Fomannoxin,a phytotoxic metabolite of Fomes annosus: in vitro production,host toxicity and isolation from naturally infected Sitka spruce heartwood

The effect of different culture conditions on growth and production of fomannoxin and the sesquiterpene phytotoxin fomannosin by a single isolate of Fomes annosus was studied. Whereas fomannoxin was produced by actively growing hyphae, fomannosin production was associated with the declinning growth phase of the fungus. The presence of fomannoxin in chloroform extracts from the stained stein heartwood zone of Fomes annosus diseased Sitka spruce trees was established. Fomannosin however was not detected. Toxicity of fomannoxin to germinating seeds and young seedlings of Sitka spruce was demonstrated.     

Fomes annosus Butt-Rot of Sitka Spruce: II. Loss of Strength of Wood in Various Categories of Rot

The results of static bending tests on small (150mm ? 10mm ?10mm) green samples of sound, stained, incipiently decayed anddecayed Sitka spruce wood from 18 naturally infected and 8 healthytrees showed that there were marked differences in the Modulusof Rupture (M of R) and Modulus of Elasticity (M of E) of woodin the various categories of rot, but that differences in densitywere slight. However, when the underlying systematic distributionof strength properties within stems of healthy Sitka spruceof this age (45 and 47 years old) were taken into account bya method involving multiple regression analysis, estimated lossesin strength due to the decaying action of Fomes annosus werenot so marked. Thus, stained wood was not significantly reducedin strength compared to healthy wood. Incipiently-decayed wood,which was not readily distinguishable from sound wood, sustainedan average 3 per cent loss in M of R and 11 per cent loss inM of E. In contrast, the average M of R of wood in the decaystage was reduced by 26%, and the average M of E by 39%. Therewere no significant reductions in density in wood in any ofthe various categories of rot. Factors affecting loss of strengthof wood in the various rot stages are considered, and the usesto which infected wood may be put are briefly discussed. The method used to estimate strength loss by taking into accountthe systematic variation in strength properties of Sitka sprucewood is, as far as is known, new and is therefore describedin some detail.     

Timber Improvement: II. The Effect of Vigour on Young-Growth Sitka Spruce

A study of the effect of vigour on the within-ring componentsof young, plantation-grown Sitka spruce (Picea sitchensis (Bong.)Carr.) has been made as a contribution to a more effective selectionof timber having superior timber yields and to appraise thelikely effect of forest management practices which, by influencingvigour of growth, affect wood quality. It was found that as ring width in Sitka spruce increases:

1. Thereis an increase in early wood width without a correspondingincreasein late wood and so a greater proportion of early wood.
2. Thereis a reduction in the average density of the early woodcomponentof the rings.
3. Because of the combined effects of 1 and 2,there is a reductionin wood density as vigour of growth increases.
4. There is a lower minimum early wood density.

The significance of these observations on the growth and technicalperformance of Sitka spruce timber is considered. The possibility of appraising adult wood characteristics onthe basis of juvenile wood performance is examined and the scopefor assessing fibre length and density of adult wood from anexamination of wood laid down at about six years from the pithis demonstrated.     

Comparison of the bordered pits of two species of spruce (Pinaceae) in a green and kiln-dried condition and their effects on fluid flow in the stem wood in relation to wood preservation

The relationship between bordered pit aspiration, pit sizesand permeability measured as preservative uptake and expressedas porosity was examined in two species of spruce, Sitka spruce(Picea sitchensis (Bong.) Carr.) grown in the UK and Easternspruce (Picea orientalis (L.) Link.) grown in Turkey, before(in the freshly felled green condition) and after kiln drying.A 2.5 per cent chromated copper arsenate preservative solutionwas allowed to flow in either the longitudinal or tangentialdirection of the stem wood and the uptake was assessed. Borderedpit anatomy was examined by light and scanning electron microscopyand image analysis was used to characterize the samples. Thepermeability of the wood declined following drying but lessso in the Sitka spruce. From an analysis of measurements madeon the wood features it appeared that basic density, latewoodpercentage and degree of pit aspiration were the most importantfeatures explaining these results. The structure of the borderedpits varied between the two species and the relative size ofthe aperture in comparison with the pit chambers was greaterin the Eastern spruce. The effects of these and other variablesincluding differences in conventional drying systems and naturaltree responses to environmental conditions on pit behaviouraffecting permeability are discussed.     

THE DISTRIBUTION OF MOISTURE IN THE LIVING STEM IN SITKA SPRUCE AND DOUGLAS FIR

1. Equilibrium in the moisture content of the stem appears to bereached at a given percentage of saturation rather than at apercentage based on the dry weight, and this method of expressingmoisture content eliminates many of the fluctuations apparentwith the latter.
2. Summer moisture content in Sitka spruce (Piceasitcbensis, Carr.)was highest on the site with the highestrainfall and lowestwith the lowest rainfall. It decreased inlate summer, suddenlyin Sitka spruce (in August) and graduallyin Douglas fir (Pseudotsugataxifolia Brit.).
3. There was asharp moisture gradient from cambium to heartwood,the saturatedzone being very narrow except on the wet Sitkaspruce site.In the Douglas fir it appeared that water couldbe withdrawnfrom the layers just behind the transpiration streamfasterthan it could be replaced, leaving this zone drier thanthesurrounding layers.
4. Lateral root pruning in Douglas fir ledto the drying out ofa narrow strip of tissue in the stem.

     

The effect of wood moisture on infection of Sitka spruce stumps by basidiospores of Heterobasidion annosum

In an inoculation experiment to test the effect of wood moisture content on infection of Sitka spruce (Picea sitchensis) stumps by basidiospores of Heterobasidion annosum, exposure to high rainfall increased infection in the heartwood and reduced sapwood infection compared to covered stumps. This was associated with a greater moisture content in both wood types. Within-treatment variation in the amount of infection was high and it is suggested that endogenous factors in stumps may have a greater influence on infection than the environment or the availability of spores.     

Fomes annosus Butt Rot of Sitka Spruce: III. Losses in Yield and Value of Timber in Diseased Trees and Stands

Direct losses in yield and value sustained through the rejectionof butt-rotted wood either in the forest or at the sawmill werecalculated for 484 butt-rotted Sitka spruce trees, 23 to 50-years-old,from 27 stands in Britain. Losses were calculated followingthe rejection of either decayed or incipiently-decayed wood. The results suggest that approximate losses in a stand may notbe difficult to estimate since the average loss per tree (percent of tree volume or value) did not vary widely in standsof trees of different age or size and overall losses were closelyassociated with the numbers of affected trees. The mean lossper tree following rejection of butt lengths containing incipiently-decayedwood was 33 per cent of volume, and 43 per cent of value, comparedwith 22 per cent and 27.5 per cent respectively for losses followingrejection of butts containing decayed wood. These value losseswere estimated using the Forestry Commission 1977 price/sizecurve and depended on notional changes in the breast-heightdiameter of affected trees following rejection of rotted buttlengths in the forest. A computer-simulated sawmilling study of 202 trees of sawlogsize from the main study suggested that losses in value sustainedthrough the rejection of decayed or incipiently-decayed buttlengths might be reduced by about 10 per cent if such lengthswere converted into pallet boards instead. The consequences of these various methods for estimating directlosses due to F. annosus butt rot are considered in relationto their use in standard forest management financial appraisals.Aspects of indirect losses, i.e., the increased susceptibilityto windblow and possible reductions in increment of butt-rottedtrees, not considered in detail in this paper, are also discussed.     

Genetic variation in Picea abies (L.) Karst. and Fomes annosus (Fr.) Cke. shown by growth of the fungus on wood dust

Growth of Fomes annosus is studied by a test based on growth of previously starved hyphae on sawdust of heartwood of Picea abies as the only nutrition. Our observations show that the method can be used to distinguish beween different spruce individuals or clones, between different Fomes annosus strains and between different growing sites of the trees.     

Growth and Wood Properties of Sitka Spruce (Picea sitchensis (Bong.) Carr.) in Nursing Mixtures Established on Nitrogen-deficient Mineral Soils

Rate of growth and wood properties of Sitka spruce (Picea sitchensis (Bong.) Carr.) were investigated in triplet mixtures with lodgepole pine (Pinus contorta Loud.) (Alaskan provenance) and Japanese larch (Larix kaempferi (Lamb.) Carr.), established on nitrogen-deficient, iron pan soils. These ?nursing? mixtures were compared with pure stands of Sitka spruce that had been either regularly or periodically fertilized with nitrogen. Japanese larch promoted a growth rate in Sitka spruce greater than that achieved in the lodgepole pine-nursed spruce and equivalent to the two pure spruce treatments over the duration of the experiment (current age 28 yrs). Growth of regularly fertilized pure Sitka spruce was not significantly greater than that of periodically fertilized pure spruce. Alaskan lodgepole pine controlled branch size on the lower part of the spruce stems more effectively than the other treatments, although this may have been a function of tree size. Branch characteristics of Japanese larch-nursed spruce, however, were similar to those of the pure spruce treatments. Japanese larch caused an imbalance in crown development in the spruce, although it is unclear from the present study whether this will have an influence on stem and wood quality by the end of the rotation. Overall, the evidence from this study suggests that Japanese larch is an effective nurse of Sitka spruce on nitrogen-deficient iron pans, maintaining a rate of growth similar to that of pure Sitka spruce periodically fertilized with nitrogen and higher than that observed in spruce nursed by Alaskan lodgepole pine.     

Beziehungen zwischen der Ausbreitung künstlicher Fomes annosus-Infektionen in den Stämmchen zweier Fichtenklone und einigen holzchemischen Eigenschaften

The spread of Fomes annosus from artificial infections of stems, in relation to the chemical characteristics of timber of two spruce clones . Differences in the spread of Fomes annosus in two spruce clones (Picea abies Karst.), which were found by DIMITRI, may be attributed to differences in the properties of the wood from the two clones, detected in laboratory tests. Wood meal from the more resistant clone R inhibited Fomes annosus in bioassays more than wood meal from the more susceptible clone A. Wood from clne A-trees showed a higher nitrogen content than wood from clone R-trees.     

Silviculture of the Spruces in West Scotland

An account of the silviculture of Norway and Sitka spruce (Piceaabies and P. sitchensis) practiced in the West (Scotland) Conservancyof the Forestry Commission in the past 50 years. Present methodsare summarized and future developments forecast. A more intensiveform of silviculture is advocated for Sitka spruce.     

CONIFEROUS LITTER AMENDMENTS AND THE GROWTH OF SITKA SPRUCE

The growth of semi-checked Sitka spruce (Picea sitcbensis Carr.)on heathland has been stimulated to different degrees by theannual application of litter of Scots pine (Pinus sylvestrisL.), Corsican pine (P. nigra var. calabrica Schneid), Lodgepolepine (P. contorta Dougl.), Japanese larch (Larix leptolepisGord.), and Sitka spruce, at rates corresponding to normal plantationconditions, following an initial heavier rate. Foliar analysissuggests that the response is at least partially attributableto the influence of the litters on the nitrogen nutrition ofthe spruce and differences between litters appear to be largelydetermined by their total nitrogen contents. In this respect,Japanese larch, with an annual needle fall generally greaterthan that of the pines and a higher nitrogen content, offersthe best promise as a nurse species for spruce.     

An Experiment to Control Fomes annosus in Second Rotation Pine Crops

Stump removal was found to singnificantly reduce killing byFomes annosus in second rotation crops of pine. Poisoning andgirdling of trees prior to felling and also stump poisoningfailed to control the disease. In this experiment no significantdifferences were detected in the susceptibility of Scots andCorsican pine to attack. Increasing periods of delay beforereplanting resulted in less mortality. An equation is presented,based on factors of the first rotation crop which may be usedto predict losses likely to occur when a site is replanted.Root attack by F. annosus results in reduced growth and yieldas well as mortality. The results from the experiment are discussed in trems of themangement of pine crops attacted by F. annosus in Theford Chase.     

Distribution and Spread of the Great European Spruce Bark Beetle, Dendroctonus micans, in Britain--1982 to 1989

The great European spruce bark beetle (Dendroctonus micans),which had for many years been seen as a potential threat toBritain's spruce plantations, was first discovered in Britainduring August 1982, breeding in Sitka spruce. Surveys in spruceplantations were initiated to determine the distribution ofthe beetle, a necessary background for development of controlstrategies. This paper reports the development and evolutionof survey techniques from 1982 to 1989, as well as the spreadof the D.micans populations during this time. Details of controlstrategies and legislation to contain the outbreak are alsogiven, along with conclusions concerning the natural dispersalof D.micans. Received 23 July 1990.     

Le champignon mycorrhizien Gomphidius glutinosus,un puissant antagoniste de Fomes annosus en culture pure

Gomphidius glutinosus a powerful antagonist of Fomes annosus in pure culture. F. annosus isolated from spruce was strongly inhibited by Gomphidius glutinosus found under Picea abies. In presence of the pathogen, Suillus placidus, a very probable mycorrhizal fungus of Pinus cembra and a moderate antagonist of F. annosus, produces a yellow reacting antibiotic substance.     

Distribution of the Green Spruce Needle Miner Epinotia nanana Treitschke (Lepidoptera: Tortricidae) within and between Trees at Redesdale, Northumberland

Differences were observed in the intensities of infestationof E. nanana on crops of Norway and Sitka spruce of differentages at Redesdale Forest, Northumberland. Attacks were moreserious in stands on northerly aspects. Norway spruce was moreintensely infested than was Sitka spruce, attacks being moresevere in older stands. Attacks occurred more frequently onsuppressed and subdominant trees. The intensity of infestationincreased progressively with increasing height of foliage upto 3.5 m above ground level. Attack occurred preferentiallyon current and 1-year-old needles. Continental experience withthis pest suggests that the risk of cumulative long-term damageis slight.     

Some Methods of Cold Storage can Seriously Affect Root Growth Potential and Root Moisture Content and Subsequent Forest Performance of Sitka Spruce and Douglas Fir Transplants

Sitka spruce and Douglas fir transplants were kept under threecold storage regimes: (1) bare-root in a humidified cold store(H); (2) sealed in polythene bags in a humidified cold store(HP); (3) sealed in polythene bags in a direct cold store (D).Regimes H and D are routinely used in current practice. Plants of both species had significantly (P < 0.001) lowerroot moisture content (RMC) in treatment H within 4 weeks ofstorage; this difference was maintained throughout the periodof storage and potentially damaging levels of RMC were reachedwithin 8 weeks. Sitka spruce had significantly (P < 0.001)higher root growth potential (RGP) than Douglas fir throughoutthe storage period. Differences in RGP between storage treatmentswere not significant until 12 weeks after storage when treatmentH was poorer (P < 0.05) than treatments HP and D. The survival of plants from treatment H after 1 year in thefield was significantly poorer (P < 0.001) than the othertreatments in both species. Height increment was also less intreatment H than the other treatments (P < 0.001) after 1year. However, this difference disappeared in the second season.After 1 year there were no differences in root collar diameter(RCD) increment between storage treatments but Douglas fir showedgreater increment (P < 0.001) than Sitka spruce. Rapid assessment of RMC in slightly over 48 h makes this a potentiallyuseful test of planting stock quality during and after coldstorage.     

Zum Vorkommen von Fomes annosus (Fr.) Karst. im Boden von Fichtenbeständen (Picea abies Karst.)1

Occurrence of Fomes annosus in the soil of spruce stands (Picea abies Karst) . In stands of spruce Fomes annosus was found to occur in a viable state in the litter and soil to a depth of 25 cm. Successful isolations were obtained from 153 samples out of a total of 216. In ca. 40% of the 153 samples Fomes annosus could be isolated from 9 mg of soil; in the remaining samples it was found either in 90 mg, 230 mg or in 900 mg. The results raise the possibility of direct infection of the roots of spruce by Fomes annosus from the soil.     

Timber Improvement: I. A Study of the Variation in Wood Characteristics in Young Sitka spruce

As part of a programme aimed at improving Sitka spruce timber(Picea sitchensis (Bong.) Carr.), a study has been made of thevariation in some wood characteristics of significance in affectingtechnological behaviour, and the effect on these characteristicswhen trees of outstanding form and vigour are selected. It wasfound that:

1. There is a similar pattern of within-tree variationin density,tracheid length, and grain inclination for bothselected andaverage, final crop trees.
2. There is a very appreciablevariation in these timber characteristicsbetween trees at comparableages, indicating the potential forimprovement by selection.
3. There is a reduction in density and some increase in graininclinationbut no difference in tracheid length in vigorouscompared withaverage-growth trees at comparable ages.
4. Thereis no evidence that selection for above average densityhasan adverse effect on tracheid length; it tends to favourtreeshaving a high minimum early wood density and, to a limitedextent,wood with narrow cells.

     

Tree-to tree variation on Picea abies in growth inhibition against Fomes annosus

The spread of Fomes annosus was measured on a set of 20 mature trees which were artificial inoculated. These observations were compared with growth observations and laccase activity of F. annosus grown on wood dust from the same 20 trees. Although variation between Fomes strains as well as between trees was recorded, correspondance between field and laboratory observations was absent in the present material.