Effect of wind damage on the habitat suitability of saproxylic species in a boreal forest landscape

Many forest-dwelling species are dependent on deadwood. Sources of deadwood include competition- and senescence-related mortality of trees, and various damages. This study described a methodology for predicting the effect of wind damage on the amount of deadwood and suitability of the forest for saproxylic species. The methodology was used in a forested boreal landscape of 360 ha to analyze the effects of wind damage on the habitat quality for 27 groups of saproxylic species differing in their requirements for the species, size and decay stage of deadwood objects. A reference plan maximized net present value (MaxNPV) while others either minimized or maximized height differences between adjacent stands. Maximization of height differences resulted in high amount of wind damage and deadwood while minimizing height differences minimized wind damage and the amount of damage-related deadwood. The fourth plan maximized the average habitat suitability index (HSI) of the 27 groups of saproxylic species. The plans were compiled with and without even-flow harvesting constraints for three 10-year periods. Maximization of height differences between adjacent stands resulted in higher HSI values than obtained in the MaxNPV plan or in the plan than minimized height differences between adjacent stands. The average HSI of shade-demanding species correlated negatively with the amount of harvested timber. No strong correlations were found for light-demanding and indifferent species.

Evaluation of Four Methods for Restoring a Degraded Swamp Forest

Swamp Forests occur in permanently wet soils, with specific ecosystem which contributes to the conservation of biodiversity and water resources. However, there are many gaps in knowledge about the restoration of these forests. The present study was conducted in a degraded wetland in the town of Mineiros do Tietê, located in the state of S?o Paulo, Brazil, in order to test the efficiency of four methods for restoring a Swamp Forest (small mound, acclimated seedling, dry season and conventional tillage), using six forest tree species typical of this type of forest: Calophyllum brasiliense Cambess., Citharexylon myrianthum Cham., Cedrela odorata L., Tapirira guianensis Aubl., Ficus insipida Willd. and Croton urucurana Baill. The least favorable methods for all plant species were: conventional and soil pit tillageindry seasons. Analyzing the plant species individually, the best results in descending order were: Croton urucurana Baill. (acclimated seedling tillage in dry season), followed by Calophyllum brasiliense Cambess. (insmall mounds), Citharexylon mirianthum Cham. (with acclimated seedlings), Ficus insipida Willd. and Tapirira guianensis Aubl. (insmall mounds). Cedrela odorata L. presented low performance in all conditions, probably because it suffered the Hypsipyla grandella Zeller. The results have been successful for the establishment of Swamp Forest restoration strategies.

Indicators and tools for assessing sustainability impacts of the forest bioeconomy

The sustainable use of renewable resources has become an important issue worldwide in the move towards a less fossil-fuel-intensive future.Mainstream method for fulfilling this aim is to increase the share of renewable energy and materials to substitute fossil fuels and to become fully independent from fossil fuels over the long-term.However, the environmental sustainability of this endeavor has been questioned.In addition,economic and social sustainability issues are also much debated topics in this particular context.Forest resources are often thought to contribute partially to achieving a so-called ＂carbon-neutral society＂.In this review, we discuss sustainability issues of using forest biomass.We present several sustainability indicators for ecological,economic and social dimensions and discuss the issues in applying them in sustainability impact assessments（SIAs）.We also present a number of tools and methods previously used in conducting SIAs.We approach our study from the perspective of the Finnish forestry; in addition, various aspects regarding the application of SIAs in a broader context are also presented.One of the key conclusions of the study is that although sufficient data are available to measure many indicators accurately, the impacts may be very difficult to assess（e.g.impact of greenhouse gases on biodiversity） for conducting a holistic SIA.Furthermore, some indicators, such as ＂biodiversity＂, are difficult to quantify in the first place.Therefore, a mix of different methods, such as Multi-criteria Assessment, Life-cycle Assessment or Cost-Benefit Analysis, as well as different approaches（e.g.thresholds and strong/weak sustainability） are needed in aggregating the results of the impacts.SIAs are important in supporting and improving the acceptability of decision-making, but a certain degree of uncertainty will always have to be tolerated.

On the potential to predetermine dominant tree species based on sparse-density airborne laser scanning data for improving subsequent predictions of species-specific timber volumes

Background： Tree species recognition is the main bottleneck in remote sensing based inventories aiming to produce an input for species-specific growth and yield models. We hypothesized that a stratification of the target data according to the dominant species could improve the subsequent predictions of species-specific attributes in particular in study areas strongly dominated by certain species. Methods： We tested this hypothesis and an operational potential to improve the predictions of timber volumes, stratified to Scots pine, Norway spruce and deciduous trees, in a conifer forest dominated by the pine species. We derived predictor features from airborne laser scanning （ALS） data and used Most Similar Neighbor （MSN） and Seemingly Unrelated Regression （SUR） as examples of non-parametric and parametric prediction methods, respectively Results： The relationships between the ALS features and the volumes of the aforementioned species were considerably different depending on the dominant species. Incorporating the observed dominant species inthe predictions improved the root mean squared errors by 13.3-16.4 % and 12.6-28.9 % based on MSN and SUR, respectively, depending on the species. Predicting the dominant species based on a linear discriminant analysis had an overall accuracy of only 76 % at best, which degraded the accuracies of the predicted volumes. Consequently, the predictions that did not consider the dominant species were more accurate than those refined with the predicted species. The MSN method gave slightly better results than models fitted with SUR. Conclusions： According to our results, incorporating information on the dominant species has a clear potential to improve the subsequent predictions of species-specific forest attributes. Determining the dominant species based solely on ALS data is deemed challenging, but important in particular in areas where the species composition is otherwise seemingly homogeneous except being dominated by certain species.

Predicting stand age in managed forests using National Forest Inventory field data and airborne laser scanning

Background: The aim of this study was to construct a nationwide stand age model by using National Forest Inventory(NFI) data and nationwide airborne laser scanning(ALS) data. In plantation forestry, age is usually known.While this is not the case in boreal managed forests, age is still seldom predicted in forest management inventories.Measuring age accurately in situ is also very laborious. On the other hand, tree age is one of the accurately measured sample tree attributes in NFI field data. Many countries also have a nationwide coverage of airborne laser scanning(ALS) data. In this study, we merged these data sources and constructed a nationwide, area-based model for stand age.Results: While constructing the model, we omitted old forests from the data, since the correlation between ALS height metrics and stand age diminished at stands with age > 100 years. Additionally, the effect of growth conditions was considerable, so we also utilized different geographical and NFI variables such as site fertility and soil type in the modeling. The resultant nationwide model for the stand age of managed forests yielded a root mean square error(RMSE) of about 14 years. The model could be improved further by additional forest structure variables, but such information may not be available in practice.Conclusions: The results showed that the prediction of stand age by ALS, geographical and NFI information was challenging, but stil possible with moderate success. This study is an example of the joint use of NFI and nationwide ALS data and re-use of NFI data in research.

Inventory of aspen trees in spruce dominated stands in conserva-tion area

Background： The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging. Methods： We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes： volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collected from three separate forest stands in Koli National Park, eastern Finland. At each site, we measured breast height diameter and coordinates of each aspen. The comparison of inventory methods of aspens within the three stands was based on simulations with mapped field data. We mimicked stand level inventory by locating varying numbers of fixed area circular plots both systematically and randomly within the stands. Additionally, we also tested if the use of airborne laser scanning （ALS） data as auxiliary information would improve the accuracy of the stand level inventory by applying the probability proportional to size sampling to assist the selection of field plot locations. Results： The results showed that aspens were always clustered, and the diameter distributions indicated different stand structures in the three investigated forest stands. The reliability of the volume and number of large aspen trees varied from relative root mean square error figures above 50% with fewer sample plots （5-10） to values of 25%-50% with ]0 or more sample plots. Stand level inventory estimates were also able to detect spatial pattern and the shape of the diameter distribution. In addition, ALS-based auxiliary information could be useful in guiding the inventories, but caution should be used when applying the ALS-supported inventory technique. Conclusions： This study characterized European aspen populations for the purposes of monitoring and management of boreal conservation areas. Our results suggest that if the number of sample plots is adequate, i.e. 10 or more stand level inventory will provide accurate enough forest attributes estimates in conservation areas （minimum accuracy requirement of RMSE% is 20%-50%）. Even for the more ecologically valuable attributes, such as diameter distribution, spatial pattern and large aspens, the estimates are acceptable for conservation purposes

Using mixed integer programming and airborne laser scanning to generate forest management units

Airborne laser scanning(ALS)has been widely applied to estimate tree and forest attributes,but it can also drive the segmentation of forest areas.Clustering algorithms are the dominant technique in segmentation but spatial optimization using exact methods remains untested.This study presents a novel approach to segmentation based on mixed integer programming to create forest management units(FMUs).This investigation focuses on using raster information derived from ALS surveys.Two mainstream clustering algorithms were compared to the new MIP formula that simultaneously accounts for area and adjacency restrictions,FMUs size and homogeneity in terms of vegetation height.The optimal problem solution was found when using less than 150 cells,showing the problem formulation is solvable.The results for MIP were better than for the clustering algorithms;FMUs were more compact based on the intravariation of canopy height and the variability in size was lower.The MIP model allows the user to strictly control the size of FMUs,which is not possible in heuristic optimization and in the clustering algorithms tested.The definition of forest management units based on remote sensing data is an important operation and our study pioneers the use of MIP ALS-based optimal segmentation.

Prospects of Synthetic Biodiesel Production from Various Bio-Wastes in Jordan

The main objectives of this technical experiment are to quantify the amount of various bio-wastes available for the bioenergy development in Jordan and investigate the prospects of biodiesel potentials from such bio-wastes using catalytic depolymerization technology developed in the German company ALPHAKAT. The quantification process revealed substantial quantities of bio-wastes originated from various sectors such as dairy and poultry farms, by-products of wastewater treatment plants, and agriculture by-products. The results show that olive cake provides the highest potential for biodiesel production with a ratio of 39%. Chemical analysis showed varying levels of sulfur contents, which required desulfurization unit to produce standard quality biodiesel. Chemical analysis also showed high phosphorus content, which provided another economic opportunity to use the biodiesel by-products as a fertilizer. The statistical correlation test showed a strong linear correlation between the percentage of organic content and caloric value and biodiesel output. The study also unveiled that the C:H ratio is strongly correlated with the biodiesel production model. The regression analysis generated a model for biodiesel production, which can be used to evaluate the biodiesel production based on the net dry biomass and C:H ratio in the substrate. Based on the model, the study estimated the potential of biodiesel from olive cake to reach up to 4 million liters annually. Policymakers and involved governmental institutes are advised to develop new regulations and laws to increase the share of bioenergy in the primary energy mix through attracting co-public investments accompanied by supportive economic tools such as starter loans, tax exemptions, and feedin-tariffs. Further research is needed to quantify other sources of bio-wastes such as cooking-oil wastes.

Checking of Radially Sawn Scots Pine and Norway Spruce Wood

In exterior use, wood is subjected to weathering that causes checking and other deterioration in the appearance and technical properties. We studied quantitatively the surface checking of radially and tangentially sawn specimens of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies Karst.) wood in a cyclic climate chamber test. The results strongly suggested that the sawing direction determines the checking performance of both Scots pine and Norway spruce wood. The radial surface of Scots pine specimens had 62% less checks than the tangential one, and the cumulative area of checks was 74% smaller. For Norway spruce, the respective figures were: 83% less in the check number and 91% less in the check area. Different from pine, in spruce specimens the checks of radial surface were significantly smaller. Thus, spruce timber gained clearly more about radial sawing pattern. The effect of annual ring width was similar for pine and spruce: the reduction in annual growth worsened the checking. The increase in density worsened the checking of spruce but did not change the performance of pine. In pine wood, the increase of heartwood proportion reduced the fluctuation of moisture content and the formation of checks.

The coppice-with-standards silvicultural system as applied to Eucalyptus plantations-a review

We review the management of Eucalyptus species under a coppice-with-standards （CWS） silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from the same stand. Eucalyptus species are suitable candidates for CWS management because： there are large worldwide plantation areas, sprouting capacity is high, and eucalypts are multipur- pose species. We discuss （1） short rotation Eucalyptus coppice manage- ment for energy and pulping and （2） Eucalyptus seedling management for solid wood products. We review the literature and discuss experi- ences with Eucalyptus managed under the CWS system. We also assess projects dealing with Eucalyptus coppice management, stand density regulation, pruning, and stand and wood quality. The growth environ- ment of the standard trees （heavy competition up to the first harvest, free growth afterwards） coupled with long rotations （〉20 years） results in high quality logs for solid wood products. Early pruning should be ap- plied to enhance wood quality. We propose a system for the silvicultural management of Eucalyptus under the CWS system, elaborating on the consequences of initial planting density, site productivity, and standard tree densities as well as timing of basic silvicultural applications.

Experimental evidence on biodiversity impacts of variable retention forestry,prescribed burning,and deadwood manipulation in Fennoscandia

Intensive forest management has been applied in most Fennoscandian forests for a period of almost one felling rotation.This paradigm has produced even-aged and even-structured forests of different successional stages that cover about 90%of forest land.At the same time,wildfires have been nearly eliminated in most of the Fennoscandian nature.Consequently,hundreds of species are red-listed because of forest management.To support these species,forest management requires improvements.Variable retention forestry and habitat restoration have been suggested to mitigate negative effects of forest management on biodiversity,and these have been practiced to some extent during the past few decades.Here,we review experimental results on the effects of variable retention and two restoration measures(prescribed burning and artificial addition of coarse woody debris)on different species groups in Fennoscandia.Our key findings are as follows:(i)Many species respond positively to felling within a few years,apparently due to released and often ephemeral resources,such as fresh residue and stumps.Species associated with shady conditions are negatively impacted,but any retention supports many of these,and their species composition remains almost unaffected with 50-70%retention of the initial tree volume.(ii)These effects remain detectable for at least 10-30 years or,according to some studies,nearly 100 years,e.g.,in polypore fungi.(iii)Initial effects of prescribed burning on most species groups(apart from pyrophiles)are negative,but within 10-15 years post-fire sites begin to support many rare and threatened deadwood-dependent species.Epiphytic lichens,however,remain negatively affected.(iv)Artificial addition of deadwood(mostly high stumps)supports a wide spectrum of deadwood-dependent species,but the species composition differs from that of naturally died trees.(v)Moisture and micro-habitat variation are crucial for forest species at harvested sites,at least in forests dominated by Norway spruce.We conclude that felling method as such is of little importance for threatened forest species,although retention mitigates many negative effects.These species require microclimatic continuity,and maintenance and active increase of legacies,such as deadwood of different qualities(species,downed/standing,snag/log/stump,decay stage),very old trees,and tree species mixtures.

Combining spatial and economic criteria in tree-level harvest planning

Background:Modern remote sensing methods enable the prediction of tree-level forest resource data.However,the benefits of using tree-level data in forest or harvest planning is not clear given a relative paucity of research.In particular,there is a need for tree-level methods that simultaneously account for the spatial distribution of trees and other objectives.In this study,we developed a spatial tree selection method that considers tree-level(relative value increment),neighborhood related(proximity of cut trees)and global objectives(total harvest).Methods:We partitioned the whole surface area of the stand to trees,with the assumption that a large tree occupies a larger area than a small tree.This was implemented using a power diagram.We also utilized spatially explicit tree-level growth models that accounted for competition by neighboring trees.Optimization was conducted with a variant of cellular automata.The proposed method was tested in stone pine(Pinus pinea L.)stands in Spain where we implemented basic individual tree detection with airborne laser scanning data.Results:We showed how to mimic four different spatial distributions of cut trees using alternative weightings of objective variables.The Non-spatial selection did not aim at a particular spatial layout,the Single-tree selection dispersed the trees to be cut,and the Tree group and Clearcut selections clustered harvested trees at different magnitudes.Conclusions:The proposed method can be used to control the spatial layout of trees while extracting trees that are the most economically mature.

Biochar as adsorbent in purification of clear-cut forest runoff water:adsorption rate and adsorption capacity

Forest management practices in boreal peatlands increase nutrient export and suspended solids to watercourses calling for development of new water protection methods.One potential solution could be adsorption-based purification of runoff water using biochar.The aim of this study was to determine the adsorption rate and capacity for Norway spruce and silver birch biochars to design a biochar-filled reactor for a ditch drain.In a 10-day laboratory experiment,biochar was stirred with runoff water from a clear-cut peatland forest,and changes in water pH,total nitrogen,nitrate nitrogen,ammonium nitrogen,phosphorus,and total organic carbon concentrations were measured.Based on the concentration changes,adsorption was quantified and adsorption model containing the adsorption rate and capacity was fitted to the data.Our results indicate that biochar effectively adsorbs both inorganic and organic nitrogen from runoff water.Birch biochar had higher adsorption capacity of nitrogen than spruce biochar.This study demonstrates that the adsorption of nitrogen compounds onto biochar surfaces increases with increasing initial concentrations.Thus,aquatic ecosystems exposed to high nutrient loads from fertile peatlands would particularly benefit from biochar-based water purification.

A Technical Experiment on Biogas Production from Small-Scale Dairy Farm

The key objective of this study was to evaluate the economic feasibility of producing biogas from privately-owned dairy farm in the North of Jordan. This experiment did not adopt Best-Available-Technology (BAT) but rather traditional unit manufactured with minimized costs through installing locally produced materials to avoid economic burden on the farmers’ production costs. A thermophilic biodigester unit was built sub-surface with 22 m3 capacity (15 m3 manure tank plus 7 m3 biogas holder) in a relatively small scale dairy farm. The daily feed was about 500 liter of cow slurry (150 - 200 liter cow manure) and the remaining were production liquids. The retention time was approximately 25 - 30 days and the seasonal temperature measured was about 18°C - 20°C. The unit was thermally insulated;therefore, the temperature fluctuation was slightly around +/-3°C. The daily biogas production was estimated at 7 m3 equivalent to 4 kg of Liquefied Petroleum Gas (LPG) or 11 (12.5 kg) LPG cylinders per month worth US$140. The methane percentage was 60% in relatively warm temperature (18°C - 20°C) and approximately 56% in colder

Most similar neighbor imputation of forest attributes using metrics derived from combined airborne LIDAR and multispectral sensors

In the context of predicting forest attributes using a combination of airborne LIDAR and multispectral(MS)sensors,we suggest the inclusion of normalized difference vegetation index(NDVI)metrics along with the more traditional LIDAR height metrics.Here the data fusion method consists of back-projecting LIDAR returns onto original MS images,avoiding co-registration errors.The prediction method is based on nonparametric imputation(the most similar neighbor).Predictor selection and accuracy assessment include hypothesis tests and over-fitting prevention methods.Results show improvements when using combinations of LIDAR and MS compared to using either of them alone.The MS sensor has little explanatory capacity for forest variables dependent on tree height,already well determined from LIDAR alone.However,there is potential for variables dependent on tree diameters and their density.The combination of LIDAR and MS sensors can be very beneficial for predicting variables describing forests structural heterogeneity,which are best described from synergies between LIDAR heights and NDVI dispersion.Results demonstrate the potential of NDVI metrics to increase prediction accuracy of forest attributes.Their inclusion in the predictor dataset may,however,in a few cases be detrimental to accuracy,and therefore we recommend to carefully assess the possible advantages of data fusion on a case-by-case basis.

Research on retention forestry in Northern Europe

Retention approaches in forest management are today common in several North European countries,integrated into the clearcutting practice as a way to promote biodiversity and maintain ecosystem functions.Individual green trees and retention patches(tree groups)are retained at final harvest,and deadwood is left at site or created.Here,we review research on retention in Sweden,Finland,Norway,the Baltic States,and NW Russia,with special focus on biodiversity.Following the first publication in 1994,about 180 peer-reviewed articles have been published.We present results from a systematic search of the retention literature,separated into the following topics:buffer zones,retention patches,high stumps,other types of deadwood,European aspen Populus tremula,and cost-efficiency.Russian literature is synthesized separately since studies from this region have so far almost exclusively been published in the Russian language.Furthermore,we describe six ongoing large-scale,replicated experiments with varying retention levels,five in Finland and one in Sweden,and summarize their main results.Among main conclusions for practice from the literature and experiments are that retention patches as large as 0.5 ha and 10-mwide buffers to watercourses are not enough to maintain pre-harvest species composition but survival of forest species is still larger than on conventional clearcuts.Deadwood on clearcuts may present important habitats to saproxylic species,including rare and red-listed ones and a prioritization of tree species per stand is recommended.We identify several important future research directions including switch of focus towards the landscape as well as the species population level.Surveys in parts of European Russia where retention has been unintentionally implemented already for a century would indicate possible future trajectories of biodiversity and their drivers in other regions of Northern Europe.A stronger link to ecological theory would help in study designs and in the formulation of predicted outcomes.

长白落叶松人工林多目标经营模式研究

【目的】我国林业目前处于提高森林资源质量和转变发展方式的关键阶段,林分水平的经营决策对科学制订森林经营规程、提高森林质量具有重要意义。利用模拟-优化系统,探究不同林分条件下的最佳经营模式,可为提高黄花落叶松(Larix olgensis)(俗名长白落叶松)人工林多目标经营水平提供理论基础和实施方案。【方法】以标准长白落叶松人工幼龄林为研究对象,利用多属性效用函数和妥协性分析构建包括净现值、大径材产量和林木碳储量的多目标经营模型,链接林分生长模型与粒子群优化算法,优化不同经营方程并提出经营模式。【结果】在不同造林密度(2 500和3 300株/hm^(2))及不同地位指数(16~22 m)下两种多目标方程(MOF1和MOF2)估算的林分主伐年龄为54~96 a,净现值为38 047.8~109 194.9元/hm^(2),大径材年均产量为1.8~4.4 m3/(hm^(2)·a),轮伐期内年均林木碳储量为59.7~103.1 t/(hm^(2)·a)。随着林木碳储量权重的增加(从MOF1到MOF2),大径材产量提高,但净现值降低。【结论】本研究提出的多目标经营模式可以满足对木材产量、质量和经济效益的需求,同时兼顾了森林碳储量,其中多目标经营方程MOF1是权衡各目标效益的折中方案,研究结论对提升我国森林多功能经营管理水平具有重要借鉴意义。

Bamboo biochar greater enhanced Cd/Zn accumulation in Salix psammophila under non-flooded soil compared with flooded

As a metal immobilizer,biochar can be used to remediate contaminated soil.Biochar’s effect on the phytoremediation process in flooded conditions under a scenario of increasing flooding frequency as global climate change is not well understood.This study investigated bamboo biochar(BBC)effects on growth and metal accumulation of Salix in multi-metal contaminated soil under non-flooded versus flooded conditions.Salix cuttings were cultivated in pots with severely contaminated soil by Cd and Zn,for 120 days,with four treatments including non-flooded treatment,flooded treatment,non-flooded with 3%BBC application(BBC/soil,w/w),and flooded with 3%BBC addition.BBC,flooding,and BBC×flooding significantly decreased the bioavailability of metals in soils(P<0.05).The BBC addition markedly stimulated Cd concentration in leaves under non-flooded(94.20%)and flooded conditions(32.73%)but showed little effect on roots.The BBC significantly boosted Cd and Zn transport from roots to aboveground parts by 68.85%and 102.27%compared with no BBC amendment under non-flooded treatment,while showing insignificant changes under flooded treatment.Although the plant biomass was little affected,BBC significantly increased Cd and Zn accumulation in the whole plant by 52.53%and 28.52%under non-flooded while showing an insignificant impact under flooded conditions.Taken together,BBC enhanced the phytoremediation efficiency of Salix to Cd and Zn in severely polluted non-flooded soil,while flooding offset this effect.The results indicated the effects of BBC varied under different soil moisture,which should be considered in the biochar-assisted phytoremediation to variable and complex environments.