New observation of cone flies attacking cones ofPicea obovata andLarix sibirica in central Siberia

Two species of cone flies (Strobilomyia anthracina andS. svenssoni) emerged from puparia were collected under Siberian spruce (Picea obovata) trees in the central part of the Krasnoyarsk region, central Siberia. Parasites of the Figitidae and Braconidae families emerged from 28.1% of the puparia, and fungal and bacterial diseases destroyed 24.8% of the puparia. Weight and length of the puparia depended on the sanitary status. Two types of cone fly eggs were observed on spruce cones. At least three species ofStrobilomyia (S. Infrequens, S. laricicola, and S. sibirica) attacked cones of Siberian larch (Larix sibirica) in central Siberia. (Responsible editor: Zhu Hong)     

NEWCONE AND SEED PESTS COLLECTED IN NORTHEASTERN CHINA BARBARA FULGENS KUZNETSOV (LEPIDOPTERA:TORTRICIDAE) THE LUSTROUS SPRUCE CONE MOTH

Arecentsurveyofconeandseedinsectsoccuringinsomeconiferforests'ofHeilongiiangandInnerMongoliaprovinces.gaveustheopportunitytocol1ectseveralspeciespreviouslyunknownfromChina(Fangetal.,1988).ThispaperisthefirstofaseriesprovidinginfOrmationgathereduponthemorphologicalcharacteristics,biologicalcycleanddamagecorrespondingtothesespeciesinNortheasternChina.Thelustrousspruceconemoth,BarbarafulgensKuznetsov,wasprevious-lyrecordedfromthesingleFarEastSovietUnion(intheKhabarovskarea),yetclosetoHeilon…     

New observation of cone flies attacking cones of Picea obovata andLarix sibirica in central Siberia

lntroductionConeniesofgenusStfObilOmwiMichelsen(=LasiOmmaSteinAuct-partim=ChorthOPhil8Macquart=HtwiaRobineau-Desvoidy,DiPtera:Anthomyiidae)arewidespreadpestsdamagingconesandseedsofconifers(Roquesetal1996)-SpeciesofthisapparentIymonophyleticgenusoccurmainlyintheborealandMontanapartsoftheHoIartic,wherelarvaIinstarsdevelopexclusivelyintheconesofvariousgroupsofPinaceaeexceptthepinespecies(Michelsen,1988).AtotalOf19SbobiIOmyisspecieswereidentified(TUrgeonetal1994;Roquesetal1996),moStof…     

EFFECTIVENESS OF ACEPHATE IMPLANTS IN PROTECTING CONES FROM INSECT DAMAGE IN SOME CONIFERFORESTS OF NORTHEASTERN CHINA

lNTRoDUCTloNInChina,onlyafewexperimentshavebeenperfbrmedtotestinsecticidessusceptibletopreventconesandseedsfrominsectdamage(Anonymousl986,GaoBuquetal.l99l,YueShukuil992,LiuYikong1993).Moreover,thesetestsonlyconsistedofsprayingchemi-cals,thatmayinduceharInfulconsequencesuponenvironment.TheintensifiedeffoftofafforestationinNortleasternChinarecentlyrequiredtoestablishlnyenumbersofseedorchards,aswellasparent-trCestands,inordertoprovideforesterswithhigh-qualityseeds,especiallyinlarch.Thispr…     

Cone traits of jack pine and black spruce in young seedling seed orchards

The number of fertile and infertile scales, filled and empty seeds, cone volume, seed efficiency and the incidence of insect and disease damage to seed were evaluated for seven jack pine (Pinus banksiana Lamb) and six black spruce (Picea mariana [Mill.] B.S.P.) seedling seed orchards in northern Ontario, Canada. On average, the seed potential of jack pine and black spruce cones was 50 and 82 seeds, respectively. Cone volume and the number of fertile scales were under strong genetic control and well correlated with one another for both species. Seed efficiency values were high for jack pine (60%) but poor for black spruce (24%). The incidence of seed insect damage was less than 2.5% for both species and nil for seed diseases.     

Chrysomyxa ledi,a new rust fungus sporulating in cone scales of Picea abies in Finland

Abstract

Seasonal fruiting and sporulation of cone rusts were investigated in Norway spruce cones during the growing season of 2007, a year after an excellent cone crop and a severe outbreak of rust. Current-year and 1-year-old cones were collected bimonthly to monthly from case-stands in southern and northern Finland and checked for rust fruitbodies. A previously unreported species of rust formed spermogonia and aecia, and sporulated on the cone scales of Norway spruce in two study areas. Morphologically, the rust was distinct from other spruce cone rusts and, based on ultrastructure of aecia and aeciospores, most closely resembled Chrysomyxa ledi. Molecular analysis of the aeciospores confirmed that the rust belonged to the C. ledi/C. rhododendri complex. The rust fruited frequently but only colonized a few scales per cone and presumably had a minor effect on cone development and seed crop.     

Biogeographic differences in cone, needle and seed morphology among natural Picea asperata populations in Western China

This study represents a geographical approach to morphological variation of cones, needles and seeds in natural dragon spruce (Picea asperata Mast.) populations across western China and the relationship between morphological traits and weather variation for the origins of populations. Significant differences were found for all cone, needle and seed traits among populations and trees within populations. The coefficients of variation in 2 higher latitude populations were higher than those in other populations in all traits except for needle width and seed width. Fairly high within-population variability was also detected for cone dry weight, seed dry weight and needle traits in this study. Cone length, cone width, cone dry weight, seed scale length, seed scale width and seed wing length were strongly positively intercorrelated. Seed length and seed dry weight showed a significantly positive correlation with seed wing length. And needle width showed a significant negative correlation with cone traits, seed scale length, seed wing length and seed length. The higher the annual mean temperature, the higher the average cone length. This study also revealed a negative linear dependence on latitude: the higher the latitude, the lower the population average seed length. Seed dry weight was positively and linearly related with altitude.     

Prevalence and incidence of the root-inhabiting fungi, Fusarium, Cylindrocarpon and Pythium, on container-grown Douglas-fir and spruce seedlings in British Columbia

Surveys were made at the end of the 1990 and 1991 growing seasons for root-inhabiting fungi in the genera Fusarium, Cylindrocarpon and Pythium from the roots of one year-old container-grown Douglas-fir and spruce seedlings grown under greenhouse conditions. In the 1990 survey of four nurseries, it was found that 61–97% of both Douglas-fir and spruce roots were colonized with Fusarium, Cylindrocarpon or Pythium. There were significantly (p0.05) more Douglas-fir roots than spruce roots colonized by Fusarium at all nurseries, however, there were significantly (p0.05) more spruce roots than Douglas-fir roots colonized by Cylindrocarpon and Pythium. Root colonization of Douglas-fir and spruce by the three fungal genera during 1991 varied from 0–82% at three nurseries, however, only at a south coastal nursery was there significantly (p0.05) more spruce than Douglas-fir roots colonized by Cylindrocarpon. Significantly more seedlings were infected in 1990 than in 1991. In 1991, there were few significant differences between Douglas-fir and spruce, in the percentage of seedlings with colonized roots and in the percentage of growth medium colonized by the fungi. However, there were significant differences between nurseries.     

Annual and spatial variation in coning shown by the Forest Condition Monitoring programme data for Norway spruce, Sitka spruce and Scots pine in Britain

Conifer seed is a valuable forest resource; as well as beingreproductive material, it is an important foodstuff for manywoodland species. Information on cone and therefore seed productionof the main forest species are useful in the fields of bothforest management and forest ecology. Coning has been recordedsince 1989 in plots of Norway spruce, Sitka spruce and Scotspine across Britain as part of the Forestry Commission's ForestCondition Monitoring programme. An 11-year period of these recordswas analysed and a summary of annual cone production by speciesand coning synchrony is presented. Both Norway spruce and Sitkaspruce coned sporadically, with a 4-year period between mastcrops during which cone density was very low or cone productionabsent, whereas Scots pine produced a good cone crop in mostyears throughout Britain. Coning was synchronous within andbetween Norway and Sitka spruce across the whole of Britain(at distances >600 km) but coning within Scots pine was insynchrony only over distances of up to 200 km. Synchrony ofcone production was not evident between the spruce species andScots pine. These findings have implications when planning andinterpreting monitoring used to predict cone crops and in thedesign of forests for wildlife conservation.     

Further description ofStrobilomyia melaniola (Fan) (Diptera: Anthomyiidae)

In a recent paper, V. Michelsen(1988, Systematic Entomology 13: 271–314) revised 18 world species of anthomyiid cone and seed pests and described a new genus,Strobilomyia gen. n. He consideredS. melaniola of Northeast China to be a synonym ofS. viaria of North America. That they are the same species is not accepted. We compared the morphological characters of male and femaleS. melaniola adults with the close relatives,S. viaria andS. sibirica. We conclude that they are not the same species and that S.melaniola is an independent species.     

The importance of seedling competition in the segregation of spruce and fir in the southern Appalachians

Fraser fir (Abies fraseri [Pursh] Poir.) and red spruce (Picea rubens Sarg.) are codominants of southern Appalachian spruce-fir forests. Fraser fir generally dominates above 1740 m, while red spruce usually dominates below this elevation. This study was designed to determine whether the present segregation of the two species along elevational gradients is associated with seedling competition or contrasting physiological responses to environmental factors. Seedlings were grown for two years in a replacement series experiment along two elevational transects extending from 1300 m to 1900 m, and harvested for growth analysis.Competition increased with decreasing elevation and Fraser fir was apparently the stronger competitor. Mortality was inversely correlated with elevation and was most evident in red spruce in May, and in fir in late summer. Fir growth increased with elevation and red spruce grew most at the middle elevation (1600 m). Neither competitive interactions nor growth responses completely explained the elevational segregation of red spruce and Fraser fir. We hypothesize that the early-successional Fraser fir quickly dominates at higher elevations following disturbance and that continued disturbance will favor its dominance at higher elevations. However, the late-successional noncompetitive red spruce slowly establishes itself and, while consistently present, may only dominate in the absence of disturbance and where other species are at the margins of their distribution.     

Influence of slope position, stand type and rhododendron (Rhododendron ponticum) on litter decomposition rates of Oriental beech (Fagus orientalis Lipsky.) and spruce [Picea orientalis (L.) Link]

Oriental beech (Fagus orientalis Lipsky.) and Oriental spruce [Picea orientalis (L.) Link] are the two most common tree species in northeast Turkey. Their distribution, stand type and understorey species are known to be influenced by topographical landforms. However, little information is available as to how these changes affect litter decomposition rates of these two species. Here, we investigated the effects of slope positions (top 1,800 m, middle 1,500 m and bottom 1,200 m), stand type (pure and mixed stands) and purple-flowered rhododendron (Rhododendron ponticum) on litter decomposition rates of Oriental beech and spruce for 4 years using the litterbag technique in the field. Among these three factors, stand type had the strongest influence on litter decomposition (P < 0.001, F = 58.8), followed by rhododendron (P < 0.001, F = 46.8) and slope position (P < 0.05, F = 11.6). Litter decomposition was highest under mixed beech/spruce forest, followed by pure beech and spruce forest. Beech and spruce litter decomposed much faster in mixed bags (beech–spruce) than they did separately under each stand type. Purple-flowered rhododendron significantly reduced litter decomposition of Oriental beech and spruce. Beech and spruce litter decomposed much slower at top slope position than at either bottom or middle position. Differential litter decomposition of Oriental beech and spruce was mainly due to adverse conditions in spruce forest and the presence of rhododendron on the ground which was associated with lower soil pH. Higher elevations (top slope position) slowed down litter decomposition by changing environmental conditions, most probably by decreasing temperature as also other factors are different (pH, precipitation) and no detailed investigations were made to differentiate these factors. The adverse conditions for litter decomposition in spruce forest can be effectively counteracted by admixture of beech to spruce monoculture and by using the clear-cutting method for controlling rhododendron.     

Effects of overstory retention and site preparation on growth of planted white spruce seedlings in deciduous and coniferous dominated boreal plains mixedwoods

Survival and growth of planted white spruce was assessed under partial harvest treatments and different site preparation techniques in mixedwood forests of two compositions prior to logging: deciduous dominated (d-dom) – primarily comprised of mature trembling aspen (Populus tremuloides Michx.) and coniferous dominated (c-dom) – primarily comprised of mature white spruce (Picea glauca (Moench) Voss). Levels of overstory retention were 0% (clearcut), 50% and 75% of original basal area, and site preparation techniques were inverted mounding, high speed mixing, scalping and control (no treatment). The survival and growth of white spruce were assessed seven years after planting. The experiment was established as a part of the Ecosystem Management Emulating Natural Disturbance (EMEND) experiment located in northern Alberta, Canada. In the c-dom, the 50% and 75% retention of overstory resulted in reduced growth and survival of white spruce seedlings compared to clearcuts. In contrast, in the d-dom, the seedlings performed best in sites that had 50% of the overstory retained. For the c-dom, the mounding and mixing treatments yielded the best growth of spruce seedlings, while scalping yielded the worst. In the d-dom, spruce growth was highest in sites with the mixing treatment. In the d-dom, growth and survival of the planted spruce was greater than in the c-dom. The natural regeneration of deciduous trees was suppressed by the retention of canopy regardless of original composition.     

Regeneration niches of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> [L.] Karst.) saplings in small canopy gaps in mixed mountain forests of the Bavarian Limestone Alps

Natural regeneration measurements are the main silvicultural objective in overaged protective forests of the Bavarian Limestone Alps. While manifold problems with these stands, especially the impact of browsing, are widely recognised, the regeneration niches of Norway spruce (Picea abies [L.] Karst.) are insufficiently known. The purpose of this study was to determine favourable combinations of site factors for the development of spruce in small, unfenced canopy gaps, located on Aposerido-Fagetum caricetosum albae forest sites. We recorded the occurrence of spruce saplings (as dependent variable) and of six site factors (as independent variables) on 480 0.5 m²-subplots. In addition, we estimated the coverage of six acid adapted plant species to determine correlations with the humus depth. A binary logistic regression analysis was used to predict the probability of the occurrence of a spruce sapling in dependency of the different site factors. Supported by other studies, we assumed that the supply of solar radiation was adequate for the sufficient regeneration of spruce within the canopy gaps. Other site factors significantly determined the regeneration niches of spruce saplings. More spruce saplings were found near hindrances and on rough surfaces than would be expected from a random occurrence of saplings. These microsite types may have characteristics, especially protection against snow gliding that promotes spruce establishment. A calculated “hindrance index”, which accounted for the number, and the distance of surrounding hindrances might be a good specific value to describe the influence of hindrances on steep slopes. The sapling establishment decreased on thin humus layers. Our assumption for the sites was that thick organic layers might represent a good seedbed for spruce. Decayed dead wood was scarce, but was exceedingly favoured by spruce saplings. Results obtained suggest that the natural regeneration establishment of spruce on steep slopes can be successfully influenced by site factors which inhibit the influence of snow gliding. According to a “positive microsite” concept, we recommend for artificial regeneration measurements with spruce, microsites close to hindrances (e.g. stumps, downed trees) and Vaccinium myrtillus as a predictor for thick, acid humus layers.     

The effects of Douglas-fir on tree-specific arthropod communities in mixed species stands with European beech and Norway spruce

The ecological effects of planting exotic Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] in Central Europe are still poorly understood. The aim of this study was to answer the question of whether Douglas-fir affects tree specific arthropod communities in different mature forest types (Douglas-fir, spruce and beech dominated) in Southern Germany. Therefore, arthropod communities of stem and tree crown strata of Douglas-fir and spruce (Picea abies L.) were sampled in the years 1999–2001 using arboreal photo-eclectors and flight interception traps. Statistical analysis was conducted for all species and focused on conifer specialists at three levels: (1) species diversity, (2) guild structure and (3) community structure. Within the stem stratum, species diversity was significantly higher on spruce than on Douglas-fir independent of year and stand composition. This could not be explained by a single feeding guild, rather by species changing strata during the vegetation period. In contrast, species diversity in tree crowns was approximately the same for both conifer species. However, communities in Douglas-fir crowns were conspicuously different from those in spruce crowns, especially in the Douglas-fir dominated stand type. While zoophagous insects exhibited higher activity on Douglas-fir in 2000, xylophagous beetles were more abundant on spruce in 2001. In European beech stands with widely spaced Douglas-fir trees, the site specific and broad-leaved tree related fauna might be maintained. In addition, Douglas-fir with its resource of Adelges cooleyi and crowns that overtop the broad-leaved tree canopy, offer additional resources for several aphidophagous and thermophile species.     

Regeneration growth in different light environments of mixed species, multiaged, mountainous forests of Romania

Growth of regenerating trees in different light environments was studied for the mountainous, mixed-species forests in the Carpathian Mountains of Romania. The primary species in these mixtures were silver fir (Abies alba Mill.), European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst). Seedlings/saplings of these species were selected and measured in different stands from two different geographical locations. Regenerating trees were measured for height and diameter growth during the summer of 2002. For each seedling/sapling, percentage of above canopy light (PACL) and stand basal area (BA) were used to assess available and occupied growing space respectively. Regeneration growth was compared against these two variables and regression relationships were developed. Using these models, we predicted the dynamics of regeneration as both growth and species composition. Our results showed that in low-light environments (PACL<20–35%; BA>30 m²/ha), shade tolerant fir and beech clearly outcompeted the spruce. Therefore, in dense stands, spruce could be eliminated by the shade tolerant species. For intermediate levels of cover (PACL=35–70%; BA=15–35 m²/ha) the spruce grew at comparable rates as the beech and fir. All three species showed similar growth rates in open conditions (PACL>80–90%; BA<15–20 m²/ha) with the spruce having a tendency to outgrow the others. However, in terms of establishment, such conditions favor spruce and inhibit fir and beech.     

Seed production of western larch in seed-tree systems in the southern interior of British Columbia

A series of surveys and experiments were conducted on four sites to identify constraints to seed production and natural regeneration in western larch seed-tree systems in the southwestern interior of British Columbia, Canada. These surveys included pollen monitoring, a cone analysis to evaluate seed production potential, seed trapping to estimate seed rain and the installation of field germination trials to assess the effects of germination substrate and seed losses due to bird and rodent predators. Pollen shedding was found to be adequate for moderate seed production with filled seed counts ranging from 9 to 30 per cone (10–34% of all seeds/cone). No significant differences in seed yields per cone and cone characteristics were observed between uncut control stands and seed-tree stands. Seed rain was generally good in 1995, ranging from 70,000 to 4.6 million seed/ha. For the four seed-tree stands, the average filled seed percentage of the trapped seeds ranged from 9–30%. Seed rain and seed quality were much reduced in 1996. Field germination trials showed western larch seeds germinated and survived best (15–70%) on mineral soil but rodent and/or bird predation reduced germination success significantly. Germination/germinant survival on undisturbed forest floor, covered with predator exclusion screens, was intermediate.     

Impacts of fructification on biomass production and correlated genetic effects in Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> [L.] Karst.)

For the period 2003–2006, fructification of Norway spruce (Picea abies [L.] Karst.) was recorded at the Kranzberg forest site in Southern Germany by employing a crane with access to the canopy of more than 266 trees. For each tree, stem diameter and growth parameters were assessed annually as well as biomass of cones and seeds, number of seeds per cone, and proportions of empty seeds for a total of 371 trees with cone crop. Genotypes at 19 enzyme coding gene loci of 110 trees were included in the study of correlations between morphological and genetic traits. Re-scaling the observed values for a virtual pure Norway spruce stand of 1 ha, cone biomass including winged seeds (oven-dried at 38°C) varied between 706.8 kg/ha in 2006 (average value per tree was 3.6 kg) and values close to zero in 2005. Corresponding values for vegetative biomass increment of the coning trees in 2006 were 9,273.0 kg/ha and 10.8 kg/tree. A significant higher biomass investment was determined for dominant trees in terms of absolute cone mass as well as in terms of cone mass relative to vegetative biomass and fructification frequency. No trade-off effects in decreased vegetative biomass growth were found in the fructification year, compared to trees that did not grow cones. Although the dominant trees invested proportionally considerable biomass in cones, they showed no significant reduction in vegetative biomass growth. In the following year no decrease in vegetative growth was detected. Based on logistic regressions and homogeneity tests, respectively, significant genetic effect became evident with respect to the gene loci AAP-B and AAT-C concerning fructification probability in the year with maximum generative biomass investment. These and closely related loci also have been found to be indicative for growth and viability, respectively, in other species.     

Virulence of ophiostomatoid fungi associated with the spruce bark beetleIps typographus f.japonicus in Yezo spruce

Yezo spruce trees (Picea jezoensis), approximately 40-year-old were inoculated with eight ophiostomatoid fungi associated withIps typographus f.japonicus to compare relative virulence of the fungi. Among them,Ophistoma penicillatum formed the longest necrotic lesion on inner bark around inoculation points, followed byO. aenigmaticum, Ceratocystis polonica, andO. bicolor, whileC. polonica formed a larger dry zone in sapwood than the other fungi. Yezo spruce trees were also mass inoculated withC. polonica, O. penicillatum, O. piceae singly or mixed to demonstrate the ability of the fungi to kill Yezo spruce trees. The trees inoculated withC. polonica, O. penicillatum or the mixed inoculum showed discoloration of needles in the early summer of the next year and died by autumn. However, the trees inoculated withO. piceae or the control inocula did not die, except for one tree. These results indicated thatC. polonica andO. penicillatum were more virulent thanO. piceae and suggested that they might be at least partially responsible for the mortality of the beetle-infested Yezo spruce trees. Part of this study was supported by the Sumitomo Foundation, Japan to Y. Yamaoka and I. Takahashi. Part of this study was presented at the 107th meeting of the Japanese Forestry Society, April 1–4, 1996, Tsukuba, Ibaraki, at the 42nd annual meeting of the Mycological Society of Japan, May 16–17, 1998, Kyoto, and at the 110th meeting of the Japanese Forestry Society, April 2–5, 1999, Matsuyama, Ehime. Contribution No. 143, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

Pronounced fluctuations of spruce bark beetle (Scolytinae: Ips typographus) populations do not invoke genetic differentiation

The dynamics of a recent outbreak of the spruce bark beetle (Ips typographus) in Switzerland was ruled by a devastating winter storm in 1999 and the drought and heat of the summer 2003. Starting from a similar level of population sizes, estimated as the rate of infested growing stock, beetle populations increased differently in magnitude and time among different regions in Switzerland. Accordingly, we expected local or regional genetic differentiation as a result of such repeated population expansion/breakdown dynamics. We analyzed 5 nuclear microsatellites of spruce bark beetles sampled from pheromone traps at 30 locations distributed over Switzerland. Our genetic results did not indicate any sign of population differentiation, structure, isolation by distance, or recent bottlenecks. This complete lack of genetic structure suggests that spruce bark beetles are highly mobile, precluding the formation of a spatial structure at neutral molecular markers. Thus, this molecular–genetic approach does not allow us to discriminate among regional gene pools and to identify the origin of expanding beetle populations.