Issues

Abstract

Rehabilitation of degraded forest ecosystems requires introduction of fast-growing productive and adaptive tree species, such as Douglas-fir. However, introduction of new species always carries an element of risk. This risk can be decreased by appropriate testing. Therefore, it is necessary to investigate the origin and success of species and to select the most suitable provenances. A very important stage in the process of provenance testing is the early control of seed material, which can improve and increase the growth of good-quality seedlings and provide better results in afforestation and establishment of new vegetation. Therefore, the Institute of Forestry in Belgrade set the germination test of Douglas-fir seed under different test conditions in order to identify and select the best seed sources for afforestation. Original Douglas-fir seed of different provenances in Canada was taken as seed material. The test included collection of seeds originating from thirteen different provenances in natural forests of Canada. The aim of the research was to determine the potentials and germination differences among the seeds of common provenances in different conditions - in laboratory and in nursery - and to select the best provenances. The relationship of seed germination and the geographic origin could be another important indicator for selection of Douglas-fir provenances. Regression and correlation analyses were used to determine the statistical dependence of the seed germination in different condition on the geographical origin of Douglas-fir seeds.

Abstract

In the frame of implementation of International Cooperative Program 'Forests' - second level - (ICP Forests), since 2011 phenologycal observations of beech vegetation in the station of 'Vitinya' were conducted. The targets of this study, along with the data from the many years of observations (2001), related to the assessment of defoliation, phytocenotic changes, leaf analysis, meteorological parameters, air pollution, soil, etc., were to identify the key factors and processes in the functioning of it. The results of observations of the phenologycal development of common beech (Fagus sylvatica L.) in 2012 are: duration of vegetation, start and end of leafing, timing of autumn discolouration of leaves, beginning and end of leaf fall. Assessment of the results was combined with the average minimum and maximum air temperature in 2011 and 2012 and average monthly relative air humidity in both years. 

Abstract

The present study aims at investigating the effects of gibberellic acid (GA3) application and cold stratification on the germination of Sorbus domestica L. and Sorbus torminalis (L.) Crantz seeds. In particular, seeds of both species were treated with 500, 1000 and 2000 ppm GA3 for 30 hours and were, subsequently, cold stratified at 3-5 ºC for 0, 1, 2 and 3 months. In addition, seeds from each species were only cold stratified for 0, 1, 2 and 3 months (control). In both species, non-stratified and 1-month cold stratified seeds, despite having been treated with GA3 solutions, exhibited very low germination percentages (0.8-4.2 % for S. domestica and 0.0-1.7 % for S. torminalis). However, in control seeds and seeds treated with GA3 solutions an increase in the cold stratification period from 2 to 3 months increased germination percentages significantly in both species. In S. domestica, after a 2-month period of cold stratification, the germination percentage of the seeds treated with 2000 ppm GA3 (30.8 %) was significantly higher than that of control seeds (18.3 %). In 3 months of cold stratification, there were no significant differences in the germination percentages between control seeds (87.5 %) and seeds treated with GA3 solutions (89.2-91.7 %). In S. torminalis, the GA3 application significantly improved the germination of 2 and 3-month cold stratified seeds. After a 2-month period of cold stratification, the germination percentage of seeds, which had been treated with 2000 ppm GA3 (30.0 %), was higher than the germination percentages of the seeds which had been treated with 500 and 1000 ppm (15.8 and 14.2 % respectively). After a 3-month period of cold stratification there were no significant differences in the germination percentages between seeds treated with GA3 solutions (88.3-91.7 %). The results demonstrated that the optimum germination percentages of S. domestica and S. torminalis were obtained after a 3-month cold stratification period. In both species, the application of GA3 did not replace or shorten the required cold stratification period. 

Abstract

Mature seeds of Sycamore maple have a physiological dormancy. Different studies suggest fall sowing or cold stratification for a period varying from 3 weeks to 3 months. The aim of the study is to find optimal way for dormancy breaking of sycamore seeds in South-East Europe conditions. Variants of fall sowing, spring sowing of stored in dry substratum (untreated) seeds and sowing after 1, 2, and 3 months cold stratification were tested. The results showed that during a 2 and 3 months cold stratification the seeds germinate in substratum (relatively 51.5 % and 71.8) and they become useless for sowing. Only 7.0 % of seeds germinate during 1 month cold stratification period in the substrate. The germination after fall sowing is 68.8 %. After spring sowing of untreated seeds and 1 month cold stratificated seeds the germination is relatively 82.3 % and 82.75 %. The height of seedlings was smaller after fall sowing - average 9.76 cm. The seedlings produced after spring sowing of untreated seeds had average height 12.3 cm. The seedlings of seeds, which were cold stratified for 1, 2 or 3 months prior to spring sowing, exhibited the best growth in height (18.5-19.5 cm). The results bring to some conclusions. It is not recommended to store Sycamore maple seeds till spring in wet substrate because it has characteristics of cold stratification and lead to their early germination. The best way for seed dormancy breaking is 1 month cold stratification at 4 °C. The germination dynamics show that stratification have to begin 45 days before the date of last spring frost and the sowing have to be done 15 days before the determinate date. Second variant is spring sowing of seeds stored in dry substrate. In this case germination begins 25 days after the sowing and there is no danger of frost caused damages. 

Abstract

The main objectives of the EU project 'CORINE Land Cover' are creation of a unified European land cover map through interpretation of satellite images and preparation of a digital database of land cover and the changes in it. The results are used for assessment of land cover and its state and policy formulation on protection of the environment, planning and management of agriculture, forestry, transportation, etc. at European and national level. The databases created in different stages of the project 'CORINE Land Cover' - Bulgaria are analysed, some of the most typical changes in the forest territories of Bulgaria concerning the forested areas during the period 1990-2012 are identified, and from there the trends in their development are found. 

Abstract

The aim of the present study was to assess the total standing dead trees of Chir pine and their potential of carbon stock in the forests. Chir pine (Pinus roxburghii) in Himalayan forest plays a major role in carbon sequestration. Chir pine is a very prominent forest cover in Uttarakhand, out of total 24,414.80 km2 area under forests; it occupies 3,943.83 km2 which is 16.15 % of total forest area of the state. In sub-tropical region of Garhwal Himalaya, large numbers of standing dead trees have been observed on southern aspect and increasing continuously last few years. Dead standing (snag) trees in the forest play equal role in carbon sequestration as live trees. Although regular inputs of dead tree components play important role in enrichment of forest floor though litter, twigs, fruits and some time entire tree. The results show that the average standing dead trees were reported 14.83 ha-1 of which mean volume and carbon stock values were of 23.14 m3.ha-1 and 14.67 t.ha-1 respectively. 

Abstract

 Between August 2009 and May 2010 74 Chukar Partridge (25 August to November 2009 and 49 from February to May 2010) were released. Chukar Partridges inhabit different size areas between 31.5 and 65.7 ha, but about 10 % of the area of the habitat. Birds prefer thorn bushes during the day to the other areas (χ2 = 13.185, df = 4, p < 0.05). Data show low efficiency of the release and the need to change the practices of resettlement of Chukar Partridges in Bulgaria. 

Abstract

Enzyme activity of forest soils affected by forest fire under conifers (Pinus sylvestris L., Larix desidua Mill.) and mixed (Pinus sylvestris L., Quercus cerris L.) forests from north slopes of Rila Mountain (region of Dolna Bania) have been analysed in samples, collected 7 days after wildfire occurrence. Results on catalase, cellulase and protease enzyme activities in fire-affected soils show a considerable increase in comparison with the same enzyme activities of the control (fireunaffected) site. The activities of these three enzymes can be used as indicators of the on-going biological processes in post fire-affected soils. The values of catalase and cellulase were lower in the forest litter, and higher in the subsequent layers of soil. Protease activity increases in depth in three of analyzed fire-influenced soils. In the control soil the activity of this enzyme remains constant in depth of the soil profile. Higher pH values and lower soil humidity were established in fire-affected soils compared to the control soil. A higher content of organic carbon and nitrogen in the soil of surface fire as compared to those with crown fire and control soil was established. 

Abstract

The extraction of minerals in an open way inevitably leads to generation of large amounts of mining waste for storage and disposal. The last require vast areas. And although the present priority continues to be prevention of already generated waste it is important to try to cease pollution by achieving the requirement of getting to the process of 'end of waste'. Typically, this conversion of waste into materials is matched with the process stage of pre-treatment ensuring reliable recovery. Mining waste contains valuable and often searched substances that can be used as an alternative to natural materials. 

Abstract

Dormancy is a period when temperate species are not active. Their physiological processes are delayed until the appearance of stimuli interrupt the dormancy. This period is commonly separated in two stages. The first stage is a rest period, when the buds remain dormant due to growth-arresting physiological conditions and the second is a quiescent period when buds are waiting favourable environmental conditions to burst. The Chill Days Model is a sequential model that uses the accumulation of chill days to break the rest and accumulation of anti-chill days to overcome quiescence. Predicting the beginning of the growing season and the duration of cooling is important for the analysis of forest ecosystems. The Chill Days Model gives a good prediction of the bud burst. The site-specific temperature threshold for Fagus sylvatica L. with this model was established as 7.3 °C and chill requirements were defined as 124 chill days in Balkan Range. 

Abstract

Two provenance tests with 29 German, American and Bulgarian Douglas-fir provenances were established in Bulgaria with 2-year-old plants in 2006. The trials were established in the forest enterprises 'Berkovitsa' (Western Balkan Range) and 'Borima' (Central Balkan Range). The spacing was 2 x 2 m, with 49 and 25 plants per plot, respectively, with three replications. The trials were evaluated for survival, mean growth and current annual height increment in the last (the sixth) year after outplanting. The results show that the trees in 'Berkovitsa', which grow on more suitable site according to climate, had less mortality and better growth compared to these on the site 'Borima'. Statistical analysis shows the beginning of differentiation between the provenances. Differences between the provenance regions are insignificant. Indications are given for the procurement of Douglas-fir seed for Bulgaria. 

Abstract

For the Aleppo pine of Tatoi forest (Parnitha, Attica, Greece), regression models that estimate the volume using diameter at breast height and/or total height were fitted. A random sample of 100 trees was taken. Eighty of these trees were used for fitting and 20 for validation. The selected model is V = 0.267·D2·H with R2 = 0.93 and standard error of estimate 0.199. Comparison with a pre-existing model of 2004, revealed the similarity of the old model for the estimation of the volume of Pinus halepensis for the specific area. 

Abstract

Forests represent a veritable barrier against land degradation, being the best choice for soil erosion control. Romanian woody flora consists of more than 300 species of forestry interest. Among them, approximately 50 shrub and tree species are often used in afforestation of degraded terrains. The aim of this review paper was to highlight the most important species used in forest land reclamation. Aspects regarding the ecological requirements and the results obtained by using these species in afforestation of the degraded lands were also presented. In conclusion, it could be stated that the Romanian experience acquired in this sphere of activity is very important considering the global warming, and afforestation of degraded terrains being the best way to counteract degradation phenomena and to mitigate the effects of climate change