwarders were operated by seven experienced operators during the follow-up study, covering 1238 loads in total. A split-plot design was applied to isolate effects of the boom-control system being used (CBC, IBC). We found that using IBC for loading work (crane work and driving included) saved 5.2% of productive machine time compared to using CBC (pââ¤â0.05). The corresponding saving when using IBC for unloading work was 7.9% (pââ¤â0.05). Depending on geophysical factors, this corresponds to approximately 4% savings in productive machine time for forwarding as a whole, including pure transport (with and without load). Moreover, the study introduced in cut-to-length context a novel field-study design to collect a large follow-up dataset in the course of ordinary forwarding operations. We found the study design to be a cost-efficient way to combine the representativeness of conventional follow-up datasets with the ability to establish causal relationships. Establishment of causal relationships has traditionally been possible only through observational time studies or standardized experiments.
{"title":"Comparing forwarder boom-control systems based on an automatically recorded follow-up dataset","authors":"Jussi Manner, Anders Mörk, M. Englund","doi":"10.14214/SF.10161","DOIUrl":"https://doi.org/10.14214/SF.10161","url":null,"abstract":"Crane work is the most time-consuming work element in forwarding. Hence, assist systems like boom-tip control are of interest. The first commercially available boom-tip control for forwarders was introduced in 2013. In this study we analysed whether replacing conventional boom control (CBC) with John Deereâs version of boom-tip control (named Intelligent Boom Control, IBC), increases crane-work productivity. We used data automatically gathered from 10 final-felling stands, covering typical logging conditions for southern, central and northern Sweden. Two John Deere 1510E and two John Deere 1910G forwarders were operated by seven experienced operators during the follow-up study, covering 1238 loads in total. A split-plot design was applied to isolate effects of the boom-control system being used (CBC, IBC). We found that using IBC for loading work (crane work and driving included) saved 5.2% of productive machine time compared to using CBC (pââ¤â0.05). The corresponding saving when using IBC for unloading work was 7.9% (pââ¤â0.05). Depending on geophysical factors, this corresponds to approximately 4% savings in productive machine time for forwarding as a whole, including pure transport (with and without load). Moreover, the study introduced in cut-to-length context a novel field-study design to collect a large follow-up dataset in the course of ordinary forwarding operations. We found the study design to be a cost-efficient way to combine the representativeness of conventional follow-up datasets with the ability to establish causal relationships. Establishment of causal relationships has traditionally been possible only through observational time studies or standardized experiments.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"34 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on data from long-term experimental fields with Norway spruce ( (L.) H. Karst.), we developed new stem taper and bark functions for Norway. Data was collected from 477 trees in stands across Norway. Three candidate functions which have shown good performance in previous studies (Kozak 02, Kozak 97 and Bi) were fitted to the data as fixed-effects models. The function with the smallest Akaike Information Criterion (AIC) was then chosen for additional analyses, fitting 1) site index-dependent and 2) age-dependent versions of the model, and 3) fitting a mixed-effects model with tree-specific random parameters. Kozak 97 was found to be the function with the smallest AIC, but all three tested taper functions resulted in fairly similar predictions of stem taper. The site index-dependent function reduced AIC and residual standard error and showed that the effect of site index on stem taper is different in small and large trees. The predictions of the age-independent and age-dependent models were very close to each other. Adding tree-specific random parameters to the model clearly reduced AIC and residual variation. However, the results suggest that the mixed-effects model should be used only when it is possible to calibrate it for each tree, otherwise the fixed-effects Kozak 97 model should be used. A model for double bark thickness was also fitted as fixed-effects Kozak 97 model. The model behaved logically, predicting larger relative but smaller absolute bark thickness for small trees.Picea abies
基于挪威云杉(L.)长期试验田数据H. Karst)，我们为挪威开发了新的茎锥度和树皮功能。数据是从挪威各地的477棵树中收集的。在以往的研究中表现良好的三个候选函数(Kozak 02、Kozak 97和Bi)被拟合为固定效应模型。然后选择赤池信息准则(Akaike Information Criterion, AIC)最小的函数进行进一步分析，拟合1)地点指数依赖的模型和2)年龄依赖的模型，以及3)具有特定树木随机参数的混合效应模型。发现Kozak 97是AIC最小的函数，但所有三个测试的锥度函数对茎锥度的预测结果相当相似。立地指数依赖函数降低了AIC和残差标准误差，表明立地指数对树干锥度的影响在小树和大树中是不同的。年龄独立模型和年龄依赖模型的预测结果非常接近。在模型中加入特定于树的随机参数，可以明显降低AIC和残差。然而，结果表明，只有在有可能对每棵树进行校准时，才应使用混合效应模型，否则应使用固定效应Kozak 97模型。双树皮厚度模型也拟合为固定效应Kozak 97模型。该模型表现得合乎逻辑，预测小树的相对树皮厚度较大，但绝对树皮厚度较小。挪威云杉
{"title":"Stem taper and bark functions for Norway spruce in Norway","authors":"T. Pukkala, K. Hanssen, K. Andreassen","doi":"10.14214/sf.10187","DOIUrl":"https://doi.org/10.14214/sf.10187","url":null,"abstract":"Based on data from long-term experimental fields with Norway spruce ( (L.) H. Karst.), we developed new stem taper and bark functions for Norway. Data was collected from 477 trees in stands across Norway. Three candidate functions which have shown good performance in previous studies (Kozak 02, Kozak 97 and Bi) were fitted to the data as fixed-effects models. The function with the smallest Akaike Information Criterion (AIC) was then chosen for additional analyses, fitting 1) site index-dependent and 2) age-dependent versions of the model, and 3) fitting a mixed-effects model with tree-specific random parameters. Kozak 97 was found to be the function with the smallest AIC, but all three tested taper functions resulted in fairly similar predictions of stem taper. The site index-dependent function reduced AIC and residual standard error and showed that the effect of site index on stem taper is different in small and large trees. The predictions of the age-independent and age-dependent models were very close to each other. Adding tree-specific random parameters to the model clearly reduced AIC and residual variation. However, the results suggest that the mixed-effects model should be used only when it is possible to calibrate it for each tree, otherwise the fixed-effects Kozak 97 model should be used. A model for double bark thickness was also fitted as fixed-effects Kozak 97 model. The model behaved logically, predicting larger relative but smaller absolute bark thickness for small trees.Picea abies","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Laine, L. Hamberg, Veli-Matti Saarinen, T. Saksa
The use of a white-rot fungus, (Pers. Ex Fr.) Pouzar, as a biocontrol agent against sprouting has been studied with good results. The aim of the study was to investigate the efficacy of two pre-commercial thinning machines, Tehojätkä and Mense, to spread an inoculum of as a biocontrol agent on freshly cut birch ( Roth and Ehrh.), European aspen ( L.), rowan ( L.), and goat willow ( L.) stumps (the fungal treatment) and compare that to the control (cutting only, done by Tehojätkä). Efficacy was investigated in terms of stump mortality and the number of sprouts per stump. This study was conducted in one stand and sprouting was investigated for three years after treatment. The fungal treatment resulted in higher mortality of stumps (34.0% for Tehojätkä and 41.5% for Mense after three years), compared to the control (13.4%). However, the fungal treatment did not decrease the number of sprouts per stump compared to the control. The low occurrence of basidiomata indicates that the accuracy of the spreading mechanism was not satisfactory, causing low mortality figures for the fungal treatment compared to previous studies. In the future, this mechanized method may provide a promising alternative in sprout control if the spreading mechanisms, the accuracy of the treatment, and consequently the efficacy could be improved.Chondrostereum purpureumC. purpureumBetula pendulaB. pubescensPopulus tremulaSorbus aucupariaSalix caprea
{"title":"The efficacy of Chondrostereum purpureum against sprouting of deciduous species after mechanized pre-commercial thinning","authors":"T. Laine, L. Hamberg, Veli-Matti Saarinen, T. Saksa","doi":"10.14214/SF.10195","DOIUrl":"https://doi.org/10.14214/SF.10195","url":null,"abstract":"The use of a white-rot fungus, (Pers. Ex Fr.) Pouzar, as a biocontrol agent against sprouting has been studied with good results. The aim of the study was to investigate the efficacy of two pre-commercial thinning machines, Tehojätkä and Mense, to spread an inoculum of as a biocontrol agent on freshly cut birch ( Roth and Ehrh.), European aspen ( L.), rowan ( L.), and goat willow ( L.) stumps (the fungal treatment) and compare that to the control (cutting only, done by Tehojätkä). Efficacy was investigated in terms of stump mortality and the number of sprouts per stump. This study was conducted in one stand and sprouting was investigated for three years after treatment. The fungal treatment resulted in higher mortality of stumps (34.0% for Tehojätkä and 41.5% for Mense after three years), compared to the control (13.4%). However, the fungal treatment did not decrease the number of sprouts per stump compared to the control. The low occurrence of basidiomata indicates that the accuracy of the spreading mechanism was not satisfactory, causing low mortality figures for the fungal treatment compared to previous studies. In the future, this mechanized method may provide a promising alternative in sprout control if the spreading mechanisms, the accuracy of the treatment, and consequently the efficacy could be improved.Chondrostereum purpureumC. purpureumBetula pendulaB. pubescensPopulus tremulaSorbus aucupariaSalix caprea","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"43 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Sirén, J. Ala-Ilomäki, Harri Lindeman, J. Uusitalo, Kalle E.K. Kiilo, A. Salmivaara, Ari Ryynänen
Factors affecting soil disturbance caused by harvester and forwarder were studied on mid-grained soils in Finland. Sample plots were harvested using a one-grip harvester. The harvester operator processed the trees outside the strip roads, and the remaining residues were removed to exclude the covering effect of residues. Thereafter, a loaded forwarder made up to 5 passes over the sample plots. The average rut depth after four machine passes was positively correlated to the volumetric water content at a depth of 0â10 cm in mineral soil, as well as the thickness of the organic layer and the harvester rut depth, and negatively correlated with penetration resistance at depths of both 0â20 cm and 5â40 cm. We present 5 models to predict forwarder rut depth. Four include the cumulative mass driven over a measurement point and combinations of penetration resistance, water content and the depth of organic layer. The fifth model includes harvester rut depth and the cumulative overpassed mass and provided the best fit. Changes in the penetration resistance (PR) were highest at depths of 20â40 cm. Increase in BD and VWC decreased PR, which increased with total overdriven mass. After four to five machine passes PR values started to stabilize.
{"title":"Soil disturbance by cut-to-length machinery on mid-grained soils","authors":"M. Sirén, J. Ala-Ilomäki, Harri Lindeman, J. Uusitalo, Kalle E.K. Kiilo, A. Salmivaara, Ari Ryynänen","doi":"10.14214/SF.10134","DOIUrl":"https://doi.org/10.14214/SF.10134","url":null,"abstract":"Factors affecting soil disturbance caused by harvester and forwarder were studied on mid-grained soils in Finland. Sample plots were harvested using a one-grip harvester. The harvester operator processed the trees outside the strip roads, and the remaining residues were removed to exclude the covering effect of residues. Thereafter, a loaded forwarder made up to 5 passes over the sample plots. The average rut depth after four machine passes was positively correlated to the volumetric water content at a depth of 0â10 cm in mineral soil, as well as the thickness of the organic layer and the harvester rut depth, and negatively correlated with penetration resistance at depths of both 0â20 cm and 5â40 cm. We present 5 models to predict forwarder rut depth. Four include the cumulative mass driven over a measurement point and combinations of penetration resistance, water content and the depth of organic layer. The fifth model includes harvester rut depth and the cumulative overpassed mass and provided the best fit. Changes in the penetration resistance (PR) were highest at depths of 20â40 cm. Increase in BD and VWC decreased PR, which increased with total overdriven mass. After four to five machine passes PR values started to stabilize.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bioeconomy development will create new opportunities for firms operating in the international wood products markets, and identifying and exploiting these opportunities is emphasized as a key concept to achieving business success. Our study will attempt to address a gap in the literature on sawmill industry business development from the viewpoint of international opportunity recognition. The aim of our study is to provide a holistic description on how small and medium-sized enterprises (SMEs) in the wood products industry recognize and exploit international business opportunities, and how they utilize network perspectives in this context. The subject was examined through Finnish wood product industry SMEs by interviewing 11 managers and industry representatives. The results suggest that SMEs recognize international opportunities reactively per se. Social networks formed in professional forums were an important information channel for identifying international opportunities. Through vertical business networks, such as sales agents, firms have been able to increase their international market presence and free their own resources for other important activities. Horizontal dyadic business networks were seen to facilitate new international opportunities through cooperation, while excessive reliance on vertical networks raised concerns and seemed not to be effective in international opportunity recognition. Institutional networks formed a systematic way of recognizing international opportunities, but more so at the initial market entry stage.
{"title":"Networks in international opportunity recognition among Finnish wood product industry SMEs","authors":"J. Hietala, R. Hänninen, M. Kniivilä, A. Toppinen","doi":"10.14214/sf.10151","DOIUrl":"https://doi.org/10.14214/sf.10151","url":null,"abstract":"Bioeconomy development will create new opportunities for firms operating in the international wood products markets, and identifying and exploiting these opportunities is emphasized as a key concept to achieving business success. Our study will attempt to address a gap in the literature on sawmill industry business development from the viewpoint of international opportunity recognition. The aim of our study is to provide a holistic description on how small and medium-sized enterprises (SMEs) in the wood products industry recognize and exploit international business opportunities, and how they utilize network perspectives in this context. The subject was examined through Finnish wood product industry SMEs by interviewing 11 managers and industry representatives. The results suggest that SMEs recognize international opportunities reactively per se. Social networks formed in professional forums were an important information channel for identifying international opportunities. Through vertical business networks, such as sales agents, firms have been able to increase their international market presence and free their own resources for other important activities. Horizontal dyadic business networks were seen to facilitate new international opportunities through cooperation, while excessive reliance on vertical networks raised concerns and seemed not to be effective in international opportunity recognition. Institutional networks formed a systematic way of recognizing international opportunities, but more so at the initial market entry stage.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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