scholarly journals The Effect of Season of the Year on the Frequency and Degree of Damage during Commercial Thinning in Black Alder Stands in Poland

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 668 ◽  
Author(s):  
Witold Grzywiński ◽  
Rafał Turowski ◽  
Bartłomiej Naskrent ◽  
Tomasz Jelonek ◽  
Arkadiusz Tomczak

The aim of this study was to investigate the effect of season of the year on the frequency and degree of damage to residual trees caused during winter and summer timber harvesting operations in young alder stands. Analyses were conducted in pure black alder (Alnus glutinosa Gaertn.) stands aged 38 and 40 years, located in north-eastern Poland. Chainsaw logging was performed in the cut-to-length (CTL) system, while timber was extracted using an agricultural tractor with a trailer with manual timber loading and unloading. Damage caused in the stand as a result of early thinning operations was evaluated in terms of: (1) damage location, (2) wound size, (3) wound depth, and (4) the distance of the damaged tree from the skid trail. Timber harvesting caused damage in 8.3% of trees remaining in the stand. Both the total number of damaged trees (p = 0.001) and the number of trees damaged during felling (p = 0.01) and extraction of timber (p < 0.001) were greater in summer than in winter. Irrespective of the season, two-thirds of all cases of damage were caused during timber extraction, with 67.7% of damage recorded on trunks or root collars and 32.3% on roots. Irrespective of the season and the technological operation, slightly over 50% of cases of damage were small wounds of max. 10 cm2. The proportions of medium-sized wounds (11–100 cm2) and large wounds (over 100 cm2) were comparable. The majority of damaged trees (85.1%) were found in the vicinity (<1 m) of the skid trails. The frequency of tree damage near the skid trail was twice as large in summer as in winter (p < 0.001).

2013 ◽  
Vol 74 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Zbigniew Karaszewski ◽  
Dieter F. Giefing ◽  
Piotr S. Mederski ◽  
Mariusz Bembenek ◽  
Anita Dobek ◽  
...  

Abstract Damage to the remaining stand is an unavoidable consequence of thinning operations. The different machines used for timber extraction differ in the level of damage of trees they cause, mainly through wounds to the bark and cambium which can make a substantial impact on the remaining trees. Three different methods of timber harvesting with a chainsaw were analyzed: the short wood system (SWS), the long wood system (LWS) and the full tree system (FTS) in which an agricultural tractor is used for timber extracting. All systems were analyzed in stands containing three different age classes: 2nd (21-40 years), 3rd (41-60 years) and 4th (61-80 years). The level of damage to the remaining stand was assessed considering the percentage of trees exhibiting wounds (scratched bark and/or damage to the cambium) to calculate an index of stand damage (WDI) which incorporated the volume of harvested timber per hectare. The SWS produced the lowest damage to trees in stands of all age classes: average 5%, with the less damage in the oldest stand. After using the LWS, 9% of trees were wounded; in this method there was no statistical difference in frequency of wounding across all the analyzed stands. The highest level of damage was incurred after the FTS, causing 11% of trees to be injured. In stands of the 2nd age class, the method of timber harvesting had no statistically significant effect on the amount of wounding endured. The WDI was lowest in SWS: 0.08, higher in LWS: 0.15 and the highest, 0.23, when FTS was applied.


Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1081
Author(s):  
Witold Grzywiński ◽  
Rafał Turowski ◽  
Bartłomiej Naskrent ◽  
Tomasz Jelonek ◽  
Arkadiusz Tomczak

The purpose of this study was to establish the impact of season on productivity, labour consumption, and working time structure during timber harvesting from young alder stands (Alnus glutinosa Gaertn.). An early thinning process was performed in summer and winter in pure alder stands (38 and 40 years old) in the Płaska Forest Division (NE Poland). The felling and processing operations were performed by experienced loggers using the cut-to-length (CTL) system, and forwarding with manual loading and unloading involved the use of a Zetor 7045 (65 HP) farming tractor and trailer. In both summer and winter, the loggers spent most of their labour time on felling trees (approx. 23%) and bucking (approx. 36%). Assistant loggers spent most of their time stacking logs (49.2% in summer and 58% in winter). The most time-consuming activities in forwarding were loading, unloading, and transportation. The average time consumption of tree felling and processing amounted to 0.36 ± 0.11 h/m3; that of forwarding was lower, at 0.24 ± 0.07 h/m3. No statistically significant differences in the labour consumption of tree felling were identified between winter and summer (p = 0.863). For forwarding, labour consumption was significantly higher in winter (0.28 h/m3) than in summer (0.19 h/m3, p = 0.001). Average productivity was 3.02 ± 1.09 m3/h for tree felling and 4.76 ± 1.80 m3/h for forwarding. The productivity of felling was similar in winter (2.83 m3/h) and in summer (3.22 m3/h). For forwarding, productivity was significantly higher in summer (5.70 m3/h) than in winter (3.81 m3/h, p < 0.01).


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 558
Author(s):  
Emilia-Adela Salca ◽  
Tomasz Krystofiak ◽  
Barbara Lis ◽  
Salim Hiziroglu

The objective of this study was to evaluate the glossiness of black alder wood (Alnus glutinosa L.) samples coated with two varnish types as a function of exposure to dry heat and artificial aging. The chemical resistance of the coated samples to cold liquids was also evaluated. Based on the findings in this work, it appears that the varnish types and their structural differences influenced the overall glossiness of the coated samples. The UV varnish exhibited higher gloss values than those coated with the water-borne product within the range of silky gloss and silky matte grades. The heat exposure influenced the surface glossiness of the UV-coated samples more than the samples coated with water-borne varnish. The overall gloss values of the samples decreased with the exposure time to artificial aging, resulting in no layer cracks. The cold household liquids left less visible traces on the surfaces and alcohol was found to be the strongest agent. This study could have practical applications in the furniture industry to produce value-added furniture units according to their specific conditions of indoor use.


2020 ◽  
Vol 144 (7-8) ◽  
pp. 378-378
Author(s):  
Simon Lendvai ◽  
Jurij Diaci ◽  
Dušan Roženbergar
Keyword(s):  

Područje poplavnih šuma crne johe (Alnus glutinosa (L.) Gaertn.) u Sloveniji čini samo 0,4 % (približno 4708 ha) ukupne površine šumskog zemljišta (Čater i sur., 2001.). Veći kompleks takvih sastojina u Sloveniji su Črni i Polanski Log, a istraživanje je provedeno na području potonjeg (slika 1). Kako čiste sastojine johe odlikuju brojne specifičnosti, potrebno im je prilagoditi šumskouzgojne postupke. Da bi se utvrdio odgovarajući intenzitet prorjede takvih sastojina, 1967. godine u Polanskom Logu postavljene su pokusne plohe. Od tada do 2018. godine na plohama je izvršeno pet do sedam mjerenja. Sva stabla na plohama su bila obrojčana. Izvršeno je mjerenje prsnih promjera i procjena sljedećih elemenata na stablima: pripadnost etaži, vitalnost, uzgojna perspektiva, uzgojna uloga, duljina krošnje i kvaliteta (tablica 3). Svaka ploha bila je podijeljena u tri polja (40 x 50 m) s različitim metodama rada: bez intervencije, umjereno i intenzivno prorjeđivanje. Uzgojni postupci koji su poduzeti tijekom praćenja pokusa prikazani su u tablici 2. Danas su te sastojine u zreloj fazi razvoja, stoga smo u ovom radu analizirali reakcije crne johe na različite intenzitete prorjeđivanja i dobivene rezultate usporedili s preporukama autora tradicionalnih uzgojnih modela i modela koji se temelje na situacijskoj njezi šuma. Ustanovili smo da se na plohama s intenzivnim prorjeđivanjem gustoća sastojine koja je u dobi između 50 i 70 godina i na kraju je ophodnje kreće od 295 do 690 kom/ha (slika 3), dok se na plohama bez intervencije ova vrijednost kreće u rasponu od 370 do 790 kom/ha. Drvne zalihe u istom su se razdoblju kretale u rasponu od 277 do 458 m<sup>3</sup>/ha na plohama s intenzivnim prorjeđivanjem, dok su na plohama bez intervencije bile veće, u rasponu od 309 do 516 m<sup>3</sup>/ha (slika 4). U to su se doba temeljnice nalazile u rasponu između 23 i 41 m<sup>2</sup>/ha na plohama s intenzivnim prorjeđivanjem, a na plohama bez intervencije u rasponu od 26 do čak 51 m<sup>2</sup>/ha (slika 5). Tijekom cijelog razdoblja praćenja ploha, stabla su, bez obzira na metodu rada, narasla za tri do četiri debljinska stupnja (slika 2). Na plohama s umjerenim prorjeđivanjem i onima bez intervencije, debljinski prirast stabala bio je skoro jednak (0,33 cm godišnje) (slika 6). Statistički je značajan veći debljinski prirast stabala na plohama s jako intenzivnim prorjeđivanjem (0,37 cm godišnje). Debljinski prirast dominantnih stabala bio je nešto veći, od 0,46 cm godišnje na plohama bez intervencije do 0,50 cm godišnje na plohama s jako intenzivnim prorjeđivanjem, ali statistički značajne razlike između metoda rada nisu utvrđene (slika 6). Međutim, otkrili smo da kod dominantnih stabala ne postoje statistički značajne razlike s obzirom na njihovu slojevitost, vitalnost, tendenciju, dužinu krošnje i kvalitete s obzirom na korištenu metodu rada. U usporedbi s uzgojnim modelima koji su se koristili za manji broj odabranih stabla, gustoća i temeljnica ispitivanih sastojina je znatno veća, a debljinski prirast manji. Autori tradicionalnih i modela s manjim brojem odabranih stabala zagovaraju rano prorjeđivanje takvih sastojina (tablica 1). Veće razlike nastaju u konačnom broju stabala po hektaru i u intenzitetu intervencije. Razlog malog debljinskog prirasta i razlike između metoda rada na našim plohama pripisali smo nedovoljnom intenzitetu i djelomično nedosljednoj provedbi postupka prorjeđivanja. Ipak, ukazala se potreba za intenzivnim prorjeđivanjem i pospješivanjem rasta stabala najvećeg prsnog promjera, vitalnosti i tendencije, lijepo oblikovane i duge krošnje (slika 7, slika 8).


2014 ◽  
Vol 56 (3) ◽  
pp. 135-140 ◽  
Author(s):  
Iwona Skrzecz ◽  
Alicja Sowińska ◽  
Wojciech Janiszewski

Abstract The aim of the study was to evaluate the possibility of using botanic antifeedants to reduce the damage caused by Melolontha spp. grubs. To achieve the objective, the experiments were established in semi-field conditions to estimate the antifeedant activity of rutin, quercetin (flavonoids from buckwheat Fagopyrum esculentum) and an extract from black alder Alnus glutinosa leaves against Melolontha melolontha grubs. The grubs were placed individually in the pots with a soil in which 2 year old Pinus sylvestris trees were planted. The pots were put in garden pavilions placed in the open area. Then the soil in the pots were watered with the emulsions of rutin, quercetin, an extract from A. glutinosa leaves, and with pure water-comparative variant. After 4 months, the weight and mortality of grubs were compared, as well as the weight of tree roots in all pots. There was no effect of the antifeedants on the development and extent of damage caused by M. melolontha grubs. The results do not indicate the use of botanic antifeedants in the protection of forests against the cockchafer grubs


2020 ◽  
Vol 41 (2) ◽  
pp. 243-249
Author(s):  
Oscar Manuel de Jesús Vera Cabral ◽  
Eduardo da Silva Lopes ◽  
Carla Krulikowski Rodrigues ◽  
Afonso Figueiredo Filho

Demand for higher value-added wood products stimulates research for new, mainly mechanized, thinning operations in order to increase productivity and reduce production costs. In this context, the aim of this study was to evaluate the impact of distance between strip roads on forwarder productivity and costs of thinning operations in Pinus taeda stands. The study was carried out in 10-year-old Pinus taeda stands located in Parana State, Brazil. Two thinning methods were evaluated: (1) TH5: systematic harvest in every fifth tree row and selective harvest in adjacent rows; and (2) TH7: systematic harvest in every seventh tree row and selective harvest in adjacent rows. Working cycle times, productivity and costs were determined through a time-motion study of the forwarder. The additional variables evaluated were wood assortments (industrial wood and energy wood) and extraction distances (50, 100, 150 and 200 m), and mean values were compared between thinning methods using t tests for independent samples (α=0.05). Loading and unloading elements consumed the most time in the working cycle, with lower participation time in TH7 due to greater availability of logs along the strip roads (higher pile volumes), influencing total cycle time up to the mean distance of 150 m for both assortments. TH7 consequently showed 6% higher productivity, its energy yield was 5.3% lower and its production cost was 3.0% lower.


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