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1

The comparison of some selected aspects of forest economy in frontier regions of Poland, the Czech Republic and Germany

100%
Giefing D. F., Bembenek M.
Electronic Journal of Polish Agricultural Universities. Series: Forestry
|
2004
|
tom 07
|
nr 1
2

Harwester w drzewostanie liściastym

100%
Bembenek M., Mederski P. S.
Drwal. Pismo Przedsiębiorców Leśnych
|
2008
|
nr 02
3

Analysis of the time of exposure to noise of the Vimek 606 6WD forwarder operator in selected conditions of pile timber forwarding

81%
Mederski P. S., Bembenek M., Hoffman L.
Electronic Journal of Polish Agricultural Universities. Series: Forestry
|
2005
|
tom 08
|
nr 3
4

Analysis of soil surface damage due to mechanised thinning operations in pine stands

81%
Hoffman L., Mederski P. S., Bembenek M., Jakubowski M.
Zeszyty Naukowe Akademii Rolniczej w Krakowie. Sesja Naukowa
|
2005
|
tom 91
161-166
5
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Rozmiar uszkodzeń i strat olszowego drewna łuszczarskiego pozyskanego harwesterem Valmet 911.4 z głowicą 360.2

81%
Karaszewski Z., Lacka A., Bembenek M., Mederski P. S.
Sylwan
|
2016
|
tom 160
|
nr 12
The delimbing and bucking of timber using a harvester head is very productive in comparison with a chainsaw operations, however it can cause damage to the outer layer of round wood. This damage can originate from the delimbing knives or from the feed roller spikes. As a consequence, grey fungi can develop on coniferous species, and faster wood drying is also observed (with no regard to the species). Feed roller spikes create cuts and dents on the outer layers of the wood. When plywood is processed, the cuts and dents are recognised as damage as a consequence, they lower the wood quality and value. The objective of the presented research was to find out: 1) the depth of cuts, 2) the potential loss of volume, and 3) product value loss due to damage to plywood caused by feed roller spikes. The research was carried out on alder (Alnus glutinosa Geartn.) plywood logs harvested by a Valmet 911.4 with a 360.2 head. Measurements were taken using an electronic calliper with an accuracy of 0.01 mm. 16 plywood logs were considered, on which 384 measurement points (depth of spike cuts) were selected on different areas along the length of the log: 1, 2, 3 and 4 m from the butt end. The maximum depth of the spike cut was observed on the bottom part of the logs (1 m from the butt end) and amounted to 3.9 mm. This damage depth was statistically different to those at the 2nd, 3rd and 4th metre points, amounting to 1.9, 1.9 and 2.1 mm, respectively. The biggest volume losses were on the 1st metre of the plywood assortments: 0.004 m³ (4% of the volume), while on the further parts (2nd, 3rd and 4th metres) only 0.002 m³ of the plywood had damage (2% of the volume). In addition, the highest product value loss was on the butt end logs and amounted to 302 PLN/€72 per 100 m³. The following plywood assortments (2 nd , 3th and 4 th metres) had a loss of 76 PLN/€18 per 100 m³. Therefore, when plywood assortments are processed using a Valmet 911.4 harvester with a 360.2 head, it is recommended that after cutting and felling a tree, the plywood section of the alder tree trunk is cut off without feeding it through the harvester head.
6

Results of large-size timber extracting with a grapple skidder

81%
Bembenek M., Mederski P. S., Erler J., Giefing D. F.
Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria
|
2011
|
tom 10
|
nr 3
A new HSM 904Z 6WD skidder of a large size was tested in a 140-year-old beech stand in northern Poland. The aim of the study was to analyse machine productivity and impact on the soil (bulk density and cone penetrometer test) and the remaining natural regeneration caused by skidding. Trees were cut by chainsaw and, if possible, felled into the direction of the skidroads. After delimbing, logs with a top diameter of a minimum 7 cm over the bark were prepared. The average skidding operational productivity including piling was 21.0 m3x h-1. At the same time, the level of damage in natural regeneration was: 18% (38% due to both: felling and skidding). An analysis of the soil after skidding showed that the density had grown by 15-30 gx cm-3. Increase of penetration resistance was up to 2.77 MPa as the biggest.
7
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Dynamika zmian liczby harwesterów w Polsce oraz czynniki determinujące ich występowanie

81%
Mederski P. S., Karaszewski Z., Rosinska M., Bembenek M.
Sylwan
|
2016
|
tom 160
|
nr 10
In recent years, rapid changes related to forest operations have been observed in the forestry sector in Poland. A growing number of harvesters, an increased volume of harvested timber and a larger proportion of broadleaved species are considered the most important. The objective of this paper was to recognise the dynamics of harvester fleet change in Poland. In particular, there was an emphasis on finding out: 1) the total number of harvesters currently used in Poland (with respect to regions), 2) where and what type of machines were bought, and 3) which main factors influence the occurrence of these machines. In January 2014, a survey was sent to all forest districts. Questions related to harvesters and relevant for this paper included information about: 1) the number of harvesters in use, 2) the serial number of each harvester, 3) place of purchase (within the country or abroad), 4) status of the machine when bought (new or used), and 5) the forest district, in which an open tender was won for 2014. To avoid double counting the same harvester working in two or more forest districts, the serial number of each machine was used for identification. There were 368 harvesters reported in the survey in early 2014, although at the end of 2015 this number rose to 530 machines. The Central−West, North−West and North of Poland had the highest number of harvesters. Most of the harvesters were bought as used, though there may be a growing trend towards the purchase of new machines. A strong correlation was observed between the number of machines used in a region and the total area of lowland coniferous sites and forests, as well as the volume of harvested merchantable softwood. Currently, private forests and broadleaved species are the main factors limiting the application of harvesters in Poland.
8

Effects of innovative thinning operation in a birch stand

81%
Mederski P. S., Bembenek M., Erler J., Giefing D. F.
Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria
|
2011
|
tom 10
|
nr 4
Cut-to-length technology for broadleaved species is a novelty in forest operations, also causing various difficulties. The purpose of the study was to find effects of an application of the CTL 40HW head1 for broadleaves mounted on the UTC 150-6LS harvester used in a thinning operation in a birch stand in northern Poland. For this, productivity, the level of damage in the remaining stand and soil disturbances were analysed. The results present a satisfactory outcome: the average productivity was 13.4 m3-h"' (h of operational time). Analysis of the remaining stand showed 4-7% trees with damage. Analysis of the soil on the harvester strip roads showed a bulk density increase of 0.16- -0.21 g em"3. It was also observed that there was lower mean soil moisture after harvesting, though this change was not statistically confirmed. The biggest soil penetration resistance increase was observed after two machine drives: 50% on 30 cm of depth and after a single drive 45% on 10 cm of depth.
9
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Porównanie metod określania wydatku energetycznego na przykładzie leśnictwa

81%
Grzywinski W., Mederski P. S., Bembenek M.
Leśne Prace Badawcze
|
2014
|
tom 75
|
nr 4
10

Nacięcia ochronne

80%
Piotrowski M., Bembenek M.
Głos Lasu
|
2017
|
nr 05
11

Variability of features of birch (Betula pendula L.) wood comes from seed orchard

71%
Jakubowski M., Wyszogrodzka A., Pazdrowski W., Bembenek M., Mederski P.
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
|
2008
|
tom 65
12
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Uszkodzenia drzew w następstwie trzebieży wczesnych w nizinnych drzewostanach świerkowych

71%
Bembenek M., Giefing D. F., Karaszewski Z., Mederski P. S., Szczepanska-Alvarez A.
Sylwan
|
2013
|
tom 157
|
nr 10
The paper presents analysis of tree damage after early thinning in lowland spruce stands. Percentage of tree with damage and weighted damage index (WDI) were considered. Three different thinning operations were analysed, in which different cutting method was applied. The smallest level of damage was observed when short wood system (SWS) was used. There were no significant differences between frequency of damage when full tree (FTS) and long wood (LWS) systems were compared.
13
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Uszkodzenia drzew w nizinnych drzewostanach świerkowych podczas zabiegu trzebieży późnej

71%
Bembenek M., Giefling D. F., Karaszewski Z., Mederski P. S., Szczepanska-Alvarez A.
Sylwan
|
2013
|
tom 157
|
nr 12
The paper studies tree damage after late thinning operation in lowland spruce stands. The research was done in the 4th age class stands, where three different methods of timber harvesting were applied: full tree system (FTS), long wood system (LWS), short wood system (SWS). The lowest level of damage was observed in SWS.
14

Wpływ podkrzesywania na przyrost sosny zwyczajnej (Pinus sylvestris L.) z plantacyjnej uprawy nasiennej

71%
Mederski P. S., Bembenek M., Karaszewski Z., Nadolna D., Giefing D. F.
Forestry Letters
|
2013
|
tom 105
15
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The parallel application of two probability models, logit and probit, for the accurate analysis of spruce timber damage due to thinning operations

71%
Bakinowska E., Mederski P. S., Szczepanska-Alvarez A., Karaszewski Z., Bembenek M.
Drewno. Prace Naukowe. Doniesienia. Komunikaty
|
2016
|
tom 59
|
nr 197
16
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Damage caused by harvester head feed rollers to alder, pine and spruce

71%
Karaszewski Z., Lacka A., Mederski P. S., Noskowiak A., Bembenek M.
Drewno. Prace Naukowe. Doniesienia. Komunikaty
|
2016
|
tom 59
|
nr 197
17
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Strip road impact on selected wood defects of Norway spruce (Picea abies (L.) H. Karst)

71%
Bembenek M., Giefing D. F., Karaszewski Z., Lacka A., Mederski P. S.
Drewno. Prace Naukowe. Doniesienia. Komunikaty
|
2013
|
tom 56
|
nr 190
Creating strip roads in second age class stands is an indispensible operation for carrying out thinning. It is especially important in places where there is an intention to do a first thinning using mechanised thinning operations. Felling trees to create strip roads results in altered conditions for the tree growth of neighbouring trees.In particular, this is due to an increase in exposure to sunlight. This can lead to changes in the growth of trees and consequently changes in the morphology of the trunk and the development of defects. The objective of this paper was to analyse the frequency of the presence of particular defects in the structure and shape of spruce ina five-year period after the creation of a strip road. The research was carried out in an artificially regenerated spruce stand within the spruce’s natural, northern habitat in Poland. A 34-year-old stand underwent a systematic thinning scheme which involved the removal of every eighth tree row. The analysis was carried out on trees growing both adjacent to the strip roads (which had a greater growing area around them and greater access to sunlight) as well as trees from further within the stand. Diameter growth was taken in three places: at breast height, in the middle of the trunk between breast height and the base of the crown, as well as at the base of the crown. The average incremental growth, pith eccentricity taper and ovality were calculated. No statistically significant difference in defects between the trees growing by the strip road and those growing further in the stand was observed. Greater taper on mid-tree logs in comparison to butt logs was observed. Insignificant changes in the morphology of the trunks, supports the validity of cutting strip roads in second age class stands.
18
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Oak bark share at different heights of stem

71%
Karaszewski Z., Bembenek M., Giefing D. F., Szczepanska Alvarez A., Maderski P. S.
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
|
2014
|
tom 86
19
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Range in depth of wood damage caused by Valmet 360.2 harvester head feed rollers

71%
Karaszewski Z., Noskowiak A., Lacka A., Bembenek M., Mederski P. S.
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
|
2015
|
tom 92
20
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Density and mechanical properties of Scots pine (Pinus sylvestris L.) wood from a seedling seed orchard

61%
Mederski P. S., Bembenek M., Karaszewski Z., Giefing D. F., Sulima-Olejniczak E., Rosinska M., Lacka A.
Drewno. Prace Naukowe. Doniesienia. Komunikaty
|
2015
|
tom 58
|
nr 195
Seedling seed orchard (SSO) growing conditions are different to those in the forest. Trees grow in wide spacing with more access to sunlight and competition between trees is less intense causing larger annual rings and limited height growth. The objective of this research was to: 1) determine the density and mechanical properties of Scots pine (Pinus sylvestris L.) wood grown in an SSO and 2) suggest the most suitable use of this wood. Five trees (25-year-old) were selected using the Urich II method. Final samples (from the height of dbh) were cut from pith to bark, in the four cardinal directions. From all five trees, 159 samples were used to determine: 1) the wood density, 2) the compressive strength parallel to the grain, 3) the modulus of rupture, and 4) the strength quality coefficient. For each property the following mean values were obtained: 327 kg m-3, 32 MPa, 59 MPa and 0.10, respectively. The density did not depend on the dbh or mean width of annual ring. At the same time, the mechanical properties depended strongly on the wood density. In all cases, the wood property values of the Scots pine from the SSO were lower in comparison with those published for Scots pine grown in regular stand conditions. Therefore, pine wood from SSOs should be used in the paper industry.
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