Silva Fennica最新文献_第10页

Carbon emissions from dryland shifting cultivation: a case study of Mexican tropical dry forest. 旱地轮作产生的碳排放：以墨西哥热带干林为例的研究。

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2017-03-02 DOI: 10.14214/SF.1553

M. Salinas-Melgoza, M. Skutsch, J. Lovett, A. Borrego

{"title":"Carbon emissions from dryland shifting cultivation: a case study of Mexican tropical dry forest.","authors":"M. Salinas-Melgoza, M. Skutsch, J. Lovett, A. Borrego","doi":"10.14214/SF.1553","DOIUrl":"https://doi.org/10.14214/SF.1553","url":null,"abstract":"The article considers the relation of shifting cultivation to deforestation and degradation, and hence its impacts in terms of carbon emissions and sequestration potential. There is a need to understand these relationships better in the context of international policy on Reduced Emissions from Deforestation and Forest Degradation (REDD+). The article reviews the way in which shifting cultivation has been incorporated in global and national estimations of carbon emissions, and assembles the available information on shifting cultivation in Tropical Dry Forests (TDF) in Mexico, where it is widely practiced. It then takes the case of two villages, Tonaya and El Temazcal, which lie within the basin of the River Ayuquila in Jalisco, Mexico. Field data for the typical carbon stocks and fluxes associated with shifting cultivation are compared with stocks and fluxes associated with more intensive agricultural production in the same dry tropical forest area to highlight the carbon sequestration dynamics associated with the shortening and potential lengthening of the fallow cycles. The biomass density in the shifting cultivation system observed can reach levels similar to that of old growth forests, with old fallows (>20 years) having higher carbon stocks than old growth forests. Per Mg of maize produced, the biomass-related emissions from shifting cultivation in the traditional 12 year cycle are about three times those from permanent cultivation. We did not, however, take into account the additional emissions from inputs that result from the use of fertilizers and pesticides in the case of permanent agriculture. Shortening of the fallow cycle, which is occurring in the study area as a result of government subsidies, results in higher remaining stocks of carbon and lower emissions at the landscape level.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2017-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44380253","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}

引用次数: 14

Effect of deployment-type on stem growth, biomass partitioning and crown characteristics of juvenile Sitka spruce clones 展开型对锡特卡云杉幼树无性系茎生长、生物量分配和树冠特性的影响

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2017-01-31 DOI: 10.14214/sf.1714

L. Donnelly, O. M. Grant, C. O'Reilly

{"title":"Effect of deployment-type on stem growth, biomass partitioning and crown characteristics of juvenile Sitka spruce clones","authors":"L. Donnelly, O. M. Grant, C. O'Reilly","doi":"10.14214/sf.1714","DOIUrl":"https://doi.org/10.14214/sf.1714","url":null,"abstract":"Competitive interactions in clonal forestry are not well understood and this needs to be addressed to develop better deployment strategies. Eight juvenile Sitka spruce (Picea sitchensis (Bong.) Carriére) clones were grown in monoclonal and clonal mixtures in a field experiment for three years to assess the effects of genetic diversity on shoot growth, aboveand below-ground biomass partitioning and crown characteristics. Shoot elongation was measured throughout the growing season, while diameter was measured twice annually in May and December. After the third year, crown silhouette area was estimated from digitised images for one ramet per plot and ramets were then destructively harvested. Deployment × clone interactions were observed for tree height and diameter with reductions observed in mixed plots. Mixed plots had significantly greater height and diameter heterogeneity and more asymmetrical competition than monoclonal plots. Results from this study demonstrate that stem growth can be significantly altered when clones are planted in multi-clonal mixtures but for most clones, deployment-type will not significantly reduce their productivity.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2017-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45443201","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}

引用次数: 1

The effect of mechanization level and harvesting system on thinning cost and impact under Mediterranean forest conditions 地中海森林条件下机械化水平和采伐制度对间伐成本和影响的影响

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2014-01-01 DOI: 10.14214/SF.1003

R. Spinelli, C. Lombardini, N. Magagnotti

引用次数: 31

Spatial statistics in ecological analysis: from indices to functions 生态分析中的空间统计:从指标到功能

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2014-01-01 DOI: 10.14214/SF.1008

J. Szmyt

{"title":"Spatial statistics in ecological analysis: from indices to functions","authors":"J. Szmyt","doi":"10.14214/SF.1008","DOIUrl":"https://doi.org/10.14214/SF.1008","url":null,"abstract":"This paper presents a review of the most common methods in ecological studies aimed at spatial analysis of population structures (horizontal and vertical), based on point process statistics. Methods based on simple spatially explicit indices as well as more sophisticated methods relying on functions are described in a comprehensible manner. Simple indices revealing the information on spatial structure at the scale of the nearest neighbor can be easily implemented in practical forestry. On the other hand, spatial functions, based on much more detailed data, describe the spatial structure in terms of the spatial relationships between the natural processes and population structures and because of this complexity they are rarely used in forest practice. Including both methods in a single paper is also valuable from the potential reader’s point of view saving their time for searching and choosing the appropriate method to make their spatial analysis. This paper can also serve as an initial guide for young researchers or those who are going to start their studies on spatial aspects of bio-systems. Avoiding the statistical and mathematical details makes this paper understandable for readers who are not statisticians or mathematicians. Readers will","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767273","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}

引用次数: 57

Reconstructing leaf growth based on non-destructive digitizing and low-parametric shape evolution for plant modelling over a growth cycle 基于非破坏性数字化和低参数形状演化的叶片生长重建，用于植物生长周期建模

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2014-01-01 DOI: 10.14214/SF.1019

M. Henke, S. Huckemann, W. Kurth, B. Sloboda

引用次数: 8

Evaluation of growth functions used in the Swedish Forest Planning System Heureka 瑞典森林规划系统中使用的生长函数评价

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2014-01-01 DOI: 10.14214/SF.1013

Nils Fahlvik, B. Elfving, P. Wikström

{"title":"Evaluation of growth functions used in the Swedish Forest Planning System Heureka","authors":"Nils Fahlvik, B. Elfving, P. Wikström","doi":"10.14214/SF.1013","DOIUrl":"https://doi.org/10.14214/SF.1013","url":null,"abstract":"The performance of growth models implemented in the Swedish Forest Planning System Heureka was evaluated. Four basal area growth models were evaluated by comparing their predictions to data from five-year growth records for 1711 permanent sample plots of the National Forest Inventory (NFI-data). Also, two alternative implementations of Heureka, including a combined stand- and tree-level basal area growth model and a single tree-level model, respectively, were evaluated using data from 57 blocks in a thinning experiment (GG-data) involving Scots pine ( Pinus sylvestris L.) and Norway spruce ( Picea abies (L.) Karst) in which the trees were monitored for 30 years after the first thinning. The predicted volume growth was also compared to observed values. Growth models based on data from 1970’s and 1980’s overestimated growth in the NFI test plots from the early 2000’s by about 3%. Stand-level models had larger precision than tree-level models. Basal area growth was underestimated in dense NFI-plots and overestimated in non-thinned GG-plots, illustrating an un-solved modelling problem. Basal area growth was overestimated by 2–5% also in the GG-plots over the whole observation period. Volume growth was however accurately predicted for pine and underestimated by 2% for spruce. The relative prediction error did not increase with increasing length of prediction period. Thinning response models calibrated with GG-data worked well in the total application and produced growth levels for different thinning alternatives in line with observations.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767417","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}

引用次数: 71

On the possibility to monitor and assess forest damage within large scale monitoring programmes – a simulation study 关于在大规模监测方案内监测和评估森林损害的可能性-模拟研究

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2013-01-01 DOI: 10.14214/SF.1000

S. Wulff, C. Roberge, Anna H. Ringvall, S. Holm, G. Ståhl

{"title":"On the possibility to monitor and assess forest damage within large scale monitoring programmes – a simulation study","authors":"S. Wulff, C. Roberge, Anna H. Ringvall, S. Holm, G. Ståhl","doi":"10.14214/SF.1000","DOIUrl":"https://doi.org/10.14214/SF.1000","url":null,"abstract":"There is a growing demand for information on forest health due to fears that climate change may cause new kinds of damage that have not previously been encountered. In many cases, forest damage monitoring is conducted exclusively within sparse large-scale grids of sample plots and it is doubtful whether these are capable of providing relevant information to support mitigation programmes or other actions required to reduce economic losses due to damage outbreaks. In this study, we used simulated sampling to assess the precision of estimators related to forest state and changes in the damage sustained by trees within an area corresponding to the Swedish region Götaland, assuming a sampling design corresponding to that used in the Swedish National Forest Inventory (NFI) under different damage scenarios. Large and uniformly distributed damage outbreaks were well captured by an NFI-type inventory, but scattered damage outbreaks produced estimates with poor precision. As a consequence, we propose that there might be a need to revise current forest damage monitoring programmes to make them more useful for monitoring the kinds of damage that are likely to arise as a consequence of climate change.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66766965","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}

引用次数: 10

Carbon stores and fluxes in even- and uneven-aged Norway spruce stands 年龄均匀和不均匀的挪威云杉林的碳储量和通量

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2013-01-01 DOI: 10.14214/SF.1024

P. Nilsen, L. Strand

{"title":"Carbon stores and fluxes in even- and uneven-aged Norway spruce stands","authors":"P. Nilsen, L. Strand","doi":"10.14214/SF.1024","DOIUrl":"https://doi.org/10.14214/SF.1024","url":null,"abstract":"This investigation compares present C stores, fluxes and historic tree C sequestration in an uneven-aged and an even-aged Norway spruce stand under similar high productive soil conditions in south-eastern Norway. A selection cutting system has been performed in the uneven-aged forest stand for 81 years and the even-aged stand was established after clear-cutting 81 years ago. Timber productivity has been measured in the uneven stand for 81 years and in the even-aged stand for 52 years. C storage was determined based on tree measurements, tree biomass functions, soil samples and C analyses from trees and soil. Litter fall was sampled during one year and CO2 efflux from the soil was measured during one growing season. The present tree C storage (including roots) was 210 Mg C ha–1 in the even-aged stand and 76 Mg C ha–1 in the uneven-aged stand, while the corresponding figures for C in the soil was 178 and 199 Mg C ha–1. The long term timber production in the uneven-aged stand was measured to be 95% of the even-aged stand and the difference in net C sequestration was 37 Mg ha–1 in an 81 year period in favour the even-aged stand. The highest present CO2 efflux from soil was measured in the even-aged stand. The total net C sequestered in trees during 81 years minus the present soil C-stock accounts to 16 Mg ha-1 in favour the even-aged system.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767733","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}

引用次数: 24

Estimating the bioenergy potential of forest chips from final fellings in Central Finland based on biomass maps and spatially explicit constraints 基于生物量图和空间明确约束估算芬兰中部最终采伐的森林碎片的生物能源潜力

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2013-01-01 DOI: 10.14214/SF.1022

E. Muinonen, P. Anttila, J. Heinonen, J. Mustonen

{"title":"Estimating the bioenergy potential of forest chips from final fellings in Central Finland based on biomass maps and spatially explicit constraints","authors":"E. Muinonen, P. Anttila, J. Heinonen, J. Mustonen","doi":"10.14214/SF.1022","DOIUrl":"https://doi.org/10.14214/SF.1022","url":null,"abstract":"The technical potential of forest chips from final fellings in Central Finland was estimated using a method based on biomass maps derived from a multi-source forest inventory technique. Image segmentation techniques were applied to a satellite image mosaic to detect stand boundaries. The technical potential of forest chips was computed based on primary forestry residues, i.e. logging residues and stumps from final fellings. Harvesting level definitions for final fellings were established using realized statistics for roundwood at the municipality level as well as larger area statistics. The sensitivity of the potential to ecological and technical constraints in the model was also examined. The technical recovery rate of stump harvesting according to biomass harvesting guidelines was evaluated separately. The critical prerequisites for using the advanced, spatially explicit approach to analysing forest energy potentials may lie in the existence of spatially explicit forest inventory data and the biometric models for tree biomass assortments. The method applied was capable of taking into account the constraints that rely upon map data, such the actual forwarding distance or steepness of the slope in the terrain. The calculation results can be used for strategic decision making in the field of forest bioenergy production.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66768117","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}

引用次数: 8

Effects of the number of assortments and log concentration on time consumption for forwarding 分类数和日志集中度对转发耗时的影响

IF 1.8 3区农林科学

Silva Fennica Pub Date : 2013-01-01 DOI: 10.14214/SF.1030

Jussi Manner, T. Nordfjell, O. Lindroos

{"title":"Effects of the number of assortments and log concentration on time consumption for forwarding","authors":"Jussi Manner, T. Nordfjell, O. Lindroos","doi":"10.14214/SF.1030","DOIUrl":"https://doi.org/10.14214/SF.1030","url":null,"abstract":"Forwarding has been carried out for 50 years, but much is still unknown about this work. Its complexity comes from both stand features and essential decision-making. Forwarding time consumption is influenced by e. g. log concentrations and number of assortments. Traditionally, focus has been on the total log concentration (TLC), referring to all logs at the harvesting site. However, we focused on forwarded log concentration (FLC), the load-specific log concentration which depends on the assortment distribution at harvesting site and the load-specific number of assortments. To evaluate the effects of TLC, number of assortments in a load and FLC on the loading and unloading times, a standardized field experiment was carried out. Pile and load sizes were constant, while TLC and FLC were manipulated by varying the pile distribution on the test path. For all work elements, the time consumption per m(3) was significantly affected by the number of assortments that were loaded, but only the \"driving while loading\" work element was also significantly influenced by TLC. However, when untangling the intercorrelation between tested factors, it was found that the time consumption for driving while loading significantly decreased as a function of FLC and was unaffected by the number of assortments in a load. That FLC influences the forwarding time consumption highlights the need to study the effects of combining various assortment proportions in a load. Such knowledge will enable analysis of the most efficient number and assortment proportions to combine in the various loads required to forward a given stand.","PeriodicalId":49520,"journal":{"name":"Silva Fennica","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66767706","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}

引用次数: 137