Croatian Forest Research Institute

Jastrebarsko, Croatia

Croatian Forest Research Institute

Jastrebarsko, Croatia
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Balenovic I.,Croatian Forest Research Institute | Milas A.S.,Bowling Green State University | Marjanovic H.,Croatian Forest Research Institute
Remote Sensing | Year: 2017

Digital aerial photogrammetry has recently attracted great attention in forest inventory studies, particularly in countries where airborne laser scanning (ALS) technology is not available. Further research, however, is required to prove its practical applicability in deriving three-dimensional (3D) point clouds and canopy surface and height models (CSMs and CHMs, respectively) over different forest types. The primary aim of this study is to investigate the applicability of image-based CHMs at different spatial resolutions (1 m, 2 m, 5 m) for use in stand-level forest inventory, with a special focus on estimation of stand-level merchantable volume of even-aged pedunculate oak (Quercus robur L.) forests. CHMs are generated by subtracting digital terrain models (DTMs), derived from the national digital terrain database, from corresponding digital surface models (DSMs), derived by the process of image matching of digital aerial images. Two types of stand-level volume regression models are developed for each CHM resolution. The first model is based solely on stand-level CHM metrics, whereas in the second model, easily obtainable variables from forest management databases are included in addition to CHM metrics. The estimation accuracies of the stand volume estimates based on stand-level metrics (relative root mean square error RMSE% = 12.53%-13.28%) are similar or slightly higher than those obtained from previous studies in which stand volume estimates were based on plot-level metrics. The inclusion of stand age as an independent variable in addition to CHM metrics improves the accuracy of the stand volume estimates. Improvements are notable for young and middle-aged stands, and negligible for mature and old stands. Results show that CHMs at the three different resolutions are capable of providing reasonably accurate volume estimates at the stand level. © 2017 by the authors.

Agency: European Commission | Branch: FP7 | Program: CSA-CA | Phase: REGIONS-2009-1 | Award Amount: 2.29M | Year: 2010

RoK-FOR aims to create a region of knowledge in the forestry sector in Europe, and will significantly contribute to forest sector supporting sustainable use of natural resources, renewable energy, sustainable construction materials and biobased products, without jeopardizing the environment. RoK-FOR is a Coordination Action of five regional research-driven clusters from six European countries: Germany (Baden-Wrttemberg); Finland (North Karelia); Spain (Catalonia), and the cross-border clusters from Croatia-Serbia and France-Spain (Aquitaine-Basque). These regional research-driven clusters collectively form a European level meta-cluster that will be working together to increase the coherence and address the needs of the three Lead Market Initiatives (renewable energy, sustainable construction, and bio-based products) under the umbrella of the sustainable forest management in an innovative and competitive manner. The RoK-FOR work programme is divided into seven interconnected and state of the art work packages which will be instrumental in fulfilling the objectives of the project in a three year period. The project will analyse the regional R&D needs, capacities and policies of the participating clusters, and will integrate them in regional research agendas and a Joint Action Plan to be developed in the course of the project. RoK-FOR will also take measures towards implementing the Joint Action Plan, including business plans and R&D design. RoK-FOR will address the European need of capacity building of the clustersin contributing to regional strategies in the central theme of the project, will support integration of SMEs in RTD, and has a specific Work Package for mentoring the cross-border region of Croatia-Serbia.

Krstin L.,University of Zagreb | Krstin L.,Josip Juraj Strossmayer University of Osijek | Novak-Agbaba S.,Croatian Forest Research Institute | Rigling D.,Swiss Federal Institute of forest | Curkovic-Perica M.,University of Zagreb
Plant Pathology | Year: 2011

Cryphonectria parasitica, the causal agent of chestnut blight, has been present in Slovenia since at least 1950. To improve understanding of its diversity, 254 isolates of the fungus from 11 Slovenian populations were sampled. Fifteen vegetative compatibility (vc) types were identified. The dominant vc type was EU-13, comprising 40·1% of all isolates tested, followed by EU-1 (19·7%), EU-2 (12·2%) and EU-12 (9%). The vc type diversity in the most diverse population sampled in Slovenia was higher than in the populations found previously in northern Italy and Croatia. Both mating types and perithecia were observed in surveyed populations. Natural hypovirulence was found in six out of seven populations tested, with frequencies ranging from 72·2% in the population sampled near the Croatian border to 11·1% in the population sampled near the Austrian border. All identified hypoviral isolates (21) belonged to the Italian subtype of Cryphonectria hypovirus 1 and were closely related to the hypoviruses found in other European countries. Despite the high vc type diversity, incidence of hypovirulence was also high, indicating widespread natural biological control of the disease. © 2011 The Authors. Plant Pathology © 2011 BSPP.

Pilas I.,Croatian Forest Research Institute | Medved I.,University of Zagreb | Medak J.,Croatian Forest Research Institute | Medak D.,University of Zagreb
Forest Ecology and Management | Year: 2014

Croatia is positioned in the transitional zone of South-eastern Europe and the Mediterranean, a region with frequent occurrence of severe droughts and dry spells, which makes it particularly vulnerable to the impact of climate change. It distends across three main European biogeographical regions - Continental, Alpine and Mediterranean - and therefore has a very high level of forest diversity comprised of 11 out of 14 European forest types. This makes it very convenient to study the exposure of main European forest types to extreme climatic events in the southern limits of their species distribution range. This study provides an assessment of responses of forest vegetation under episodes of climatic anomalies consisting of the most severe historical dry and warm spells in 2000 and 2003, together with the extremely rainy season in 2005 across Croatian territory. The question of interest in this study was to reveal how the existing forest types across the territorial gradient respond to highly expressed extreme climatic variations and to infer some clues about related adaptive strategies. The regional scale approach was applied which previously performed structural delineation of forest cover into eleven main forest groups or bioclimates and were examined considering functional differences. Responses of eleven bioclimatic types were analyzed by time series (1998-2005) of monthly FAPAR (The Fraction of Absorbed Photosynthetic Active Radiation) coverage with a spatial resolution of 1.2. km, freely available from JRC FAPAR project. To quantify and differentiate the vegetation response in the considered years we adopted indices of resilience (resistance, recovery, resilience and relative resilience). We also provided a modified approach by applying these indices on a seasonal scale to examine the relationship between variations of phenology and ecosystem responses. The results confirmed the modification of seasonality of photosynthetic activity in relation to the altitudinal and spatial gradient. At the intra-seasonal scale, we distinguished specific opportunistic behavior of the common beech and oak forest types to alternating climatic conditions. Beech forest types show a very high ability to shift their phenology to earlier spring warming as a consequence of global warming. However, continental and Mediterranean oak forest types and in particular Aleppo pine and holm oak forests showed a higher increase of FAPAR during rainy events. The revealed capability of some tree species to better exploit rainfall in very wet periodic episodes has to be further evaluated in drawing conclusions about the overall resilience of forests under future climate change scenarios. © 2014 Elsevier B.V.

Cvjetko Bubalo M.,University of Zagreb | Hanousek K.,University of Zagreb | Radosevic K.,University of Zagreb | Gaurina Srcek V.,University of Zagreb | And 2 more authors.
Ecotoxicology and Environmental Safety | Year: 2014

We studied the effects of five imidiazolium based ionic liquids with different anions and length of alkyl chains linked to imidazolium ring on the early development of barley (Hordeum vulgare). The inhibitory effect depends on the ionic liquids concentration and chemical structure, whereby the most toxic one was [C10mim][Br], followed by [C7mim][Br], [C4mim][Br], [C4mim][CH3CO2] and [C4mim][BF4]. Both anion and cation structures affected the toxicity of ionic liquid indicating that selection of more biocompatible anions such as [CH3CO2] does not necessarily indicate lower toxicity. Alternation in the extent of oxidative stress and antioxidant enzymes activities were found in barley plants due to ionic liquid treatments. When seedlings were exposed to higher concentrations of ionic liquids, antioxidant system could not effectively remove reactive oxidative species, leading to lipid peroxidation and damage of the photosynthetic system. However, overall data indicated that the performance of barley seedling was improved when all measured enzymes involved in scavenging of reactive oxygen species (ROS) were increased with special emphasis on GPX activities. Since there are no studies about ionic liquid (IL) toxicity in plants, that simultaneously evaluates the antioxidative enzyme system in response to different ILs, this work is valuable for gaining knowledge about the protection mechanism of plants from oxidative stress caused by IL exposure. © 2014.

Stevanov M.,University of Novi Sad | Bocher M.,University of Gottingen | Krott M.,University of Gottingen | Krajter S.,Croatian Forest Research Institute | And 2 more authors.
Forest Policy and Economics | Year: 2013

Policy-makers articulate a growing need for science-based policy advice that supports their decisions, especially in fields that are dependent on scientific knowledge like natural resources or forestry. Publicly funded organizations, such as departmental research institutes, have been established in many countries to provide science-based policy advice. To assess the activities of two public research institutes, namely, Serbia's Institute of Lowland Forestry and Environment (ILFE) and the Croatian Forest Research Institute (CFI), we use the new theory-based analytical model of departmental research developed by Böcher and Krott (2010). This model describes scientific policy advice as the connection between Research (R), Integration (I), and Utilization (U) - the RIU-model. Primary and secondary evidence refer to 148 ILFE and CFI projects conducted from 2005 to 2010. Our critical analysis of empirical data, which were collected through semi-structured face-to-face interviews and project documentation, shows the following: (i) it is possible to analyze all activities of the two research institutes with the RIU-model of departmental research and present the results using "production lines"; (ii) activities of ILFE and CFI can be presented by the same types of production lines revealing their similar profile; (iii) all three spheres of the RIU-model can be found in the successful ILFE and CFI projects, only the Integration sphere is found in all projects; and (iv) the RIU-model is able to describe comprehensive activities of both research institutes, which opens the possibility to improve current evaluation procedures by taking into account both practical and scientific activities and outputs. © 2013 Elsevier B.V.

Krajter Ostoic S.,Croatian Forest Research Institute | Konijnendijk van den Bosch C.C.,Swedish University of Agricultural Sciences
Urban Forestry and Urban Greening | Year: 2015

The concept of urban forestry is addressed from a discursive perspective, with focus on identifying and describing various scientific discourses, their strength and development over time and on different continents. This work can help obtain a deeper understanding of the scientific discourses in terms of identifying research trends and reasons behind these trends, as a possible way forward for research. Scientific publications (. N=. 519) issued during the period 1988-2014 (and as listed in the SCOPUS database) were analysed with the aims to 1) systematically identify and describe scientific urban forestry discourses, 2) discuss implications of these findings for scientific practice, and 3) propose ways forward. Six discourses of various strength and geographical distribution were identified. Scientific production was found to be dominated by North American and European authors with modest contributions from authors from other continents. Scientific discourses proved mostly expert driven and reflecting the positivist scientific paradigm. Prevailingly managerial orientation and absence of qualitative approaches indicate a lack of deeper understanding of human-environment relations. Studies related to active participation of citizens and partnerships in urban forestry have been missing. More emphasis should be placed on the testing of existing, and developing new methods and modalities of public participation, and on the value of civic involvement for the decision making. Moreover, a more solid evidence base is needed for benefits from urban forests, while economic aspects of biodiversity and other ecosystem services are still insufficiently explored. Study findings also call for more research on urban forest governance and relation between urban forest benefits and existing policies (e.g. climate change adaptation, energy policy or health). © 2015 Elsevier GmbH.

Halder P.,University of Eastern Finland | Paladinic E.,Croatian Forest Research Institute | Stevanov M.,University of Novi Sad | Orlovic S.,University of Novi Sad | And 2 more authors.
Renewable and Sustainable Energy Reviews | Year: 2014

Private forests in Croatia and Serbia are highly fragmented in small plots with low productivity and owned by a large number of small-scale nonindustrial private forest owners (NIPFs). The study conducted surveys among 232 NIPFs in these two countries to find out their perceptions and attitudes related to energy wood production from their forests. The secondary objective of the study was to provide policy recommendations to the public authorities and professionals in these countries for improving the preconditions for energy wood mobilization from private forests. The study found that the NIPFs perceived underdeveloped market and low price for energy wood, absence of favorable policies, fragmented forests properties, older NIPFs' lack of interests in energy wood production, and difficulties in getting bank loan for energy wood related business activities as barriers against energy wood production from private forests. However, the NIPFs showed positive attitudes towards producing energy wood from their forests and they considered the possibilities of creating new jobs and commercial opportunities as strengths of energy wood production. The NIPFs' socio-demographic background had statistically significant relations with their perceptions and attitudes related to energy wood production. The dimensions of the NIPFs' perceptions and attitudes related to energy wood production showed two key dimensions - institutionalists and enthusiasts. The variables to explain the NIPFs' attitudes to energy wood production were different between the two countries and they indicated the differences in the country level circumstances for energy wood production. The results appeared to be relevant for understanding the issues that the NIPFs perceived as barriers against developing a viable energy wood market in their countries. When new forestry institutions and policies are emerging in these countries, the existing public and private forestry institutions need to play an important role for improving the preconditions for energy wood production from private forests. © 2014 Elsevier Ltd. All rights reserved.

Matosevic D.,Croatian Forest Research Institute | Melika G.,Plant Health and Molecular Biology Laboratory
Bulletin of Insectology | Year: 2013

Research on recruitment of native parasitoids on the recently introduced invasive species Dryocosmus kuriphilus has been carried out on four sites in 2011 and 2012 in Croatia. In total 15 species of native parasitoids were reared which belong to 5 of 6 chalcid families attacking native oak cynipid gallwasps (Eupelmidae - 2, Eurytomidae - 4, Ormyridae - 1, Pteromalidae - 4 and Torymidae - 4 species). This research has shown that the time lag between introduction of new host and recruitment of native parasitoids is short. Sex ratios for the most abundant parasitoid species appeared to be female-biased and the parasitoid emergence rate for all sites was relatively low. Torymus flavipes was recorded from D. kuriphilus at all sites and in both years and was the most abundant species exploiting the new host. Among other species, especially T. flavipes and Megastigmus dorsalis, which have been reared from D. kuriphilus galls, could provide a good possibility for biological control but further research is needed.

Prka M.,State company | Krpan A.P.B.,Croatian Forest Research Institute
Acta Silvatica et Lignaria Hungarica | Year: 2010

The effects of management of even-aged beech stands on the quality of beech timber assortments by type of cut were investigated in the region of Bjelovar. The research was carried out using Croatian timber standards. Assortment tables were developed separately for thinning and intermediate felling, and separately for regeneration and final felling in accordance with the interventions of management. The average shares of assortments maintained the same ratios by quality classes regardless of the applied standards (HRN or HRN EN). The research identified the problems in production of assortments, and justified the need for developing separate tables for thinning, intermediate felling, and for regeneration and final felling. Through forest management the quantity and quality of timber assortments may be oriented to a certain extent towards the production target. With the application of tending measures the value of the stand and timber assortments increases over time. In economic respect, the development of false heartwood shows an opposite trend. Therefore a compromise must be achieved by proper management and determination of appropriate harvesting age of beech stands.

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