Warsaw, Poland
Warsaw, Poland

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Brach M.,Katedra Urzadzania Lasu | Bielak K.,Katedra Hodowli Lasu | Drozdowski S.,Katedra Hodowli Lasu
Sylwan | Year: 2013

Paper presents results of measurement accuracy evaluation of two laser rangefmders (TruPulse and ForestPro integrated with MapStar compass) mounted on monopod and tripod under the forest conditions. The precise data on spatial coordinates of 34 trees in the Rogów Arboretum and 8 points from the geodetic control network in the Głuchów Forest were used. The results show that the measurement sets equipped with ForestPro and MapStar were more accurate than TruPulse ones. However, no significant influence of applied stands on the measurement accuracy was observed.

Tracz W.,Katedra Urzadzania Lasu | Mozcawa J.,Katedra Urzadzania Lasu | Sterenczak K.,Katedra Urzadzania Lasu
Sylwan | Year: 2011

The paper describes the procedure of calculation of surface fractal dimension based on using raster datasets: preprocessed LIDAR data. The procedure was used to assess the surface complexity of forest stand canopy. Relationships between size of the pixels of raster image and fractal dimension of canopy surface presented on that image were recognized. Dependence of fractal dimension on age and species composition of a stand was also found.

Forest management in the State Forests in the past two decades (1990-2009) focused solely on the aging of forest stands and augmentation of forest resources. This period saw an increase in the average age of forest stands from 54 to 61 years, the average standing volume from 186 to 245 m3/ha, and the share of harvested volume in annual increment volume from 50 to 58%. As a result, the share of stands older than 80 years increased from 21 to 28% while that of plantations and young stands decreased from 14.4 to 11%. This resulted in the deterioration of the health and sanitary condition of forests.

The studies initiated by Włoczewski in 1936 revealed changes in the species composition of forest stands in the Bialowieża National Park. This led to the question about what these changes would be in the future. The aim of our study was to predict changes in the volume of tree species in the so called Strict Reserve in the Białowieża National Park over the period of 40 years. A size-class growth model was developed for this purpose. The average merchantable timber volume for each of the eleven taxa was calculated for the successive 10-year intervals, and the increase in standing volume as well as the volume of tree loss (mortality) and ingrowth were calculated for these intervals. The empirical material was taken from the permanent and temporary sample plots. The permanent plots (160) were measured in 2000, 2002, 2004 and 2011. The empirical data were used to determine, separately for each species, the relationship between trees dbh and mortality (fig. 1), diameter growth (fig. 2) or the rate of saplings (height of 0.3-1.3 m) growth into the first dbh class (0.1-1.9 cm). The temporary sample plots (460) were measured in 1995 and 2005, and the data were used to validate the size-class growth model and predict timber volume in the period 1995-2005 (tab.). The results of the validation may indicate significant changes in standing volume for the majority of tree species in the period 2005-2045 (fig. 3). In 2045, hornbeam will dominate. The volume increment in the period 2005-2045 will remain at almost the same level, the volume of tree loss will decrease and the volume of ingrowth will slightly increase, beginning from 2015 (fig. 4). Only five taxa will have a significant share in the ingrowth throughout the period 2005-2045, of which approx. 85% will be hornbeam in the period 2035-2045 (fig. 5). The observed changes in the species composition of forest stands in the Bialowieza National Park may be the result of global, regional as well as local factors such as the pressure of herbivorous ungulates on young trees. Anticipating changes in the structure of forest stands may be useful in planning the protection of forest areas by reducing the impact of local factors on forest stands (regeneration) in an indirect way.

Airborne laser scanning (ALS) technology allows collecting data describing top forest layer in a very accurate way. This provides a possibility to generate crown height models (CHM) with resolution in which single tree crowns can be detected. In presented study highly automatic algorithm for single tree detection is presented. FALCON II ALS acquired data in Forest Experimental Station in Rogów (central Poland). Data used for algorithm accuracy evaluation were acquired by measuring sample plots on VSD photogrammetric station. CHM with the resolution of 0.5 m has been used in the presented research. Algorithm, in automatic or semi-automatic way, defines single crowns. Each of the end segments was additionally processed for correctly defined size and area of the crown projection. Received accuracy of correctly detected trees was 69% for all samples (71% for pine stands and 61% mixed stands) in automatic method and 74% (78% and 65% respectively) in semi-automatic method.

In spite of the growing importance of the protective and social functions of forests, their productive function, including production of raw wood with a diversified assortment structure, is still prominent. Changes in the assortment structure depend to a large extent on tree species, habitat conditions and intensity of tending treatments. However, for the temporal organization of forest management, it is essential to recognize the dynamics of these changes in relation to stand age. The paper contains an analysis of quantitative and qualitative changes in the assortment structure of the Ist site index pine stands in the Wilcze Bagno Forest Compartment (Pisz Forest District), depending on the length of the primary production of standing timber. Data from 10 forest stands similar in terms of habitat, stand density and management treatments were taken for analysis. These stands form a homologous series ranging in age between 40 and 130 years.

Tracz W.,Katedra Urzadzania Lasu | Mozcawa J.,Katedra Urzadzania Lasu
Sylwan | Year: 2013

The need for effective management of uncertainty and incomplete information is the main factor of interest in the rough set theory and multi-use methods of analysis based on this theory, both in scientific research and in solving practical problems. Rough sets can be used for processing of both non spatial and spatial data. Five areas of application of rough set in decision-support systems in forestry and forest research are presented in the study. The example of using rough sets methods for data processing in order to determine cause-effect relationships and making classification is also presented.

The paper presents determination of the rotation age in Scots pine stands of 1st site index class on the example of Pisz Forest District (northern Poland). The development of quantitative and qualitative changes in the structure of 10 stands, forming a homologous series ranged between 40 and 130 years was the basis for determining their rotation age. Stand maturity for cutting was determined taking into account three variants of production targets considered alternatively. Traditional criteria and financial indicators were adopted to determine the rotation age. The traditional criteria included the absolute yield of a given variant, the average yield of an assortment per hectare and per year and the percentage share of each assortment group in relation to the growing stock of stands. The financial criteria included the assortment value of the considered variants of production targets, the average change in the value of these assortments, the percentage share of each assortment group in relation to the total growing stock and the average price of one cubic meter of the selected assortments groups.

The adopted rotation age and prescribed cut are found not to be fully respected at any stage of regulation, planning and implementation of cutting plans. As a result, timber, the main crop in forestry, is not uniform in terms of rotation age and fails the adopted criteria of crop maturity. Protective forests are not subject to management unless cut determination derives from silvicultural needs, without specifying the criteria for these needs. The level of cuts subjectively determined by quality control inspectors is not respected in forest management practice and should be recommended for use in the forests administered by the State Forests.

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