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.     

The Effects of Clear Polythene Cloches on Conifer Seedling Growth and Shoot Morphology

Nursery seedbeds sown with lodgepole pine, Scots pine, Douglasfir, Japanese larch and Sitka spruce were covered with clearpolythene cloches for 0, 8, 13 or 18 weeks from sowing. Sitkaspruce germinated poorly and was not studied further. In bothpine species longer durations of cloche cover increased thenumber and length of stem units resulting in taller 1 + 0 seedlings.The number of internodes held at the apex for elongation inthe second season was also increased but transplant shock preventedfull expression of this potential such that differences betweenthe treatments were reduced. Only when covered for 18 weeksdid Douglas fir and Japanese larch produce 1 + 0 seedlings whichwere taller than the uncovered treatments. Through the productionof ‘summer shoots’ in their second season Douglasfir and Japanese larch were able to compensate partially forthe reduction in ‘spring shoot’ length caused bytransplanting.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Comparative susceptibility of pine,spruce and larch to sapstain

Summary This study compared the susceptibility of five UK‐grown conifer species to colonization by sapstain fungi in two trials carried out in consecutive years. The conifers consisted of Sitka spruce (Picea sitchensis), Japanese larch (Larix kaempferi), Norway spruce (Picea abies), Scots pine (Pinus sylvestris) and lodgepole pine (Pinus contorta). Freshly cut 1‐m logs were exposed to the available inoculum of sapstain fungi from April to August in a woodland environment in the south east of England. Logs of each species were removed after 1‐, 2‐ and 4‐month exposure and sampled destructively to assess the amount of sapstain. In the second trial, per cent moisture content and concentrations of nitrogen, carbohydrate and phenolic compounds in the sapwood were also measured at the start and end of the trial. After 2 months, only the sapwood of both pine species had significant levels of sapstain; mean values of 37% and 19% for lodgepole pine (year 1 and year 2 respectively) and 12% and 1% for Scots pine. After 4 months, the levels of sapstain in both pine species exceeded 60% in both years. By contrast, very little sapstain developed in the other conifer species with maximum mean values of 10% for Norway spruce, 3.5% for larch and less than 1% for Sitka spruce. Overall, the moisture content of the logs decreased progressively in all species over the length of the trial. However, pine logs tended to retain higher levels of moisture throughout the trial compared with spruce or larch. The relatively higher moisture content of pine sapwood may be closer to the optimal moisture content that sapstain fungi require for infection and colonization, thereby contributing to the increased susceptibility of pine compared with the other conifer species. The pine logs also suffered from some colonization by bark beetles (Ips sexdentatus), which increased the inoculum potential and the opportunity for colonization by sapstain fungi. In addition, particular phenolic compounds in conifer sapwood may play a role in determining the resistance of some species to sapstain. Notably the most resistant species, Sitka spruce, was the only softwood that still retained detectable levels of phenolics in the sapwood to the end of the trial.     

Grass and legume seeding on a scarified coastal alluvial site in northwestern British Columbia: response of native non-crop vegetation and planted Sitka spruce (Picea sitchensis (Bong.) Carr.) seedlings

The success of various grass-legume mixtures in controlling competing vegetation, and their effect on subsequent survival and growth of Sitka spruce seedlings was studied on a coastal alluvial site in northwestern British Columbia. Mechanically scarified (bladed) strips were hand seeded to pure and combined mixtures of legumes, bunchgrasses, and sodforming grasses. An unseeded control (bladed but not seeded) was also established.Alsike clover (Trifolium hybridum L.) was the most successful legume species. Orchardgrass (Dactylis glomerata L.), big bluegrass (Poa ampla Merr.), and creeping red fescue (Festuca rubra L.) were the most successful grass species. Red alder (Alnus rubra Bong.) density and height were lower in legume-seeded treatments. Red elderberry (Sambucus racemosa L.) and salmonberry (Rubus spectabilis Pursh.) were effectively reduced by blading and have reestablished slowly. A combination of blading and early establishment of either sodforming grasses or bunchgrasses effectively decreased reinvasion by thimbleberry (Rubus parviflorus Nutt.).Growth of Sitka spruce was best in the unseeded control treatment or in the treatments with legumes but no sodforming grasses. Presence of sodforming grasses decreased both diameter and height growth. Sitka spruce diameter decreased with increasing red alder density. After 5 growing seasons, spruce has outgrown all competitors except red alder.     

Movement of Injected Dyes in Gymnosperm Stems in Relation to Tracheid Alignment

The path of upward movement of acid fuchsin dye was traced inpole-size stems of Japanese larch (Larix leptolepis Murr.),European larch (Larix decidua Mill.), Lawson cypress (Chamaecyparislawsoniana (A. Murr. Parl.)), Sitka spruce (Picea sitchensis(Bong. Carr.)), Norway spruce (Picea abies (L.) Karst.), andScots pine (Pinus sylvestris L.). In all of these species amarked, preponderantly clockwise spiral pattern of dye ascentwas observed. In general the upward movement of the dye followedtracheid alignment, except at the sapwood-heartwood boundary.The characteristic patterns of dye movement indicated that spiralgrain was much commoner than was straight grain among the pole-sizegymnosperms investigated. Large differences in spiral grainwere found among species, among trees within species, in differentannual rings within trees, and at different stem heights. Patternsof dye uptake were influenced somewhat by the method of injection.Dye injections through tubes driven into the stem were foundmore suitable for determining tracheid arrangement than wereinjections through individual roots immersed in dye. Factorsinfluencing spiral grain development and applications of thedye injection technique to spiral grain determination are discussed.     

Mycorrhizal and associated fungi of Sitka spruce in Irish forest mixed stands

Identity of mycorrhizas and isolation of symbionts and associated fungi from Sitka spruce growing in pure and mixed stands with either Japanese larch or Lodgepole pine are described and compared. More mycorrhizal types and sporocarps of the Agaricales were collected from mixed stands. Mycorrhizas of Lactarius rufus, Paxillus involutus and Suillus spp. were more prevalent on roots from mixed stands. The most common unidentified mycorrhizal type (type B) had features similar to synthesized mycorrhizas of two Basidiomycete isolates. Suillus grevillei and three un-identified types were associated specifically with Japanese larch. The main associating fungi were Oidiodendron sp. and Mycelium radicis atrovirens. The association of a “nurse” tree with Sitka spruce provides a more diverse mycorrhizal flora, the majority of which are shared between the tree species.     

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.     

Multiplex real-time PCR detection of pathogen colonization in the bark and wood of Picea sitchensis clones differing in resistance to Heterobasidion annosum

A quantitative multiplex real-time polymerase chain reaction (PCR) procedure was developed to assess the extent of Heterobasidion annosum (Fr.) Bref. growth in Sitka spruce (Picea sitchensis (Bong.) Carr.) bark and wood and to determine correlations between lesion length and fungal colonization. Based on lesion length and real-time PCR, the responses of four 3-year-old Sitka spruce clones to inoculation with H. annosum were characterized as showing either resistance or susceptibility to the pathogen. In susceptible clones, the extent of bark colonization did not differ from the visible length of the bark lesion, whereas lesions were longer than the extent of fungal colonization in resistant clones. The resistant clones contained considerably less fungal DNA than the susceptible clones, relative to the amount of host DNA in both the bark and the wood, indicating less resistance and more host cell death in the susceptible clones following inoculation. In both resistant and susceptible clones, fungal colonization in the wood extended beyond the visible necrotic lesion in the bark, indicating that host defense responses are weaker in wood than in bark. The spread of the pathogen in both bark and wood was less in the resistant clones than in the susceptible clones, indicating that defenses in both bark and wood of the resistant clones were superior to those in the susceptible clones.     

Interception of precipitation by pole-stage Sitka spruce and lodgepole pine and mature Sitka spruce at Kielder Forest, Northumberland

Interception loss was measured indirectly for 3 years in adjacentunthinned 25-year-old stands of Sitka spruce and lodgepole pineand for 2 years in a 63-year-old selectively thinned stand ofSitka spruce. For each stand measurements were made of grossprecipitation, throughfall and stemflow. Interception loss wasderived by subtracting the sum of throughfall and stemflow (netprecipitation) from gross precipitation. For the years 1977–78, 1978–79 and 1979–80,interception losses in the pole-stage Sitka spruce were 32,28 and 27 per cent of gross precipitation respectively whilethose in the lodgepole pine were 33, 29 and 26 per cent. For1979–80 and 1980–81 interception losses in the matureSitka spruce were 44 and 53 per cent of gross precipitation.The average interception loss was 29 per cent for both pole-stagecrops and 49 per cent for mature Sitka spruce. The proportions of net precipitation reaching the ground asstemflow and throughfall were 0.18 and 0.82 respectively forthe pole-stage Sitka spruce, 0.14 and 0.86 for the pole-stagelodepole pine and 0.02 and 0.98 for the mature Sitka spruce.     

Blight of conifer seedlings caused by Colletotrichum gloeosporioides

In a growth chamber experiment, 70-day-old seedlings of 10 conifer species were inoculated with Colletotrichum gloeosporioides conidia to determine the host range of the fungus. Based on the percentage of seedlings affected and the disease severity on individual seedlings, the order of most to least susceptibility was: western hemlock (WH), mountain hemlock, western larch, Sitka spruce, Engelmann spruce, Douglas-fir (coastal form, then interior form), white spruce and ponderosa pine; lodgepole pine and western red cedar remained unaffected. Inoculation of WH needles showed that within 24 h C. gloeosporioides conidia germinate and appressoria (penetration structures) form. A growth chamber study demonstrated that the pathogen can infect WH at needle wetness periods as short as 15 min; number of needles affected was higher at 0.5 h, but did not increase further even when wetness was extended up to 8 h. The results are discussed in relation to blight management of greenhouse-grown conifer seedlings.Portion of a Bachelor of Science (Honors) thesis, Department of Biology, University of Victoria, Victoria, British Columbia.     

Growth in supplementarily planted Picea abies regenerations

Abstract

An experiment was established in 1978 in two Norway spruce [Picea abies (L.) Karst.] plantations in southern Sweden to study yield after mortality in patches with and without supplementarily planted (SP) seedlings. Gaps of different sizes were created by removing the originally planted seedlings. The gaps were either left unplanted or a supplementary planting was performed with one of four species [Norway spruce, Scots pine (Pinus sylvestris L.), lodgepole pine (Pinus contorta Dougl.) or hybrid larch (Larix deciduas Mill×L. Leptolepis Gord.)] 2 (at Knäred) or 6 years (at Ullasjö) after the original plantation. In 2002, most of the SP Scots pine, lodgepole pine and hybrid larch seedlings were dead or severely damaged by roe deer and moose. Survival was high among SP Norway spruces, but they had slower growth than the originally planted spruces. Growth was lower at Ullasjö than at Knäred. In Ullasjö, growth was lower in small gaps than in large gaps. Trees in original regeneration in areas surrounding unplanted gaps were larger than trees surrounding gaps with SP seedlings, which in turn were larger than originally planted trees in plots without gaps. In conclusion, because the original plantation surrounding unplanted gaps used a large part of the open space and growth of SP seedlings was slow, supplementary planting resulted in an insignificant growth increase. However, supplementary planting may increase the timber quality of trees surrounding the gaps, although this effect remains to be quantified.     

The Influence of Shelter and Weeds on Early Growth of Sitka Spruce and Lodgepole Pine

An experiment in Helmsdale Forest (Highland Region, Scotland)examined the effects of shelter and weed competition on Sitkaspruce (Picea sitchensis (Bong.) Can.) and lodgepole pine (Pinuscontorta Douglas ex Loudon). Different levels of shelter fromwind were achieved by using netting and were measured usingtatter flags. Three treatments compared weed competition byremoving no vegetation, heather (Calluna vulgaris L.) only orall ground vegetation respectively. Results indicate a definiterelationship between material lost from tatter flags and treedry weight at five years. Even the smallest increase in shelterresulted in increased growth of Sitka spruce and the beneficialeffect of shelter became most apparent 4 to 5 years after planting.Tree dry weight was found to be correlated with root collardiameter and height but not fifth year height increment. Resultsfrom weeding treatments were unclear and differed between species.This was because bird damage interacted with weeding, the completelyweeded plots being most heavily damaged; and because the methodof hand weeding (pulling out the whole plant including roots)damaged fine tree roots. Bird damage was prevented by nettingbut in unnetted plots it was found impossible to separate birddamage from other factors although it was clearly more seriouson lodgepole pine.     

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.     

Evaluation of competitive effects of green alder,willow and other tall shrubs on white spruce and lodgepole pine in Northern Alberta

In boreal forests of western Canada, lodgepole pine (Pinus contorta Dougl. ex. Loud.) and white spruce (Picea glauca (Moench) Voss) often grow together with numerous tall shrubs such as green alder (Alnus crispa (Ait.) Pursh) and little-tree willow (Salix spp.). In an area south of Grande Prairie, Alberta, Canada, we examined the effects of shrubs, herbs and other trees on nutrient and light availability and growth of white spruce and lodgepole pine. For white spruce the best competition measure (tested against volume increments of the past 3 years) was visually estimated % ground cover times the height of the competitor (VCHT) with light (DIFN) ranking in third place. For lodgepole pine, DIFN was the best competition measure for predicting volume increment and the best competition index was again VCHT. Taller conifers had a stronger competitive effect than tall shrubs, with their effect on white spruce being larger than that on lodgepole pine.     

The effect of nitrogen supply on root growth and development in sycamore and Sitka spruce trees

Sycamore (Acer pseudoplatanus L.) and Sitka spruce (Picea sitchensis(Bong.) Carr.) were grown in sand culture in glasshouses withtwo levels of N supplied with irrigation 1.0 (deficient) and6.0 (sufficient) molNm^–3, all as NH₄NO₃. Providing trees with a sufficient N supply increased both theirabove ground growth and N content compared with the N deficientplants. Provision of the generous N supply also altered thedistribution of growth between leaves and roots, with the N-deficientplants having a higher root:leaf or root:needle ratio than thewell fertilized trees. Provision of a generous N supply stimulatedroot growth, especially at the later harvests, which was reflectedmainly in growth of the tap root in sycamore. There was an increasein both root mass and root diameter with N supply. When thegrowth of white roots was monitored using a borescope, it wasshown that there were significantly more new roots producedby the well-fertilized trees. The borescope data also showeddetail of the bimodal seasonal pattern of root growth underhigh N in Sitka spruce which related to trends in nitrogen uptake.     

Height growth of planted conifer seedlings in relation to solar radiation and position in Scots pine shelterwood

Seedlings of different provenances of Scots pine (Pinus sylvestris L.), lodgepole pine (Pinus contorta Dougl., var. latifolia Engelm.) and Norway spruce (Picea abies (L.) Karst.) were planted in three Scots pine shelterwoods (125, 65 and 43 stems ha⁻¹) and a clear-cut, all in northern Sweden. The sites were mounded and planting took place during 2 consecutive years (1988 and 1989). The solar radiation experienced by the individual seedlings was determined using a simulation model. Height development of the seedlings was examined during their first 6 years after planting. During the final 3 years of the study, height growth of Norway spruce was relatively poor, both in the shelterwoods and the clear-cut area. Height growth of lodgepole pine was significantly greater than that of Scots pine, both in the shelterwoods and the clear-cut. In contrast to Norway spruce, Scots pine and lodgepole pine displayed significantly greater height growth in the clear-cut than in the shelterwoods. For all three species in the shelterwoods, regression analyses showed that height growth was more strongly correlated with the distance to the nearest tree than with the amount of radiation reaching the ground, i.e. growth was reduced in the vicinity of shelter trees. Therefore, we conclude that the significant reduction in height growth of seedlings of Scots pine and lodgepole pine in Scots pine shelterwoods was partially caused by factors associated with the distance to the nearest shelter tree. Because the substrate was a nitrogen-poor sandy soil, we suggest that root competition for mineral nutrients, especially nitrogen, accounts for the reduction in height growth.     

Outdoor exposure of untreated Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst.] wood samples

Abstract

Untreated Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) samples were exposed above ground in a durability test for 6 years. The samples consisted of three pieces of wood, 22×95×500 mm, screwed together; two pieces lengthwise with a third piece overlapping. Weight was measured, to calculate moisture content (MC), and samples checked regularly for cracks and fungal growth. Parameters investigated were heartwood/sapwood (pine), annual ring orientation (spruce), stand site, annual ring width and density. Stand site, annual ring width and density had no influence on MC or fungal growth for either pine or spruce. Spruce samples with vertical annual rings had fewer cracks than samples with horizontal annual rings. Pine sapwood samples had a high MC and a large amount of rot fungi, while heartwood had a lower MC and no rot. Most spruce samples were similar to pine heartwood, except from a few samples that had high MC and fungal growth. Those were all sawn from the outer part of the log. Therefore, it can be stated that spruce sawn from the inner part has almost the same properties as pine heartwood, while spruce from the outer part of the log has similar properties to pine sapwood.     

Aboveground production and N and P use by Larix occidentalis and Pinus contorta in the Washington Cascades, USA

Aboveground net primary production (ANPP) and N and P use patterns were determined for western larch (Larix occidentalis Nutt.), a deciduous conifer, and lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), an evergreen conifer, in the Cascade Mountains of Washington, USA. Western larch and lodgepole pine retranslocated 87 and 66% of foliage N and 66 and 78% of foliage P, respectively. At the stand level, N use efficiency of western larch was greater than that of lodgepole pine, whereas P use efficiency of lodgepole pine was greater than that of western larch. Western larch and lodgepole pine were comparable in ANPP and production efficiency (ANPP/foliage mass) if needle longevity is considered. The similarity in ANPP of the evergreen lodgepole pine and the deciduous western larch may be related in part to the lower initial construction cost of the foliage, and the efficient use of nitrogen by western larch.     

Stem deformation in young plantations of black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.) in the boreal forest of Quebec,Canada

Stem deformation has often been observed in young black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.) plantations. Whenever important stem deformations are observed at the time of harvesting, timber value is negatively affected especially during the wood transformation process. The present work was undertaken to quantify and qualify the importance of stem deformation of black spruce and jack pine in the boreal forest of central Quebec at the stand and tree levels. In 30 black spruce and jack pine plantations, approximately 22% of spruce trees and 27% of pine trees exhibited stem deformation. The proportion of deformed trees was higher in the youngest plantations and decreased with the age of the plantations. Stem deformation caused the formation of compression wood which is another factor that can reduce the value of wood products. Thirty-nine black spruces and 34 jack pines were analysed at the tree level. On average, compression wood represented 14% and 20% of stem volume in 7- and 10-year old black spruce plantations, respectively. These proportions ranged from 18% in the youngest jack pine plantation to 26% in the oldest one. Stems of both species classified as normal contained a lower volume of compression wood than stems classified as deformed or very deformed. Annual percentages of compression wood and annual shoot length increased significantly with tree age (p < 0.0001 for both variables). Statistically significant correlations were also found between the range of displacement of the stem and the percentage of compression wood. The fewer number of trees with deformed stems in older plantations combined with high compression wood formation suggests that, over time, a deformed tree can become normal and straight in appearance.