**Шумарски преглед, год. 47, бр. 2**

**Forest Review, Vol. 47, No. 2**

**Issue Articles**

**Impact of flooding on wood assortment production**

**Authors:** Milorad Danilović, Miodrag Perović, Dušan Stojnić, Ljupco Nestorovski, Srđan Dražić, Aleksandar Vorkapić

⇑ DOI:

Original scientific article

**Abstract:**

This paper presents the results of a study of the impact of flooding on the total revenues generated by the production of wood assortments in poplar plantations. The research was carried out in two sample plots in the PE “Vojvodinašume”. The impact of flooding on the qualitative structure of assortments is estimated on the basis of the curvature of the lower part of the stem. The method applied in this paper is the method of quality factor isolation [1]. The results of this research show that flooding has an impact on the curvature of the most valuable, lower, part of the stem, i.e. on the total value of produced assortments. The analysis of the loss of wood mass cut after a flooding was performed in the area of the Special Nature Reserve “Gornje Podunavlje” in the FA “Apatin” and the “Apatinski rit” FMU. The analysis was conducted in the period from 2009 to 2013. The data for the analysis were obtained from the commission reports. After the flooding, the annual loss of wood accounted for 0.03 to 1.90% of the total amount of felled wood in the area of FA “Apatin”. In value terms, this percentage is even lower, considering the large share of firewood. The share of classical and multi-purpose wood for heating and cellulose accounts for 85.59% of the total losses. In order to minimize losses in unprotected areas, works in compartments and sections at the lowest elevations need to be carried out during the dry season of the year, i.e. during the period with the lowest probability of flooding.

* Keywords:* flooding, poplar, structure of assortments, wood losses, dynamics of works.

**Soil erosion rates in two successive reservoir catchments: Spilje and Globocica reservoir, Macedonia**

**Authors:** Ivan Mincev, Aleksandar Trendafilov, Ivan Blinkov, Dragan Ivanovski

⇑ DOI:

Original scientific article

**Abstract:**

The catchments of the reservoirs Spilje and Globocica are positioned in the western part of Macedonia. This part is known for the more than average rainfall (800-900 mm/annually) for the country and large portion of the catchment is consisted of forests and natural grasslands. In the past, this region had been a huge economic centre. As a part of the process of migration, many of the mountainous regions of Macedonia have been practically deserted. This had a huge effect on the environment and it largely diminished the human impact. The catchment of the reservoir Globocica is beginning from the outflow of the river Drim from the Ohrid Lake. The main water source for this reservoir is the river Drim and some minor tributaries. The catchment of the Spilje reservoir is beginning from the Globocica dam, continuing the flow of the Drim River and also form north the second main tributary is Radika River. The two catchments were mapped for erosion according to the Erosion Potential Method (EPM) by Gavrilovic. The two erosion maps created for the two reservoir catchments show very different results. The catchment of the reservoir Globocica is one of the most preserved catchments from soil erosion point of view with average erosion coefficient (Z) of 0.29, specific annual production of erosive sediment is 394 m^{3}km^{-2}yr^{-1}., and the specific annual transport of erosive sediment is 247m^{3}km^{-2}yr^{-1}. On the other hand, the catchment of the reservoir Spilje is one of the most erosive areas in the country, with average erosion coefficient (z) of 0.44, specific annual production of erosive sediment is 776 m^{3}/km^{2}/ann., and the specific annual transport of erosive sediment is 541 m^{3}/km^{2}/ann.

* Keywords:* Soil erosion, erosion rate, EPM, reservoir sedimentation

**Timber production in poplar plantations with different plant spacing**

**Authors:** Ranko Sarić, Milorad Danilović, Slavica Antonić, Pajo Vojvodić, Vladimir Ćirović

⇑ DOI:

Original scientific article

**Abstract:**

The paper presents the results of a study of the impact of plant spacing of different poplar clones on the revenues generated per unit area. The research was carried out in six sample plots in the period from 2007 to 2016. The research object are clones *Populus×euramericana* ‘I-214’, *Populus×euramericana* ‘M1’ and *Populus deltoides *PE 19/66. On the basis of the results of this research, it can be concluded that larger plant spacing causes an increase in revenues at the same age of a plantation, with a small difference in production costs. The type of clone has a significant impact on the potential qualitative structure of the assortments, as shown by the results of the analyses of increment of clones PE 19/66 and I-214 at the same age. Until the fifth year of age, a higher diameter increment was found for clone PE 19/66, and from the fifth year of age for clone I-214. In addition, hexagonal plant spacing produced a higher diameter increment compared to tetragonal plant spacing.

* Keywords:* poplar, plant spacing, assortment structure, revenues and costs

**Testing the applicability of the mathematical model for forest openness**

**Authors:** Zdravko Trajanov, Ljupco Nestorovski, Pande Trajkov

⇑ DOI:

Original scientific article

**Abstract:**

In order to establish the applicability of the mathematical model for determining the theoretical optimal density of the forest roads in Republic of Macedonia, a testing of the model in practice has been conducted. Mathematically, the theoretical optimal density is acquired as a sum of the optimal density of forest roads and the density of the receptors. Additionally, models for the optimal density of forest roads have been graphically designed in the software ARC MAP. The existing network of forest roads, as well as the area which is theoretically opened, have been taken as a basis for these graphic models. Additionally, the necessity for building new forest roads in order to create the complete network of forest roads in the area has been determined. At that, the new roads have been designed on the basis of the optimal distance of the forest roads acquired according to the mathematical model for optimization of the density of truck roads. Seven forest economic units at the area of the Forestry Plackovica in Radovis have been tested, and at the results that were obtained from the design of the optimal network and the theoretical optimal density of the forest roads, average relative absolute variation of 14% has been determined. The results that were obtained confirm the application of the mathematical model which was set for the optimal density of forest roads in Republic of Macedonia, drawing a conclusion that certain deviations from the mathematical solution are possible.

* Keywords:* forest openness, optimal density, theoretical density, receptors, mathematical model, relative absolute variation

**The Eurasian Dry Grassland Group (EDGG) 13th Eurasian Grassland Conference Report: Management and conservation of semi-natural grasslands: from theory to practice (20-24 September 2016, Sighişoara, Romania)**

**Authors:** Renata Ćušterevska

⇑ DOI:

Scientific and professional meetings report

In this report made is review of what is the Eurasian Dry Grassland Group (EDGG) and since when exists? Listed are the main activities of the EDGG. Given is review of so far realized 13 conferences, with special emphasis on the last realized 13th Eurasian Grassland Conference “Management and conservation of semi-natural grasslands: from theory to practice”, held on 20-24 September 2016 in Sighişoara, Romania.