A new biomassretrievalalgorithmbased on P-band multi- polarization backscatter has been developed and evaluated based on SAR and ground data over borealforest. SAR data collections were conducted on three dates at a test site in southern Sweden (Remningstorp, biomass < 300 tons/ha; late winter to early summer 2007) and on a single date at a test site in northern Sweden (Krycklan, biomass < 200 tons/ha; fall 2008). The retrievalalgorithm is a multiple linear regression model including the HV-polarized backscatter coefficient, the VV/HH backscatter ratio and the ground slope. Regression coefficients were determined from Krycklan data followed by algorithm evaluation using Remningstorp data. The results from the latter show that RMS errors vary in the range 29-42 tons/ha depending on date and stand type. The new algorithm is also compared with alternative algorithms and found to give significantly better performance. The developed model is a significant step towards an algorithm which gives consistent results across multiple sites and dates, i.e. when forest structure, topography and moisture conditions is expected to vary.
Temporal Survey of P- and L-Band Polarimetric Backscatter in Boreal Forests
Albert R. Monteith , Student Member, IEEE, and Lars M. H. Ulander , Fellow, IEEE
Abstract—Environmental conditions and seasonal variations af- fect the backscattered radar signal from a forest. This potentially causes errors in a biomassretrieval scheme using data from the synthetic aperture radar (SAR) data. A better understanding of these effects and the electromagnetic scattering mechanisms in forests is required to improve biomass estimation algorithms for current and upcoming P- and L-band SAR missions. In this paper, temporal changes in HH-, VV-, and HV-polarized P- and L-band radar backscatter and temporal coherence from a borealforest site are analyzed in relation to environmental parameters. The radar data were collected from a stand of mature Norway spruce (Picea abies (L.) Karst.) with an above-ground biomass of approximately 250 tons/ha at intervals of 5 min from January to August 2017 us- ing the BorealScat tower-based scatterometer. It was observed that subzero temperatures during the winters cause large variations (4 to 10 dB) in P- and L-band backscatter, for which the HH/VV backscatter ratio offered some mitigation. High wind speeds were also seen to cause deviations in the average backscatter at P-band due to decreased double-bounce scattering. Severe temporal decor- relation was observed at L-band over timescales of days or more, whereas the P-band temporal coherence remained high ( >0.9) for at least a month neglecting windy periods. Temporal coherence at P-band was highest during night times when wind speeds are low. Index Terms—Backscatter, borealforest, L-band, P-band, syn- thetic aperture radar (SAR), temporal coherence, time series.
The ability of the SAR signal to detect forest canopy components (trunks, branches and leaves) depends on its frequency, incidence angles and polarisations (HH, VV, HV or VH, with H and V representing the horizontal and vertical transmit/receive polarisation, respectively). The range of signal sensitivity to forest structure also depends on the canopy type (homogeneity to complex density) and environmental conditions (moisture content) . The co-polarised channels (i.e., HH or VV) exhibit a large amount of scattered microwave energy with the strongest return at HH-polarisation due to double-bounce scattering from the vertical trunk structure lying perpendicular to the ground surface (unless in undulating terrain). In all forest types, microwaves emitted at longer SAR wavelengths (L- and P-band) are more sensitive to forest AGB due to deeper penetration and more interaction with the larger woody branches, trunks and ground surface, e.g., in boreal [23,24], temperate [25,26] and tropical forest . This has been largely related to the cross-polarised channels (HV or VH) which have comparatively lower returns but generally increase asymptotically to the amount of woody biomass. SAR signals at shorter wavelengths (C- and X-bands) are known to saturate rapidly with forestbiomass due to lower canopy penetration. The microwave pulse primarily interacts with the foliage and smaller branches in the upper canopy layers at these wavelengths . However, using high revisit C-band data from the Envisat’s Advanced Synthetic Aperture Radar (ASAR), Santoro, et al.  were able to estimate forest growing stock volume (GSV) using the BIOMASAR algorithm. On the basis of converting GSV to AGB using an expansion factor, wall-to-wall estimates of forest stock and carbon density have been generated over the temperate-boreal region of the northern hemisphere . Further, sensitivities of forestbiomass levels from multi-frequency SAR data (C-, L- and P-band) have also been reported from different forest types, e.g., coniferous (Les Landes and Duke) and broadleaved evergreen (Hawaii) achieving around 20 t/ha, 40 t/ha and 100 t/ha saturation levels respectively . Vegetation optical depth (VOD) derived from passive microwave data is sensitive to high biomass density levels (e.g., in rainforests) . Using the VOD data (1993–2012), an EO-based ABC (aboveground biomass carbon) estimation at global scale was produced for all vegetation types at >10 km resolution .
The study further aimed to investigate changes in environmental variables across the island gradient and link these to lichen community properties. Island size was clearly responsible for most of the changes in those environmental variables considered important for lichens. Light, bark pH and bark roughness stood out as the most important factors influencing lichen species richness, diversity and coverage in this study. The importance of bark roughness in structuring the lichen flora is well recognized (Brodo, 1973; Kuusinen, 1994; Gustafsson & Eriksson, 1995; Mistry & Berardi, 2005). As bark structure increases the lichen colonization rates probably increases as their diaspores more easily attach to the trunk. Increased bark structure also results in a higher micro-habitat heterogeneity and water holding capacity which may also allow higher lichen diversity. While an open forest structure can generally support a diverse lichen flora, the highest incident light values in this study are associated with a more open forest that will also allow greater weather and sun exposure. This could in turn serve to stress lichens through exposing them to higher variations in temperature, desiccation and mechanical damage by wind (Esseen, 1994). Similarly, intermediate and low values of incident light should be associated with more protected and shady conditions with higher humidity. This could explain the negative correlation between light and the response variables.
The study showed that fertilization improves the profit- ability of forestry; the sum on discounted net benefits from forest management is increased, at least with 3% discount rate. The analyses do not indicate the internal rate of return (IR) of a single fertilization investment. However, is can be easily calculated that if 75% of the additional volume increment is harvested as saw logs (and 25% as pulpwood) 10 years after fertilization, the IR of the investment would be around 8%. If only 50% of additional harvest is saw log, the IR would be 6% and with 25% share of saw log the IR would be 4%. If the cutting is earlier, or fertilization increases the share of saw log, as compared to non-fertilized stand, the IR may be substantially higher.
Insekters mångfald på hyggen i boreala skogslandskap
Intensivt skogsbruk och brist på naturlig störningsdynamik i boreala skogar leder till en minskning och försämring av habitat för skogslevande arter. Det leder till att många arter minskar och riskerar att försvinna, framförallt arter som är beroende av död ved. Därför är det nödvändigt att integrera naturvårdsåtgärder i skogsbruket för att bevara mångfalden av arter i den boreala skogen. För att kunna optimera naturvårdåtgärder behöver vi förstå arters habitatkrav och diversitetsmönster i brukade skogslandskap. Målet med denna avhandling är att öka förståelsen för insekters diversitetsmönster på hyggen i brukad boreal skog. Jag har inventerat vedskalbaggar och gaddsteklar i Hälsingland och Dalarna och undersökt betydelsen av lokala habitatfaktorer och det omkringliggande landskapets sammansättning för arters förekomst och diversitetsmönster. Mängden död ved på hyggen var viktig för hög artrikedom och förekomst av enskilda vedskalbaggsarter. Artrikedomen av gaddsteklar ökade med hög rikedom av blommande växter och hyggesstorlek. Landskapets sammansättning var minst lika viktig som lokala faktorer för de observerade diversitetsmönstren. Mängden bränd skogsmark i omgivande landskap var positiv för artrikedomen av skalbaggar, medan lokal hyggesbränning hade liten påverkan på skalbaggar och gaddsteklar. Detta beror troligtvis på att bränd skogsmark på landskapsskala innefattar högre habitatdiversitet med större mängder död ved jämfört med brända hyggen. Gaddsteklarnas artrikedom ökade med mängden tidiga successionshabitat i landskapet, vilket tyder på att de flesta arter är knutna till öppna habitat. Olika landskap hade även olika arter av gaddsteklar. Därför behöver naturvårdsåtgärder spridas ut i regionen för att bevara hela faunan. För att öka artrikedom av insekter på hyggen behöver större mängder och variation av död ved skapas. Arter beroende av solexponerad död ved eller hög blomrikedom skulle gynnas om delar av hyggen hålls öppna längre. För att skapa habitat av tillräckligt hög kvalitet i landskapet behöver naturhänsynen troligtvis koncentreras så att nivån av hänsyn blir högre på vissa hyggen i varje landskap.
western borealforest, and Alberta-speciﬁcally, lack a shrub-less, low-density woodland phase or bark beetles as a disturbance agent (Chen and Popadiouk 2002). The extremely low rate of successful recruitment over the previous 30 yr means that a new cohort, if one begins, will take decades to structurally replace the rapidly dying overstory. Results from our study suggest that historical successional pathways have been stymied and could be a new normal for other stands in this ecotone, particularly if the bark beetle species seen in our stand outbreak and encroach into regional stands. The recent, wide- spread die-off of Populus across the region has been documented (Michaelian et al. 2011) and the defoliation years (1979–1988) within the GLR match years of outbreaks of M. disstria across Alberta (Hogg et al. 2002a). Multiple years of defoliation can cause high mortality (Moulinier et al. 2014) and long-term changes in cell-ﬁbers with possible negative implications for structure and drought response (Hillabrand et al. 2019). The trees used to reconstruct the history of defoliation in the GLR were the sur- viving, non-rotten cohort, and it is possible that the Populus that died before 2017 suffered addi- tional defoliation events or died as a direct result of defoliation. The decline of Populus over- laps the continuing drought-related decline of Picea growth within the region (Hogg et al. 2017). In addition to being implicated in the depressed Picea growth, the extreme 2002 drought was likely associated with the outbreak of bark beetles. Previous research has linked outbreaks of Dendroctonus ruﬁpennis to drought (Berg et al. 2006) with warming temperatures hastening generation time (Hansen et al. 2001) and increasing the likelihood of outbreak (Han- sen and Bentz 2003). Predictably, the initial bee- tle outbreak at the GLR plot, in 2002, occurred during the driest year since stand establishment in the 1920s. We speculate that the weakened Picea were unable to mount an effective defense against bark beetles, and that this led to the expansion and outbreak within the stand. The combined effects of bark beetles and the severe droughts of recent decades likely stressed Picea and resulted in precipitous declines in density, growth, recruitment, and biomass. The conﬂuence of these disturbances seems to have
JSBACH is a process-based ecosystem model and the land surface component of the MPI-ESM. We used JSBACH of- fline using an observational atmospheric data set to force the model. Implications of this one-way coupling with the atmosphere include lack of feedback from the surface en- ergy balance to the atmosphere; i.e. latent and sensible heat fluxes and surface thermal radiation do not directly affect prescribed air temperature or humidity. Similarly, the feed- back of surface to the vertical transfer coefficients within the atmospheric surface layer is missing, as the wind speed that drives mixing is prescribed. Furthermore, since we use site level data (a single grid point), the grid resolution does not affect the results (Tesfa et al., 2014; Singh et al., 2015). We give here a general introduction to JSBACH, whereas a more complete model description can be found in Roeckner et al. (2003).
Fig.1 shows over the whole working process of case-based reasoning, case retrieval is a critical step in this process, when there are fewer cases in case base, according to the similarity threshold,the success rate is lower relatively for retrieval of similar cases with the passage of running time for the system, through case studies, the case retrieval success rate is increased gradually.Traditional comparative case similarity algorithm is as follows:
In our image retrieval system, we have used Haar wavelets to compute feature signatures, because they are the fastest to compute and also have been found to perform well in practice. Haar functions have been used from 1910 when they were introduced by the Hungarian mathematician Alfred Haar. The Haar transform is one of the earliest examples of what is known now as a compact, dyadic, orthonormal wavelet transform. The Haar function, being an odd rectangular pulse pair, is the simplest and oldest orthonormal wavelet with compact support 6 . Figure 3.3 shows a block diagram of Wavelet – Based Color Histogram i.e. feature extraction method used in our image retrieval system.
Some of the changes we are interested in are expected to be dependent on tree species and on age. The prevailing tree species are, according to [ 9 ], Scots pine (Pinus sylvestris; mainly in dry upslope areas), Norway spruce (Piceas abies (L.) Karst: mainly in wetter, low-lying areas), and birch (Betula spp.; in the riparian forest along larger streams). In Figure 12 , the estimated growth rate, GR, is illustrated, and we mark stand values by x, and those stands with >60% Picea with an additional dark blue triangle, those with >60% Pinus with light blue dots, and those with at least 30% deciduous with red diamonds. From Figure 12 , the young stands with >30% deciduous show high growth, and young Pinus tends to grow faster than Picea, while old Pinus grow slower than Picea, in line with practical experience. Four stands with an age in the interval 123–162 years have a low growth rate (0.6–1.1 Mg/ha/yr) which for three (ID = 3611, 3689, and 15,100) can be related to suspected thinning summer 2011, 2013, and 2012, respectively. Stand 1764 (age 162 years) is clear cut before 2011, and the age is then incorrect. It is hard to draw conclusions regarding growth of different species, since the site properties vary and we do not have stands with dominating species in all AGB intervals. This also illustrates the need for satellite information on growth results for different stands. From literature related to forest growth, see e.g., [ 15 , 40 – 42 ], we typically find a low growth rate for small as well as high stand age. The present results show a high growth rate in the interval 60–150 years of age.
Information Retrieval (IR) is concerned with indexing and retrieving documents including information relevant to a user’s information need. Although the end user can express his information need using a variety of means, queries written in natural language are the most common means. However, a query can be very problematic because of the richness of natural language. Indeed, a query is usually ambiguous; a query may express two or more distinct information needs or one information need may be expressed by two or more distinct queries. Text Retrieval Conference(TREC) test collection from which the query is submitted to an IR system based on the Vector Space Model (VSM). This system would return both relevant documents and irrelevant documents. Finding relevant document is one of the hard tasks. Information retrieval (IR) is the activity of obtaining information resources relevant to an information need from a collection of information resources. Searches can be based on full-text or other content-based indexing. Automated information retrieval systems are used to reduce what has been called "information overload". Many universities and public libraries use IR systems to provide access to books, journals and other documents. web search engine are the most visible IR application .An information retrieval process begins when a user enters a query into the system. Queries are formal statements of information needs, for example search strings in web search engines. In information retrieval a query does not uniquely identify a single object in the collection. Instead, several objects may match the query, perhaps with different degrees of relevancy.
on forest production of older trees. Monitoring approaches of ozone damage that are either capable of measuring the ac- tual increment of biomass or quantify at the leaf and canopy level the change in net photosynthesis over the growing sea- son would allow us to develop injury/damage estimates that could be more readily translated into modelling frameworks. The extrapolation of results from short-term experiments with young trees to estimate responses of adult trees grown under natural conditions is subject to several issues, e.g. due to the differing environmental conditions and changing ozone sensitivities with increasing tree size or age (Schaub et al., 2005; Cailleret et al., 2018). It is still uncertain whether the simulation of injury to photosynthesis based on exper- iments with young trees can indeed be transferred to adult trees to yield realistic biomass damage estimates. The sparse knowledge of ozone effects on the biomass of adult forest trees prevents an evaluation of simulated ozone damage of adult trees. Ozone fumigation is mostly found to reduce the biomass or diameter of adult trees (e.g. Matyssek et al., 2010 for an overview), but this is not always the case (Samuelson et al., 1996; Percy et al., 2007). Results from phytotron and free-air fumigation studies suggest that in natural forests, a multitude of abiotic and biotic factors exist that have the po- tential to impact the plants ozone effects (Matyssek et al., 2010). If more data become available, e.g. regarding the changes in ozone sensitivity between young and mature trees, a more realistic damage parameterisation of mature forests in terrestrial biosphere models might become possible.
Two closely related papers to the present analysis are [ 10 , 33 ] investigating the same study sites as in this paper. The analyses in those papers were based on regression between field or ALS data and TanDEM-X phase height and coherence. Since local data are used for the investigation and the regression coefficients are optimized for each site it is expected that the estimated accuracy is high, about the same or higher than in this paper. Also, for the change analysis, which is based on regression, similar results are reported although the analyzed plots are not exactly the same. Karila et al. [ 40 ] investigated change detection by means of TanDEM-X digital surface models, of two TanDEM-X acquisitions from 2012 and 2014 and compared with ALS for a site in southern Finland. They used a regression technique for the InSAR digital surface model change and arrived at results indicating that the phase height change correlates more with vegetation density change than with height change. In the present paper the phase height was found to be equally sensitive to a relative variation of height and vegetation density but the difference in result seems related to how to compare a change in cover with a change in height.
Abstract — This paper describes the development and implementation of feature selection for content based image retrieval. We are working on CBIR system with new efficient technique. In this system, we use multi feature extraction such as colour, texture and shape. The three techniques are used for feature extraction such as colour moment, gray level co- occurrence matrix and edge histogram descriptor. To reduce curse of dimensionality and find best optimal features from feature set using feature selection based on genetic algorithm. These features are divided into similar image classes using clustering for fast retrieval and improve the execution time. Clustering technique is done by k-means algorithm. The experimental result shows feature selection using GA reduces the time for retrieval and also increases the retrieval precision, thus it gives better and faster results as compared to normal image retrieval system. The result also shows precision and recall of proposed approach compared to previous approach for each image class. The CBIR system is more efficient and better performs using feature selection based on Genetic Algorithm.
Esah and Rahman developed a management informa- tion system for managing of blood bank based on informa- tion provided by the donor and recipient of blood. 6 This system consists of three modules which are the donor module, the patient module, and the blood module. However, some crucial issues were left aside in their approach, such as the person responsible for the adminis- tration of the system.
Speciated monoterpene emission measurements in field conditions are often conducted using branch enclosures (e.g. Staudt et al., 1997; Tarvainen et al., 2005; Holzke et al., 2006), and emission factors (EFs) are calculated based on these empirical measurements for isoprene and sums of mono- and sesquiterpenes. Due to the laborious sampling and analysis procedure, the number of replicate trees in de- termining standard emissions at specified conditions is of- ten very limited, and especially the long-term monitoring of compound-speciated branch scale BVOC emissions has been bound to one or a couple of trees. In the current em- pirical approach, the main external controlling factor for incident monoterpene emissions is temperature (Tingey et al., 1980), although recently also significant light-dependent emissions have been detected from e.g. Scots pine (Shao et al., 2001; Ghirardo et al., 2010). Many caveats have lately been presented towards the original empirical algorithm ap- proach (Niinemets et al., 2010a, b). The compound-specific physico-chemical properties are very variable (Copolovici and Niinemets, 2005) and may influence the EFs (Niinemets et al., 2010a), and since plant emissions are almost always composed of several compounds, the use of a summed emis- sion strength is not sufficient for detailed air chemistry cal- culations. In longer term, both the quantity and quality of emitted compounds varies diurnally, within the season and along with environmental stressors (e.g. Janson et al., 1999; Tarvainen et al., 2005; Hakola et al., 2006; Holzke et al., 2006), and thus an intrinsic species-specific EF, invariable in time and space is hard to define.
Following drainage, the tree stand has grown bigger and the coverage of mire species has decreased and forest species increased in the bottom and field layers. However, many mire species are still present at the peatland. Forest floor vegetation consists mainly of forest and mire dwarf shrubs (Vaccinium myrtillus L., V. vitis idaea L., V. uliginosum L., Ledum palustre L.), with patches of cottongrass (Eriopho- rum vaginatum L.) and cloudberry (Rubus chamaemorus L.). The dominant moss species are Pleurozium schreberi (Brid.) Mitt., covering 48 % of the study area, and Dicranum poly- setum (37%), but Sphagnum mosses such as S. angustifolium (Russ.) C. Jens., S. russowii Warnst., and S. magellanicum Brid. are also abundant in moist patches (coverage 15 %; Badorek et al., 2011). The ditches have not been cleaned since digging in 1971 and are nowadays totally vegetated, mainly with Sphagnum riparium (and S. russowii, S. angusti- folium), some cottongrass (Eriophorum vaginatum) and spo- radic dwarf shrubs (Ledum palustre).
In contrast to sectorial planning, MCP should include all the important land use activities and needs that occur within a municipality’s territory [ 19 , 41 ]. We argue that the municipalities need reliable and continuous data of all kinds about land use to develop effective MCP. Yet, as discussed by Stjernström et al. [ 43 ] and Bjärstig et al. [ 47 ], MCP provides limited integration of forest land such as agriculture, reindeer husbandry, mining, and wind power development. However, MCP is clearly influenced by the business sectorization of authorities and data (general information, statistics, geographic data, etc.) and by property rights and other legislation [ 48 ]. Sectorization makes it difficult to develop a more holistic view of natural resource use in society, the aim of MCP [ 35 , 49 , 50 ]. In present planning processes, property rights have a strong position relative to the public interest. However, the balancing act between property rights and the public interest is formally handled in the public planning process through the possibility of expropriation if the public interest is endangered or limited [ 43 ]. Laws and regulations associated with the environment and spatial planning separate forestry interest from the public planning to protect property rights and forest production [ 42 , 43 ]. Nevertheless, MCP aims for sustainable development, which implies planning for vital natural ecosystems, sustainable land use, social services, and infrastructure. This planning should be done for the benefit of all local inhabitants and businesses, including forest owners and forest enterprises, with consideration to regional and national policies and goals [ 21 , 29 , 35 , 51 ]. One argument for incorporating information about forest land use into the MCP is therefore the prospect of finding a more equal balance among the interests of private land owners, the public, and the state. A concrete example from the Swedish case is the Swedish practice of the Right of Public Access, which is commonly accepted by the public as well as by all forest owners. In many ways, this practice is a prerequisite for various land uses such as organized as well as privately-conducted recreational activities and tourism (which should be strategically planned for in MCP), but to some extent it limits property rights [ 19 , 52 ]. Furthermore, areas of national interest—e.g., natural and cultural environments, recreation, reindeer husbandry, wind and hydro power production, and mineral deposits—should be addressed in the MCP [ 19 , 41 ], often affecting property rights. The same situation applies for the legal rights of reindeer husbandry on all land within the official reindeer herding area, which covers half of Sweden’s land area [ 53 ].
by assigning a single value (or a range of values) to each value on land cover, forest type or other thematic map classes that have been derived from satellite data (or other map sources) and placed into various categories (such as natural lowland forest, logged and secondary forest). These thematic classes are then multiplied by the assigned values to estimate the total biomass values. Geographic information system ( GIS ) is more useful tool to conduct