Survival and Early Development of Lodgepole Pine

The effect of site fertility, spacing and mode of regeneration on the survival and stand development of lodgepole pine, Scots pine and Norway spruce was studied in a series of experiments comprising 22 study areas in Finland. After 13-14 yrs, lodgepole pine had a mean survival of 68% in planted and 61% in seeded plots, while Norway spruce had the highest (92%) and Scots pine the second highest survival (82%). The survival of planted lodgepole pine was better the wider the spacing. Best survival was achieved on subdry and dry sites, both with planting and with direct seeding. Dominant height was not affected by spacing, but both basal area and volume at the age of 13-14 yrs were significantly higher the denser the spacing. The average difference in the value of the estimated site index H ⁵⁰ was slightly under 3 m for the superiority of lodgepole compared with Scots pine. Seeding resulted in site indices almost as high as those of lodgepole planting.     

The Infection of Corsican Pine by Crumenula sororia Karst

For germination ascospores of Crumenula sororia require freemoisture. A temperature range of 20–25 °C was optimal.In these conditions rate of germination was increased by extractsof lodgepole pine bark and extracts of Corsican pine bark andwood. Irrespective of whether spores or hyphae were used, C. sororiaonly Successfully invaded Corsican pine through wounds madewith a scalpel or by removing needle fascicles. Lesions didnot develop when frozen tissues were inoculated. In field inoculation experiments different isolates of the fungusdiffered significantly in pathogenicity. Infections developedmore severely on 4-year-old than on 1-year-old branches, andthis agrees with the incidence of natural branch-infections.     

The Pine Shoot Beetle Tomicus piniperda as a Vector of Blue Stain Fungi to Windblown Pine

After the great gale of 1987, the role of the pine shoot beetle,Tomicus piniperda, as a vector of blue stain fungi to windblownpine in southern England was examined by macerating adult beetlesand culturing the macerate on various agar media. Isolationswere also made from pine tissue associated with beetle galleriesand tunnels. Using data from between three and nine sites, it was found that17 per cent of the overwintered adult beetles were carryingfast-growing Leptographium spp. as they began to construct breedinggalleries in spring 1988. More than half the new generationof adult beetles were contaminated with these fungi when theyemerged in June-July 1988, but this proportion dropped as thelife cycle of shoot-feeding and overwintering progressed. Itaveraged 26 per cent at the time of brood gallery constructionin spring 1989. Isolations made from pine tissue around the galleries also showedchanges in the frequency of blue stain fungi. Of early broodgalleries 25 per cent yielded Leptographium, while the figurefor late galleries was 51 per cent. These results were consistentwith the direct introduction of Leptographium by the parentbeetles into some galleries, and the subsequent rapid hyphalgrowth of the fungus within the tree to colonize tissue adjacentto other galleries. The principal species identified was L. wingfieldii. However,L. lundbergii, L. huntii, L. procerum and an unidentified Leptographiumspecies were occasionally recorded, both on the beetles andin the trees. Graphium species were quite common also. In addition,the black yeasts, Hormonema dematioides and Aureobasidium pullulans,were frequently present, particularly in the pine shoot samples.     

Structure and abundance of arachnid communities in Scots and lodgepole pine plantations

Between April and September 1994, six plots within Aberfoyle Forest in Scotland, three of Scots (Pinus sylvestris) and three of lodgepole pine (Pinus contorta), were surveyed for spiders and harvestmen, as these are predators of several forest invertebrate pests.A total of 64 species of spider were trapped in Scots and lodgepole pine; 56 in Scots pine and 32 in Lodgepole pine. The most abundant spiders, both in Scots and Lodgepole pine, were Linyphiidae.Scots pine plots were floristically more diverse and structurally more complex than lodgepole pine plots. More species of spiders and harvestmen (midsummer only) were found at ground level in Scots pine than lodgepole pine plots. More species and a greater numbers of spiders were found in the canopy of Scots pine than in that of lodgepole pine. However, no differences in the abundance of harvestmen were found between the canopies of Scots and lodgepole pine. Spider species diversity was greatest in Scots pine.     

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.     

Growth and survival of lodgepole pine and Scots pine after 25 years in a reciprocal transplant experiment in Canada and Sweden

Lodgepole pine is native to western North America, but it is also planted as a fast-growing alternative to Scots pine in Sweden. The production of these two species, when grown as native and as exotic species, was compared in a transcontinental two-species provenance experiment. The tests were planted in 1986 on five sites in northwestern Canada and two sites in Sweden, and included full-sib families, half-sib families, seed orchard collections and natural stand seed collections of both species. After 25 years, lodgepole pine produced 48% more volume (m³ha^?1) and had 27% higher survival than Scots pine at one Swedish site, and had similar volume production and survival at a second. In the five Canadian sites, Scots pine produced on average 22% more volume than lodgepole pine. The variation between sites was, however, large. This higher volume of Scots pine in Canada could be due to higher survival (+28%) and less frequent damage; but higher top height for lodgepole pine in Canada indicated higher potential productivity. The results indicate that an exotic species may produce more than the native species, possibly thanks to higher survival, but it is also possible to increase production with successful population selection of the native species.     

Biomass and element capital of a 7-year-old lodgepole pine (Pinus contorta dougl.) stand growing on deep peat

Total biomass and element contents were determined for eight sample trees taken from a stand of 7-year-old lodgepole pine growing on a deep peat which had received P fertiliser at planting. Estimated uptake (ha⁻¹) of elements by the stand was 143 kg N, 14 kg P and 54 kg K. Trees were estimated to contain 27% of the applied fertiliser.     

Soil Aeration Response to Draining Intensity in Basin Peat

Improvement in soil aeration was assessed following drainingto a range of intensity on a peatland afforestation projectat Flanders Moss in Central Scotland. A polarographic techniquewas used to measure oxygen diffusion rates in the rooting zoneof lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.)planted in 1965 on ploughed furrows. There were soil aerationdifferences because of draining intensity. Below the plantingturf oxygen diffusion rates rapidly decreased and tree rootingwas restricted to the surface layers. Aeration was found tobe closely correlated with depth of water in boreholes whichprovide a simple and reliable index of response to draining.Oxygen diffusion rate was a more sensitive means of assessingsoil aeration than oxidation-reduction potential at the lowoxygen concentrations encountered in the basin peat on the Moss.     

Variation in Lodgepole Pine with reference to Provenances Planted in Great Britain and Ireland

Variation in growth habit and bark type of lodgepole pine (Pinuscontorta Douglas) in its native habitat is described and illustratedwith photographs. Needle morphology is assessed from plantationsamples and some of the problems associated with the assessmentof variation are discussed. The problem of ensuring that importedseed is collected from the right stands is considered.     

Phosphorus Nutrition of Lodgepole Pine and Sitka Spruce Stands as indicated by a Root Bioassay

A bioassay for determining P-deficiency, based on the rate ofuptake of ³²P-labelled phosphorus by roots from a standard solutionand developed on pot grown tree seedlings, has been appliedto roots from 10–18 year old lodgepole pine and Sitkaspruce stands in field fertilizer trials on peat. Rates of ³²-phosphorusuptake by roots were negatively related to quantities of P fertilizerpreviously given and to tree heights. The P content of firstwhorl needle samples were generally high but were not significantlydifferent between fertilizer treatments nor related to treeheights. There was, however, a general relationship between rates of³²P uptake by roots and P content of needles over all sitesand tree species. The bioassy, however, rapidly detects changesin internal P status of the tree which takes time to manifestitself in a change of needle P content. Preliminary work suggests that the bioassay detects a P-statusin trees, not identifiable from needle analyses. A number offactors which might influence the results of the bioassay andtherefore the field applicability of the method are discussed.     

Growth of young Pinus ponderosa and Pinus contorta on compacted soil in central Washington

Growth in height, diameter, and volume was measured on 9- to 18-year-old ponderosa pine (Pinus ponderosa) and 10- to 13-year-old lodgepole pine (Pinus contorta) trees growing on or near compacted skid trails in the Yakima Indian Reservation in south-central Washington. Soil bulk density of the 0- to 30.5-cm deep layer was measured with a single-probe nuclear densimeter on two sides of each sample tree and in adjacent undisturbed soil. On three ponderos pine sites logged 23 years before the study, average bulk density on skid trails was 15% greater than on adjacent undisturbed soil. On a lodgepole pine site logged 14 years before the study, soil on skid trails averaged 28% greater bulk density than undisturbed soil.Total growth of ponderosa pine and the last 5 years of growth were significantly related (P = 0.07) by regression analysis to age of trees, site index, basal area of the adjacent overstory, and the percentage of increase in soil bulk density. At the mean increase in soil bulk density, total height, diameter, and volume growth were reduced 5%, 8%, and 20%, respectively.Total growth of lodgepole pine and the last 5 years of height, diameter, and volume growth were significantly related to tree age and the percentage of soil organic matter. Increase in soil bulk density was not significantly related to growth of this species.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.     

Competitive Interactions between Norway Spruce and Scots Pine at Gisburn Forest, NW England

Species mixtures, although promising for improving the growthof spruce on nitrogendeficient sites, carry a risk of competitionfrom the admixed nurse species. The mixture of Scots pine (Pinussylvestris) and Norway spruce (Picea abies) planted at GisburnForest in 1955, in which nutritional benefits have been observed,provided a unique opportunity to study competition between thesespecies. Pure plots of both species as well as the mixture werereplicated in three blocks, allowing the effects of interplantingon the survival and mean diameter of each species to be testedstatistically. Further, the grouped arrangement of the speciesin mixed plots presented a variety of competitive configurationsbetween the two species. Instead of demonstrating the nursing benefit of pine to spruce,comparisons of mean diameters in pure and mixed stands indicatedthat spruce suffered and pine benefited from their interplantingat this site. Frequency distributions of tree diameters confirmedthat spruce tended to be suppressed in mixture and pine dominant.Neighbour analysis revealed that spruce were significantly smallerwhen adjacent to pine and that this effect was mainly due tothe larger size of pines. The increased height of spruce atthis site, previously attributed to a nutritional benefit conferredby pine, was probably due to competition for light from an overtoppingnurse. Nurse varieties must be carefully selected if they areto promote rather than suppress the growth of crop trees.     

Root growth and water use efficiency of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and lodgepole pine (Pinus contorta Dougl.) seedlings

One-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and lodgepole pine (Pinus contorta Dougl.) seedlings were grown for 17 weeks in 100-cm deep, 7.8-liter containers. Two Douglas-fir provenances, one from a wet and one from a dry site in coastal British Columbia, and two lodgepole pine provenances, one from a wet and one from a dry site in interior British Columbia, were grown in wet (522% water content) or dry (318% water content) peat/vermiculite soil in a factorial design. Each container was sealed so that water loss occurred only through the seedling. Five harvests were made at three to five week intervals and water use, dry matter increment, root length and root weight were determined at each harvest. Stomatal conductance and shoot water potentials were measured during the last 12 weeks of the experiment. Lodgepole pine seedlings had greater dry matter production, water use, stomatal conductance and new root length than Douglas-fir seedlings. New root weight of lodgepole pine seedlings exceeded that of Douglas-fir seedlings during the last five weeks of the experiment, and specific root length (root length per unit root weight) of new roots was higher for lodgepole pine seedlings throughout the experiment. Douglas-fir seedlings showed higher water use efficiency (WUE) than lodgepole pine seedlings, and both species showed higher WUE in the dry soil treatment. Douglas-fir seedlings had lower water potentials and higher water uptake rates per unit of new root length than lodgepole pine seedlings, although water uptake rates per unit of root dry weight showed little difference between species. Soil water treatment influenced specific root length of new roots, water uptake per unit of new root length, and WUE in Douglas-fir seedlings more than in lodgepole pine seedlings.     

Lodgepole pine in the Republic of Ireland I. Site types,ground preparation and nutrition

About 80 000 ha of lodgepole pine have been planted on organic soils and on podsolised mineral soils in the Republic of Ireland, mostly over the last 30 years. The popularity of the species centres around its high growth potential (yield class 14–18 m³) on poor sites, many of which twenty years ago were considered unsuitable for afforestation. Most sites are ploughed and treated with about 350 kg/ha rock phosphate before planting. Bare-rooted seedlings are used almost exclusively. However, results from experiments using containerised plants are promising, particularly with regard to reducing the incidence of basal sweep, a problem with the south coastal provenance. Many foresters consider the species as a pioneer, the assumption being that it will be possible to grow more demanding species such as Sitka spruce for the second rotation on sites which have carried a first rotation of lodgepole pine. On poor soils these more demanding species, unlike lodgepole pine, normally require regular inputs of fertiliser nitrogen to sustain an acceptable growth pattern.     

The Use of Clear Polythene Cloches to Improve the Growth of One-Year-Old Lodgepole Pine Seedlings

Unsterilised nursery seedbeds, prepared in a conventional mannerand sown with lodgepole pine (Pinus contorta Dougl. ex Loud,ssp contorta) were covered with clear polythene cloches, withor without the edges buried, from the date of sowing for 0,8, 16 and 21 weeks. Germination rate and numbers of seedlingsgerminating were increased by all the cloche treatments. Deathsof seedlings under cloches with unsealed edges were greaterthan for the cloche treatments with completely buried edges.Due to increases in both stem unit number and stem unit length,the cloche treatments increased height growth in proportionwith duration of cloche cover. Seedlings covered for 16 or 21weeks were over 3 times the height of the controls and almostall were over 10 cm but they were not sufficiently sturdy forforest use. The use of polythene cloches for the productionof seedlings suitable for lining-out or forest planting is discussed.     

Physiological Effects of Natural and Artificial Defoliation on the Growth of Young Crops of Lodgepole Pine

Field experiments involving naturally occurring population levelsof larval European pine sawfly Neodiprion sertifer (Geoff. )and artificial defoliation in both field and glasshouse experimentswere used to investigate physiological effects of defoliationon lodgepole pine. Reductions in total projected leaf area,annual height and volume increments of 19, 33 and 32 per cent,respectively, were recorded on trees where larvae had consumedall mature foliage. Leader growth was up to 48 per cent lesson defoliated trees after two years reflecting a delayed growthimpact. Similar effects were found on trees which had been defoliatedby hand in a manner resembling sawfly feeding. Artificial defoliationof transplants also showed that this type of damage can haveserious consequences on below-ground growth, particularly offine roots. Root:shoot ratios were found to be 0.64 in undamagedplants and 1. 05 in defoliated plants. A high concentration(1300 ppm) of the insecticide fenitrothion, used to maintaincontrol treatments in the field, was found to have no significanteffects on the major growth parameters being assessed.     

Seedling shoot,needle and bud development in three provenances of Pinus sylvestris and Pinus contorta cultivated in northern Sweden

The patterns of current‐year shoot, needle and terminal bud elongation in seedlings of three Scots pine (Pinus sylvestris L.) and three lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) provenances were compared during the third and fourth growing seasons after planting. Lodgepole pine produced longer shoots and buds than did Scots pine, mainly because lodgepole pine formed more stem units and elongated at a faster rate. Stem unit length and the duration of shoot and bud elongation differed relatively little between species and provenances. Lammas or polycyclic growth occurred in some lodgepole pine provenances, but not in any Scots pine provenance, and was associated with enhanced shoot elongation. Needle elongation commenced earlier, proceeded at a faster rate, and was greater in lodgepole pine than in Scots pine, but ceased about the same time in all species and provenances. The heat sum required to attain 50% of final length was lower for shoots and needles in lodgepole pine than in Scots pine, and for shoots in northern provenances than in southern ones. Mitotic activity in the apical meristem of the terminal bud, which occurred less than one week after the seedlings were free from snow, started and ceased about the same time in each species, but was higher in lodgepole pine than in Scots pine early in the shoot elongation period.     

Silviculture of Weymouth Pine

The advantages of being able to grow Weymouth pine (Pinus strobusL.) on a commercial scale are indicated. The growth of thisspecies in Thetford Forest is described, and the point is madethat serious infection from White Pine Blister Rust (Cronartiumribicola J. C. Fischer) has occurred in dense unthinned plantationsonly. Maintenance of vigour by early heavy thinning, and earlybrashing and high pruning to remove moribund branches, are suggestedas means of minimizing deaths from the disease. Whilst individualWeymouth pines in pure plantations treated in this way are nomore susceptible to Blister Rust than individuals in mixturewith other species, mixed plantations have the advantage ofproviding alternative species for the final crop if the Weymouthpine fails.     

Effects of Afforestation with Pinus contorta on Nutrient Content, Acidity and Exchangeable Cations in Peat

Nutrient contents, acidity and exchangeable cations in the upper300 mm of peat beneath lodgepole pine have been compared withthose in peat from contiguous unplanted areas at each of sixsites. Nitrogen, phosphorus and potassium contents, which aresignificantly higher in flushed blanket bog peat than in peatfrom either raised bog or unflushed blanket bog, are not significantlyaltered by the presence of trees. Calcium and magnesium contents,on the other hand, although similar in peat from different bogtypes, are lower in peat beneath the tree crop. ExchangeableCa²⁺ Mg²⁺ and K²⁺ are replaced by Na⁺ and H⁺ in planted peatbut the increase in H⁺ content exceeds the loss of base cations,reflecting a higher number of exchange sites. This increaseaccounts for lower values of both base saturation and pH inplanted peat and is attributed to enhanced decomposition promotedby aerobic conditions beneath the tree crop.