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

《Scandinavian Journal of Forest Research》2012,27(4):339-347

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.  相似文献   

Geological controls on conifer distributions and their implications for forest management in Finnish Lapland     

《Scandinavian Journal of Forest Research》2012,27(6):476-487

Abstract

Soil water and nutrient regimes of naturally established old-growth conifer stands and those of intensively managed Norway spruce [Picea abies (L.) Karst.] sites were assessed over a range of lithological provinces in Finnish Lapland. Soil dielectric permittivity (ε), as a measure of soil water content (θ _v) and soil electrical conductivity (σ _a), as a measure of soil solute content, were species specific, such that high soil θ _v>0.27 cm³cm^?3 (ε>15) constitutes an edaphic constraint for Scots pine (Pinus sylvestris L.) and low soil solute content (σ _a<0.5 mS m^?1) is constraining for Norway spruce. The spatial pattern of the soil θ _v was temporally stabile, such that intraseasonal and interseasonal soil θ _v was significantly higher in silty tills of spruce stands compared to sandy tills of pine stands. Scots pine was the only conifer on tills derived from felsic rocks of Hetta granite (HG) and Lapland granulite (LG). Norway spruce dominated on tills derived from the mafic rocks of Lapland greenstone belt (LGB), but tills of LG and HG constitute a dispersal barrier for spruce. Mechanical site preparation (MSP) with ploughing (Marttiini) was not able to amend soil θ _v to meet site requirements of Scots pine at former spruce sites. MSP resulted in significant reduction in soil nutrient content such that untreated control σ _a>tilt/shoulder σ _a>trench σ _a. The results imply that MSP treatments through which cross-contour tracks are created pose a risk to the sustainability of soil quality in Lapland.  相似文献   

Influence of precommercial thinning grade on branch diameter and crown ratio in Pinus sylvestris in southern Sweden     

《Scandinavian Journal of Forest Research》2012,27(3):243-251

Precommercial thinning is regarded as one of the most important measures for influencing timber quality in stands of Scots pine (Pinus sylvestris L.). The present study considers the influence of both thinning intensity and tree height at the time of thinning on diameter of the thickest branch and crown ratio. A total of 115 plots (either naturally regenerated, planted or sown, and either thinned down to 528–8000 stems?ha^?1 or untreated) included in 20 sites in southern Sweden were analysed. The average tree height after thinning varied from 1.2 to 8.3?m. An increasing number of remaining stems resulted in a reduction in branch diameter, although the reduction appeared to be only minor if the number of stems after thinning was more than 3000 stems?ha^?1. It was found that late thinning reduced the diameter of the thickest branch. The crown ratio decreased with stand height, number of stems after thinning and average height at thinning. The results were consistent for all trees and for the 500 thickest trees per hectare.  相似文献   

Spatial distribution of dead wood and the occurrence of five saproxylic fungi in old-growth timberline spruce forests in northern Finland     

《Scandinavian Journal of Forest Research》2012,27(6):527-540

Abstract

Adequate understanding of the factors that determine the establishment and survival of dead-wood-dependent species in natural forests is a prerequisite to the successful maintenance of these species in managed forests. This study investigated the factors affecting the occurrence of five wood-inhabiting polypores in old-growth timberline spruce forests in northern Finland, including the substrate availability and the spatial arrangement of large-diameter logs. The volume of coarse woody debris (CWD) varied significantly between the sites (range 15–30 m³ ha^?1), large-diameter logs comprising on average 35% of the total CWD volume. However, the within-site variation in CWD volume was 10–15 times larger than the between-site variation. The spatial distribution of large-diameter logs was aggregated or initially aggregated on four sites and random on one site, creating local patches of high CWD volume. An individual target species occurred on average on 8% of all large-diameter logs, and on 11% of optimal logs (as determined by the decay stage). The characteristics of the logs and stand variables explained partly the occurrence of the target species; furthermore, the mortality pattern of trees (stem breakage versus uprooting) and the presence of primary decomposers also significantly affected the occurrence of the target species. The results indicate that besides substrate availability and quality, local habitat factors and species interactions also play a role in the occurrence of wood-inhabiting fungi in boreal timberline forests.  相似文献   

The Lintula Larch Forest     

《Scandinavian Journal of Forest Research》2012,27(3):252-282

The Lintula Larch Forest, also called the Raivola Larch Forest, is one of the most magnificent cultivated forests in northern Europe. It has had a major impact on the cultivation of larch throughout the world, and it became part of the Unesco's World Heritage list in 1991. This article summarizes for the first time to an international audience the establishment, administration and management, stand development and research carried out in Lintula Park. It is based on Russian and Finnish papers and earlier unpublished results. The forest is located 63 km north-west of St Petersburg in the Karelian Isthmus. It was established by order of Peter the Great to supply the Russian fleet with timber for shipbuilding. Ferdinand Gabriel Fockel, a German forest expert, established the oldest stands in 1738–1750 with seed from the Province of Arkhangelsk. Since then the area of the forest has expanded and now the total area of larch stands is 55.9 ha; 23.5 ha of the “old stands” established in 1738–1851 still remain. The Lintula larch stands were famous for their high yield, but part of the reputation was based on small sample plots that were not representative of the stands. However, the high volumes of different tree stands are impressive. For example, in a 255-year-old stand with 339 trees ha^?1 the volume of growing stock was 1284 m³ ha^?1. In small sample plots much higher volumes are found. The average annual growth of the oldest larch stands has never exceeded 6.2–7.2 m³ ha^?1. The volume increment was, however, long-lasting, and annual growth started to decrease only after 148–166 years. Some plots had an increase in yield even at the age of 257 years. The yield of the larches clearly surpassed that of Norway spruce and Scots pine in nearby stands. The Lintula Larch Forest has provided valuable experience on the cultivation of larch. The root system of larch is relatively weak, and it is therefore susceptible to wind damage and rot fungi. An important conclusion drawn from the development of the Lintula Larch Forest is that the cultivation of larch is worthwhile only when grown as pure stands using intensive growing techniques.  相似文献   

Predicting knottiness of Pinus sylvestris for use in tree bucking procedures     

《Scandinavian Journal of Forest Research》2012,27(6):521-533

Abstract

The quality and accompanying value of Scots pine (Pinus sylvestris L.) lumber varies markedly in the Nordic countries. Consequently, tree bucking has a great impact on the economic result. The objectives of this study were (1) to analyse which knot characteristics usually reduce pine lumber sawn from the butt-logs to the next quality grade, (2) to determine the most appropriate characteristics that could be used in predicting lumber quality, and (3) to develop models that could be used in practice for predicting the probability of certain quality grades. The study was based on field experiments and test sawing data on 100 Scots pine stems from south-western Finland. Since the results showed that the maximum dead knot is the most crucial knot characteristic when the first cross-cutting point is determined, models were created that predict the height of the first dead knot that lowers grade A to B (B-grade dead knot). Both early growth rate and dead branch height should be measured to predict pine butt-log quality. Early growth rate seems to be appropriate in predicting between-stand variation, while dead branch height is appropriate for predicting within-stand variation.  相似文献   

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

《Scandinavian Journal of Forest Research》2012,27(6):533-539

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.  相似文献   

水曲柳、胡桃楸等天然次生林生长情况调查   总被引：2，自引：0，他引：2  

刘立波  王清君  张志环  赵科研  张庆发 《林业科技开发》2012,26(1):50-54

通过标准地调查,对现有天然次生林水曲柳、胡桃楸和黄菠萝幼龄林林分特征、优良单株径级分布、生长过程进行研究,指出相应的抚育技术措施,为小兴安岭天然次生林中水曲柳、胡桃楸和黄菠萝等珍贵阔叶树种单株定向培育提供科学依据。  相似文献   

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

《Scandinavian Journal of Forest Research》2012,27(1-4):356-363

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.  相似文献   

Distribution and frequency of Cronartium flaccidum on Melampyrum spp. in permanent sample plots in Finland     

《Scandinavian Journal of Forest Research》2012,27(5):413-420

Abstract

In 2006, the distribution and frequency of pine stem rust Cronartium flaccidum was studied on Melampyrum spp. in permanent sample plots of an EU forest health monitoring program and of a BioSoil program in Finland. The frequency of Melampyrum spp. infected with C. flaccidum was low, but the rust was recorded in new locations of eastern Finland. No uredinia of C. flaccidum were observed in samples collected from over 700 plots. Telia were common on Melampyrum sylvaticum but were occasionally also found on Melampyrum pratense and Melampyrum nemorosum. Melampyrum pratense was the most common species growing in plots on mainly dry sites. Melampyrum sylvaticum was seldom detected, suggesting that alternate hosts are absent from northern Finland or that the current sample plot network is too sparse for effective disease monitoring in the north. No relationship between C. flaccidum, Melampyrum spp. and rust incidence in host trees was observed, which implies that the autoecious Peridermium pini is a more likely pathogen than C. flaccidum locally. Because plots containing M. sylvaticum occur almost solely in southern Finland, the plots with M. sylvaticum reflect the best changes in rust epidemics in that area. In the future, nutrient-rich sites containing M. sylvaticum may serve as a source of rust epidemics. It is unlikely that C. flaccidum will spread to dry sites via M. pratense.  相似文献