Time filter

Source Type

Blujdea V.N.B.,Forest Research and Management Institute | Blujdea V.N.B.,European Commission - Joint Research Center Ispra | Pilli R.,European Commission - Joint Research Center Ispra | Dutca I.,Transilvania University of Brasov | And 3 more authors.
Forest Ecology and Management | Year: 2012

The possibility of estimating young trees biomass is rather limited because forest yield tables are constructed starting from higher thresholds of proxy, such as diameter or height, and lack of availability of allometric equations. The aim of this study is to provide species-specific and general biomass equations for young plants often used for plantations on marginal lands in southern and eastern Romania. Power functions based on log-transformed data were applied to seven tree species (Robinia pseudoacacia (L.), Quercus sp., Populus alba (L.), Gleditsia triacanthos (L.), Elaeagnus angustifolia (L.), Salix alba (L.) and Fraxinus excelsior (L.)), one shrub (Rosa canina L.) and to the overall dataset with all the species pooled together (406 plants), using the diameter at collar height (D ch), diameter at breast height (D bh) or height (H) as single predictor.D ch resulted as being the best predictor for each compartment for very young trees, but H also proved to be a promising individual predictor both for species-specific or general equations. D bh could satisfactorily predict the aggregated aboveground biomass, but generally could not adequately estimate all biomass components (i.e., belowground biomass or foliage). The goodness of regression was lowest for the foliage and highest for the stem and aggregated biomass compartments. The scaling coefficient (a) and exponent (b) of power functions were influenced both by species-specific factors and by the growth stage of the trees. Parameters to be used for a general equation were also provided for each biomass compartment and predictor. Using D ch as independent variable, we observed that the value of the general scaling exponent estimated to predict total aboveground biomass was the same as the value (2.66) predicted by the WBE functional model. Using D bh as predictor for the general allometric equation, the resulting value of b (2.36) coincided with the values empirically estimated by previous studies. Equations were finally compared against three independent datasets. Parameters provided by the general equation highlighted permanent overestimation for aggregated biomass compartments and underestimation for branches or roots, but always fell into the range provided by the upper and lower values estimated for a and b. This suggests that, at least for young trees, our equation could be applied without regard for local fertility conditions or plantation management. © 2011 Elsevier B.V.

Pilli R.,European Commission - Joint Research Center Ispra | Grassi G.,European Commission - Joint Research Center Ispra | Kurz W.A.,Natural Resources Canada | Smyth C.E.,Natural Resources Canada | And 2 more authors.
Ecological Modelling | Year: 2013

The estimation of past and future forest carbon (C) dynamics in European countries is a challenging task due to complex and varying silvicultural systems, including uneven-aged forest management, and incomplete inventory data time series. In this study, we tested the use of the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) in Italy, a country exemplifying most of these challenges. Our objective was to develop estimates of forest carbon budgets of the Forest Management area (including all forests existing in 1990) for the period 1995-2009, and to simulate alternative scenarios of natural disturbance (fire) and harvest rates to 2020. A number of methodological challenges required modifications to the default model implementation. Based on National Forest Inventory (NFI) data, we (i) developed a historic library of yield curves derived from standing volume and age data, reflecting the effect of past silvicultural activities and natural disturbances, and a current library of yield curves derived from the current net annual increment; (ii) reconstructed the age structure for a period antecedent to the reference NFI year (2005), to compare the model results with data from other sources; and (iii) developed a novel approach for the simulation of uneven-aged forests. For the period 2000-2009, the model estimated an average annual sink of -23.7Mt CO2yr-1 excluding fires in Italy's managed forests. Adding fires to the simulation reduced the sink to -20.5Mt CO2yr-1. The projected sink (excluding all fires) for the year 2020 was -23.4Mt CO2yr-1 assuming average (2000-2009) harvest rates. A 36% increase in harvest rates by 2020 reduced the sink to -17.3Mt CO2yr-1. By comparing the model results with NFI data and other independent studies, we demonstrate the utility of the CBM-CFS3 both for estimating the current forest sink in even-aged and more complex uneven-aged silvicultural systems in Italy, and for exploring the impact of different harvest and natural disturbances scenarios in managed forests. This study demonstrates the utility of the CBM-CFS3 to national-scale estimation of past and future greenhouse gas emissions and provides the foundation for the model's future implementation to other European countries. © 2013 Elsevier B.V.

Strimbu V.F.,Norwegian University of Live science | Strimbu B.M.,Louisiana Tech University | Strimbu B.M.,Forest Research and Management Institute
ISPRS Journal of Photogrammetry and Remote Sensing | Year: 2015

This work proposes a segmentation method that isolates individual tree crowns using airborne LiDAR data. The proposed approach captures the topological structure of the forest in hierarchical data structures, quantifies topological relationships of tree crown components in a weighted graph, and finally partitions the graph to separate individual tree crowns. This novel bottom-up segmentation strategy is based on several quantifiable cohesion criteria that act as a measure of belief on weather two crown components belong to the same tree. An added flexibility is provided by a set of weights that balance the contribution of each criterion, thus effectively allowing the algorithm to adjust to different forest structures.The LiDAR data used for testing was acquired in Louisiana, inside the Clear Creek Wildlife management area with a RIEGL LMS-Q680i airborne laser scanner. Three 1ha forest areas of different conditions and increasing complexity were segmented and assessed in terms of an accuracy index (AI) accounting for both omission and commission. The three areas were segmented under optimum parameterization with an AI of 98.98%, 92.25% and 74.75% respectively, revealing the excellent potential of the algorithm. When segmentation parameters are optimized locally using plot references the AI drops to 98.23%, 89.24%, and 68.04% on average with plot sizes of 1000m2 and 97.68%, 87.78% and 61.1% on average with plot sizes of 500m2.More than introducing a segmentation algorithm, this paper proposes a powerful framework featuring flexibility to support a series of segmentation methods including some of those recurring in the tree segmentation literature. The segmentation method may extend its applications to any data of topological nature or data that has a topological equivalent. © 2015 The Authors.

Dragoi M.,Stefan Cel Mare University of Suceava | Popa B.,Transylvania University | Blujdea V.,Forest Research and Management Institute
Forest Policy and Economics | Year: 2011

One of the most visible components of the Forestry Development Project, carried out between 2003 and 2009 by the World Bank and Romanian Government was 'PR support, Awareness Campaign and Development of PR products', meant to improve the communication between all stakeholders involved in sustainable forest management. The awareness campaign mainly consisted of nine meetings with the forest owners and nine workshops with all stakeholders, i.e. representatives of the forest inspectorates, county headquarters of the national forest administration, mass media, forest landowners, forest managers, logging companies and local authorities, including police and gendarmerie. The discussions, facilitated in each meeting by the three authors, were recorded and the minutes produced there have been further used for diagnosing the main interaction bottlenecks occurred between stakeholders. These discussions have been examined through the transactional analysis method in order to find out the main communication problems needed to addresses at national, regional and local level by the representatives of the public authorities in charge with implementing and supervising the forest policy. The main results of this analysis consist of a list of problems supposed to generate conflicts of various kinds (legal, technical, managerial and communicational) in Romanian forestry. The study has also revealed some important and frequent pitfalls that jeopardize the communication between prevailing stakeholders. Explaining them and their root causes could be a very useful input for further PR training programs and for the academic curricula. © 2010 Elsevier B.V.

Sofletea N.,Transilvania University of Brasov | Budeanu M.,Forest Research and Management Institute | Parnuta G.,Forest Research and Management Institute Bucharest
Silvae Genetica | Year: 2012

The performance of 33 Norway spruce [Picea abies (L.) Karst.] seed sources from the Romanian Carpathians was evaluated with respect to growth and wood characteristics in comparative trials located at two different site conditions: Avrig- outside of the natural range of Norway spruce and Breţcu - within the natural range of this species. The radial increment (RI), latewood percentage (LWP) and conventional wood density (CWD) traits were evaluated at age 30 years after plantation. Phenotypic correlations between the evaluated traits, on the one hand, and between the same traits and the geographic gradients of the origin of seed sources, on the other hand, were calculated. Analysis of variance showed significant (p<0.01) differences between seed sources for RI, while for LWP and CWD, the differences were highly significant (p<0.001). These results suggest that selection at seed sources level could be possible. The test sites influence the LWP and CWD, while the RI is almost similar in both sites. For RI, the most valuable populations are situated in the Eastern and Western Romanian Carpathians. The highest LWP was registered for the Eastern Carpathian populations, while the lowest was recorded for the Western Carpathian populations. The Southern Carpathian populations, characterized by a lower growth rate, had higher values for wood density.

Levanic T.,Slovenian Forestry Institute | Popa I.,Forest Research and Management Institute | Poljansek S.,Slovenian Forestry Institute | Nechita C.,Forest Research and Management Institute | Nechita C.,Stefan Cel Mare University of Suceava
International Journal of Biometeorology | Year: 2013

Increase in temperature and decrease in precipitation pose a major future challenge for sustainable ecosystem management in Romania. To understand ecosystem response and the wider social consequences of environmental change, we constructed a 396-year long (1615-2010) drought sensitive tree-ring width chronology (TRW) of Pinus nigra var. banatica (Georg. et Ion.) growing on steep slopes and shallow organic soil. We established a statistical relationship between TRW and two meteorological parameters-monthly sum of precipitation (PP) and standardised precipitation index (SPI). PP and SPI correlate significantly with TRW (r = 0.54 and 0.58) and are stable in time. Rigorous statistical tests, which measure the accuracy and prediction ability of the model, were all significant. SPI was eventually reconstructed back to 1688, with extreme dry and wet years identified using the percentile method. By means of reconstruction, we identified two so far unknown extremely dry years in Romania-1725 and 1782. Those 2 years are almost as dry as 1946, which was known as the "year of great famine." Since no historical documents for these 2 years were available in local archives, we compared the results with those from neighbouring countries and discovered that both years were extremely dry in the wider region (Slovakia, Hungary, Anatolia, Syria, and Turkey). While the 1800-1900 period was relatively mild, with only two moderately extreme years as far as weather is concerned, the 1900-2009 period was highly salient owing to the very high number of wet and dry extremes-five extremely wet and three extremely dry events (one of them in 1946) were identified. © 2012 ISB.

Popa I.,Forest Research and Management Institute | Bouriaud O.,Forest Research and Management Institute
International Journal of Climatology | Year: 2014

Tree-ring series from a single site and a single species were used as proxies to reconstruct past summer temperatures over 550years in the Eastern Carpathian Mountains. The chronology was built using standard procedures in order to provide comparable information about this under-sampled region while preserving the low-frequency signals. The studied site offered abundant samples of both living trees and dead wood, which were carefully selected in order to minimize heterogeneity sources owing to a reduced availability of suitable material as e.g. in the Alps. The ring-width chronology spanned over 550years with satisfying replication and showed an even segment length. The chronology correlated to temperature over quite a narrow window, temperatures of June and July only being significant. The reconstruction showed that the last 180years was the warmest period with only three short episodes of anomalies. We present evidence that the summer temperatures in the Eastern Carpathian Mountains showed divergences as compared to the Alps and a clear regionality, the coolest period over the last 600years occurring during 1720-1850. © 2013 Royal Meteorological Society.

Strimbu B.M.,Louisiana Tech University | Strimbu B.M.,Forest Research and Management Institute
Forestry | Year: 2014

Forest resources can be assessed using two ground measurements approaches: one centred on preset intensity and the other centred on sampling error. The objective of the present research is to evaluate the efficiency of the two sampling approaches using a factorial design, the factors being intensity, area, sampling error and coefficient of variation. Overall, an inventory executed using sampling error is likely more efficient than using a preset intensity (i.e. 89 per cent of the investigated cases). For small tracts (i.e. =5 ha) or tracts with one stratum, forest inventories using preset intensities are more efficient, but mainly for reduced intensities (i.e. 5 per cent). For larger tracts and moderate variability (i.e. coefficient of variation =30 per cent), resource estimation based on sampling error is more efficient than the intensity-based, especially when the tract is stratified. Stratified random sampling inventories are almostalwaysmoreefficient than10percent intensity cruises, and, in90percent of the cases,5per cent cruises. For balanced strata, the efficiency is so large that tracts with same size but different variability are indistinguishable, from sampling efficiency perspective. Therefore, a preliminary cruise can focus on attributes that are not the objective of the inventory but are related to the attributes of interest, easy, fast and accurate to measure, such as diameter at breast height, basal area or tree height. © Institute of Chartered Foresters, 2013.

Blada I.,Forest Research and Management Institute | Tanasie S.,Forest Research and Management Institute
Annals of Forest Research | Year: 2013

By using an incomplete factorial mating design between twenty Pinus strobus L. female and seven P. wallichiana Jack. male trees, a number of 34 full-sib families were obtained. The objective of this experiment was to combine the fast growing of the former species with moderately to high resistance to blister rust (Cronartium ribicola Fich. in Rabenh.) of the latter one. The hybrid families were artificially inoculated at age two, and field planted at age four. The plantation took place within an old black current (Ribes nigrum L.) heavy infected by blister rust. In order to provoke new infections, this time naturally, the pine rows were planted in between the black currant ones. Diameters at breast height, tree height, tree growth rate volume, stem straightness and tree survivals were the traits measured at age 32 from seed. The first trial thinning was simultaneously applied with the present measurements. The average tree survival was 74.8% in hybrids, 8.3% in Pinus strobus and 27.8% in P. wallichiana. Highly significant (p < 0.01) differences were found between hybrid families for all traits except stem straightness. Genetic coefficient of variation at family level was 13.7% for tree volume growth rate and 15.9% for tree survival, but only 2.1% for tree straightness. Broad-sense family heritability estimates were 0.530 for diameter at breast height, 0.596 for stem height, and 0.564 for stem volume growth rate, 0.166 for stem straightness, and 0.539 for tree survivals. Similarly, the individual tree narrow-sense heritability estimates were 0.138 for diameter at breast height, 0.209 for stem height, 0.149 for stem volume growth rate, and 0.022 for stem straightness. If the best 5, 10 and 15 of 34 families were selected, a genetic gain of 17.7%, 13.4% and 10.2%, respectively, may be achieved in tree survival or blister rust resistance. Similarly, if the best 5%, 10% and 15% individuals within the best hybrid families were selected, a genetic gain of 4.7%, 4.0% and 3.6% in diameter at breast height and 10.7%, 9.1% and 8.1% in tree volume growth rate could be made. The estimated genetic gains indicated that a program aimed at improving growth traits and survival through interspecific hybridization could be successfully achieved.

Nechita C.,Forest Research and Management Institute
European Journal of Science and Theology | Year: 2014

Knowing the growth and formation pattern of trees has been always essential, especially when the correspondence between the anatomic elements and the environment factors was studied. An important feature in the wood formation consists in differentiation between the early wood and the late wood, which formed together the yearly radial growth ring. The macroclimate has decisively influenced the beginning and the end of the vegetation period, as comparing to the regional climate and the microclimate, which induces variations of the yearly ring width. More rings of low width, together with others bigger, will induce a new pattern, founded to the trees within a region. The correspondence of time series resulted from measuring the rings width will be carried out upon basis of such model, procedure known under the name of cross-dating. The mode of gathering and processing the biological material and eventually of using it within the dating process is analyzed in detail in this study. Theological importance of this science derives from answers that dendrochronology can offer to support biblical writings. Understanding the theoretical basis, not presented in detail so far in any specialized study, facilitates knowledge of the influence of environmental factors on cultural heritage, with direct implications on human spirituality. The need of such presentation derives from many assigned questions, regarding the dating of items, and especially the way such process is carried out, since not any wood item can be placed certainly in space and time, by means of the dendrochronological method.

Loading Forest Research and Management Institute collaborators
Loading Forest Research and Management Institute collaborators