Fichten-Mykorrhizen auf Standorten der Schwäbischen Alb und ihre Beziehung zum Befall durch Fomes annosus

Spruce mycorrhizac and heart rot incidence caused by Fomes annosus in southwestern Germany. Naturally occurring spruce mycorrhizac on calcareous soils of southwestern Germany were investigated and classified. These soils are characterized by a relatively high incidence of heart rot caused by Fomes annosus. On comparable sites stand history (former woodlands versus former sheep pastures), though influencing heart rot incidence, had no effect on the overall distribution of mycorrhizal types. The occurrence of rare types, however, varied between sites with different stand history. For all mycorrhizal types found, isolation of the fungal symbiont was attempted. Where isolation was successful, the isolates showed no antibiotic activity against Fomes annosus.     

Establishment of the Second Rotation in the Jutland Heath Plantations

The paper describes briefly the silvicultural methods used toregenerate stands of pure Norway spruce (Picea abies Karst.)or Norway spruce mixed with a small proportion of Silver fir(Abies alba Mill.) on the poor heath soils of Jutland. Regenerationafter clear felling, uniform shelterwood, and shelterwood stripfelling is described. The last method has advantages over theother two.     

Overstorey density influence on the height of Picea abies regeneration in northern Sweden

The study aimed specifically at investigating if canopy opennesswas a better predictor of the height growth of Norway spruce(Picea abies (L.) Karst.) advance regeneration than overstoreybasal area or overstorey standing volume. In 1990, a field experimentwith 3 x 2 factorial design and two replications (blocks) wasestablished in an uneven-aged Norway spruce forest. Plots hada net plot area of 30 x 30 m, each with a 10-m-wide treatedbuffer zone. Three overstorey density levels retained approximately15, 40 and 70 per cent of the pre-harvest overstorey standingvolume and were allotted to the plots. Two types of thinningthat harvested smaller trees or harvested larger trees wererandomly allocated to each pair of overstorey density plots.In mid-June 2000, canopy openness was estimated from hemisphericalphotographs taken at five marked points in the centre of eachof the plots at 0.9 m from ground to the top of the ‘fish-eye’camera lens. Regression results showed that canopy opennesswas a better predictor of height increments of spruce seedlings(0.1< height < 0.5 m), saplings (0.5 height < 2.0m), and small trees (height 2.0 m, diameter at 1.3 m height< 5 cm) than with overstorey basal area (m² ha^–1) oroverstorey standing volume (m³ ha^–1). The height incrementof the spruce advance regeneration was not significantly correlatedto stand basal area or to standing volume. Overstorey basalarea in the net plots was significantly negative (P 0.05) withmean canopy openness estimates, and the r² value was 0.40. Resultsindicated that basal area was not linearly related to canopyopenness as it increased, which might explain the lack of predictivepower of retained basal area on spruce regeneration height indense stands in boreal Sweden.     

THE IMPORTANCE OF SHELTER TO EARLY TREE GROWTH ON UPLAND MOORS

A comparison of the effects of differing methods of cultivationcarried out on typical Calluna moor in the Cleveland (Yorkshire)massif has revealed that single-furrow deep forestry ploughing,by reason of its pronounced plough-ridges, has advantages overother more shallow and complete deep methods of ploughing ingiving shelter from cold off-shore winds which cause die-back.Orientation of the plough-ridges transverse to the wind directionand the use of leeward ridge slopes as planting positions enhancesthis shelter effect. The paper ends by drawing attention tothe need for forest meteorological reasearch upon the wind-treegrowth relationship.     

Soil compaction by grazing livestock in silvopastures as evidenced by changes in soil physical properties

Livestock, pasture, and timber trees are intimately interrelated in silvopastures. Most silvopasture research to date has focused on forage/animal/tree interactions, with less attention paid to animal/soil interactions in silvopastures. While a considerable body of work has been devoted to understanding the effects of livestock trampling on plants and soils in pastures, less has been done for livestock grazing in forests, and even less is available for silvopastures. Three replications of Douglas-fir forest, Douglas-fir/subclover pasture/sheep silvopasture, and subclover/sheep pasture were established in 1989 near Corvallis, Oregon USA. Pastures and silvopastures were grazed each spring during 1990–2001. These plots were sampled in 2002, after 11 years of grazing, and again in 2004 following 2 years without grazing. Soil in the silvopastures had 13% higher bulk density and 7% lower total porosity than those in adjacent forests in 2002. Most of the difference in total porosity was air-filled pores. Average water infiltration rate was 38% less in silvopastures than in forests, however total water stored in the top 6 cm of soil at field capacity was similar. Soil bulk density, total porosity, and air-filled pore space was similar for forests, pastures, and silvopastures after 2 years without livestock grazing. The infiltration rate of silvopasture soils in 2004 had increased to be similar to those of forests in 2002, however, forest soil infiltration rates also increased and continued to be higher than those of silvopastures. Plant production was not sensitive to changes in any of the soil parameters measured. Although livestock grazing did change soil infiltration rates, soil bulk density, and soil porosity, the effects were quickly reversed following cessation of grazing and had little detrimental effect on silvopasture forage or tree production.     

Sheep vegetation management for controlling competing vegetation in young conifer plantations in the central interior of British Columbia,Canada

In British Columbia, sheep vegetation management (SVM) is a relatively new technique; thus, limited data are available for examining its benefits on conifer growth. We collected field data from young mixed-conifer plantations of lodgepole pine (Pinus contorta) and hybrid spruce (Picea glauca × P. engelmannii) in blocks which had been grazed in 2005 and 2006 as well as from ungrazed blocks. Our main objective was to determine if sheep grazing had a significant effect on the growth of hybrid spruce. We measured stem diameter at 15 cm height above the root collar (D15) and cumulative internodal length (IL). Cumulative IL was calculated from the node corresponding to the year 2002–2010 (positions 2–10). The height to diameter ratio (height to the base of the leader (position 10)/D15; HDR) was calculated to determine if seedlings prioritized growth in terms of height or diameter. There was no significant grazing treatment effect on D15 and HDR when compared to the control treatment; however IL was significantly affected after the second grazing treatment in 2006 (position 6) and became increasingly important with time (positions 7–10). Based on our results, we suggest that SVM could be an effective method for controlling competing vegetation and thus, increase annual tree growth for areas with similar site characteristics as those found within the plantations sampled.     

Norway or Sitka Spruce?

The deep and wide continental range and climate occupied bythe European species Picea abies is contrasted with the long,narrow, and humid coastal strip which the American species Piceasitchensis inhabits. Norway is the more plastic spruce and cansuffer thinner soils and much more drought, but neither spruceis a shallow rooter where soils are good and deep. Of the two,the litter of Sitka is less harmful to the soil. To date thereis no evidence that height for height Norway is more stableunder high wind pressures, but the belief that it is less sensitiveto frost than Sitka is well established. Sitka is far superiorto Norway for planting at high altitudes and in exposed placesand on Molinia peatlands in Britain, which accounts for thevast preponderance of the American species used in the westand north of the British Isles. The present popularity of Norwayspruce with foresters and timber merchants is admitted, butthe point is made that in planting it where Sitka could growwell, only some 75 per cent, of the volume will be secured.Finally, the types of site which each spruce requires and alsowhich each cannot take are considered in detail. A plea is madefor mixtures in certain circumstances, and the belief expoundedthat only deeper and better cultivation of the hardpacked materialunder-lying thin soils will make it possible to extend considerablyour acreage of really stable crops of these high-volume producers.     

The Incidence of Root-Surface Fungi on Naturally Regenerated Picea sitchensis Seedlings in Southeast Alaska

The root-surface fungi were examined from naturally regeneratedSitka spruce obtained from recently exposed glacial outwashand mature upland soils where spruce had grown alone and inmixture with alder. Roots from the poorest trees on least fertilesoil had a high incidence of Mortierella and few other fungibut as growth and soils improved the numbers and genera of otherfungi increased The same genera occurred on roots from glacialdrift and upland soils and were the same as those found on intensivelygrown seedlings from acid heathland soil at Wareham forest nurseryin Dorest, England.     

Sheep grazing in young oak Quercus spp. and ash Fraxinus excelsior plantations: vegetation control, seasonality and tree damage

An experiment was carried out where sheep were grazed in temporary fenced paddocks at a stocking rate of 178 LSU ha⁻¹ in a 5-year old broadleaf plantation of oak (Quercus spp.) and ash (Fraxinus excelsior) (1.5 m spacing) on fertile, former lowland pasture in Northern Ireland. The grazing regime was rotational and intensive, with two grazing periods of 5 days in February and October 2001. Results showed that a significant proportion of the rank herbage height was removed within the first 24 h of livestock introduction. Herbage biomass was reduced by approximately half after 5 days. Sward height in grazed plots remained significantly lower than control plots for over 6 months after cessation of grazing, whilst biomass remained significantly lower for over 4 months after cessation of grazing. No significant tree damage to either oak or ash was measured during the February grazing trial, however significant damage to the lateral branches of both oak and ash was observed in the October grazing trial. Leader damage did not occur on trees greater than 152 cm. Ash was more commonly browsed than oak. Annual height increment of both tree species was unaffected by grazing, but annual stem diameter increment was significantly reduced in both oak and ash in February grazed plots. Oak trees in both February and October grazed plots were found to have a significantly smaller annual increase in canopy diameter than those in control plots. Results are discussed with regard to practical implementation of controlled grazing in young broadleaf forestry plantations on fertile, lowland soils.     

The chemical composition of needle and leaf litter from Scots pine, Norway spruce and white birch in Scandinavian forests

Needle litter from 14 stands of Scots pine (Pinus silvestris,L.), 13 stands of Norway spruce (Picea abies (L.) Karst.) andleaf litter from three stands of white birch (Betula pubescensEhrh.) were analysed for chemical composition. The concentrationsof the elements N, P, K, Ca, Mg and Mn as well as solid organiccomponents (lignin, cellulose and hemicelluloses) and solubleswere determined. When the average chemical compositions werecompared the Scots pine needle litter was clearly the most nutrient-poorlitter type. Of the solid organic-chemical components the ligninfraction dominated in the spruce and birch litter whereas thecellulose dominated in the pine needle litter. When Norway spruce and Scots pine were growing in adjacent standson soils with the same bedrock origin the spruce litter hadsignificantly higher concentrations of nutrients (N, P, K, Ca,Mg, Mn) than the pine needle litter. At sites where Norway spruceand white birch were growing in adjacent stands, the birch leaflitter had generally higher concentrations of nutrients. However, significant or nearly significant differences were onlyobtained for Mg (P = 0.002), K (P = 0.056) and N (P = 0.087),probably due to the few replicates of stands compared. Concerningorganic chemical components, the spruce needle litter had significantlyhigher concentrations of lignin and mannan than all the otherlitters and lower levels of ethanol-soluble substances, celluloseand galactan than the pine needle litter. Further, it had lowerconcentrations of water solubles, rhamnan and xylan than thebirch litter. No relationships were established between the nutrient statusof the conifer litters and the site index H100 (the dominantheight of the trees at a reference age of 100 years) of thestands. Concentrations of solid carbohydrates in the litterswere, however, positively correlated with site index (P <0.001). Further, the concentration of nitrogen in the pine needlelitter was negatively correlated with the latitude of the sites(P < 0.01). The influence of litter chemistry on the decompositionof litter and nutrient cycling of forests is discussed.     

Carbon storage in forest soils

The amounts of carbon stored in soils and vegetation in Britain,and the potential of forestry to influence, whether soils actas sinks or sources, are discussed. Soils are estimated to containc.22 x 10⁹ t carbon, while the amount in vegetation includingforests is only 115 x 10⁶ t. Some 86 per cent of the soil carbonis present in peats and peaty-surfaced soils, mainly in north-westBritain. Soil carbon content is strongly related to climateand altitude. Conversion of lowland cultivated land to forestcan result in carbon accumulation in soils, as it can followingthe planting of some uplands, but quantities appear to be smallin relation to the amounts carbon released to the atmospherethrough fossil fuel use. Forest felling may result in decreasesin soil carbon store, due to soil disturbance and changes inmicroclimatic conditions, but several decades after reafforestationthe carbon store may recover to near original levels. Shorteningforest rotations may result in long-term declines in soil carbonstore. The main concern is the potential for forestry to convertpeats, which contain amounts of carbon equivalent to 100 years'fossil fuel use at 1988 levels and which are normally slow sinksfor atmospheric carbon, into carbon sources returning it tothe atmosphere. The possible impacts of forestry and globalwarming on rates of carbon loss from upland soils includingpeats are discussed.     

Ecology, history and silviculture of Scots pine (Pinus sylvestris L.) in western Norway - a literature review

Results from a literature review on pinewood ecology, silviculture,genetics, aspects of history and forest resources of Scots pine(Pinus sylvestris L.) in western Norway are presented. The pinewoodscover 40 per cent of the forested land, 0.31 million ha. Duringthe last 75 years, the area has increased by 17 per cent andthe growing stock has risen from 10 to 34 million m³. The impactof man in previous times was very marked, and has had a significantinfluence on the present forest conditions. The pronounced climaticgradients mixed with the topographic variation – fromthe coastal plains via the fjord systems to the high mountains– is reflected in rather steep gradients in the pine forestvegetation. Various floristic elements can be distinguished,from oceanic via the suboceanic in the outer islands to thethermophytic, boreonemoral and boreal elements in the innerfjord districts and valleys. The introduction of spruce (Piceaspp.) plantations on 10–15 per cent of former native pineforests has not negatively affected the bird fauna at the landscapescale. Although not particular species rich, the pine forestsharbour species usually not found in other forest types. Sofar, most work in the field of silviculture and forest ecologyin the pinewoods of West Norway has been in the form of casestudies. Implications of the results for forestry in the regionare briefly discussed.     

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.     

Sitka Spruce and Douglas fir Seedlings in the Nursery and in Cold Storage: Root Growth Potential, Carbohydrate Content, Dormancy, Frost Hardiness and Mitotic Index

Seedlings (transplants) of 2+1 Sitka spruce (Picea sitchensis(Bong.) Carr.) and 1 + 1 Douglas fir (Pseudotsuga menziesii(Mirb.) Franco) were grown in a nursery at the Bush Estate,Scotland. Batches were lifted and cold stored at 0.5°C inNovember, December and January. Changes in growth, shoot apicalmitotic index, root growth potential (RGP), carbohydrate content,bud dormancy and shoot frost hardiness were monitored throughoutthe winter by taking samples at intervals from the nursery andfrom cold storage. Frost hardening occurred during the later stages of bud development(as mitotic indices decreased); autumn hardening was arrestedwhen seedlings were put in cold store, and some dehardeningoccurred in cold storage, especially in spring. Bud dormancystarted, and was greatest, just after bud growth (mitotic activity)virtually ceased; chilling in cold store was almost as effectivein releasing dormancy as natural chilling. The concentrationof total nonstructural carbohydrates stayed more or less constantat 100–150mg g^–1 from September to April in thenursery; in cold storage carbohydrates were depleted at 0.4–0.6mgg^–1 d^–1 (corresponding to respiration at 0.03–0.05mgCO₂ g^–1 h^–1) until there was only 40–50mgg^–1. Root growth potentials in the nursery increased in December,once the buds ceased growth, became dormant and had receivedsome chilling. Sitka spruce was ‘storable’ in November,before RGPs increased, but they then failed to achieve maximalfrost hardiness or ROP. Winter RGPs were high in Sitka spruceand were increased or maintained in cold storage, whereas RGPswere low in Douglas fir and decreased immediately after storage(except when stored in January). By the end of April, the RGPof cold stored Sitka spruce was much higher than that of directlifted plants. ROP changes in the nursery and in cold storagewere not consistently related to changes in seedling carbohydratecontents, shoot frost hardiness or bud dormancy. In practical terms, it was concluded that (1) the optimum dateto start lifting bare- rooted conifer transplants in the autumnis when their shoot apical mitotic indices have decreased tonear zero, and their RGPs have risen sharply; (2) high RGPsmay depend as much on the morphology of the roots (e.g. numberof undamaged root apices) as on the physiology of the shoots(e.g. carbohydrate status, dormancy and frost hardiness); and(3) in spring, transplants kept in cold storage since November,December or January are more frost hardy, slightly more dormant,and (in May) have higher RGPs than transplants lifted from thenursery.     

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.     

Of forest,snow and lichen: Sámi reindeer herders’ knowledge of winter pastures in northern Sweden

Over the last few decades, the use of forests both by Sámi reindeer herders and for commercial forestry has been a source of increasing conflict in northern Sweden. Forestry disturbs forest ecosystems and thus damages reindeer pastures, especially those rich in ground lichen, for which reindeer forage during the wintertime by digging through the snow. Despite increased communication between the two groups, the Sámi still feel that their interests are not adequately considered by the commercial forestry sector. This paper presents the results of an interdisciplinary study that comprised semi-directed interviews and participant observations. The objective was to understand the Sámi reindeer herders’ extensive ecological knowledge of winter forest pastures, and the characteristics they observe when managing this resource. The study also analysed specific terminology used by the Sámi herders, to describe, analyse and communicate these properties. These terms, as well as Sámi herder knowledge in general, emphasize the importance of snow cover for reindeer grazing in forest pastures, as well as the effects of forest structure and ground vegetation on variations in snow cover during the winter. Whereas the Western use of the word ‘pasture’ is often associated with a specific plant community, the Sámi herders’ understanding of the word also includes the effect of snow on grazing and for this they use a culturally specific word in their language: guohtun. This term conveys the additional notion of whether it is possible for reindeer to access the pasture under the snow. Sámi herder knowledge and know-how allow them to use the mosaic of forest ecosystems to accommodate variability in snow cover during the wintertime, using different forest areas in response to different grazing conditions. Finally, the authors argue that, in order to promote the balanced, multiple use of boreal forest ecosystems, it is necessary to acknowledge and understand Sámi reindeer herders knowledge and thus to fully integrate their needs and aspirations.     

THE GROWTH OF SITKA SPRUCE ON SHALLOW SOILS IN RELATION TO ROOT-DISEASE AND WIND-THROW

The paper considers in detail the evidence from the examinationof some Sitka spruce (Picea sitcbensis Carr.) 35 to 50 yearsold, and old enough therefore to begin to reflect the potentialitiesof the sites occupied which are normally considered suitablefor the species. The examination was made to ascertain whatfactors other than parasitic infestations or infections wereacting to cause the thinning of crowns, the death of trees,and the susceptibility to wind-throw. In these shallow soils,factors of fundamental importance are those which determinethe regularity of the supply of water and air, and it is consideredthat where, as in the cases examined, the soils are mainly intractable,early development of disease and of wind-throw will have tobe expected.     

Cattle grazing and pine survival and growth in subterranean clover pasture

When combining pines and cattle on tame pasture, grazing is often delayed for several years until trees are large enough to resist injury. As an alternative approach to delayed or deferred grazing during the early years, this study in central Louisiana, USA, examined the effects of cattle grazing in subterranean clover (Trifolium subterraneum L.) pastures on slash (Pinus elliottii Engelm.) and loblolly pine (P. taeda L.) seeding survival and growth during the first 3 years of tree establishment. Pines were planted at about 1200 trees/ha in 3 rows on 0.4-ha subclover units with 1.3 m spacing within rows. Three grazing treatments included: (1) ungrazed pines, (2) limited grazing with a single-wire electric fence above the planted pines, and (3) grazed pines. Thirty Brahman crossbred cows with calves and a bull grazed the tame pasture on a controlled grazing, rotational basis from December through May each year, during the subterranean clover growing season. Pine trampling injury during the year was 8% on the grazed seedlings while essentially none occured under limited grazing. During the first 2 growing seasons, survival and height of the pines were significantly less on the grazed seedlings than on either the limited grazing or ungrazed seedlings. Pine heights from the limited grazing and ungrazed treatments were not different during the 3-year study; loblolly pine heights from the limited grazing treatment continued to be taller than the grazed treatment through the third year while the slash pine heights were similar for all treatments by the third year. Seedling mortality became more acute as severity of grazing injury increased; the greatest mortality occured when the terminal bud and needles were both browsed off.     

Some Phenomena Associated with Pruning

Drastic early pruning on young Norway spruce (Picea abies Karst.)on poor soils in Central Jutland resulted in an improvementin the colour of the needles and an increase in their nutrientcontent lasting, however, only a few months. Thereafter therewas a decrease in N and a return to the previous bad colourof the needles. The author offers an explanation for these changesand considers its bearing on any attempt to assess the contributionmade to stem increment by different branch whorls. He pointsout that the results of pruning may vary considerably accordingto whether single trees are pruned or all the trees in the plotare pruned.