Retrospective Genetic Tests of Pinus sylvestris L. in Growth Chambers with Two Irrigation Regimes and Two Temperatures

The objective of this study was to estimate genetic correlations between stem volume in seven 19-30-yr-old field progeny trials and growth traits assessed in 1-yr-old Pinus sylvestris seedlings in growth-chamber treatments with optimal and limiting water availability at two temperatures. The seedlings in the growth-chamber experiment were open-pollinated families from two Swedish seed orchards. The field trials were established with full-sib families with the same parents. The genetic correlations between stem volume in the field progeny trials and height and biomass traits in the growth chamber were mainly low or zero. There was no clear pattern of juvenile-mature correlations with respect to combinations of growth-chamber treatments, field test site temperature and water availability. Periodic drought in the juvenile stage did not improve the juvenile-mature correlations, suggesting that at the juvenile stage, the mature stage, or both, the families used in this study do not appear to be specifically adapted to drought conditions.     

Flowering and Airborne Pollen Occurrence in a Pinus sylvestris Seed Orchard Consisting of Northern Clones

To explain the high background pollination rate detected in earlier studies, this study investigated the flowering phenology of a Scots pine seed orchard with respect to airborne pollen occurrence during 1992 and 1993. The receptive period of the female strobili and the shedding period of the male strobili were observed visually. Airborne pollen was monitored with Rotorod traps located inside and outside the seed orchard. There was no time gap in the onset of flowering between the earliest female and male strobili in 1992. Female flowering began 3 days earlier than male flowering in 1993, and the earliest strobili were probably pollinated by pollen transported long distance from more southerly areas. The almost simultaneous peak in pollen occurrence inside the seed orchard and in surrounding pine stands indicates that the seed orchard clones are not temporally isolated from sources of contamination. However, pollen concentrations inside the seed orchard were higher than those in the surrounding stands. Therefore, flowering phenology cannot sufficiently explain the observed pollen contamination rates in this seed orchard.     

Age-dependent Changes in Needle-fascicle Dynamics of Pinus sylvestris (L.)

Age-dependent dynamics of needle fascicles on the main stem of Scots pine trees in Estonia and Finland were investigated by the needle trace method. Mean fascicle longevity increased with tree age. Fascicle pool size, fascicle production and shedding were not related to tree age for trees less than 50 yrs old. Thereafter, the mean values of these characteristics declined linearly. Thus, younger trees had more fascicles attached to the stem, but fascicle survival in the third and fourth age classes tended to be greater in older trees. A short-term pattern of variation in dynamics was seen: higher values in the rates of fascicle shedding and production, and in the quotient of fascicle loss, in any one year were regularly followed by lower values in the following year.     

Patterns of Stem Damage by Moose (Alces alces) in Young Pinus sylvestris Stands in Sweden

The incidence of recent moose browsing of the main stem on young Scots pine (Pinus sylvestris L.) trees, and correlations with tree or stand characteristics, were examined using data from a large-scale survey in Sweden. On average, 10% of all Scots pine main stems showed one or more types of recent damage, with browsing of the apical leader accounting for about 75% of all damage recorded. Stripping of bark off the main stem occurred most frequently in the southern area, where site productivity is highest. Apical leader browsing was negatively correlated with height of the main stems, length of the apical leader and incidence of pre-commercial thinning, whereas bark stripping and stem breaking were positively correlated with the same variables. All types of recent stem damage correlated positively with the extent of previous stem damage and also with the extent of recent browsing of lateral shoots.     

Short-term Effect of Thinning on Pinus sylvestris Damage and Sporulation Caused by Cronartium flaccidum

The short-term effect of thinning on cronartium rust on Scots pine ( Pinus sylvestris L.) was investigated in a stand of Scots pine (artificially seeded and in the pole-stage) severely infected by the stem-rust fungus Cronartium flaccidum (Alb. & Schwein) G. Winter. The disease rate (the number of old and fresh infections) was recorded before thinning, after which all trees with a resin-top as well as all individual branches with sporulating lesions were removed from the thinned plots, while the comparison plots remained non-thinned. The numbers of sporulating lesions were recorded on the plots annually for 2-5 yrs after thinning. Thinning had no significant short-term effect on the year-to-year relative number of sporulating lesions. The relative number of sporulating lesions, however, increased in both thinned and nonthinned trees, varying significantly from year to year. Thinning had no significant effect on the year of formation of the shoot bearing annual sporulating lesions, the duration of sporulation or the growth of the fungus along the infected shoot in perennial lesions during the first 5 yrs after the treatment.     

Functions for Biomass Estimation of Young Pinus sylvestris,Picea abies and Betula spp. from Stands in Northern Sweden with High Stand Densities

New silvicultural regimes with high within-stand competition require new functions for estimation of standing stock and growth of biomass components, since the allometry of trees is changed by light competition. This paper presents functions for estimation of the aboveground biomass dry weights for stem wood, stem bark, branches and leaves of young (diameter at breast height <10 cm) Scots pine (Pinus sylvestris L.), Norway spruce [Picea abies (L.) Karst.] and birch (Betula pendula Roth. and Betula pubescens Ehrh.) trees growing in dense mixed stands. The functions were derived from a sample consisting of 84 Scots pine, 43 Norway spruce and 66 birch trees from six stands in northern Sweden with high stand densities (>10000 st ha^-1). The logarithmically transformed power function displayed a good ability to stabilize the variance of dry weights and showed a good fit to the material (0.37< R ² <0.99). A comparison with the most commonly used biomass functions in Sweden today showed that they overestimated the weight of stem wood and branches, while the weight of foliage was underestimated. The nature of these discrepancies suggested that the precision of biomass estimations might also be improved for young trees at wider spacing.     

落叶松杂交子代生长表现及遗传增益研究

通过对12 a生落叶松杂交子代测定林10个家系的树高、胸径及立木材积进行分析,结果表明:3个性状基本呈正态分布,且家系间及家系内均存在较丰富变异,生长最好家系与最差家系的比值由大至小顺序为材积、胸径和树高.3个性状的遗传力均较高,属强度遗传,其遗传增益随树木年龄增加而下降.筛选出的5个家系(日3×兴2、兴7×日77-2、日5×长77-3、日5×长78-3、日3×兴9)表现优良,其中,日3×兴2的树高生长遗传力尤为突出,其遗传增益较3个对照(当地生产用种、小北湖种源、长白落叶松种子园混合)分别提高33.6%、26.2%、和20.9%.     

Effects of Seed Invigoration and Microsite Preparation on Seedling Emergence and Establishment After Direct Sowing of Pinus sylvestris L. at Different Dates

Seed properties and seedbed conditions influence forest regeneration following direct seeding. It might therefore be possible to improve result by improving seed quality and seedbed conditions. In a direct seeding experiment designed to determine the effects of seed invigoration (incubation at 30% moisture content for 7 days) and microsite preparation (2-cm-deep pyramidal indentations) on the regeneration, sowing was repeated on eight different occasions, and seedling emergence, survival and height growth were recorded. Seedling emergence, mainly after early sowing, was improved by invigoration when used in combination with microsite preparation. Both survival and growth were impaired by delaying sowing until later in the growing season, but were not significantly affected by invigoration or microsite preparation. It is concluded that an improved and less varying regeneration result after direct sowing may be achieved by using invigorated seeds in combination with microsite preparation.     

Growth and survival of spontaneous provenance hybrids of Pinus sylvestris

Survival and growth were assessed for 17 provenance hybrids and three natural populations of Pinus sylvestris (L.) planted in three field trials in central and northern Sweden. Restricted to the high mortality site the 18‐year hybrid survival percentage increased by three units per degree north latitude and one percent per 100 m higher altitude of the mother. The hybrid height was less influenced by the geographical origin than hybrid survival. For both traits the natural populations were better than or equal to hybrids with the same geographical mean origin. The variance component of the mother was mostly 2–3 times larger than the provenance component. The effect of the grandmother was nonsignificant for both traits.     

Survival and strobili production in topgrafted scions from young Pinus sylvestris seedlings

Abstract

Reducing the generation turnover increases the genetic gain in a breeding programme. Topgrafting, new genetic material being grafted into the crown of ramets of reproductive mature trees, can deliver this aim since it is able to induce strobili production in young material of conifers. To this end, I studied the effect of scion age (seedlings of 4–6 years from seed) on topgraft vitality/survival, and female and male strobili production in Pinus sylvestris (L.) over 5 years. The seedlings' growing environment prior to topgrafting had a significant impact on topgraft vitality, with more vital topgrafts obtained from potted seedlings than from seedlings grown in raised nursery beds. However, the growth environment had no clear effect on female or male strobili production. In the second year, after grafting up to 76% of the topgrafted seedlings had female strobili. Vitality increased with age of the seedling from which the scions were collected, but differences in both female and male strobili production were only marginal. The position of the topgraft within the interstock crown influenced both vitality and strobili production, with higher vitality and greater male strobili production in low positions and greater female strobili production in high positions. Based on these results, breeders should perform topgrafting as soon as the seedlings have enough scions for planned crossing activities.     

Development and transferability of two multiplexes nSSR in Scots pine (Pinus sylvestris L.)

Single sequence repeat(SSR) multiplexing is a semi high-throughput PCR methodology for the analysis of multiple SSRs.We developed two SSR multiplexes selected from SSR loci previously reported in the pine literature and tested the transferability of both SSR multiplexes in nine other pine species.We tested 234 nuclear SSR loci(n SSRs) previously described in the pine literature and selected ten n SSRs following the simple criteria of interpretability and reproducibility.Selected nuclear loci were divided into two n SSRs multiplex sets and their amplification was optimized for three different multiplex PCR methods based on:(a) a custom PCR protocol,(b) a custom protocol with hotstart taq polymerase,and(c) a commercially available kit for SSR multiplexing.To validate their performance,the level of genetic diversity was assessed in three Scots pine natural populations(Hungary,northern Sweden and southern Sweden).In addition,we also tested the transferability of these multiplexes in nine other pine species.We have developed two n SSRs multiplexes of five loci each that will contribute to reduce the costs of n SSR scoring,while increasing the capacity of n SSR loci analysis.Amplification was successful in all three populations(94 % success) and the level of polymorphism(7.1 alleles/marker) was similar to that previously reported for other Scots pine natural populations.Transferability of both multiplexes was successful for those pine species closely related to Scots pine.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Genetic expression for monoterpenes in clones of Pinus sylvestris grown on different sites

The terpenic profile for 8 major monoterpenes determined on ten grafted clones of Scots pine grown on three different sites in Sweden. As graft effects could not be detected, oleoresin, samples from primary and secondary grafts were used to study genetic variation. In three quite different environmental conditions, a strong broad sense heritability was demonstrated for 3‐carene, myrcene, limonene and β‐phellandrene. Pinenes and sabinene seem to be much more dependent on environmental factors. Both site and clone × site interaction have a small effect on overall phenotypic variation. There is a strong positive correlation between concentrations of 3‐carene and terpinolene, which supports a possible pleiotropic effect of the same major gene on the two monoterpenes. The results show that there is no risk of an important bias when the comparison is made between genotypes sampled on very different sites (stands or comparative trials). The relative concentration of monoterpenes is to a great extent independent of environmental conditions.     

Long-term Growth Effects Following Forest Nitrogen Fertilization in Pinus sylvestris and Picea abies Stands in Sweden

Forest nitrogen (N) fertilization induces changes in the soil and soil microorganisms that could hypothetically affect the long-term productivity of the soil. The tree growth response following a normal (i.e. 150 kg N ha^?1) single shoot N fertilization has a duration of 7–10 yrs. The aim of this study was to investigate whether any residual effects on tree growth persist, which could be attributed to previous N fertilization. The study included six Pinus sylvestris L. and three Picea abies (L.) Karst. experimental sites, sampled for growth parameters 14–28 yrs after the last fertilization. Residual growth effects were on average small, and not statistically significant. Negative residual growth effects of varying duration could be discerned, especially at low-fertility P. sylvestris sites. However, there was an overall tendency for growth to increase in the long term after N fertilization. The main conclusion is that operational forest N fertilization with a normal N dose should not be regarded as a threat to long-term forest production.     

Age and spatial structure of natural Pinus sylvestris stands in Latvia

Abstract

The age and spatial structure of six natural old growth Pinus sylvestris stands in Latvia were investigated, to attempt to identify retrospectively the past features of development. In each stand, one or two plots of size 200–900 m² were established. Tree locations were mapped, stem diameter was measured, and tree age was determined from cores or by counting branch whorls. Tree distribution was assessed by Ripley's K function. A clumped spatial pattern was shown for P. sylvestris younger than 100 years. The temporal patterns of establishment could be partly linked to favourable climatic periods. The major disturbance affecting pine stands along the coast was windblown sand, which partly buried some stems and probably affected the patterns of seedling recruitment and mortality. Disturbance caused by fire had a major role in determining the past regimens of mortality and establishment in dry stands located inland. The successful invasion during the last century of spruce in more mesic plots with a pine overstorey may be due to fire suppression.     

Models for Predicting Wood Properties in Stems of Picea abies and Pinus sylvestris in Sweden

To study and model the variation of wood properties, sample trees were selected from 42 Norway spruce and 20 Scots pine stands covering a wide variation in climatic and site conditions, stand maturation and tree sizes. Plot and tree measurements were followed by sampling wood from different heights in each sample tree and laboratory measurements of wood properties. Mixed linear and non-linear prediction models were developed using diameters, number of annual rings and climatic indices as explanatory variables. The variation in spruce properties explained by these variables was: basic density 50%, latewood content 52%, juvenile wood diameter 85%, heartwood diameter 94% and bark thickness 76%. The corresponding values for pine were 59, 54, 79, 92 and 85%. Random among-tree variance was an important contributor to the remaining variation for density and latewood. In general, only a minor part of the random variation was related to variance between stands. Predictions derived from the models for density and juvenile wood in both species, and heartwood in pine showed good agreement when validated with data sets from two other studies. The resulting models may be used for predicting wood properties in forest planning and in bucking computers in harvesters, provided that the essential information is available.     

Development of Pinus sylvestris Main Stems Following Three Different Precommercial Thinning Methods in a Mixed Stand

Reducing competition by point cleaning may be an attractive alternative to conventional precommercial thinning in forestry. In this study, survival and development of main stems of Scots pine (Pinus sylvestris L.) following point cleaning were examined in a mixed stand of mainly Scots pine and birch (Betula pendula Roth and Betula pubescens Ehrh.) in northern Sweden. Treatments studied were: no precommercial thinning, conventional precommercial thinning, point cleaning of all secondary stems, and point cleaning of only the secondary stems that were higher than the main stem, within a radius of 0.8 m from the main stem, respectively. A randomised complete block design with three replicates was used. Measurements taken 13 growing seasons after these treatments showed that conventional precommercial thinning was the best treatment for retaining Scots pines as main stems. However, conventional precommercial thinning resulted in the poorest timber quality of the remaining Scots pines in terms of stem taper, thickest branch diameter and relative live crown height. In conclusion, point cleaning has to be followed by a complementary cleaning operation if the objective is to retain Scots pines as main stems in such mixed stands.     

Responses of Pinus sylvestris and Picea abies Seedlings to Limited Phosphorus Fertilization and Treatment with Elevated Ozone Concentrations

Scots pine ( Pinus sylvestris L.) and Norway spruce [ Picea abies (L.) Karst.] seedlings were exposed to high phosphorus (HP) or low phosphorus (LP) availability for one growing season in the open field, and to combined P availability and elevated ozone (O 3 ) concentrations (0, 55, 110 and 210 ppb for Scots pine and 0, 40, 75 and 150 ppb for Norway spruce, respectively) for 28 days in controlled laboratory chambers. Compared with HP, the LP treatment reduced Scots pine current-year (C) shoot and root dry masses and Norway spruce total dry mass, whereas the highest O 3 concentrations increased the magnesium concentration of Scots pine C needles and P concentrations of the C needles of both tree species. Chlorophyll a, a+b and carotenoid concentrations of Scots pine C needles were significantly higher in the LP treatment compared with HP under the highest O 3 concentration (210 ppb). In the mesophyll tissue of C needles of both tree species, LP treatment increased the size of mitochondria and elevated O 3 -induced granulation of chloroplast stroma and disintegration of cytoplasm. Exposure to elevated O 3 concentrations increased swelling of chloroplast thylakoids and reduced the amount of vacuolar tannin in the LP Scots pine C needles. The results suggest disturbances in needle photosynthetic machinery due to acute exposure to the combination of elevated O 3 and low P availability. However, clear additive effects were found only in needle P concentrations < 1 mg g -1 in short-term O 3 exposure.     

ISSR标记对樟子松遗传变异的分析及种源区划的研究

Inter Simple Sequence Repeat （ISSR） was used to detect genetic variation among nine provenances, including 135 individuals. A total of 108 loci were amplified using 10 random primers. The differentiation of the percentage of polymorphic bands （PPB） among different provenances was evident, ranging from 27% to 54%. of which Honghuaerji provenance had the highest PPB and Kalunshan provenance had the lowest PPB. Shannon＇s Information index （1） at species level was 0.1581 and Nei＇s gene diversity （h） was 0.2393. Coefficient of gene differentiation （Gsr） calculated by Popgene was 0.3965, these results indicated that majority of genetic variation （60.35%） was found within provenances. According to dendrogram among pinus sylvestriv provenances, nine provenances were divided into two provenance areas. namely Daxing＇an and Xiaoxing＇an Mountains provenance area and Hulunbeier provenance area.