Showing papers on "Bark published in 1983"

Effects of Fungal Antagonists and Compost Age on Suppression of Rhizoctonia Damping-Off in Container Media Amended with Composted Hardwood Bark

Abstract: Evaluation de l'antagonisme de diverses especes fongiques vis-a-vis de R. dans des composts et dans des milieux amendes avec des composts d'ecorce de feuillus

The Suberin Monomers and Triterpenoids from the Outer Bark of Betula verrucosa Ehrh.

Abstract: The composition of suberin monomers and triterpenoids from fresh and industrial outer bark of B. verrucosa Ehrh., the predominant birch species in northern Europe, was determined by high-resolution gas chromatography combined with mass spectrometry. Analytical procedures, starting with sample hydrolysis with ethanolic alkali, were developed for routine analysis, which allowed suberin monomers and triterpenoids to be determined simultaneously from a single run with the gas Chromatograph. The suberinderived long-chain acids from 20 fresh bark samples comprised an average of 322g/kg of the dry outer bark. The principal suberin monomer was 9,10-epoxy-18-hydroxyoctadecanoic acid (112g/kg dry bark and 36% of the suberin monomers). Among the other monomers, the -hydroxymonobasic acids formed the major group. The triterpenoids from the same bark samples comprised 315g/kg dry bark, with betulinol äs the dominant member. Structurally, the minor triterpenoids represented lup-20(29)-ene and olean12-ene derivatives. The industrial outer bark from a Finnish pulp mill was similar to fresh bark both in amount and composition of suberin monomers and triterpenoids.

Fungal populations in container media amended with composted hardwood bark suppressive and conducive to Rhizoctonia damping-off

Abstract: Etude quantitative et qualitative des populations fongiques dans des conteneurs dont le sol est amende avec un compost d'ecorces de feuillus

Beech bark disease.

Abstract: In forests of North America the beech bark disease (BBD) complex affects American beech, Fagus grandifolia Ehrh. BBD begins when bark tissues, attacked by the exotic beech scale insect, Cryptococcus fagisuga Lind. are rendered susceptible to killing attacks by fungi of the genus Nectria. The principal fungus, N. coccinea var. faginata Lohm. and Watson, was probably introduced also, but the native pathogen, N. galligena Bres., also attacks and kills bark predisposed by C. fagisuga.

Development of Lesions Caused by Phytophthora cinnamomi in the Secondary Phloem of Eucalyptus marginata

Abstract: Phytophthora cinnamomi Rands invaded the secondary phloem of inoculated roots and stems of Eucalyptus marginata Donn. ex Sm. For 12 months after inoculation, lesion development was followed in coppice stems. As lesions extended, the phloem or inner bark became discoloured due to the accumulation and oxidation of polyphenols. Starch also was deposited in the necrotic phloem. The primary wall material of sieve tubes and associated parenchyma was hydrolysed but fibres were unaffected. Fungal spread was most rapid in the outer phloem tissue where cells were loosely packed and characterized by many expanded parenchyma cells. Fungal invasion of the inner phloem resulted in cambial kill. Roots were not girdled by the fungus in the first 12 months after inoculation, as they resisted tangential spread of the fungus more effectively than coppice stems. Lesions were contained once necrophylactic (wound) periderms formed in the bark. Although the necrophylactic periderm restricted fungal activity during winter and spring, the fungus did 'break-out' in summer and invade new areas of phloem in 50% of the inoculated roots and stems. Summer lesion extension was usually associated with kino production: a series of kino veins reflected the intermittent activity of the fungus. Once the characteristics of typical lesions were recognized, interpretation of root lesions resulting from natural infections was possible.

Effects of Organic Components in Container Media on Suppression of Fusarium Wilt of Chrysanthemum and Flax

Abstract: Chef, D. G., Hoitink, H. A. J., and Madden, L. V. 1983. Effects of organic components in container media on suppression of Fusarium wilt of chrysanthemum and flax. Phytopathology 73:279-281. Container media amended with mature hardwood bark compost (CHB) were mildly suppressive and those amended with Canadian peat were suppressed chrysanthemum and flax Fusarium wilts, but green CHB was conducive. Heating of mature CHB negated the suppressive effect, but only significantly less suppressive. Media amended with raw and aged pine bark partially reduced the suppressiveness of green CH B.

Composition of Nonpolar Extractives in Bark of Norway Spruce and Scots Pine

Abstract: The composition of nonvolatile extractives soluble in petroleum ether was investigated separately for inner and outer bark of Norway spruce (Picea abies (L.) Karst) and Scots Pine (Pinus silvestris (L.)). The bark extractives of one spruce and one pine tree were prefractionated by thin-layer chromatography and the detailed composition of free and esterified fatty acids, free and esterified sterols, triterpenoid alcohols and fatty alcohols, resin acids and diterpene aldehydes was determined by gas chromatography. Bark of four other trees was analysed by a routine method based on direct gas chromatography of the extracts. Fatty acids, resin acids and sterols accounted for ca 80% of extractives in inner bark and for 50% in outer bark. Qualitative differences between the extractives in inner and outer bark were noticed. The total amount of fatty and resin acids was about 1.54 of spruce and pine bark dry weight and the amount of sterols was 0.2–0.5%. These levels are low considering possible technical...

Histopathology of cankers on Populus caused by Cytospora chrysosperma

Abstract: Cuttings of poplar hybrid NE-388 (P. maximowiczii Henry × trichocarpa Torr. & Gray) were inoculated with mycelium of Cytospora chrysosperma (Pers.) Fr. Bark samples for histological study were taken at varying times after inoculation from slowly enlarging cankers, blackstem, control wounds, and uninoculated healthy plants. Histological examination revealed that slowly enlarging cankers are characterized by hyphae in the xylem and necrosis of the cambium ahead of visible bark symptoms, by large- and small-diameter hyphae both between and within host cells, and by hyphal aggregations associated with the leading edge of bark colonization. The blackstem symptom is characterized by rapid colonization of the cortex and phloem by large-diameter intercellular hyphae followed by the digestion of cell contents by small-diameter intracellular hyphae. Histochemical tests indicate degradation of pectic substances, loss of cellulose and starch, and deposition of wound gums. Lignification is not involved. Host response ...

Constituents of the root bark of Ailanthus altissima Swingle. Isolation and X-ray crystal structures of shinjudilactone and shinjulactone C and conversion of ailanthone into shinjudilactone.

Abstract: Two new quassinoids, shinjudilactone and shinjulactone C were isolated from the root bark of Ailanthus altissima SWINGLE and their structures were established to be 1β,11α-dihydroxy-2,16-dioxo-13(12→11α)abeo-picras-3-en-12,20-olide and 1α,12α : 5α,13α-dicyclo-1β,12β,20-trihydroxy-9βH-picras-3-ene-2,11,16-trione, respectively, by X-ray diffraction analysis. Shinjudilactone was prepared from ailanthone by benzilic acid rearrangement.

Estimating bark thickness in Pinus radiata

Abstract: Bark thickness in Pinus radiata D. Don is related to over-bark diameter, position up the stem, tree height, and breast-height over-bark diameter. Equations have been derived for predicting bark thickness as a function of these variables and as a function of over-bark diameter alone. By using the bark thickness equations, routine bark-gauge measurements together with their associated measurement errors can be eliminated, which should accelerate the derivation of new, more precise, stem volume functions. The bark thickness equations, used in conjunction with a tree or log taper function, can provide estimates of the volume of bark to be harvested or available for utilisation. INTRODUCTION As all standing timber is encased in bark, measurement of wood volume requires some adjustment to reduce over-bark to under-bark diameters. Most tree volume equations predict the under-bark volume of the stem from a few, efficiently measured, tree variables. To derive these equations a sample of trees is usually sectionally measured to determine "actual" under-bark volume. In New Zealand the adjustment to over-bark diameters is generally made by subtracting the sum of two bark thickness readings from a Swedish bark gauge. By sampling the bark thickness, bias and imprecision are introduced to the "actual" under-bark volume and so to the derived volume and taper equations. But, as volume and taper equations are the primary building blocks for many mensuration systems, accuracy and precision are essential at this stage to avoid multiplicative errors. The Swedish bark gauge is not an ideal instrument for a number of reasons. Over-estimation of bark by this gauge has been noted by von Althen (1964) and specifically for P. radiata by Carron & Mclntyre (1959). Tests on P. radiata in New Zealand have shown a resulting 1.44% under-estimate in the volume of 72 logs which were peeled to measure "actual" volume (J. Beers, pers. comm.). The imprecision in volume estimate owing to sampling bark thickness was 1.31% (standard error of the mean as a percentage of "actual") for two readings at each diameter point, decreasing to 0.83% for five readings. This sampling error associated with only two* readings tended to increase toward the base of the tree where the bark is rough and the stem New Zealand Journa l of Fores t ry Science 13(3): 340-53 (1983) Gordon — Estimating bark thickness 341 can be fluted. Operator fatigue due to bruised hands can cause bias, especially when measuring large P. radiata whose lower bark often exceeds 50 mm in thickness. The importance of operator experience was noted by Gray (1956) who also mentioned that inaccurate readings are easily made. Seasonal bias, due to changes in the density and moisture content of the outer wood layers, results from the gauge entering this wood easily in early summer and so over-estimating (von Althen 1964). When felled trees are being measured, the bark on the underside is effectively removed from the sampling frame unless the logs are destroyed by sectional cutting. Finally, the time involved in bark measurement increases the cost of taking sectional measurements and/or decreases the size of the tree sample. Thus although over-bark volume can be measured comparatively accurately and rapidly, the under-bark volumes derived using Swedish bark gauge adjustments are less reliable, despite the amount of effort that goes into bark measurement. As interest increases in efficient use of timber harvesting residues, prediction of the volume and proportions of bark will become important. Although regression equations have been derived to predict bark thickness and volume for P. radiata at Kaingaroa Forest (C. J. Goulding, unpubl. data), the data were collected using a Swedish bark gauge and so incorporate the errors mentioned above. The work reported here is based on data derived solely from taped diameter measurements taken (a) over-bark and (b) under-bark after removing the bark. The following notation is used: D = Taped diameter over-bark (cm) d = Taped diameter under-bark after bark peeled (cm) B = D d = double bark thickness (cm) Di.4 = Taped over-bark diameter 1.4 m above ground (cm) H = Total tree height (m) h = Level of measurement above ground (m) V0b = Volume over-bark (m ) V u b = Volume under-bark (m ) Vb = V0b Vub = bark volume (m ) Vbs = Volume of bark substance (m ) SbS = Cross-sectional surface area of bark substance (m 2 ) A n impor tan t distinction mus t be m a d e between bark volume (Vb) and the volume of bark substance (Vbs). T h e former is equivalent to

The relationship between bark moisture and invasion of eucalyptus marginata by phytophthora cinnamornl

Abstract: Stent's pessimism was quite unjustified or at the least, very premature. I am an optimist, and I believe the next decade will see the new ideas and techniques of molecular biology and molecular genetics successfully applied for the benefit of man in the control of plant diseases and in many other fields as well. rapid colonization by P. cinnamomi, we also had observed renewed and rapid invasion of inoculated jarrah coppice stems after unusually heavy rainfall at Dwellingup during January 1982 (January rainfall, 1982 was 237 mm; average 13 mm).

Allelopathic effects of Engelmann spruce bark stilbenes and tannin-stilbene combinations on seed germination and seedling growth of selected conifers.

Abstract: The allelopathic effects of Engelmann spruce bark and bark extacts on seed germination and seedling growth of several conifer species were examined. Extracts were hydroxystilbenes (isorhapontin and astringin) and condensed tannins. Experiments included the following: (i) seed germination in petri dishes with various concentrations of stilbenes and tannin–stilbenes; (ii) seed germination in petri dishes containing Engelmann spruce bark fragments; (iii) seedling growth in varying mixtures of peat/Engelmann spruce bark, the latter added either before or after seedling establishment; (iv) seedling growth in samples of Engelmann spruce forest soil horizons. In all experiments and in all species there was an allelopathic response to bark extracts. This response was expressed through inhibition of seed germination (seed-coat rupture and radicle emergence), necrotic discoloration and protoplasmic disruption of root-tip cells, suppression of root hairs, and repressed growth in general. Among the conifers tested Pi...

Changes in nitrogen levels and free amino acids in rooting cuttings of mulberry (Moms alba)

Abstract: Total and protein nitrogen in bark and wood of parent stems of mulberry (Morns alba L. cv. Ichinose) decreased readily and to the same extent during leafing-out of the buds, but the decrease in wood was less marked than in bark. Simultaneously, soluble nitrogen in both bark and wood also declined but the depletion was less marked than that of total and protein nitrogen. During the same period total nitrogen in the new shoots and adventitious roots increased drastically; however, the increase in total nitrogen in the growing parts during rooting was almost the same as the decrease in total nitrogen in the parent stems. Proline, the prevalent amino acid in wood and bark of the parent stems, decreased drastically during rooting, whereas during the same period asparagine in the developing buds, callus and adventitious roots increased markedly and became the predominant amino acid. The amount of arginine was relatively high in bark of the parent stems but Low in wood and the buds. The level of arginine in bark decreased considerably during the experiments (as did that of proline). The results suggest that the nitrogen required by the growing parts (sinks) in the rooting cuttings comes mainly from protein breakdown in bark of the parent stems (source), although stored protein in wood (source) and soluble nitrogen in bark and wood (sources) also play a part in storage of nitrogen. Asparagine is suggested to be the main nitrogen transport compound in the new growth of the tree and the initiating roots of cuttings.