The effect of scalping on seedling establishment after seed tree cutting of Scots pine stands in drained peatlands in northern Finland

We studied the establishment of natural seedlings after seed tree cutting and scalping in two drained Scots pine peatland stands in northern Finland (Simo and Sievi). Approximately, 50?ha^?1 of Scots pine stems were retained on both sites. During the six subsequent years, five seedling surveys were conducted. The effect of site preparation was analysed using generalized linear mixed models (GLMM). The mean density of pine seedlings increased more quickly in the scalped plots and was ca. 1.1?m^?2 after six years compared to 0.87?m^?2 in the non-scalped plots, on average. Scalping increased the number of pine seedlings 2-fold compared to that in non-treated plots in Simo, however, in Sievi non-treated plots had 30% higher pine seedling density after six years. Downy birch seedling density was 9–10-fold compared to that of non-treated plots in both sites. In terms of seedling density, seed tree cutting led to satisfactory pine regeneration after just two growing seasons in drained pine peatlands, even without scalping. Scalping significantly increased the number of pine seedlings, but it also enhanced the germination of birch seedlings strongly.     

Testing prescribed fire as a tool to promote Scots pine <Emphasis Type="Italic">Pinus sylvestris</Emphasis> regeneration

Techniques for encouraging natural tree regeneration are of increasing interest to managers of Scots pine Pinus sylvestris forests. We tested prescribed fire at a management scale, with deer present or excluded, as a means of increasing rates of Scots pine forest expansion on heathland. At a semi-natural pinewood in Scotland, ten experimental blocks were established, within range of pine seed-fall. Each block comprised four, 100 m² plots. Two plots at each site were burnt and two fenced, allowing the effects of burning on pine regeneration to be measured at two levels of deer abundance. We monitored pine seedlings, seed-fall, deer dung and vegetation for 5 years following treatment. Differences in seedling detection rates between treatments were quantified using dummy seedlings, and analyses corrected accordingly. Mean new pine seedling establishment was 9.8 times higher on burnt ground than unburnt ground (confidence intervals 3.2–30). Differences were even more pronounced in a year of high seed-fall, and following fires with low rates of spread. Establishment rates varied strongly between experimental blocks. Exclusion of deer increased establishment rates, but only in the first 2 years after fire. There was evidence that both seedling survival, and cumulative recruitment of older (over 12 months) seedlings, were improved by prescribed burning. Our results support the use of prescribed fire as a tool to promote increased Scots pine seedling establishment. This technique is likely to give strong fine-scale variation in seedling densities, and so would most suit areas where a variable spatial pattern of regeneration is sought, for landscape or naturalness reasons. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Control of bilberry vegetation by steam treatment – effects on seeded Scots pine and associated mycorrhizal fungi

In boreal forest, ground vegetation of bilberry (Vaccinium myrtillus L.) and feather mosses strongly suppress seed regeneration of Scots pine (Pinus sylvestris L.). We investigated a site preparation technique by steam treatment to control bilberry and moss vegetation after clear cutting. Sowing experiments were performed between 1993 and 1995 with Scots pine in four treatments: (1) untreated vegetation, (2) activated carbon added to the soil surface of otherwise intact ground vegetation, (3) steam treated vegetation, and (4) activated carbon added to the soil surface of steam treated vegetation. Activated carbon was added to adsorb possible phenolic compounds released from bilberry leaves and litter. Steam killed ground vegetation effectively and recolonisation of vascular plants and mosses was slow. Scots pine seedling establishment was improved by steam treatment especially when activated carbon was added to the soil surface. We interpret that activated carbon adsorbed and reduced the levels of phenolics from bilberry litter and humus, which otherwise may inhibit seed germination. Dry weight of four year old seedlings was three times higher in steam treated plots than in untreated plots. Seedling nutrient content was also strongly improved by steam treatment. We interpret the increased growth of seedlings in steam treated plots mainly as an effect of reduced resource competition from ground vegetation. Irrespective of treatment, almost all fine roots were colonised by ectomycorrhizal fungi. Using PCR-based molecular methods we were able to identify 28 taxa forming mycorrhiza on the seedlings. Steam treatment did not affect species richness and abundance of ectomycorrhizal inocculum. We conclude that steam treatment has the potential to be an efficient and environmentally acceptable method to reduce negative influence of bilberry vegetation on Scots pine seedling establishment and early growth.     

Interference of bracken (Pteridium aquilinum L. Kuhn) with Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst.) seedling establishment

The nature of interference of bracken with Scots pine and Norway spruce seedling establishment was considered in three field experiments. In a seeding experiment, it was found that Scots pine germination was highest on exposed mineral soil and lowest when intact bracken litter and humus were present, suggesting adverse effects of litter and humus on pine regeneration probably due to phytotoxicity. In a second experiment, smothering by bracken caused high mortality of Scots pine seedlings while Norway spruce seedlings were relatively unaffected. Mortality for both Scots pine and Norway spruce seedlings was low when planted in a adjacent Scots pine-bilberry stand with no bracken. Annual shoot growth of Norway spruce was higher in bracken than in Scots pine-bilberry vegetation while no differences in shoot growth between these two vegetation types occurred for Scots pine. In a third experiment, activated carbon was added to the ground under Norway spruce seedlings planted in bracken to adsorb possible phytotoxic compounds released by bracken. The addition of carbon had no effect on seedling mortality or growth rate, indicating that the seedlings were not susceptible to allelochemicals released by bracken. Since large Norway spruce seedlings were relatively unaffected by bracken interference in this study, artificial regeneration with containerized Norway spruce seedlings is suggested to achieve an acceptable conifer tree establishment on clear-cuts invaded by bracken.     

Damage by pine weevil Hylobius abietis to conifer seedlings after shelterwood removal

Abstract

Pine weevil (Hylobius abietis L.) damage to seedlings after overstorey removal was investigated in a survey study in six shelterwoods in the south–central part of Sweden. The shelterwoods predominantly consisted of Scots pine, except at one site where the shelter trees mainly consisted of Norway spruce. Before final cutting, 10 plots were laid out at each site and measurements of shelter trees and marked seedlings were taken. The seedlings were examined during the 2 years after final cutting. The study showed that removal of shelter trees increases the risk of severe damage by pine weevil and the variable that was most strongly correlated with the risk was the seedling root collar diameter. Both Scots pine and Norway spruce seedlings were severely damaged by pine weevil, and most of the feeding occurred during the first year after cutting. The amount of debarked area was significantly larger for Scots pine than for Norway spruce seedlings. Vitality (growth of the leading shoot before final cutting) of the seedlings also affected the probability of damage. Seedlings with high vitality were less damaged by pine weevil than seedlings with low vitality. For Scots pine the shelterwood density before final cutting was correlated to the intensity of pine weevil feeding after cutting. In conclusion, after the final cutting of a pine or spruce shelterwood, pine weevils will probably invade the area. To avoid serious damage, Norway spruce and Scots pine seedlings should have reached a diameter of at least 10–12 mm.     

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.     

Aggressiveness of Fusarium oxysporum and F. verticillioides isolates on stone and scots pine under greenhouse conditions

Scots pine (Pinus sylvestris) and Stone pine (Pinus pinea) are two important species used in re-forestation that are subject to damage by damping-off fungi in forest nurseries. Twenty-two isolates of Fusarium oxysporum and F. verticillioides from diseased seedlings of eight different hosts were tested for aggressiveness on seeds and seedlings of both pine species, including the effects on seedling emergence and mortality. Scots pine was more susceptible to damping-off than Stone pine, as indicated both by reduced seedling emergence and elevated seedling mortality. The impact of F. oxysporum and F. verticillioides on seeds and seedlings did not differ significantly for either pine species. Our findings support previous studies that found that these are damping-off pathogens on the studied pines. Whereas most isolates proved to be pathogenic, some isolates of both Fusarium species showed to be non-pathogenic.     

Light-mediated influence of three understorey species (Calluna vulgaris, Pteridium aquilinum, Molinia caerulea) on the growth of Pinus sylvestris seedlings

Depending on its developmental and morphological characteristics, shrubby or herbaceous understorey vegetation interacts differently with tree seedlings during the regeneration process. In acidic temperate forests, three common understorey plant species??Calluna vulgaris (L.) Hull, Pteridium aquilinum (L.) Kuhn in Kersten, Molinia caerulea (L.) Moench??are known to rapidly colonize forest gaps. Therefore, they often develop at the expense of light-demanding Scots pine (Pinus sylvestris L.) seedlings. An experiment was set up in a nursery in central France to mimic early competition occurring in a newly created gap between Scots pine seedlings and these three common understorey species (young forest-harvested individuals planted at 5 densities from 0 to 57 plants m^?2). Pine seedling survival and growth (height, diameter, shoot and root biomass) and a functional trait (leaf mass on an area basis, LMA) were measured for 2 years, and cross-analysed against plant density, plant cover and available light. When understorey plant density increased, pine seedling diameter growth and biomass were negatively affected by all three plant species; height growth only slowed beneath Pteridium. These negative effects were closely linked to competition for light beneath Pteridium and Molinia. The application of the Beer?CLambert law gave an extinction coefficient k that was high for Pteridium, intermediate for Molinia and much lower for Calluna. LMA was confirmed as an effective foliar trait to reflect the degree of stress undergone by pine seedlings.     

From planting to 26 years of age – actual growth and estimated volume scenarios for spruces and pines

The objective of this study was to compare the survival and volume of conifer stands at 26 years of age with their status at planting. Survival, growth and damage were studied in eight clear felled stands regenerated in 1972. Five of the areas were planted with Norway spruce (Picea abies (L.) Karst.) and three with Scots pine (Pinus sylvestris L.). The plantings were examined in 1972 and 1974. In 1974, the number of living undamaged planted seedlings was low (10–15%). However, the number of undamaged seedlings was supplemented by naturally regenerated conifer and birch seedlings. The total number of undamaged seedling in 1974 was equivalent to 20–30% of the number of seedlings planted. In 1998, the main species in three stands had changed from Norway spruce to Scots pine, and in one stand from Norway spruce to birches. Actual volume in 1998 for the stands was compared to stand volume generate according to five scenarios based on recommended and actual seedling number in 1972 and 1974. The actual volume was 64% of that expected if the recommended number of trees had been planted. Naturally regenerated Scots pine and Norway spruce increased stand density in 1998. The actual volume was 37% higher than the average volume in the surrounding county. On average, 36% of the trees were damaged. More than 50% of the total damage was caused by moose (Alces alces L.). For Scots pine, moose or other browsing animals damaged 30% of the trees. The results of this study indicate that the 1998 volume was higher than expected, considering the low number of undamaged seedlings in 1974. This was mainly due to the large amount of naturally regenerated plants. In addition, the results indicate that the volume could have been higher if the initial conditions had been better. Despite the low number of undamaged seedlings in 1974, seven of the eight studied stands produced a higher volume than the average stand for the region. In practise, high numbers of seedlings should be planted on scarified areas. In most cases there will be a supply of naturally regenerated seedlings.     

Browsing by large herbivores on Scots pine (Pinus sylvestris) seedlings in mixture with ash (Fraxinus excelsior) or silver birch (Betula pendula)

Abstract

Food selection by large herbivores occurs at a hierarchy of scales, for example landscape, patch or plant. Several hypotheses regarding food plant selection on patch or plant level have been developed. In this cafeteria-type design field experiment, conducted during one winter immediately after planting, we tested the effect of species mixture on browsing by large herbivores (mainly roe deer) on Scots pine seedlings in mixture with seedlings of ash (highly preferred) or silver birch (less preferred). Browsing on Scots pine was not affected by species mixture, neither in terms of the number of browsed pines nor browsing intensity. Instead, browsed biomass was positively and significantly correlated to the total biomass available for browsing. Also, there were differences due to species, with ash being most browsed (44.6%), followed by Scots pine (18.9%) and silver birch (11.6%). Browsed biomass per browsed seedling, however, was largest for Scots pine. In addition, browsed seedlings were initially taller compared to unbrowsed seedlings for all species. The main management implication in this study is that the species mixture did not influence large herbivore browsing on Scots pine seedlings. Hence, removing or discouraging more (or less) attractive browse species in early stages of pine regeneration activities seems unnecessary from the point of large herbivore browsing.     

Photosynthesis and root respiration of Pinus sylvestris and picea abies seedlings after different root freezing and storage temperatures

Photosynthetic performance and root respiration were measured for seedlings of Scots pine and Norway spruce under constant conditions in an open gas exchange system in the laboratory. Measurements were carried out after root exposure to ‐20, ‐5 and 0°C and subsequent longtime storage in darkness at +1 or +4°C. Stomatal conductance in relation to net photosynthetic rates was also investigated after the same treatment of seedlings. Root respiration was low for seedlings whose root system had been exposed to ‐20°C, Scots pine showing lower rates than Norway spruce. This was probably an indication of root damage. At least for one provenance of Scots pine, respiration rates were higher for seedlings stored at +1 than at +4°C. Photosynthetic performance was also lowest for seedlings whose roots had been exposed to +20°C compared to higher temperatures, the difference being more clear‐cut for Norway spruce than for Scots pine. Storage at +1 gave slightly higher photosynthetic rates than at +4°C. There was a close relation between stomatal conductance measured on individual needles and photosynthetic performance measured on the whole seedling.     

CLIMATE AND SILVICULTURAL IMPLICATIONS IN MODIFYING STAND COMPOSITION IN MIXED FIR-PINE STANDS

ABSTRACT

A growing concern exists over the decreasing proportion of Scots pine (Pinus sylvestris L.) trees in mixed Trojan fir (Abies nordmanniana subsp. equi-trojani [Asch. & Sint. Ex Boiss] Coode & Cullen)-Scots pine forests in northern Turkey. Given the changes in mean annual temperature and annual precipitation for the last 40 years in the region, understanding of the sensitivity of Trojan fir and Scots pine trees to changing climate seems to be critical so that better management strategies can be developed against the potential climate extremes of the future in the region. Moreover, our knowledge on the influence of current silvicultural methods on seedling density and growth in these forests is limited. Therefore, in this study, the growth response (i.e., radial growth) of Trojan fir and Scots pine trees to the changing climate were examined. In addition, the influence of current silvicultural practices on seedling growth and density in these forests was also monitored. Trojan fir appeared more sensitive to the climatic variables (i.e., temperature and precipitation) than Scots pine in the region. It was also found that the current silvicultural practices might favor Trojan fir over Scots pine in these forests. Natural dynamics and current silvicultural implications would benefit Trojan fir, however, given the species’ potential sensitivity to the changing climate, current silvicultural approaches can be modified to favor Scots pine, and to increase the resilience of these forests against climate extremes expected in the region’s future.     

Using cattle for conservation objectives in a Scots pine <Emphasis Type="Italic">Pinus sylvestris</Emphasis> forest: results of two trials

It has been argued that large ungulates play a key role in natural forest dynamics, but in Britain, the largest native ungulates (aurochs and elk) are extinct. Cattle could have some similar effects, and are widely used, but rarely tested, for nature conservation management. Here, we test conservation management with cattle at a native Scots pine Pinus sylvestris forest in Scotland. Our hypotheses were that cattle impacts would (a) increase the abundance of an understorey shrub of conservation importance, bilberry Vaccinium myrtillus; and (b) increase Scots pine seedling establishment. Two cattle trials were established, one for each objective, based on a 14-ha plot within the forest, and a 6.1-ha plot at the forest edge. Cattle were introduced for 2 months to both plots, giving an approximately 100- to 150-fold increase in ungulate biomass per hectare when compared to background deer abundance. The ground layer vegetation in both treatment and matched control plots was monitored before and after treatment, and subsequently over a 4-year period. At the within-forest trial, bilberry percent-cover, 4 years after treatment, was 1.9 times higher in the cattle area than in the control (95% confidence limits 1.6–2.3). Bilberry percent-cover increases were directly related to the degree of trampling impact on heather Calluna vulgaris, as recorded immediately after the trial. At the forest-edge trial, there were vegetation changes in the cattle plot that were considered favourable to pine seedling establishment: reduced moss/litter depth and vegetation percent-cover, and increased ground-level light incidence. However, too few new pine seedlings were found for formal analysis, partly due to unexpectedly low seed-fall. Nevertheless, the potential for cattle to create conditions that would subsequently promote pine regeneration was illustrated by the observation of large numbers of new, young pine seedlings at the within-forest cattle plot. We recommend that managers and researchers collaborate to develop further trials like the ones reported here, to give an improved understanding of the conditions under which cattle can yield nature conservation benefits in woodlands.     

Influence of environmental conditions on germinant survival and diversity of Scots pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.) in central Spain

The aim of the study was to investigate dynamics and pattern of natural regeneration and the influence of seedbed and light on germination and initial seedling survival of Scots pine (Pinus sylvestris L.) during three growing seasons. Four 5-m² plots in a natural Scots pine forest in central Spain were randomly established at the beginning of the regeneration process. Germination and seedling survival were recorded in 100 regeneration sampling subplots (0.25 m²) per plot, while seedbed type and the relative light intensity reaching the forest floor was characterised in 1-m² subplots. The spatial correlations between survival, light conditions and organic matter depth were analysed through cross-variograms. Germination and survival were highly variable both within and between plots (ranging from 0 to 89%) and affected by high summer temperatures (33–35°C) in 2003. The spatial pattern characterisation of survival by Ripley’s K function showed a dominant cluster distribution. Occurrence tended to be clumped when abundance was greater than 15 seedlings, whereas for lower densities, seedlings were randomly distributed. Seedlings and herbs occupied the same sites where environmental conditions were appropriate for them to live. Spatial association occurred frequently for light and organic matter depth. Results suggested that the Scots pine seedlings in our study in central Spain preferred moderate light conditions (Global Site Factor <0.40). Thus, if this forest is to be naturally regenerated with Scots pine, the shelterwood system (whereby some mother trees are left to provide shelter for at least 5 years), along with mechanical disturbance of the seedbeds, would promote seed germination, as long as a seed source is present. However, regeneration success is affected by year-to-year conditions.     

Initial growth of Pinus sylvestris advance reproduction following varying degrees of release

Initial growth of released Scots pine (Pinus sylvestris L.) advance reproduction in nine stands dominated by Scots pine was studied in north Sweden. In each stand, one 40 × 40 m plot was established for each of four different intensities of overstorey removal: 0% (control), 60%, 85%, and 100%. Seedings were monitored on one 18 × 8 m sub‐plot at the centre of each plot for two growing seasons following overstorey treatment. Only undeformed seedlings, uninjured before treatment and during the study period, were considered. In the second growing season, needle lengths and number of laterals increased or tended to increase compared to the control for all treatments. Compared to the control, leading annual shoot lengths for all treatments initially tended to decrease (seedlings > 10.0 cm), but increased or tended to increase (all seedlings) during the second growing season. It is concluded that seedling performance generally improved with increasing basal area removal.     

Outdoor winter storage of container stock on raised pallets—effects on root zone temperatures and seedling growth

Containerized seedlings of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) were overwintered on the ground and above ground on pallets. Soil temperatures in elevated containers were lower and showed greater fluctuation than containers on the ground. The lowest temperatures (‐15 to ‐16°C) were observed in containers stored on pallets with little or no snow cover during the winter. Temperatures in the edge rows of containers were lower than interior bed soil temperatures. Lower temperatures were also observed in the top than in the bottom of the container. The storage on pallets resulted in reduced shoot and root growth. Although insulation preventing air movements beneath the container units improved soil temperature conditions and subsequent seedling growth, the best result was obtained when seedlings were stored directly on the ground surface.     

Effect of Reforestation Methods on Pine Weevil (Hylobius abietis) Damage and Seedling Survival

Örlander, G.1 and Nilsson, U. (Swedish University of Agricultural Sciences, The Southern Swedish Forest Research Centre, Asa Forest Research Station, S-360 30 Lammhult, Sweden and Swedish University of Agricultural Sciences, The Southern Swedish Forest Research Centre, Box 49, S-230 53 Alnarp, Sweden). Effect of reforestation methods on pine weevil (Hylobius abietis) damage and seedling survival. Received Feb. 16, 1998. Accepted Sept. 15, 1998. Scand. J. For. Res. 00: 000-000, 199X. Damage to Norway spruce (Picea abies (L.) Karst.) seedlings by the large pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), was monitored in relation to clear - cutting age and silvicultural treatments in southern Sweden. New clear - cuttings were established on four sites during five consecutive years, and seedlings were planted on them from 1989 through 1993. In total, 31 774 seedlings were planted on 20 clear - cuttings. The measures evaluated were seedling insecticide treatment, application of herbicide to ground vegetation, scarification (mound) and planting late in the season. In addition, the effects of slash removal and seedling type were studied. The pine weevil was, by far, the dominant damaging agent. Planting without insecticide or soil treatment on fresh, one- or two - year - old clear - cuttings resulted in a mean level of weevil - caused mortality exceeding 60%. The results indicate that the risk of serious damage by pine weevils remains high until the clear - cuttings reach four or five years of age. Killing the vegetation with herbicide had no effect on pine weevil damage. Slash removal decreased damage on older clear - cuttings, but the effect was small. Scarification (mounding) strongly reduced damage. On fresh clear - cuttings the mean mortality caused by pine weevils in mounded plots was 13%, whereas it was 77% in the controls. The mounding effect varied between sites and clear - cuttings of different ages. Late planting (10 June instead of 1 May) reduced damage on two- and three - year - old clear - cuttings. Three - year - old, bare - rooted seedlings were not damaged as seriously as two - year - old, containerized ones, but the effect was probably due to the larger size of the bare - rooted seedlings. Non - lethal injury resulted in reduced seedling growth. Damage by pine weevils varied between years and within growing seasons. However, on fresh, one- and two - year - old clear - cuttings, damage was severe enough to cause high mortality during all studied years.     

Responses of conifer species of the Great Lakes region of North America to inoculation with the pitch canker pathogen Fusarium circinatum

Five conifer species grown in the Great Lakes region of North America were examined for their susceptibility to Fusarium circinatum, (syns. Fusarium subglutinans f. sp. pini and F. moniliforme var. subglutinans), the causal agent of pitch canker. Three‐year‐old (3‐0) seedlings of red (Pinus resinosa), jack (P. banksiana) eastern white (P. strobus), Scots (P. sylvestris) and Austrian (P. nigra) pine were planted in 4 l pots in a greenhouse at Auburn University in November 1998. In April and June 1999, seedlings were inoculated by removing a needle fascicle approximately 5 cm from the terminal bud and placing a drop containing F. circinatum conidia on the wound. Resin production, canker length and seedling mortality were recorded 12 weeks later. Jack, Scots and eastern white pine were the most susceptible with Austrian and red pine more resistant to the fungus. F. circinatum was re‐isolated from 37% to 96% of inoculated seedlings. The susceptibility of jack, Scots and eastern white pine indicates a potential risk to these important species of the region if F. circinatum were to be introduced into the area.     

Induced competition among scots pine seedlings and its effect on future timber quality

Height and diameter increment and timber quality in Scots pine (Pinus sylvestris L.) planted as seedlings of different sizes were studied in two experiments. When compared 32–37 years after planting, seedlings that were smaller than neighbouring seedlings at the time of planting, had generally attained lower height and diameter, and had higher mortality compared to seedlings that were of equal size or larger than their neighbours. Tree size was strongly related to seedling size two years after planting. Trees originating from small seedlings had thinner annual rings and branches than trees originating from large seedlings. These characters are of importance for timber quality. It seems that the competitive ability of a tree is to a large extent established early in stand development.     

Root growth capacity and field performance of Pinus sylvestris and Picea abies seedlings

Correlations between root growth capacity (RGC), at the time of planting, and field performance were studied for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings. Before planting a gradient in seedling viability was generated through exposure to low root temperatures and different winter storage regimes. The hypothesis that high RGC values would improve field performance was to some extent verified for pine seedlings while no correlations could be registered for spruce. Reasons for these results are discussed.