摘要:

The effectiveness of a plastic collar designed to protect planted seedlings against damage caused byHylobius abietis(L.) (Col., Curculionidae) was evaluated at 63 planting sites in southern Sweden during 1979 and 1980. Nearly 10 000 collar‐protected pine and spruce plants and 10 000 controls were carefully examined forHylobius‐damage and other injuries. In addition, the impact of some microsite factors on weevil damage and collar performance was evaluated, and the height growth was measured. The protective effect of the collar for two seasons after planting was comparable to that of insecticides and was best at sites with sparse vegetation and high weevil pressure. Proper application of the collar was crucial for good control. Collars were not observed to affect plant growth. Soil scarification reduced mortality in both collared plants and controls.

ISSN:0282-7581    

DOI:10.1080/02827588609382396

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Two‐year‐old seedlings ofBetula pendulaRoth of three provenances were cut to stump heights of 0 and 10 cm. The birch stumps were exposed to different light levels (25–400 μEm−2s−1) and temperatures (6–24°C) for 100 days in climate chambers. Birches were also cut down to seven stump heights (0, 2, 5, 10, 15, 20 and 25 cm) and exposed to light intensity 25 and 200 μEm−2s−1at 12/6°C for 100 days in climate chambers. In the third experiment 10 cm stumps of birch were exposed to different light intensities (10–400 μEm−2s−1) for 30 days in a greenhouse at 20°C. Starch content in root systems was analyzed before and after treatment. Ten stumps per treatment were used in the experiments except the third experiment where 15 stumps were used. The number of sprouting stumps was correlated with light intensity and temperature. None of the stumps exposed to 6 or 9°C produced suckers. At stump height 0 cm fewer sprouting stumps were produced than at 10 cm. The mean height of suckers was higher the higher the temperature both on 0 and 10 cm stumps. There were differences between provenances in height growth. The number of suckers per sprouting stump was not related to temperature or light intensity. Starch content in root systems of 10 cm high stumps was 4.0% compared with 14.7% in root systems of non‐stumped birch plants after 30 days in the greenhouse. Starch content decreased from 4.0 to 3.0% with decreasing light intensity (400–10 μEm−2S−1). The number of suckers and their mean height were correlated with starch content depending on light intensity.

ISSN:0282-7581    

DOI:10.1080/02827588609382397

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Leader shoots from juvenile succulent Norway spruce seedlings were used as cuttings 11 weeks after sowing. The seedlings were grown for 6 additional weeks and then apically dominant and lateral shoots were also used as cuttings. These three cutting categories, leaders, dominants and laterals, rooted 99.4, 99.0 and 97.5 % respectively and performed differently with respect to rooting development, number of roots per cutting and response to IBA and PIBA treatments (synthetic auxins). A large individual variation in number of roots per cutting, which auxin treatments did not reduce, was present within each cutting categoty. Laterals from the three different families included in the study showed a different variation than did leaders and dominants. Generally, the juvenile succulent cuttings were easy to root. Seedlings grown at a rather high light intensity (62 W/m2) had the potential to give good rooting even without hormonal treatments.

ISSN:0282-7581    

DOI:10.1080/02827588609382398

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Containerized seedlings of Norway spruce (Picea abies(L.) Karst.) and Scots pine(Pinus sylvestrisL.) 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.

ISSN:0282-7581    

DOI:10.1080/02827588609382399

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Above‐ground biomass has been measured on fertilized and control plots up to stand age 31 years. Each biomass fraction was estimated by two statistically coupled linear models with squared diameter at breast height as independent variable. All fractions except reproductive structures of pine and dead branches of spruce were estimated at high precision levels,R.between 0.93 and 0.99. The above‐ground biomass fractions per hectare could be precisely described by stem volume with bark. Application of the models for prognostic purposes is discussed. Annual above‐ground net biomass production in pine increased from 2.05 to 4.34 MT d.m./ha‐yr on control plots over 11 years, while plots given complete fertilizer mixture ranged from 6.75 to 9.09. Spruce stands with a nearly optimum water relationship and fertilizer programmes yielded from 9.50 to 11.86 MT d.m./ha‐yr. The combination of energy and timber production in highly productive peatland stands is discussed.

ISSN:0282-7581    

DOI:10.1080/02827588609382400

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In this study we applied a theoretical model for determining the projection area of a Scots pine(Pinus sylvestrisL.) crown in different directions. The model is based on the assumption that the foliage elements (shoots) are randomly distributed within a symmetrical crown envelope. The model was tested using photographically measured data for three young Scots pine crowns. The compatibility between calculated and measured values was satisfactory.

ISSN:0282-7581    

DOI:10.1080/02827588609382401

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Seedlings ofPinus sylvestriswere cold‐stored for three or six months at ‐4°C or 2°C or overwintered outdoors. Dry weight development and net photosynthetic capacity were then measured during a 60‐day cultivation period in a controlled environment. In all storage regimes the longer storage period gave a faster growth initiation. Photosynthetic recovery was faster for seedlings stored at 2°C than at ‐4°C, due to better recovery of stomatal conductance. The results suggest that there is little difference in seedling development between storage temperatures of ‐4°C and 2°C whereas outdoor storage might cause certain negative effects on subsequent growth of seedlings. This result is discussed with regard to the present winter climate.

ISSN:0282-7581    

DOI:10.1080/02827588609382402

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Cortical oleoresins were obtained from 10 natural populations ofPinus sylvestrisL. from different geographical localities. Gas chromatography was used to determine quantities of individual monoterpenes. Considerable variation was found in monoterpene composition among different populations. High proportions of limonene occurred in greater percentages in trees of northern origins, while high sabinene was frequently found in southern trees. Mean proportions of limonene and sabinene in the populations were clinal with latitude. For some monoterpenes, variation coefficients as a measure of variability within populations appeared to be clinal with latitude. 85.4% of the variance in monoterpene composition was found within populations and 14.6 between populations. Discriminant analysis differentiates populations from different geographical localities into different groups. The differences in monoterpene patterns between adjacent populations were statistically nonsignificant. It is recommended that monoterpene composition be used for more general study of genetic variation, geographical distinction between different populations and seed certification purposes.

ISSN:0282-7581    

DOI:10.1080/02827588609382403

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Peat bulk density, water content, and pH were studied on a raised bog in central Sweden with particular attentiontothe demand of the crops. Volume defined samples of the 0–30 cm soil layers were taken during 1981 and 1982 in order to find out seasonal patterns and between‐treatment variations of the soil characteristics. Four plots with different liming, fertilization, and irrigation regimes were included in the investigation. Two willow plots(Salix viminalisandS. dasyclados)and one plot withAlnus incanawere all irrigated‐fertilized by drip tubes during the growing season while an unplanted reference plot was not. Large variations in the studied soil properties occurred within all the plots at any time, to a great extent depending on variations in the mixture of Eriophorum and Sphagnum in the peat. Peat bulk density tended to be higher in the irrigated‐fertilized plots than in the reference plot and averaged about 70 and 63 g . dm−3, respectively. Water content increased rapidly with depth in the irrigated plots and the pores were filled with water to about 90% at 6 cm depth. Seasonal fluctuations were small. The reference plot contained less water than the irrigated ones and the water content increased almost linearly with increased depth in this plot. The seasonal fluctuations were large, with the lowest water content in late summer. A somewhat higher degree of humification and a higher water‐holding capacity was found in the soil of irrigated‐fertilized plots than in the reference. Microbiological activity, decomposition rate of litter, and recycling of nutrients should be high and favourable under these circumstances resulting in increased soil fertility. The soil also contained enough air in the pores to allow good root growth. Liming increased pH in the 0–30 cm soil layer and irrigated‐fertilized plots showed a faster increase of pH than the reference plot. However, the pH profiles obtained were concluded to be non‐optimal for the root growth of willow but satisfactory for grey alder. The use of KCI solution instead of distilled water in pH measurements resulted in lower pH values but also in smaller seasonal fluctuations. The difference was smaller near the soil surface than further down in the peat, indicating a higher base saturation in upper soil layers than in lower.

ISSN:0282-7581    

DOI:10.1080/02827588609382404

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Many forest trees exhibit reduced growth or are killed when the soil is low in oxygen. Anaerobic soil conditions are associated with flooding or compaction of soil but also occur commonly in soils of heavy texture. Reductions in height growth, leaf growth, cambial growth and reproductive growth of trees growing on poorly aerated soils are well documented. The amount of growth reduction varies widely among species and duration of anaerobic soil conditions during the growing season. Inhibition of growth is preceded by changes in physiological processes, including food, water, hormone, and mineral relations. Some species can adapt to soil anaerobiosis by (1) producing hypertrophied lenticels which assist in aeration of the stem and release of toxic compounds, and (2) growing new roots to replace loss of original roots under anaerobic conditions. The replacement roots assist in absorption of water and mineral nutrients and in oxidizing the rhizosphere and detoxifying soil toxins. Ethylene, together with other compounds, appears to play an important causal role in morphological adaptations to soil anaerobiosis. Some forest trees can also adapt metabolically to poor soil aeration.

ISSN:0282-7581    

DOI:10.1080/02827588609382405

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor