Search

The goal of the study was to assess the content of vitamin C in wild rose (dog rose – Rosa canina L.) in relation to the storage method and storage duration. The material for the study was collected from three sites in Poland. The first set of samples was collected in Chełmno and the city of Koło (in the region of Wielkopolska). The second set of samples was obtained in Busko Zdrój. The third set of samples was collected near the city of Mielec. 12 samples of fresh rosehips were collected from each of the areas listed above (1 sample = 1 bush). In total, 36 samples were gathered, weighing approximately between 500 g and 600 g. The material for laboratory analysis was divided into fresh fruit, fruit intended for freezing, and fruit intended for drying. Vitamin C content was determined by the use of the Tillmans method. A part of the rosehips was frozen in a freezer at a temperature of about –18°C, and stored for subsequent months. Another batch of rosehips was subjected to drying. Next, the analysis was performed on freshly preserved samples. The dried rosehips were divided into two groups: Group 1 – dried rosehips, stored at room temperature (about 21°C) in a dark room; Group 2 – dried rosehips, stored at a temperature of about 3°C in a refrigerator. Subsequent measurements were made two, three, five and nine months after freezing or drying. As a result of conducted analyses, it was determined that the highest average content of vitamin C in fresh dog rose fruit was found in rosehips from the vicinity of Mielec, followed by those collected from Wielkopolska. The lowest content was found in the rosehips collected in Busko−Zdrój. On average, after preservation, rosehips lost approximately 25% of their vitamin C content (23% loss after drying, and 25% loss after freezing). During storage of rosehips in different conditions, it was found that the content of vitamin C decreased at the slowest rate in frozen fruits, while in dried rosehips this process was much faster. It was also observed that dried rosehips stored at room temperature, after 5 months of storage, lost vitamin C faster than the dried rosehips that were stored in the refrigerator. The test results clearly show that freezing and storing frozen rosehips is the best method of rosehip stabilization as far as the preservation of the highest content of ascorbic acid is concerned. The loss in the amount of vitamin C after a prolonged storage period amounted to about 10% in relation to the amount of the vitamin measured immediately after freezing. It was also noted that after about 5 months of storage, the content of vitamin C in dried rosehips decreased rapidly, and after 9 months, the loss was about 45% for dried rosehips stored in the refrigerator, and about 80% for dried rosehips stored at room temperature., Sylwan 167 (2): 110-119

The aim of the paper was to determine the variability of selected macrostructural features and wood density for northern red oak growing in south−eastern Poland. On 4 study plots, we sampled each tree, taking an increment core from the northern side of the trunk, from the height of 1.3 m. The number of tree rings, width and the share of sapwood was measured. The cores were scanned and then tree ring and latewood widths were measured. The latewood proportion in each ring was calculated. Next, starting from the bark, the cores were divided into sections containing 10 annual rings. The relative wood density was determined for each section, then the density was calculated for entire stem cross−section. The mean sapwood width was 1.5 cm. It included 7 annual rings on average, and its share in the trunk cross−sectional area reached 17%. Younger red oaks (II and III age classes) had a significantly higher share of sapwood compared to older trees (IV and V age classes). The investigated red oaks formed narrow−ring wood with an average width of 2.16 mm. The trees growing on deciduous forest habitat had a more equal tree ring width compared to trees from coniferous forest habitats, where this feature showed also higher variability. The latewood proportion in the studied red oaks was 60% on average. The mean relative wood density was 0.578 g/cm and it was slightly higher than the value given for red oaks growing in North America. The calculated absolute density (with an assumed volumetric shrinkage from 12.9 to 13.7%) varied from 0.664 to 0.670 g/cm. It classifies the investigated wood as moderately heavy. Similar density values are given for native oaks, which allows to assume that the technical quality of the wood of red oaks growing in Poland is similar to native oak species. The wood of trees from deciduous forest habitat showed a significantly higher density and a more equal distribution compared to the trees from coniferous forest sites. The raw material of red oaks obtained from deciduous forest habitats should characterize by a better technical quality of wood in comparison with that obtained from coniferous forest sites., Sylwan 164 (10): 850-859

The aim of this work was to analyze the tree−ring width, the share of the latewood as well as the density of wood of trees growing in commercial and degraded stands. The research was carried out in the Brynek Forest District (southern Poland) in 3 commercial stands and in 4 degraded stands. For every study plot fifteen spruces were chosen and increment cores were sampled using the Pressler borer. Next, the surface of the cores was smoothed and the width of the annual rings was measured. Latewood zones were determined and the share of latewood was calculated. It was found that the average and minimum tree−ring width was the same in both commercial and degraded stands, while the maximum values were slightly and insignificantly different. In turn, the average share of latewood was higher in trees from commercial stands, but higher minimum and maximum values were recorded in stands on degraded sites. In this case, the differences turned to be statistically significant. The average density of wood was slightly lower in trees from degraded stands compared to wood from commercial stands (413 vs 418 kg/m). The minimum and maximum values were also higher in trees from commercial stands. However, this feature did not show a significant difference between analysed groups of stands. We found that despite such significant differences in the terrain formed during the production of zinc and lead ores, the wood of trees growing in these areas hardly shows any differences (except for the share of latewood) in comparison to wood from commercial stands., Sylwan 164 (1): 10-15

The aim of the study was to determine the influence of stand density index on the tree−ring width, latewood proportion and wood density for Norway spruce. Study sites were located as follows: 12 within the north−eastern species range in Poland, 7 in the south−western range, in the Sudety Mts., and 9 in the Carpathians (southern range). Clustering stands according to their stand density index, 10 data groups were established: stand density index values from 0.3 to 1.2. The study plots were 100×100 m squares. On each plot 15 trees were chosen and increment cores were sampled using the Pressler borer. The smoothed cores served for measuring the width of annual rings, latewood zones and the share of latewood as well as for determination of relative wood density. The performed analyses indicate that mean tree−ring width was the highest in trees from stands with density index from 0.3 to 0.8 (with the exception of 0.7), whereas the it was gradually decreasing in stands with index higher than 0.9. The statistically significant differences between the analyzed stands were observed (p, Sylwan 164 (9): 719-725

The aim of the study was to compare the tree−ring width, latewood share and density of spruce wood from the mature stands occupying different forest habitats. 12 study plots were located in the north−eastern Norway spruce range in Poland (lowlands), whereas 16 in the south−western one (mountains). On the lowlands we chose stands growing on fresh mixed coniferous, humid mixed coniferous, fresh mixed deciduous and fresh deciduous habitats, while in the mountains we selected alpine coniferous, mountain coniferous, mountain mixed coniferous, mountain mixed deciduous and mountain deciduous ones. On each study plot we chose 15 trees according to the Draut method and took increment cores with the Pressler borer. We measured tree−ring and latewood width and then divided the cores into 2−cm sections, for which the relative wood density was determined. The tree−rings were the widest in trees from fresh mixed coniferous (lowlands) and mountain mixed deciduous (mountains) sites, whereas the narrowest ones were observed in trees growing on fresh mixed deciduous and mountain mixed coniferous sites. We found statistically significant difference (p, Sylwan 163 (3): 209-215

The aim of the study was to determine quality of wood of 40−year old poplar cultivars introduced onto the external spoil dump of the Bełchatów Field and subjected to various reclamation systems. The research was carried out on the 1/78 trial plot located on the northern slope of the external spoil dump of the Bełchatów Field (central Poland). The dump was the result of the rock (predominantly sand) overlay storage accompanying lignite deposit. On the trial plot two blocks were established: one called ‘Humus’ where sandy sediments were covered with approximately 20−centimeter layer of fertile soil, and the other named ‘Piasek’ (sand) with only sandy sediments. To set up the experiment 9 poplar varieties were used (I−214, Robusta, Gerlica, H−194, Grandis, Oxford, Androscoggin, Geneva, H−275). Their wood quality was assessed in 2017, 40 years after their introduction on the spoil dump. The results indicate that poplars growing in the ‘Humus’ variant were characterised by higher volume in comparison to wood of poplars from the ‘Piasek’ variant. The latter however had a larger share of better wood quality classes (WB, WC). The results also showed that wood classification of all investigated varieties were significantly influenced by curvature in the case of the ‘Humus’ variant and knots in the ‘Piasek’ one. The influence of other wood defects such as galls, grain slope, multiple pith and knobs was insignificant. In order to obtain the higher volume of poplar raw material the reclamation treatments should be carried out on afforested areas with fertile outer layer whereas the better quality raw material can be obtained on less fertile sediments., Sylwan 163 (10): 855-861

The research was conducted on the external spoil heap of the 'Piaseczno' Sulphur Mine (southern Poland). This paper aimed to determine the quality of wood in 40−year−old Scots pine trees planted onto the external spoil heap of the mine, in the scope of forest reclamation, depending on the soil substrate and employed reclamation treatments. The investigations were carried out at one−are circular trial plots. A total number of 17 study plots was established, located on: Quaternary loose sands (PL), mixed Quaternary sands and Tertiary Krakowieckie clays (PI), and mixed Quaternary sands and Tertiary clays after an intense initial fertilisation (PIN). Measurements performed at the study plots included determination of diameter at breast height of every tree with a diameter 7 cm and height of every tree. We classified the wood of standing trees, including a specification of class or quality and dimension group of the butt−end part of the trunk, identifying types and variants of defects that determined the results of quality classification of raw wood. We found significant differences in trees dimensions between soil substrates. No significant difference was found for fertilised substrates, therefore it may be assumed that fertilising of more fertile soils was an unnecessary treatment. The quality of pine wood was mostly affected by knots and curvatures. An impact of knots on the results of wood classification increased with fertility of soil substrate. With regard to curvatures, the opposite trend was recorded. The frequency of occurrence of the above−mentioned defects was determined not only by the habitat type, but also by the manner of forest management. To reduce the frequency of occurrence of the defects in question in the reclaimed areas, an appropriate closure of stands should be maintained and adequate tending treatments should be performed competently and skilfully, as this is done in commercial stands., Sylwan 160 (4): 284-291

The paper compares the properties of Norway spruce (Picea abies (L.) Karst.) wood from stands growing in the lower and upper subalpine forest zone in terms of the tree−ring width, the share of latewood and the wood density. The investigation concerned material originating from plots established within the boundaries of the south−western incidence of spruce in Poland. Plots were located in the Sudety Mts. and in the Carpathians (tab. 1). On each plot fifteen Norway spruces were chosen and increment cores were sampled using the Pressler borer. The surface of the cores was smoothed and the tree−ring width was measured. The latewood zones were determined and the share of latewood was calculated. Then, the cores were divided into 2 cm sections, for which the relative wood density was determined. Tree−rings were wider in trees growing in the lower when compared with those from the upper subalpine forest zone (tab. 2). Weak negative correlation was revealed between the elevation and the tree−ring width (r=–0.308). The latewood share was slightly higher in trees from the upper than those from the lower subalpine forest zone (tab. 2). However, no statistically significant correlation between the latewood share and elevation was recorded. The wood density was slightly lower in trees from the lower than those from the upper subalpine forest zone (tab. 2), but the difference was not statistically significant. The correlation between the wood density and the elevation turned out to be insignificant., Sylwan 160 (10): 855-860

The aim of this paper was to perform a comparative analysis of the quality and the value of beech, oak, fir and spruce wood classified according to the Polish and the EU standards. The research was carried out in Lesko and Baligród forest districts (south−eastern Poland). The measurements of the investigated raw wood were taken at the upper landings. With regard to fir, spruce and beech 50 specimens per species were measured, while in the case of oak only 25 pieces were examined. Each specimen was classified in respect of its quality and size according to the Polish standards (PN) and the European Union (PN−EN) standards. Then, the results of both classifications were compared in terms of the share of volumes of particular wood quality classes, the impact of wood defects on the raw wood classification results, and the value of wood determined by the means of both standards. With regard to the beech wood, the share of the poorest class D upon applying PN−EN was smaller than that for PN norms. This decrease was in favour of other classes, due to which the value of the entire beech wood increased by ca. 16%, when classified with the use of the EU standards. The oak wood revealed a slight increase in the share of wood volume in the class C and a decrease in the class D of PN−EN when compared with the Polish norms. The value of the oak wood classified with the use of the EU standards was merely by 2.3% higher than that of the Polish norms. With regard to the softwood (fir and spruce), a decrease in the share of wood of the class C in PN−EN was recorded, which was in favour of the classes B and D. The value of raw wood classified by means of the EU standards was lower for both of the coniferous species. The decrease for fir accounted for 13.3%, while for spruce it was only 1.5%. For the evaluation of the softwood, Polish classification was more profitable, whereas for hardwood the EU standards were more favourable., Sylwan 160 (6): 459-465

The paper concerns the impact of air pollution on the content of essential oils in Scots pine twigs and vitamin C in Scots pine needles. The material used for examination of essential oils content was obtained from two locations: area within the former Aluminium Smelter in Skawina, the other sample was collected in the territory of Rudnik Forest District (southern Poland). Cetin was obtained manually from standing or felled trees. Essential oils content was determined by means of Deryng apparatus. The material used for examination of vitamin C content came from three locations: Chrzanów Forest District, Dąbrowa Tarnowska Forest Distric and the Special Economic Zone located in the area of Mielec Forest District (southern Poland). Vitamin C content in pine needles was determined by Tillman method. The content of essential oils in pine twigs in stands under smaller influence of air pollution was nearly twice the amount in twigs coming from stands under greater influence of this factor. In less polluted stands the content of essential oils in twigs increased as they grew older, whereas, in stands being more exposed to industrial influence the opposite tendency was observed. We recorded that the amount of vitamin C in pine needles coming from stands under greater influence of industry was by ca. 30% smaller than in the material collected from stands less affected by industrial pollution. In both groups of the stands, the highest content of vitamin C was detected in needles from the youngest (age class I) as well as the oldest (age class V) stands. The content of essential oils in twigs as well as vitamin C in pine needles may be considered as the indicator of the environmental pollution degree., Sylwan 159 (6): 516-522

This paper aimed to evaluate the impact of necroses occurring on trunks of standing oak trees on their wood quality and value. The research was carried out in five study plots situated in the Meszcze Forestry, Piotrków Forest District (central Poland). The investigations covered: measuring the diameter at breast height of every injured tree with diameter 7 cm, estimating the length of the trunk fragment that should be cut off to remove the defect, the assessment of the quality and size of the 3−m butt−end fragment of a trunk, excluding the detected damage or rot (classification I), as well as the quality and size assessment of the same trunk fragment, though including the encountered defect (classification II). The theoretical volume of timber within the particular quality classes was computed (WAt, WBt, WCt and WDt). Afterwards, the real volumes (WAr, WBr, WCr and WDr) were compared with those of groups S2r and S4r. Based on the analysis of the quantity of damaged trees in the investigated trial plots, the lowest share of such specimens was recorded in the compartment 2a (1.6% of defective trees). Whereas, the highest share of damaged trees was encountered in the compartment 39a (8.5%). The timber of more valuable large−sized classes 'migrated', due to damages, to the groups of medium−sized timber (S2 or S4). With respect to the total volume of timber within the particular classes and groups, the greatest loss was reported in the WB class. The timber in question 'migrated' mostly to the group S2, though a part of it was classified to the group S4 as well. The established decrease in the timber value, due to damages to trunks, accounted for ca. 26%, which amounted to ca. 5.8 thous. PLN, in relation to the entire investigated material. The obtained results indicated the necessity to reduce the damages occurring in oak stands and remove the injured trees as soon as possible to avoid a significant depreciation and a value loss of raw wood., Sylwan 159 (9): 740-746

Mountain regions are the main natural ranges of spruce forests in Poland. Their occurrence and growth in these areas is associated with the height above sea level and exposure. The attempt of the study was to determine the impact of these two characteristics on the quality of spruce timber. The research was carried out on 20 sample plots located in the Sudety (8 plots) and the Carpathians (12 plots). The trees growing on the selected plots were examined for their diameter at breast height and height, the quality of standing timber and the kinds and varieties of wood defects on tree stems. As a result of the conducted analyses it could generally be stated that forest stands from the lower montane zone produced higher quality timber in terms of both volume and quality and that the best quality stands were on the western and the poorest ones – on the southern slopes., Sylwan 155 (6): 373-383

Sylwan 152 (6): 33-43