Start  Issue
The oldest scientific journal of forestry
Issue: 2016_8

Utrata masy i zmiany gęstości średniowymiarowego surowca sosnowego pozyskanego i magazynowanego w okresie letnim
Weight loss and green density changes of Scots pine pulpwood harvested and stored during the summer

Abstract: The study objectives included: i) determination of the mass and green density of pulpwood (wood+bark) and ii) comparison of the changes in these parameters during 14−day−long storage period. The experiment was conducted between 15 and 28 July 2014 and the material was taken from the 67 year−old Scots pine stand (Tuchola Forest District, northern Poland). Using the Urich method, 30 model trees were selected. After felling and delimbing, logs of 2.5 m length were cut, with diameter at the small end not less than 7 cm outside the bark. In total, 133 logs were harvested (mean diameter inside the bark at the thicker end – 13.1 cm, in the thinner end – 11.4 cm). After diameter measurements were taken, each log was weighed (total over bark volume equaled 4.69 m³, while total weight – 3955 kg). Mass measurement took place daily between 8 and 10 a.m. In Poland, the raw material is not recommended to be stored too long in summer, due to the possibility of its depreciation. Storage time should be as short as possible and not exceed 2 weeks. The mass of the 1 m³ of wood harvested from freshly−cut trees amounted to 844 kg. After 14 days it decreased to 814 kg (–3.5%). Differences were not statistically significant. Because the moisture content has the highest influence on mass, the rain and thereby an increase in the air humidity significantly reduce drying. Mass of 1 m³ of raw material was reduced to the day of rain by 2.9 kg (–0.35%) per day on average. After the occurrence of rainfall, between 10th and 14th day of storage the mean weight loss was 1.3 kg/m³ (–0.16%). The mean weight loss reached 30 kg/m³ in analyzed period. Generally two weeks storage is too short time to obtain a large weight loss. However, in this case of total mass of haulage vehicles together with their cargo may be a few hundred kilos smaller.

Key words: Scots pine, mass of logs, timber, freshly−cut trees, bark, wood moisture

Sylwan 160 (8):619-626, 2016. DOI:

Określenie rzeczywistej powierzchni lasów w Polsce na podstawie dostępnych danych przestrzennych
Determination of the actual forest area in Poland based on the available spatial datasets

Abstract: Several studies discussed a disagreement concerning forest extent in Poland between land cadaster and status on the ground. The aim of the paper was to assess the actual forest extent in Poland based on an existing spatial datasets such as: Digital Forest Map (covering explicitly the State Forests), Topographic Database, Database of Parcel Identification System, High Resolution Layer (Copernicus Land Monitoring product based on classification of satellite data) and National Forest Data Bank. The geospatial data analyses were preceded by an accuracy assessment of the available datasets, which allowed to assign weights to each of the dataset. The result of this project was the actual forest extent map, which refers to the national definition of forest as defined in the Forest Act of 28 September 1991 (forest by definition is a homogeneous area of 0.1 hectares). This includes all forms of ownership forests and areas that are forested, but officially recorded as non−forest. Moreover, the map of the forest extent under the Kyoto Protocol, including areas that meet the criteria of actual forest extent map and additionally forest areas designed or used for housing, recreation, infrastructure, and other industrial and agricultural areas (e.g.: permanent crops – orchards) were determined. The results confirmed that the actual forest extent is higher by almost 800 thousand hectares then the official statistics provided by the Central Statistical Office of Poland. According to the official statistics forest in Poland covers 29.4% of the country, however this study revealed that 32% of the country, considering the national forest definition, and 33.5%, considering the forest definition under the Kyoto Protocol, is occupied by forest. It showed the need for the land cadaster update. Precise information on spatial distribution of forest extent is crucial for the national purposes i.e. reporting, implementation of the National Afforestation Program and also for the international commitments under the climate convention to determine the accurate forest carbon content and carbon dioxide sequestration.

Key words: forest cover, forest land definitione, forest inventory, datasets

Sylwan 160 (8):627-634, 2016. DOI:

Dokładność stałych krzywych wysokości dla drzewostanów olszy czarnej (Alnus glutinosa (L.) Gaertn.)
Accuracy of the uniform height curves for black alder (Alnus glutinosa (L.) Gaertn.) stands

Abstract: The study presents the assessment of the accuracy of two generalized height−diameter models, such as skwB [Bruchwald et al. 2001] and skwO [Orzeł et al. 2014], developed in Poland for black alder (Alnus glutinosa (L.) Gaertn.) stands. Verification of these models was conducted on empirical material that was collected in 127 alder stands located in the western part of Sandomierz Basin (southern Poland). Selected alder stands aged 6−89 years, while average breast height diameter ranged from 4.5 to 43.0 cm and average height from 6.3 to 32.7 m. The stand density varied from 222 to 4360 trees/ha. The accuracy assessment for uniform height−diameter curves was based on the analysis of single tree absolute error distributions. Synthetic indicators of goodness−of−fit, such as: average and standard errors, coefficients of variation and determination were calculated based on absolute errors. The final evaluation of the compared uniform height−diameter models results from the structure of the goodness−of−fit measures that was observed within all analyzed stands and within age classes of 20 years. The efficiency of uniform height−diameter models was also compared with stand height−diameter curve, which was developed based on the Näslund function. General height−diameter models overestimated height in alder stands on average from 0.26 (1.67) to 0.19 m (1.39%), based on skwB and skwO models, respectively. Bias depended on the age of stand and decreases from almost 3% in I age class to nearly 0.5% in IV and V age class. For both analyzed models, a positive systematic error was observed for the standardized breast height diameter. Bias in estimating the height of single stand depended on the accuracy of stand height estimations. In case of estimation based on the measurements of three trees height, bias in single stand can range from –13% to +14%. Due to the range and nature of observed systematic errors, uniform height curves should be applied to groups of stands that have different age and breast height diameter structure, as it allows for partial reduction of the error.

Key words: h−d relationship, uniform height curve, forest inventory, black alder

Sylwan 160 (8):635-646, 2016. DOI:

Wpływ rzeźby terenu na bonitację i cechy wzrostowe drzewostanów sosnowych na wydmach Kotliny Toruńskiej
Impact of land relief on site index and growth parameters of Scots pine stands on inland dunes in the Toruń Basin

Abstract: The aim of the study was to determine the impact of land relief on site index and growth parameters (height, diameter, slenderness) of Scots pine (Pinus sylvestris) stands on inland dunes in the Toruń Basin (N Poland). The study was conducted on 150 plots situated on north− and south−facing dune slopes (54 pairs of twin plots) as well as in intra−dune depressions (42 plots). Height and diameter of ten the thickest pines per 0.1 hectare was measured, and next site index as a potential height of a stand at the age of 100 years was calculated. As the results of the used equation, site index was strongly (R²=0.58) negatively biased to age, so the bias was removed using an elaborated regression model. For stands older than ca. 20 years, the clear higher site index values as well as higher heights and diameters were found for intra−dune depressions than for slopes of the two studied aspects. This was explained by the occurrence of much more fertile and moister soils in depressions. The only age class for which the advantage of site index and growth parameters was not stated for depressions was the youngest class (≤20 years old). This was likely caused by the competitive impact on young pines of Calamagrostis epigejos which prefers intra−dune depressions on inland dunes and forms in forest floor usually dense cover in this position. Impact of contrasting slope aspect was clearly related in the study to age of a stand. For the youngest studied age class both site index values as well as heights and diameters were lower on north− than on south−facing slopes. This was explained by the effect of weeds which form more dense cover on slopes of this aspect than on sunny slopes. For older stands; however higher site index values as well as heights and diameters were revealed for north−facing slopes, due to pines likely took advantage of higher moisture of soils occurring in this place. With reference to slenderness, regardless stand age the parameter was regularly the highest for north− than both for south−facing slopes and depressions. Because of the revealed distinct higher productivity of intra−dune depressions in normally dry and poor in nutrients dune landscape, it could be reasonable to use the depressions to introduce admixtures of broadleaved tree species into pine monocultures on inland dunes.

Key words: topography, Pinus sylvestris, slope aspect, tree growth, forest site, soil, inland dunes

Sylwan 160 (8):647-655, 2016. DOI:

Adaptacja wybranych pochodzeń modrzewia europejskiego do klimatu nizin centralnej Polski
Adaptation of the selected provenances of European larch to climate of lowlands in central Poland

Abstract: The study evaluated the sensitivity of European larch (Larix decidua) of two provenances to thermo−pluvial conditions on the provenance plot located in Sękocin Stary (52°05‵ N, 20°51‵ E, 125 m a.s.l.). The studied larches originated from Pelplin (lowland, northern Poland, 50 m a.s.l.) and Szczytna (upland, southern Poland, 525 m a.s.l.). The trees of both provenances differed in terms of their quantitative and qualitative breeding characteristics. The trees originated from different climatic regions whose climate was also different from the climate of the provenance plot. Values of the size of the radial increments measured at cores extracted from the trees were the measure of their sensitivity to the climatic factor. The cluster and principal component analyses were used to classify the trees according to their features of the short−term rhythm of the radial increments. The response function and pointer years analyses were used to evaluate climate−growth relationships. The results of the study show the trees of both provenances have similar sensitivity to the thermo−pluvial conditions in the previous September, the temperature in March and the precipitation in May of the year of tree−ring formation. The larches of Pelplin provenance, in contrast to the trees of Szczytna provenance, were sensitive to the low temperature in February and the low precipitation in the growing season. These features could be one of the causes of the lower incremental abilities of the trees of Pelplin provenance. The larches of Szczytna provenance had higher frost tolerance in February and drought tolerance in summer.

Key words: Larix decidua, climate, radial increment, provenance trial

Sylwan 160 (8):656-665, 2016. DOI:

Biochemiczna aktywność gleb różnych siedlisk leśnych
Biochemical soil activity of different forest site

Abstract: The aim of the study was to determine the enzymatic activity and chemical properties of soil in selected stands of different age classes on two forest site types: fresh mixed coniferous forest (BMśw) and fresh mixed deciduous forest (LMśw). The investigations were carried out in Nowe Ramuki Forest District in 2013−2015 located in the central part of Warmińsko−Mazurskie administration district Poland. In organic and humus horizons following parameters were described: acidity in 1M KCL, content of nitrogen, carbon and exchangeable alkaline cations (Na+, K+, Ca2+ and Mg2+) as well as hydrolytic acidity. Enzymatic investigation included the measurements of urease, asparaginase, acid phosphatase and dehydrogenase activity. Content of C and N, sum of base cations (S), hydrolytic acidity (Hh), cation exchange capacity (PWK), base saturation percentage were significantly higher in organic than humus horizon. Enzymatic activity was connected with the content of organic matter, what resulted in higher activity in organic than humus horizon independently of site type and stand age. The concentration of organic carbon (C), nitrogen, C/N ratio, hydrolytic acidity and cation exchange capacity was higher on BMśw than LMśw site type. Activity of urease, acid phosphatase and dehydrogenase was lower in soils of LMśw than BMśw site type. Lower enzymatic activity may suggest lower intensity of decaying process of organic matter in these soils. Significant correlations between enzymes and chemical soil parameters were found. Significant correlation between enzymatic activity and soil chemical properties shows that biochemical parameters can be used as indexes of their productivity. Investigation of biochemical reaction intensity can be complement to soil chemical studies usually used in forestry.

Key words: forest site type, enzymatic activity, soil chemistry

Sylwan 160 (8):666-673, 2016. DOI:

Gleby i siedliska drzewostanów nasiennych dębu szypułkowego (Quercus robur) i dębu bezszypułkowego (Q. petraea) w Polsce
Soils and forest site types of the seed stands of common (Quercus robur) and sessile (Q. petraea) oaks in Poland

Abstract: The aim of the study was to investigate the structure of forest site types and of soil types of oak seed stands in Poland. The study was comparatively conducted with reference to sessile (Quercus petraea) and common (Q. robur) oaks. As in Poland the seed stands are established only in stands characterized by favourable both growth parameters and timber quality, it was suspected that the results of the study would enable to indicate optimal sites and soil units for oak breeding in Poland. The study was conducted on the basis of data obtained from the SEMEN database ( which were broadened by descriptions of the investigated seed stands found in the Forest Data Bank ( For both oak species, the research was conducted with reference to the two types of seed stands: permanent (WDN) and temporary (GDN). In total, 531 stands of Quercus petraea and 2043 of Q. robur located across whole Poland were investigated in the study. It was found that optimal soils as well as forest site types overlap for both investigated oak species only for fresh broadleaved forest (Lśw). For other forest type sites distinct differences for the oak species were found. The optimum for common oak were expanded towards the wet sites (moist broadleaved forest – Lw, and riparian forest – Lł), while for sessile oak towards semi−fertile mixed broadleaved forest (LMśw). It is interesting that seed stands of both oak species overgrow not only fine−textured soils, but significant share of them (ca. 50% area of Q. petraea and 15% of Q. robur seed stands) occurs on sandy soils (Brunic Arenosols mainly). It proves that Brunic Arenosols constitute forest sites enabling production of broadleaved forests characterized by favourable growth parameters and high timber quality. However, it is possible unless the soil have been podzolized by conifers due to podzolized Brunic Arenosols were rarely represented in the oak seed stands and, if so, the stands were characterized by relatively low site index. It was also stated that on podzolized Brunic Arenosols of fresh mixed coniferous forest (BMśw) admixture of oak should enable reducing negatively impact of conifers on a soil.

Key words: Quercus, seed stands, forest site, soil, silviculture

Sylwan 160 (8):674-683, 2016. DOI:

Problemy diagnozy troficzności siedlisk leśnych na porolnych glebach aluwialnych
Problems of trophic status diagnosis in the forest habitats on former arable alluvial soils

Abstract: The morphology and properties of the post−arable soils that influence the trophic status of forest habitats on the Barycz river terraces (south−western Poland) were analyzed. The fieldwork included the characterization of the soil, tree layer, and the vegetation of the forest floor, as required for the forest habitat evaluation. In the collected soil samples, a set of physico−chemical analysis was carried out, that included: soil texture, bulk density, pH in KCl and water, total organic carbon, total nitrogen, hydrolytic acidity, base cations, and the content of plant−available phosphorus, potassium, and magnesium. Sandy post−arable soils in the Barycz valley have a thick, double− or triple−layered ploughed humus horizon, and the high stock of humified organic matter, nitrogen, and phosphorus, that emphasizes anthropogenic transformation of soils and differentiates them from the natural soils of river valleys. The diagnosis based on the soil trophic index (SIG) indicates generally lower trophic status (mesotrophic) as compared to the diagnoses based on forest floor vegetation and tree−stand (eutrophic status). The SIG model for the post−agrar moist valley habitats should be supplemented with the factors, which improve the apparent trophic status of sandy soils, including the thick humus horizon (post−ploughing) and shallow table of eutrophic ground water.

Key words: forest site type, soil trophic index, alluvial soils

Sylwan 160 (8):684-695, 2016. DOI:

Środowiskowe uwarunkowania inwazji tawuły kutnerowatej (Spiraea tomentosa L.) w Borach Dolnośląskich
Environmental determinants of the steeplebush (Spiraea tomentosa L.) invasion in the Bory Dolnośląskie Forest

Abstract: The steeplebush is a shrub growing naturally in North America. In Europe this species has been cultivated as an ornamental plant since the 18th century. It has been observed in spontaneously developing secondary localities in such countries as Belgium, Denmark, Sweden, Norway and Germany. In Poland there are three regions in which Spiraea tomentosa is known to be a permanently established anthropophyte: Puszcza Drawska, Bory Niemodlińskie and Bory Dolnośląskie forests. The greatest number of localities of this shrub can be found in the extensive area of the latter, where its expansion has caused significant changes in the natural environment and problems in woodland management. Therefore a research was carried out to find what conditions made the steeplebush ready for invasion and what types of plant communities were especially susceptible to it. The information about the distribution of S. tomentosa in the Bory Dolnośląskie Forest (SW Poland) was collected during field observations in the years 2011−2014. We also verified and used the results of a survey made in 2011 in three forest districts located in the study area: Ruszów, Węgliniec and Wymiarki. The analysis concerned the frequency of the steeplebush in the forest environment in terms of the forest habitat type, species composition, and stand growth stage as well as in non−forest environments like meadows, peatland, margins of drainage ditches, etc. Phytocoenoses in the habitats of humid mixed coniferous forests and humid coniferous forests with mature tree stands dominated by birches or alders were found to be forest communities the most susceptible to colonisation by S. tomentosa. Especially susceptible to steeplebush invasion were also forest cultures on those habitats. Much fewer steeplebush localities were recorded on fresh and mixed coniferous forests as well as fresh broadleaved forests. In a non−forest environments the steeplebush was mostly noted on margins of drainage ditches. The extensive system of such man−made environmental structures in the Bory Dolnośląskie Forest was found to be the most important factor favouring the expansion of S. tomentosa. Thus, the invasion of the discussed species is primarily determined by a large proportion of humid habitats in a single compact woodland complex connected by a dense network of drainage ditches.

Key words: Spiraea tomentosa, alien species, invasive shrub

Sylwan 160 (8):696-704, 2016. DOI:

1 - 9