scholarly journals The proportion of heartwood in conifer (Pinus sylvestris L., Picea abies [L.] H. Karst.) trunks and its influence on trunk wood moisture -

2013 ◽  
Vol 59 (No. 8) ◽  
pp. 295-300 ◽  
Author(s):  
M. Millers

As the tree age increases, the formation of heartwood takes place in the central part of the tree. Since there is a large difference in the moisture content between sapwood and heartwood in conifers, the proportion of heartwood expressed in percentage is one of the most important factors influencing the average moisture of trunk wood. The aim of the research was to find out the changes in parameters of heartwood proportion and the changes in average trunk wood moisture parameters, depending on the age of the tree. To evaluate and compare the heartwood proportion in pine and spruce trunk and its moisture, sample plots were established throughout the territory of Latvia in 2011. These sample plots were established in stands of different ages (37–143 years). The total number of sample plots was 61–29 for pines with 246 sample trees and 32 sample plots for spruces with 270 sample trees. With the increase in the tree age from 60 to 140 years, the heartwood proportion increases and the average moisture content of trunk wood decreases. With an increase of the heartwood proportion in pine from 18% to 39%, the average moisture of trunk wood decreases from 108% to 86%, but with an increase of the heartwood proportion in spruce from 30% to 49%, the average moisture content of trunk wood decreases from 107% to 81%.  

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 879
Author(s):  
Paweł Kozakiewicz ◽  
Łukasz Tymendorf ◽  
Grzegorz Trzciński

Scots pine (Pinus sylvestris L.) is one of the most important forest tree species in Europe, and its wood is a main raw material in the wood industry of many countries of the region. The high variability of pine wood density in connection with its moisture content is a challenge in transport operations. An important part of the roundwood transport of pine wood by trucks is the transport of large-size roundwood (sawlogs). As part of the research, an analysis was carried out of the influence of absolute wood moisture content, determined in various ways, on selected truck transport parameters of large-size pine wood. The analyses of the supply of wood to a large sawmill in northern Poland took into account different seasons. The results indicate that the average moisture content of the transported pine wood is at a level of approximately 95% (determined by dry weight) and the density at 0.878 Mg m−3 (determined using the stereometric method). Quick measurement with the use of a resistance hygrometer gives significantly lower results both on the side surface and on the cross-cut end of the log. Regardless of the method of measurement, the absolute moisture content of wood in loads depends on the date of delivery (season), which is reflected in the variability of the density and weight of the loads. The indicated strong correlations between the selected, tested characteristics of roundwood transports are important for forestry practice too. It is the possibility of using the methods of quick determination of fresh wood moisture to estimate the density of wood and to predict and determine the mass of the load.


Holzforschung ◽  
2014 ◽  
Vol 68 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Tristan Stienen ◽  
Olaf Schmidt ◽  
Tobias Huckfeldt

Abstract Some of the most important indoor wood-decay basidiomycetes were investigated in Erlenmeyer flask experiments, in which 50 Pinus sylvestris sapwood samples with moisture content (MC) of 16% were piled, in view of the parallel influence of wood moisture and temperature on decay in buildings. In the piles, the moisture flow from the liquid at the bottom was interrupted by a metal ring at layer 7. Laboratory incubations with Antrodia xantha, Coniophora puteana, Donkioporia expansa, and Gloeophyllum abietinum over the temperature range of 10°C–25°C showed that fungi are able to colonize, moisten, and thereafter degrade wood samples below fiber saturation, if a moisture source nearby is available. In extreme cases, mycelium grew on wood with 17.4% final MC, and wood mass loss of more than 2% occurred at 24.6% moisture.


2004 ◽  
Vol 82 (9) ◽  
pp. 1338-1345 ◽  
Author(s):  
B Metzler ◽  
U Hecht

Water saturation of wood impedes the availability of oxygen necessary for wood decay. Storage of logs under water sprinkling is therefore used as an economic method in forestry. However, sapwood decay caused by Armillaria spp. was found in logs under water sprinkling, even at a wood moisture content of more than 150% (dry weight basis). Decay was associated with the formation of tubular air channels discernible as bright streaks extending from the cambial region into the sapwood. Their light colour results from different refraction of light in gas-filled versus water-filled wood structures. To examine the structure of the tubular air spaces in greater detail, we sampled wood of Norway spruce (Picea abies (L.) Karst. and silver fir (Abies alba (Mill.)). Radial, transverse, as well as tangential sections of affected timber were examined, and a structural model of tubular air channels is presented. These structures are formed around wood rays by a tubular sheath of pseudoparenchymatous mycelium, which in its cellular structure is reminiscent of pseudosclerotial plates. This structure allows the efficiently located extrusion of water from water-saturated wood. The power necessary for this process is suggested to be the generation of gaseous CO2. Since the air channels are in contact with the external surface, they evidently act as a conduit allowing oxygen to enter and penetrate to a depth of several centimetres. By this unique arrangement of the tubular air channels, Armillaria spp. appear able to metabolize wood cells in an aerobic microenvironment within water-saturated wood. This results in wood decay leading to significant economic loss in stored timber despite the application of regular sprinkling.Key words: Armillaria spp., Picea abies, Abies alba, wood moisture content, oxygen supply, wood anatomy, wood decay.


1998 ◽  
Vol 28 (5) ◽  
pp. 759-765 ◽  
Author(s):  
Malin Bendz-Hellgren ◽  
Jan Stenlid

The effects of clear-cutting and thinning as well as heartwood and sapwood moisture content on spore infection by Heterobasidion annosum (Fr.) Bref. were investigated in summer cuttings in southern and central Sweden. At five sites, 20-100 stumps in clear-cut, thinned, and precommercially thinned stands of Norway spruce (Picea abies (L.) Karst.) were created and left for natural spore infection. An additional 20 stumps per stump type and site were artificially inoculated with conidiospores of H. annosum. The probability of natural infection was 0.73 and 0.53 for stumps in thinned and clear-cut stands, respectively. Almost all (95%) of the artificially inoculated stumps in thinned and clear-cut stands became colonized, and no differences due to stump type were found. The probability of infection of stumps in precommercially thinned stands was lower than for the other stump types of both naturally and artificially inoculated stumps. The proportion of colonized sapwood was reduced with increasing moisture content. Stump colonization seemed unaffected by temperature, even though stump temperatures exceeded 40°C for 2 h at one site.


TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 45-50 ◽  
Author(s):  
LAURENCE SCHIMLECK ◽  
KIM LOVE-MYERS ◽  
JOE SANDERS ◽  
HEATH RAYBON ◽  
RICHARD DANIELS ◽  
...  

Many forest products companies in the southeastern United States store large volumes of roundwood under wet storage. Log quality depends on maintaining a high and constant wood moisture content; however, limited knowledge exists regarding moisture variation within individual logs, and within wet decks as a whole, making it impossible to recommend appropriate water application strategies. To better understand moisture variation within a wet deck, time domain reflectometry (TDR) was used to monitor the moisture variation of 30 southern pine logs over an 11-week period for a wet deck at the International Paper McBean woodyard. Three 125 mm long TDR probes were inserted into each log (before the deck was built) at 3, 4.5, and 7.5 m from the butt. The position of each log within the stack was also recorded. Mixed-effects analysis of variance (ANOVA) was used to examine moisture variation over the study period. Moisture content varied within the log, while position within the stack was generally not significant. The performance of the TDR probes was consistent throughout the study, indicating that they would be suitable for long term (e.g., 12 months) monitoring.


Author(s):  
A N. Kabanov ◽  
◽  
S.A. Kabanova ◽  

Dendrochronological analysis was carried out in forest cultures of Pinus sylvestris of different ages growing in the green zone of Nur-Sultan city. It was found that the value of the annual radial growth is subject to a cycle with a period of 10-11 years. This is due to climatic conditions, in particular, with periods of solar insolation, which is confirmed by researches of other authors.


2014 ◽  
Vol 11 (1) ◽  
pp. 51
Author(s):  
Mohd Helmy Ibrahim ◽  
Mohd Nazip Suratman ◽  
Razali Abd Kader

Trees planted from agroforestry practices can become valuable resources in meeting the wood requirements of many nations. Gliricidia sepium is an exotic species introduced to the agricultural sector in Malaysia mainly for providing shade for cocoa and coffee plantations. This study investigates its wood physical properties (specific gravity and moisture content) and fibre morphology (length, lumen diameter and cell wall thickness) of G. sepium at three intervals according to age groups ( three, five and seven years of ages). Specific gravity (0.72) was significantly higher at seven years ofage as compared to five (0.41) and three (0.35) years age group with a mean of 0.43 (p<0.05). Mean moisture content was 58.3% with no significant difference existing between the tree age groups. Fibre diameter (22.4 mm) was significantly lower (p<0.05) for the trees which were three years of age when compared to five and seven years age groups (26.6 mm and 24. 7 mm), respectively. Means of fibre length, lumen diameter and cell wall thickness were 0.83 mm, 18.3 mm, and 6.2 mm, respectively, with no significant differences detected between trees in all age groups. Further calculation on the coefficient of suppleness and runkel ratio suggest that wood from G.sepium may have the potential for insulation board manufacturing and paper making. However, future studies should experiment the utilisation of this species for these products to determine its full potential.


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