Reconstructing forest canopy from the 3D triangulations of airborne laser scanning point data for the visualization and planning of forested landscapes

Key message We present a data-driven technique to visualize forest landscapes and simulate their future development according to alternative management scenarios. Gentle harvesting intensities were preferred for maintaining scenic values in a test of eliciting public's preferences based on the simulated landscapes. Context Visualizations of future forest landscapes according to alternative management scenarios are useful for eliciting stakeholders' preferences on the alternatives. However, conventional computer visualizations require laborious tree-wise measurements or simulators to generate these observations. Aims We describe and evaluate an alternative approach, in which the visualization is based on reconstructing forest canopy from sparse density, leaf-off airborne laser scanning data. Methods Computational geometry was employed to generate filtrations, i.e., ordered sets of simplices belonging to the three-dimensional triangulations of the point data. An appropriate degree of filtering was determined by analyzing the topological persistence of the filtrations. The topology was further utilized to simulate changes to canopy biomass, resembling harvests with varying retention levels. Relative priorities of recreational and scenic values of the harvests were estimated based on pairwise comparisons and analytic hierarchy process (AHP). Results The canopy elements were co-located with the tree stems measured in the field, and the visualizations derived from the entire landscape showed reasonably realistic, despite a low numerical correspondence with plot-level forest attributes. The potential and limitations to improve the proposed parameterization are discussed. Conclusion Although the criteria to evaluate the landscape visualization and simulation models were not conclusive, the results suggest that forest scenes may be feasibly reconstructed based on data already covering broad areas and readily available for practical applications.Peer reviewe

Assessing the provisioning potential of ecosystem services in a Scandinavian boreal forest : Suitability and tradeoff analyses on grid-based wall-to-wall forest inventory data

Determining optimal forest management to provide multiple goods and services, also referred to as Ecosystem Services (ESs), requires operational-scale information on the suitability of the forest for the provisioning of various ESs. Remote sensing allows wall-to-wall assessments and provides pixel data for a flexible composition of the management units. The purpose of this study was to incorporate models of ES provisioning potential in a spatial prioritization framework and to assess the pixel-level allocation of the land use. We tessellated the forested area in a landscape of altogether 7500 ha to 27,595 pixels of 48 x 48 m(2) and modeled the potential of each pixel to provide biodiversity, timber, carbon storage, and recreational amenities as indicators of supporting, provisioning, regulating, and cultural ESs, respectively. We analyzed spatial overlaps between the individual ESs, the potential to provide multiple ESs, and tradeoffs due to production constraints in a fraction of the landscape. The pixels considered most important for the individual ESs overlapped as much as 78% between carbon storage and timber production and up to 52.5% between the other ESs. The potential for multiple ESs could be largely explained in terms of forest structure as being emphasized to sparsely populated, spruce-dominated old forests with large average tree size. Constraining the production of the ESs in the landscape based on the priority maps, however, resulted in sub-optimal choices compared to an optimized production. Even though the land-use planning cannot be completed without involving the stakeholders' preferences, we conclude that the workflow described in this paper produced valuable information on the overlaps and tradeoffs of the ESs for the related decision support. (C) 2016 Elsevier B.V. All rights reserved.Peer reviewe

Persuasion in the need of information: Analyzing search engine results page advertisements for low and high involvement products

Objective of the study The objective of the study was to better understand the advertisements in search engine re-sults pages. Moreover, the research attempted to provide perspectives on what and how adver-tisements communicate to consumers during their purchase process and how this communi-cation has evolved over time. Hence, the main research question was: "How do advertisements differ in the search engine results page for low involvement and high involvement purchase process products?" Methodology and Theoretical Framework More than 340 advertisement texts of 2009 and 2012 were obtained from the Google search results and then analyzed. However, the research is qualitative, but especially explorative by nature. In order to study the differences of advertisement texts, genre analysis was utilized to group the corpus and understand different types and properties of advertisements. High in-volvement and low involvement product purchase processes were found meaningful factors to analyze the advertisements. The study develops and uses a holistic, multidisciplinary frame-work from branches of marketing as advertising, branding and purchase processes, communi-cation and linguistics, information retrieval, and psychology of persuasion, within which the advertisements appearing in search engine results pages are being analyzed. Findings and Conclusion Three search engine advertisement genres were identified in the data analysis: Informative, Advising, and Activating advertisements. To address the main research question, the study shows that the low involvement product related search queries are more likely to be associated with persuasive communication, whereas the high involvement product related queries are more likely to trigger call-to-action messages. The findings suggest that the search engine advertisements are not only informative or classified alike; instead they seem to adapt versatile way of communication, which the trend also emphasizes, despite being limited in the context of a search query. Furthermore, the results seem to indicate that information retrieval that occurs in the Internet search engines is an ideal moment to be exposed to persuasive advertis-ing and that also other than Informative advertisements might be beneficial for the advertiser

Effects of errors in basal area and mean diameter on the optimality of forest management prescriptions

Errors in forest stand attributes can lead to sub-optimal management prescriptions concerning the set management objectives. When the objective is net present value, errors in mean diameter result in greater losses than similar errors in basal area, and underestimation greater losses than overestimation

Kaukokartoitukseen perustuvan metsävaratiedon hyötyanalyysi : MetKu-hankkeen loppuraportti

Julkisen metsävaratiedon kerääminen on merkittävä investointi metsätalouden edellytysten parantamiseen. Jotta investointi olisi kannattava, metsävaratiedolla saavutettavien hyötyjen täytyy olla kustannuksia suuremmat. Perinteinen kustannus-hyötyanalyysi metsävaratiedosta on haastava, koska investoinnin maksaa yhteiskunta (veronmaksajat), mutta yhteiskunnalle koituva hyöty on epäsuoraa (esimerkiksi verotulojen tai viennin arvon lisääntyminen). Suoraa hyötyä muodostuu useille eri toimijoille, ja kunkin toimijan ja kunkin käyttötilanteen tuottama hyöty täytyy arvioida erikseen. Tämä raportti on yhteenveto maa- ja metsätalousministeriön rahoittamassa yhteistutkimushankkeessa Metsävaratiedon kustannushyötyanalyysi (MetKu) tehdyistä töistä. Hankkeessa tunnistettiin tahoja, jotka hyötyvät tiedosta ja kuvattiin mekanismeja, joilla hyöty realisoituu. Näin muodostuvien hyötyjen suuruusluokkaa arvioitiin tapauskohtaisesti tehdyillä laskelmilla. Laskelmissa ei pyritty kattavaan tiedon kokonaisarvoon. Jo pelkästään tapauskohtaiset laskelmat osoittavat kuitenkin kiistattomasti, että metsävaratietoon on kannattavaa investoida. Metsänomistajakunta hyötyy varttuneissa metsissä laserkeilaukseen perustuvasta metsävaratiedosta vuosittain jopa 210 miljoonaa euroa verrattuna siihen, että käytettävissä olisi satelliittikuvien luotettavuutta vastaava tieto, ja noin 60 miljoonaa vuodessa suhteessa perinteiseen maastotietoon, mikäli hyötyä tarkastellaan pelkästään kokonaistilavuuden luotettavuuden perusteella. Joidenkin muuttujien, kuten puulajiosuuksien suhteen laserkeilaus on kuitenkin maastoinventointia epätäsmällisempää, mikä vähentää nykyisenlaisen keilauksen tuottamaa hyötyä. Laserkeilaus toisaalta myös säästää kustannuksia tiedon keruussa, jolloin samansuuruisella yhteiskunnan investoinnilla voidaan kattaa vuosittain suurempi pinta-ala, mikä hyödyttää omistajia ajantasaisempana tietona. Hankkeessa tarkasteltiin myös, miten tiedonkeruun tapa vaikuttaa hyötyyn. Tätä varten verrattiin eri tavoin poimittujen opetuskoealojen tuottamaa hyötyä metsänomistajille. Tulosten mukaan koealojen poimintatapa (ositus, systemaattinen otos tai satunnainen otos) ei ollut kovin merkittävä, mutta koealojen määrän vaikutus on selkeä. Yhden lisäkoealan mittaamisesta saatava hyöty on 200 000 hehtaarin inventointialueella vielä 500 mitatun koealan jälkeen yli 3000 euroa. Tulosten perusteella myös tietojen tarkkuuden ja omistajan tulojen välillä on selkeä yhteys. Kokonaistilavuuden suhteellisen RMSE:n (keskineliövirheen neliöjuuri) pieneneminen yhdellä prosenttiyksiköllä kasvatti omistajan tuloa noin 4€/ha. Lisäksi hankkeessa selvitettiin, millaisella frekvenssillä inventointeja kannattaa toteuttaa verrattuna tietojen päivittämiseen kasvumalleilla (ja tehdyillä toimenpiteillä). Tätä varten tarkasteltiin Evon tutkimusaineistossa metsänomistajan laskennallisia tuloja vuonna 2014 mitattujen, vuonna 2009 mitattujen ja vuoteen 2014 päivitettyjen, sekä vuonna 2007 mitattujen ja vuoteen 2014 päivitettyjen tietojen välillä. Tulosten mukaan jo viiden vuoden päivitys vähensi metsävaratietojen luotettavuutta siinä määrin, että uusi laserkeilaus oli omistajan kannalta kannattavampi kuin vanhojen metsävaratietojen päivitys. Metsävaratietojen näkökulmasta laserkeilausinventointien väliä ei siis ole suositeltavaa kasvattaa kansalliseen laserkeilausohjelmaan suunniteltua kuutta vuotta pidemmäksi.201

Economic losses in carbon forestry due to errors in inventory data

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The effects of sample plot selection strategy and the number of sample plots on inoptimality losses in forest management planning based on airborne laser scanning data

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