Influence of moisture on rate of decay of loblolly pine root wood by Heterobasidion annosum

1980 ◽  
Vol 58 (1) ◽  
pp. 36-39 ◽  
Author(s):  
E. G. Kuhlman

Root segments of loblolly pine (Pinus taeda L.) were decayed by Heterobasidion annosum (Fr.) Bref. (=Fomes annosus (Fr.) Karst.) over a broad range of wood (33–317%) and soil (36–259%) moisture contents in modified soil-block tests. Maximum weight loss occurred at 50–286% wood moisture content. Decay was inhibited at wood moisture contents over 290%. Water moved rapidly into the root segments by capillarity, and some decay occurred within 2 weeks. Water uptake was faster in inoculated segments than in noninoculated segments at a soil moisture content of 172% of the 0.2 bar (1 bar = 100 kPa) moisture content.


1990 ◽  
Vol 14 (1) ◽  
pp. 48-51 ◽  
Author(s):  
J. B. Jett ◽  
L. John Frampton

Abstract At moisture contents of less than 15%, loblolly pine (Pinus taeda L.) pollen displayed a marked sensitivity to rehydration prior to in vitro germination testing. At moisture contents above 15%, percent germination was relatively insensitive to increasing moisture content. The relationshipbetween length of rehydration time and pollen moisture content was highly significant. However, the commonly used 16-hour rehydration period is longer than is necessary since 1-2 hours of rehydration adequately ensure peak germination. Shortening of the rehydration period allows operationaltree improvement programs to test a greater number of pollen lots in a given period of time. South. J. App. For. 14(1):48-51.



1959 ◽  
Vol 37 (5) ◽  
pp. 789-799 ◽  
Author(s):  
D. A. Fraser ◽  
H. T. Dirks

Wood moisture was measured in the butt of healthy and decadent yellow birch trees growing on various sites in the summers of 1950 and 1952. The moisture content decreased from almost 100% in May to about 60% in late June when the leaves were fully unfolded. Wood moisture was usually 5 to 15% higher in the butt of decadent trees than in healthy trees during the 2 years of investigations. It was higher in the trunk of trees on a dry site during a wet summer and on a wet site during a somewhat dry summer.Relative turgidity in leaves was measured in mature trees as well as in leaves of seedlings growing on soils with varied moisture contents. Relative turgidity was usually less during the day. During periods of drought it decreased even during the night. Exceptions observed may have been caused by leaf absorption of dew. In young birch seedlings relative turgidity values varied between 65 and 50% in soils ranging from 100 to 70% of field capacity. As the soil wilting point was approached, relative turgidity of leaves decreased to about 35%.



1962 ◽  
Vol 40 (10) ◽  
pp. 1281-1292 ◽  
Author(s):  
W. J. Bloomberg

A comparison was made between Populus trichocarpa Torr. and Gray, P. × canadensis Moench 'Regenerata', and P. × canadensis 'Robusta Bachelieri' with respect to shoot moisture relations and anatomy. The two hybrid varieties had slower rates of moisture loss and had higher wood moisture contents throughout most of the year than P. trichocarpa. The bark and wood moisture content of the three varieties was lower during dormancy than in the growing season. The upper region of the shoots had lower bark and wood moisture contents than the basal region during dormancy, but the reverse was true in summer. In all varieties, there was a significant positive correlation between wood and bark moisture content. Compared with P. trichocarpa, the two hybrids had larger piths, wider vessels, longer phloem rays, wider sieve tube zones, and thicker periderms; P. 'Robusta' had fewer lenticels. The upper region of the shoots had a wider pith, thicker bark, thinner periderm, and more lenticels than the basal region. The differences in moisture relations and anatomy of the three varieties suggest an explanation for the observed greater resistance to canker disease caused by Cytospora chrysosperma (Pers.) Fr. in the hybrids than in P. trichocarpa.



1970 ◽  
Vol 48 (10) ◽  
pp. 1787-1793 ◽  
Author(s):  
E. G. Kuhlman

A modified soil-block test was used to compare the bark-decomposing ability of various soil- and root-inhabiting fungi. Bark of Pinus taeda was highly resistant to decomposition by all 31 fungi tested. A brown-rot fungus, Lenzites saepiaria, caused the most weight loss, but weight losses due to decay by all fungi varied only from 3 to 15%. Isolates of Mucorales produced 3–8% weight losses from stem bark in 12 weeks. Available nutrients were used within 6 weeks; longer incubation resulted in little additional decomposition. Losses in weight from root bark and stem bark were similar, indicating little nutritional difference between these two substrates.Extraction of stem bark with ethanol or water before incubation with Fomes annosus, L. saepiaria, or Scytalidinun lignicola did not increase the amount of decomposition. This suggests that extractives in the bark may not be responsible for the slow rate of decay. Since autoclaving of the bark before incubation with the fungi enabled the fungi to cause more weight loss than did gas sterilization of the bark, the primary reason for the slow rate of decomposition by fungi is considered to be the complex molecular structure of the bark constituents.



1965 ◽  
Vol 41 (3) ◽  
pp. 352-363
Author(s):  
W. J. Bloomberg ◽  
D. Farrell

Colman electrodes were inserted into stem sections of Douglas-fir, western hemlock, western red cedar and black cottonwood and resistance readings were taken at wood moisture contents of 10% to 100% of maximum moisture content. In almost all the conifer sections tested, 85% or more of the readings lay within limits of ±10% moisture content about the mean curve, and over 50% were within ±5%. The variation was greater for black cottonwood. Variation was also greater in the larger than in the smaller sections. The curves for individual sections within each species had certain characteristics in common, but no two curves were identical.Resistance readings given by Colman electrodes inserted into living black cottonwood trees showed a fairly good correlation with soil moisture content when the trees were subjected to cycles of drought and watering.



2012 ◽  
Vol 42 (3) ◽  
pp. 574-584 ◽  
Author(s):  
Finto Antony ◽  
Laurence R. Schimleck ◽  
Richard F. Daniels

Conventionally, increment cores collected at breast height (1.4 m) have been used to measure wood properties of standing loblolly pine (Pinus taeda L.) trees. This height has been used because of the ease of sampling and cost involved in extracting the cores. In this study, the efficacy of a breast-height core to represent whole-tree specific gravity (SG) and moisture content (MC) was examined. The sampling height that best represents whole-tree SG and MC was identified using the correlation between volume-weighted whole-tree SG and MC with SG and MC measurements collected at different heights within a tree. We found a high correlation between observed whole-disk SG and MC with volume-weighted whole-tree SG and MC at most sampling heights. The strength of the correlation followed a skewed parabolic curve form for both wood properties. The strongest correlations were observed between 4.6 and 6.1 m, with marginally lower correlations at the base of the tree, and the weakest correlations were observed towards the tip of the tree. In addition, it was found that the number of stands and trees that need to be sampled to achieve a certain accuracy in overall mean whole-tree SG and MC was greater if breast height was used as a sampling height compared with the most representative sampling heights identified (4.6 m for SG and 6.1 m for MC).



1982 ◽  
Vol 6 (2) ◽  
pp. 104-107
Author(s):  
R. S. Webb ◽  
S. A. Alexander

Abstract The root systems of 70 loblolly pines (Pinus taeda L.) from three subsoiled seed orchards were excavated to determine the association of subsoiling with the incidence of resin-soaked lateral roots. The number of lateral roots and the proportion of resin-soaked and healthy root tissue were recorded. Chips from the resin-soaked margin of lateral roots were incubated for 10 days at 24°C on two general media and two media selective for Heterobasidion annosum (Fr.) Bref. Verticicladiella procera Kend. was isolated from 30 percent of the declining/subsoiled trees at one seed orchard. Monilia spp. were also isolated. Of the lateral roots severed by subsoiling, 60 percent were resin-soaked from 10 to 45 cm in length.



1958 ◽  
Vol 36 (1) ◽  
pp. 187-206 ◽  
Author(s):  
D. E. Etheridge

The moisture content in subalpine spruce was highest in overstory trees and lowest in understory trees, and it was higher in trees on a moist site than in trees of similar vigor classes on a dry site. Moisture contents of 10% of saturation for the more vigorous trees on the moist site and 7% of saturation for the less vigorous trees on the dry site represented a statistically significant difference which appeared to restrict the development of heartwood fungi to the wetter trees. A similar difference in the moisture content existed between the 1.5-ft. and the 20-ft. level of the trees, the occurrence of fungi being restricted to the wetter basal portion of the stems. In the laboratory, infection did not take place in test blocks at moisture contents lower than 8% of saturation. It is suggested that the threshold moisture content for infection in the trees occurs around the 7 to 8% saturation level. In the laboratory tests a difference in the moisture content of 3.4% of saturation in wood resulted in a statistically significant difference in the rate of decay by Coniophora puteana (Schum. ex Fr.) Karst., but differences in ring frequency and specific gravity in the test pieces corresponding to the differences between these properties in the living trees did not appreciably affect the decay rate. There was no evidence that variations in the distribution of decay-promoting or decay-retarding substances occurred in the trees from the two sites.



2016 ◽  
Vol 74 (6) ◽  
pp. 857-866 ◽  
Author(s):  
O. Oyedeji ◽  
O. Fasina ◽  
S. Adhikari ◽  
T. McDonald ◽  
S. Taylor


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