Janar Raet, Kalev Sepp and Are Kaasik
Assessment of changes in forest coverage based on historical maps
Forest has always been an important natural resource. Issues related to forest reserve, coverage area, distribution pattern and status have been important to the forest, nature protection, as well as to environment management specialists. The present studies have proved that it is not easy to find a clear and simple answer to the above-mentioned essential issues. The indicators of the importance of the forest coverage or the coverage area at a certain period of time depend on the applied assessment methodology, primary source used, etc. The main objectives of this study were to analyze the possibilities of using historical maps for studying the formation and changes of the forest coverage in the longer timely retrospect. The continuity of the forests and the possibilities of defining the variation of the areas covered with forest and open landscape were studied at the test area using the map material covering 150-year period (reference years were 1850, 1949 and 2002). The results of the analyses show that it is possible to reconstruct partially the formation of the forest in some areas and it is possible to define the areas, which have been covered with forests for tens or hundreds of years. It is possible to analyze from which land use classes the present forest community has been formed of and define the age of it. At the same time, several methodological questions arise in connection with the interpretation of the map information of the materials of the 19th century and definition of the term "forest". For example, one problematic issue is the vague definition of the class "Buschland" which in present terms could have at the time of mapping been either agricultural land or already a young forest. The comparison carried out at the test area showed that the coverage rate of the present forest areas with the areas covered with forests or such vague areas in 1850 is 75%.
T.A. Devyatova, Yu.S. Gorbunova, N.A. Sorokina and L.A. Yablonskikh
The forest fire effect on the leached chernozem results in the organic matter loss and the decrease in content of alkali-hydrolysed nitrogen compounds. The content of ash components as well as mobile forms of Cu and Zn in the topsoil has increased. It can be connected with the ashes appearing in the soil surface, which are rich in microelements.
V. Chiteculo, M. Hájek and P. Kubová
The policy of production and commercialization of timber before and after the independence of Angola was assessed. Historical production of timber under control of Portuguese settlers before 1975 in comparison to the production of timber after this period was reviewed. We used a combination of published scientific studies and government reports to support the background of the paper and a structured questionnaire survey from which analyses were drawn using a logistic regression model. It was found out that timber production declined dramatically after Angola gained independence; the production of logs dropped from 555 000 m3 in 1973 to less than 115 400 m3. Out of the 100 mills that had existed in Angola before 1975 only twenty have been in operation today with annual wood production of less than 20% of extraction capacity. The knowledge concerning the historical production of timber before and after 1975 is not sufficient to provide suggestions for a management plan on what trees, where, and when are to be cut.
Jozef Konôpka, Vladimír Šebeň and Bohdan Konôpka
General information on forest growth and development as well as different approaches of forest management are presented in the introduction of the paper. Furthermore, it shows an analysis of the development of tree species composition in the Slovak forests during the last 50 years. Historical data base for the analysis originated from the forestry records (especially Permanent Forest Inventory). Our attention was focused on reforestation with respect to tree species, tree species composition in young forest stands by age classes and relations between these forest characteristics. The next section of the paper describes new proposals for regulation of forest regeneration and reforestation with the aim to achieve desired tree species composition in all age classes, not only in accordance with natural conditions but also respecting human demands in the future.
The paper analyses the implementation of the growing stock estimation methods in the forests of Slovakia between the years 2001 and 2010. The analysis focuses on mature stands with primary timber production function in more detail. The share of more accurate and costly methods has been continuously decreasing; and since 1993 yield tables have become the most prevalent methods of estimation used in mature stands are. After more than 20 years of their implementation it is important to verify the accuracy of their application, the accuracy of the provided input variables and the methodology behind the growing stock estimation. The paper identifies the cases of their incorrect application, and the risks associated with the quantification of input data, and proposes the measures for their elimination. It stresses the importance of inspection of monitoring the quality of Forest Stewardship Programmes which operates as a specialised task since 2008. Since that time, a positive trend has been observed in mature stands of timber production forests in which mathematical- -statistical sampling methods are gaining on importance.
The present article contains a study on the evolution of afforested land in Northern Moldova Plateau. In addition, it describes some spatial aspects concerning the use and expansion of these categories of land within the study region. The present article also reflects the research results on the basis of the data submitted by the “Moldsilva” Agency, The Institute of Research and Forestry Management and Land Relations Agency and Cadastre of the Republic of Moldova. The scientific publication also depicts some current issues on the protection of land in Northern Moldova Plateau.
Hanna Kruk and Bożena Kornatowska
The conception of sustainable development has been implemented into practice in numerous economic sectors, including forestry. Forest ecosystems are extremely important in the global ecological system, therefore maintenance and appropriate management of forest resources according to sustainable development principles have engaged a great deal of attention. The concept of sustainable forest management (SFM) encompasses three dimensions: ecological, economic and social. A powerful tool to promote SFM are criteria and indicators. The aim of the article was evaluation of SFM in Poland, using one of the methods proposed by the Food and Agriculture Organization (FAO). According to data available, Polish forestry has a number of advantages: Poland has avoided the problem of deforestation, forest area has been permanently increasing, there has been observed improvement of forest health and vitality as well as a significant share of forests has carried out protective functions with no impact on timber production. Poland’s model of SFM is an adaptive process of balancing the ever-changing set of economic, environmental and social expectations. Such a complicated undertaking requires constant assessing and adjusting forest practices, in response to new circumstances, scientific advances and societal input
Željka Šiljković and Marica Mamut
Every year the Republic of Croatia, especially in its south part in Dalmatia, faces forest fire risks. The weather is exceptionally conducive to fires, so the main period of fire occurrences is between June and October, characterized by long lasting dry and warm weather with temperatures over 30°C. Research carried out by the authors in 1997 and 2012 have pointed to the fact that human impact is the main cause of ignition. This paper presents an overview of the total number of fires in the period from 1998 to 2012, with the emphasis on forest and woodland fires in the Croatian region of Dalmatia. Data on the situation in Dalmatia refer to the situation in the areas of responsibility of four Dalmatian Police Administrations. Analysis is based on official data of the Croatian Ministry of the Interior and the report of the National councillor for managing and controlling forest fires. The authors have analysed the frequency of forest fires in Dalmatia in a period of fourteen years (1998-2012) comparing it with the previous period, 1989-1996. The results that the authors have obtained reveal how forest fires most commonly (2/3) break out during the warm part of a day, from 09.00 until 18.00 hours in the warm period of the year. Particularly vulnerable are the forests of Aleppo pines and maquis being mostly thermal forests, whilst in the south of the country the forests of Holm oak (Quercus ilex) and English oak (Quercus robur) are at the highest risk. Reforesting of burned areas is very slow and Croatia has been far behind in reforesting in the continental part of the country.
Metsa katvuse ja liituse hindamine lennukilt laserskanneriga
Tests were carried out in mature Scots pine, Norway spruce and Silver birch stands at Järvselja, Estonia, to estimate canopy cover (K) and crown cover (L) from airborne lidar data. Independent estimates Kc and Lc for K and L were calculated from the Cajanus tube readings made on the ground at 1.3 m height. Lidar data based cover estimates depended on the inclusion of different order returns significantly. In all the stands first order return based estimate K1 was biased positively (3-10%) at the reference height of 1.3 m compared to ground measurements. All lidar based estimates decreased with increasing the reference height. Single return (Ky) and all return (Kk) based canopy cover estimates depended more on the sand structure compared to K1. The ratio of all return count to the first return count D behaved like crown cover estimate in all stands. However, in spruce stand D understimated Lc significantly. In the Scots pine stand K1(1.3) = 0.7431 was most similar canopy cover estimate relative to the ground estimate Kc = 0,7362 whereas Ky(1.3) and Kk(1.3) gave significant underestimates (>15%) of K. Caused by the simple structure of Scots pine stand - only one layer pine trees, the Cajanus tube based canopy cover (Kc), crown cover (Lc) and lidar data based canopy density D(1.3) values were rather similar. In the Norway spruce stand and in the Silver birch stand second layer and regeneration trees were present. In the Silver birch stand Kk(1.3) and Ky(1.3) estimated Kc rather well. In the Norway spruce stand Ky(1.3) and K1(1.3) were the best estimators of Kc whereas Kk(1.3) underestimated canopy cover. Lidar data were found to be usable for canopy cover and crown cover assessment but the selection of the estimator is not trivial and depends on the stand structure.