Journal of Forest Science, 2017 (vol. 63), issue 8

Selection of promising black locust (Robinia pseudoacacia L.) cultivars in HungaryOriginal Paper

Károly RÉDEI, Imre CSIHA, János RÁSÓ, Zsolt KESERŰ

J. For. Sci., 2017, 63(8):339-343 | DOI: 10.17221/23/2017-JFS  

In Hungary the black locust (Robinia pseudoacacia Linnaeus) is one of the most important exotic stand-forming tree species growing mostly under unfavourable ecological conditions. Considering the climate change effects its importance is increasing also in many other countries. As a result of a selection programme several black locust cultivars have been improved for setting up cultivar trials. In the paper four black locust cultivars were evaluated in Central Hungary under arid hydrological and brown forest soil conditions. Significant differences (P < 5%) were found in height, DBH, mean tree volume and average stem form value...

Changes in the nutrition and health status of young Norway spruce stands in the Krkonoše Mts. in a 17-year periodOriginal Paper

Radek NOVOTNÝ, Bohumír LOMSKÝ, Vít ŠRÁMEK

J. For. Sci., 2017, 63(8):344-354 | DOI: 10.17221/19/2017-JFS  

For 17 Norway spruce stands located in the Krkonoše Mts. in the Czech Republic a long-term assessment of defoliation, height increment, foliage concentration of nutrients (N, P, Ca, K, Mg) and stress elements (S, F) was carried out. The results show a decrease of defoliation and a slight increase of height increment, which occur in accordance with the decreasing concentration of sulphur in spruce needles. However, neither sulphur concentration nor height increment trends are significant, suggesting that both the main pollution abatement and the growth resumption took place already in the 1990's. During the late 1990's the average spruce defoliation...

Forest density and orchard classification in Hyrcanian forests of Iran using Landsat 8 dataOriginal Paper

Khosrow MIRAKHORLOU, Reza AKHAVAN

J. For. Sci., 2017, 63(8):355-362 | DOI: 10.17221/15/2017-JFS  

Satellite-based remote sensing is of crucial importance to provide timely and continuous thematic maps for practical forestry tasks. There is currently no existing remote sensing-based, large-scale inventory of canopy cover classes (and also adjacent orchards) on the full range of Hyrcanian forests. We used the freely available and large-scale coverage of Landsat 8 imagery acquired in 2014 to classify three forest density classes as well as non-forest and orchards. The supervised classification and support vector machine classifier were selected based on a pre-classification of three representative pilot regions. Classified final maps were validated...

Research on forest terrain roughness as a source of dynamic action on the vehicleOriginal Paper

Milan MIKLEŠ, Milan HELEXA, Juraj MIKLEŠ

J. For. Sci., 2017, 63(8):363-369 | DOI: 10.17221/43/2017-JFS  

The issue of terrain conditions is very complex and its description is approached from different perspectives and with different objectives. Because it consists of the gathering of basic information for a mobile object, a wheeled forestry tractor, the terrain-vehicle approach was taken as the basis. Ground conditions are part of the operating conditions of wheeled forestry tractors. Uneven ground can be regarded as a source of vibration in the vehicle - towing truck. In this respect, given the random shape of the surface roughness, the solution to vibrations leads to a terrain correlation analysis in order to obtain a correlation function and power...

Evaluation of forest fire risk using the Apriori algorithm and fuzzy c-means clusteringOriginal Paper

Ali Akbar JAFARZADEH, Ali MAHDAVI, Heydar JAFARZADEH

J. For. Sci., 2017, 63(8):370-380 | DOI: 10.17221/7/2017-JFS  

In this study we evaluated forest fire risk in the west of Iran using the Apriori algorithm and fuzzy c-means (FCM) clustering. We used twelve different input parameters to model fire risk in Ilam Province. Our results with minimum support and minimum confidence show strong relationships between wildfire occurrence and eight variables (distance from settlement, population density, distance from road, slope, standing dead oak trees, temperature, land cover and distance from farm land). In this study, we defined three clusters for each variable: low, middle and high. The data regarding the factors affecting forest fire risk were distributed in these...

Growth performance and lignin content of Acacia mangium Willd. and Acacia auriculiformis A. Cunn. ex Benth. under normal and stressed conditionsOriginal Paper

Muhammad Javed Asif, Nisha Thopla GOVENDER, Lai Hoe ANG, Wickneswari RATNAM

J. For. Sci., 2017, 63(8):381-392 | DOI: 10.17221/100/2015-JFS  

Acacia mangium Willdenow and Acacia auriculiformis A. Cunningham ex Bentham are fast-growing species with wide environmental adaptability. Fast-growing species which thrive in otherwise non-arable problematic soil and which hold the added advantage of improving the condition of the soil, can be used to increase production area, and, thus, are highly desired. We investigated the growth performance and lignin content under normal and stressed conditions for these Acacia mangium Willd. and Acacia auriculiformis A. Cunn. ex Benth. Normal growing conditions was represented by fertile soil, high water-holding capacity...