broj: 11-12/2021
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| RIJEČ UREDNIŠTVA | ||
| Uredništvo | ||
| What does the Glasgow Conference bring us? pdf HR EN | 513 | |
| IZVORNI ZNANSTVENI ČLANCI | ||
| David Mijoč, Nikola Perković, Mario Šporčić, Matija Landekić, Matija Bakarić, Andreja Đuka, Tomislav Poršinsky | UDK 630*360 +761 https://doi.org/10.31298/sl.145.11-12.1 | |
| Evaluation of the method of calculating the planned price of timber harvesting operations pdf HR EN | 515 | |
| T. Gomerčić, I. Topličanec, V. Slijepčević, S. Blašković, I. Selanec, I. Budinski, J. Tomaić, J. Kusak, Gj. Ivanov, M. Sindičić | UDK 630* 152 + 146 (001) https://doi.org/10.31298/sl.145.11-12.2 | |
| Distribution and minimum population size of Eurasian lynx (Lynx lynx) in Croatia in the period 2018–2020 pdf HR EN | 525 | |
| Lovre Panđa, Ante Šiljeg, Ivan Marić, Fran Domazetović, Silvija Šiljeg, Rina Milošević | UDK 630*174.7 https://doi.org/10.31298/sl.145.11-12.3 | |
| Comparison of GEOBIA classification algorithms based on Worldview-3 imagery in the extraction of coastal coniferous forest pdf HR EN | 535 | |
| Marina Milović, Verica Vasić, Milan Drekić, Branislav Kovačević, Saša Pekeč, Zoran Galić, Saša Orlović | UDK 630* 181.3 + 164 (001) https://doi.org/10.31298/sl.145.11-12.4 | |
| Diversity of ectomycorrhizal fungi associated with Quercus petraea in the national park Fruška gora in the Republic of Serbia pdf HR EN | 547 | |
| Zafer Yücesan, Derya Bayram | UDK 630* 232.3 (001) https://doi.org/10.31298/sl.145.11-12.5 | |
| Effects of pretreatment, sowing time, sowing environment and climate factors on germination in Acer pseudoplatanus L. pdf HR EN | 557 | |
| PRETHODNO PRIOPĆENJE | ||
| Ivan Balenović, Luka Jurjević, Krunoslav Indir, Ante Seletković | UDK 630* 587 + 622 https://doi.org/10.31298/sl.145.11-12.6 | |
| Photogrammetric estimates of stand volume in pedunculate oak stands of the Pokupsko basin pdf HR EN | 567 | |
| Summary The application of digital aerial photogrammetry in forest inventory has been in the focus of a number of studies during the last decade (White et al. 2016, Goodbody et al. 2019). The results were tested and evaluated mostly on plot-level, and less often on stand-level (Bohlin et al. 2012, Rahlf et al. 2014, Gobakken et al. 2015, Pitt et al. 2015, Stepper et al. 2015, Puliti et al. 2016, Balenović et al. 2017, Iqbal et al. 2019). In almost all studies, a classic Area-Based Approach (ABA) which includes modelling at plot-level and ‘wall-to-wall’ mapping to estimate forest variables at stand-level were applied. A somewhat different ABA approach which implies direct modelling and estimation at stand-level were proposed by Balenović et al. (2017). This new approach, hereinafter referred to as Stand-Based Approach (SBA), is based on existing and easily available photogrammetric materials and data (aerial images from regular national topographic surveys, official national digital terrain data) as well as on data from existing forest management plans. The main precondition for the SBA method application is the approximate time coincidence between the time of aerial images acquisition and the time of the field data collection for the forest management plan generation. Similar to classical ABA, SBA also requires models (equations) for forest variable estimations. However, in SBA case, models are developed on the certain number of stands (subcompartments) of similar structural characteristics (e.g. forest management classes). In SBA, independent variables are metric stand-level data obtained from aerial images and its product (normalized point clouds or canopy height models), while reference (modelling or validation) data are obtained from regular forest management plans. Compared to classical ABA, SBA does not require additional field measurements, and therefore presents a fast and cost-effective alternative to ABA. An additional assumption is that models developed for the certain area can be applied for other forest areas with similar forest characteristics. This work presents the continuation of previous study (Balenović i dr. 2017) with the aim to additionally test the effectiveness and accuracy of SBA method. More precisely, SBA method and existing models of stand volume estimation originally developed for lowland pedunculate oak (Quercus robur L.) of Spačva basin forest complex (Eastern Croatia) were tested in pedunculated oak forest of Pokupsko basin forest complex (Central Croatia). A total of 87 even-aged pedunculate oak forest stands of Jastrebarski lugovi management unit were included in this study (Figure 1, Table 1). Photogrammetric data (aerial images, digital terrain data) were provided by the Croatian State Geodetic Administration, and were used to generate Digital Surface Model (DSM) and Digital Terrain Model (DTM). A raster Canopy Height Model (CHM) of 5 m resolution was generated by subtracting DTM from DSM (Figure 2). Metrics extracted from CHM for each stand and used for stand-level volume estimation are presented in Table 2. Equations (1) and (2) present photogrammetric models for stand-level volume estimation. A more detailed description of the models can be found in Table 3. SB-1 and SB-2 models consist of independent variables and parameters (regression constant and coefficients) originally developed for the Spačva basin area (Table 4). PB-1 and PB-2 models consisted of the same variables as SB-1 and SB-2 models, but their parameters were developed for the present study area (Pokupsko basin) (Table 4). All models were validated using the reference stand volume from the forest management plan. SB-1 and SB-2 models were validated using the entire dataset (87 stands), whereas PB-1 and PB-2 models were validated using the randomly selected 29 stands (other 58 stands were used for parameters estimation). According to validation results (Table 2, Figure 3), PB models showed considerably greater performance than SB-models. Compared to SB-1 model, PB-1 model achieved 11% higher R2adj values, for 3,92% MD% values (absolute), and for 6,44% higher RMSE% values. Also, the results showed that the inclusion of stand age (SA) as an additional predictor in SB-2 and PB-2 models did not contribute significantly on model performance. All models showed a similar trend (Figure 3), i.e. volume in stands with lover volume values were overestimated, while in stands with higher volume values were underestimated. However, overestimations (&8776; 8,5%) using SB models were considerably greater than underestimations (&8776; -4%) using PB models. Differences in SB and PB models performance are probably due to differences in stand and site characteristics between two forest areas (Spačva basin and Pokupsko basin). The obtained results suggest that the model with independent variables (Equation 1) originally developed for Spačva basin area can be used for Pokupsko basin and other areas with similar forest characteristics, but local model parameters have to be estimated in order to increase estimation accuracy. It has to be emphasized that the photogrammetric method tested in this paper can not replace the conventional field methods in regular forest inventory. However, its application is based on existing and easily available data (aerial images from regular topographic surveys, official DTM, forest management plan) and does not require additional field measurements and therefore present effective and low-cost solution when in a very short period large areas have to be inventoried. Further research should be focused on other important forest variables (e.g. mean stand height, mean stand diameter, basal area, stand density, biomass, etc.) and different forest types. Key words: aerial images; digital photogrammetry; canopy height model (CHM); stand volume; forest inventory | ||
| Branislav Drašković, Marko Gutalj, Stefan Stjepanović, Boban Miletić | UDK 630* 233 https://doi.org/10.31298/sl.145.11-12.7 | |
| Estimating recent forest losses in Bosnia and Herzegovina by using the Copernicus and Corine land cover databases pdf HR EN | 581 | |