Author(s):
1. Marijana Kapovic Solomun, Faculty of Forestry, University of Banja Luka, Republic of Srpska, Bosnia and Herzegovina
2. Svjetlana Coralic, Republic of Srpska, Bosnia and Herzegovina
3. Nemanja Lazovic, Republic of Srpska, Bosnia and Herzegovina
4. Saša Eremija, Institute of Forestry Belgrade,, Serbia
5. Nemanja Jungic, Republic of Srpska, Bosnia and Herzegovina

Abstract:
INTRODUCTION Degradation of fire-affected soils is a problem that generally requires more attention in the Republic of Srpska (Bosnia and Herzegovina). Forest fires can significantly degrade the soils, especially calcareous Mollic Leptosol that is developed under specific natural conditions. Forest fires have a several negative effects on soils like decrease of humus content and organic matter as well, deterioration of structure and porosity, considerable loss of nutrients through volatilisation and soil erosion. According to Certini (2005), forest fires marked alteration of quantity and specific composition of microbial and soil-dwelling invertebrate communities. Soil changes induced by fire can be short-term, long-term or permanent, which depends on fire properties (intensity and severity) and environmental factors (climate, vegetation, soil type, geomorphology, etc). Mollic Leptosol on limestone are particularly sensitive to fire effects, due to high humus content, small depth and slow evolution as additional factor of their vulnerability. Paper is aimed to explore the influence of forest fires on Mollic Leptosol properties, to define measures for improvement of environmental conditions at fire-affected sites, and measures that will slow or prevent further soil degradation. MATERIAL AND METHOD Manjača Mountain is located in western part of the Republic of Srpska. Climate characteristics were analyzed using data from meteorological station Banja Luka, Mrkonjić Grad i Jajce for period 1981-2010. The fire was active during 2003, and research was conducted ten years later. Mollic Leptosols were analysed on 12 sample plots, where each plot represents a cross-section of site and stand properties. First four sample plots are placed in area where forest fire had medium intensity, plots 5–8 under low intensity of forest fire, and plots 9–12 are placed in non-fired mountain beech forest in the vicinity of fire-affected area. Morphological, physical and chemical soil properties are explored as well as characteristics of vegetation on each sample plot. RESULTS AND DISCUSSION Climate is mostly humid over the year. Parent material is represented by limestones and dolomites in some parts. Mountain beech forests (Fagetum montanum Illyricum, Fuk. et Stef. 1958) are dominant in research area. Depth of analyzed soil profiles range from18 to 42 cm and they are generally deeper in unburned area. The fire has significantly affected chemical soil properties. Ten years later, humus content is still reduced for almost 50% compared to non-fired Mollic Leptosols. Soil acidity is ranged between 6,1 – 7, 7 pH regardless fire impact, while carbon and nitrogen content is reduced. Degree of base saturation follows humus content. Characteristic plant groups are differentiated only on plots where the fire intensity was medium or low. Fire affected areas requires rehabilitation measures that, will have economic and environmental effects but also to prevent further soil degradation. Those measures could be: removal of young crops, sapling and pole forest, reforestation, removal of diseased adult trees and introduction of new species adjusted to soil and natural conditions. It is very important to forestall weed development, which additionally accelerates soil erosion.

Key words:
land degradation,forest fire,humus,limestone,soil nutrients

Thematic field:
Forest ecology and conservation of natural resources

Date of abstract submission:
01.09.2017.

Conference:
Šumarska nauka u funkciji održivog razvoja šumarstva
25 godina šumarstva Republike Srpske