The mycorrhizal condition of weakened Scots pine saplings grown on ploughed sites in northern Finland

1989 ◽  
Vol 19 (3) ◽  
pp. 341-346 ◽  
Author(s):  
H. Väre

The mycorrhizal condition of nursery-grown containerized Scots pine (Pinussylvestris) saplings planted in clear-cut and ploughed sites in northern Finland was investigated. The saplings, 15 years old on average, were classified on the basis of shoot condition into injured and healthy-looking saplings on the ploughed sites and control saplings on the adjoining natural sites. Ploughing after clear-cutting resulted in reduced mycorrhiza formation, the average percent infection being below 20 for injured saplings and between 60 and 85 for the control saplings. Formation of the mantle and Hartig net was weak in the injured saplings and reduced in the healthy-looking saplings compared with the control saplings, where the mantle had a mean thickness of 31.3 μm and the Hartig net was fully developed. The number of short roots and the short root biomass were greatly reduced in the healthy-looking saplings compared with the control saplings. These results indicate that the practice of ploughing in the clear-cut areas of northern Finland had caused a marked reduction in the growth of the whole short root system and in the formation of mycorrhizae in both the injured and healthy-looking saplings. The poor formation of mycorrhizae is clearly linked to the reduced growth of shoots at these sites.

2020 ◽  
Vol 50 (8) ◽  
pp. 819-828
Author(s):  
Matti Koivula ◽  
Harri Silvennoinen ◽  
Hanna Koivula ◽  
Jukka Tikkanen ◽  
Liisa Tyrväinen

Forest management, characterized in many northern countries by the predominance of clear cutting and growing even-aged and -sized trees, has simplified the structure of boreal forests. Consequences include alterations in cultural ecosystem services such as forest attractiveness, i.e., combined aesthetic and recreational values. Continuous-cover forestry might mitigate these effects through the use of selection and gap cutting, but these methods have been little studied, particularly from the attractiveness viewpoint. We used photo surveys to assess Finnish citizens’ perceptions of attractiveness of in-stand scenery of Scots pine (Pinus sylvestris L.) forests logged using different methods. (i) The attractiveness scores, given by respondents, declined steadily from unharvested forest through continuous-cover methods to seed-tree and clear-cut methods. (ii) Respondents with a negative attitude to forest management gave lower scores than respondents with a positive attitude, but the declining slopes of attractiveness against logging intensity were similar. (iii) In unharvested and less intensively managed stands, summer photos received higher scores than corresponding winter photos. (iv) Background variables (gender, education, living environment, memberships in recreational or nature NGOs, forestry profession, and forest ownership) had negligible effects on the scores. We recommend the use of continuous-cover logging methods in settlement and recreational areas.


2007 ◽  
Vol 37 (2) ◽  
pp. 404-414 ◽  
Author(s):  
Jussi Heinonsalo ◽  
Robin Sen

The aims of this microcosm-based study were to characterize Scots pine ectomycorrhizal (EcM) inoculum potential in humus (O) and underlying eluvial (E) and illuvial (B) mineral podzol soil horizons and to compare the inoculum potential 1 and 4 years following clear-cut logging. The specific horizons were collected from a Scots pine control uncut stand, the adjacent interface zone (3–10 m from the forest edge), and the adjoining clear-cut area. The highest Simpson's reciprocal diversity indices (SRDI) of ectomycorrhizal morphotypes and polymerase chain reaction – internal transcribed spacer – restriction fragment length polymorphism (PCR-(ITS)-RFLP) taxa were detected in the humus and E horizon. The B horizon supported the lowest SRDI, but the community consisted of mycorrhizas representing active rhizomorph-forming species. Identified RFLP taxa, confirmed via ITS sequence analysis, highlighted horizon specificity for some genera and species. With respect to clear-cutting impacts, the most dominant ectomycorrhizal morphotypes detected and diversity indices were the same irrespective of the sampling time, which strongly indicates that inoculum potential is maintained up to four growth seasons after the clearcut. No forest treatment dependent differences in Scots pine seedling biomass were detected, but, compared with humus, significantly reduced biomass was recorded in deeper mineral soil horizons. The data are discussed in relation with recent vertical profile studies and forest silvicultural practices.


Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 943
Author(s):  
Katri Nissinen ◽  
Virpi Virjamo ◽  
Antti Kilpeläinen ◽  
Veli-Pekka Ikonen ◽  
Laura Pikkarainen ◽  
...  

We studied the growth responses of boreal Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and silver birch (Betula pendula Roth) seedlings to simulated climate warming of an average of 1.3 °C over the growing season in a controlled field experiment in central Finland. We had six replicate plots for elevated and ambient temperature for each tree species. The warming treatment lasted for the conifers for three growing seasons and for the birch two growing seasons. We measured the height and diameter growth of all the seedlings weekly during the growing season. The shoot and root biomass and their ratios were measured annually in one-third of seedlings harvested from each plot in autumn. After two growing seasons, the height, diameter and shoot biomass were 45%, 19% and 41% larger in silver birch seedlings under the warming treatment, but the root biomass was clearly less affected. After three growing seasons, the height, diameter, shoot and root biomass were under a warming treatment 39, 47, 189 and 113% greater in Scots pine, but the root:shoot ratio 29% lower, respectively. The corresponding responses of Norway spruce to warming were clearly smaller (e.g., shoot biomass 46% higher under a warming treatment). As a comparison, the relative response of height growth in silver birch was after two growing seasons equal to that measured in Scots pine after three growing seasons. Based on our findings, especially silver birch seedlings, but also Scots pine seedlings benefitted from warming, which should be taken into account in forest regeneration in the future.


Author(s):  
Alexander Tymczuk

In a globalized world where mobility and movement is at its essence, the movement of viruses paradoxically causes a preoccupation with boundaries, containment, and control over borders, and thus keeping the “dangerous” outside separated from the “safe” inside. Through a qualitative thematic and frame analysis of news articles published on 12 Ukrainian news sites, I found that Ukrainian labour migrants conceptually constitute a challenge to such a clear-cut spatial organization in a time of a pandemic. Labour migrants are part of the national “we,” but their presence in the dangerous outside excludes them from the “imagined immunity.” This ambiguity is evident in the way labour migrants were portrayed during the first months of the outbreak in Ukraine. Initially, Ukrainian labour migrants were depicted as a potential danger, and then blamed for bringing the virus back home. However, the framing of the labour migrants as a danger is only part of the story, and the image of a scapegoat was eventually replaced with images of an economic resource and a victim. Thus, Ukrainian labour migrants have been the object of vilification, heroization, as well as empathy during the various phases of the outbreak. I would argue that these shifting frames are connected to the ambiguous conceptualization of Ukrainian labour migrants in general.


Africa ◽  
1979 ◽  
Vol 49 (2) ◽  
pp. 112-133 ◽  
Author(s):  
Cynthia Brantley

Opening ParagraphWherever belief in witchcraft permeated an African society, fear prevailed and people demanded protection and control. Even though the degree of African concern about witchcraft was not always appreciated by outsiders, it was possible, at least in centralized societies, for such outsiders to discern the processes that were involved in its control. A king or a priest who failed to control the spread of witchcraft and to alleviate the fear was unlikely to maintain his authority for long. In non-centralized societies, the problem of witchcraft and the means of control were less clear-cut. Solutions were rarely obvious and easy.


2004 ◽  
Vol 31 (10) ◽  
pp. 971 ◽  
Author(s):  
Darren M. Mingo ◽  
Julian C. Theobald ◽  
Mark A. Bacon ◽  
William J. Davies ◽  
Ian C. Dodd

Tomato (Lycopersicon esculentum Mill.) plants were grown in either a glasshouse (GH) or a controlled environment cabinet (CEC) to assess the effects of partial rootzone drying (PRD) on biomass allocation. Control and PRD plants received the same amounts of water. In control plants, water was equally distributed between two compartments of a split-root system. In PRD plants, only one compartment was watered while the other was allowed to dry. At the end of each drying cycle, wet and dry compartments were alternated. In the GH, total biomass did not differ between PRD and control plants after four cycles of PRD, but PRD increased root biomass by 55% as resources were partitioned away from shoot organs. In the CEC, leaf water potential did not differ between treatments at the end of either of two cycles of PRD, but stomatal conductance of PRD plants was 20% less at the end of the first cycle than at the beginning. After two cycles of PRD in the CEC, biomass did not differ between PRD and control plants, but PRD increased root biomass by 19% over the control plants. The promotion of root biomass in PRD plants was associated with the alternation of wet and dry compartments, with increased root biomass occurring in the re-watered compartment after previous exposure to soil drying. Promotion of root biomass in field-grown PRD plants may allow the root system to access resources (water and nutrients) that would otherwise be unavailable to control plants. This may contribute to the ability of PRD plants to maintain similar leaf water potentials to conventionally irrigated plants, even when smaller irrigation volumes are supplied.


Circulation ◽  
2014 ◽  
Vol 129 (suppl_1) ◽  
Author(s):  
Keerthana K Karumbaiah ◽  
Mazen B Omar ◽  
Bassam A Omar

Background: Non-compliance with laboratory appointments, separate from clinic visit appointments, for measuring fasting cholesterol may hinder documentation and control of patients’ lipids. Methods: A university-based cardiologist’s clinic notes, from a single year (yr 1), when patients were asked to have a fasting cholesterol a week prior to the clinic visit, were analyzed (100 patients). The poor compliance prompted a same day as the clinic visit measurement (fasting or non-fasting) of lipids, for patients who could not comply with their laboratory appointment, during the following year (yr 2; 130 patients). Lipid values were managed by a subsequent call to the patient. All patients had coronary artery disease or risk equivalent mandating LDL levels < 100 mg/dL. Results: In yr 1, 62% (62/100) of patients had documented lipid profiles compared to 83% (108/130) of patients in yr 2. The average LDL in yr 1 was 115 +/- 36 mg/dL compared with 96 +/- 31 mg/dL in yr 2 (P < 0.01). Only 22% of the patients in yr 1 reached goal of < 100 mg/dL, compared with 65% in yr 2. There were no significant differences in the HDL, TG levels or blood pressures documented during the concurrent visits. Conclusion: Better documentation and control of lipids may be obtained when lipid profiles are done on clinic visit day, with fewer burdens on the patients who cannot comply with a separate laboratory appointment. Although there were many non-fasting levels as a result, the triglyceride levels where not significantly different among the two groups, probably reflecting an overall more intensive lipid management in yr 2, commensurate with the better documentation. Therefore, as has been shown by others, a lipid profile does not necessarily have to be fasting, especially in patients being treated for stricter targets such as our cohort, which may decrease the burden on patients unable to comply with a fasting state or added clinic visits.


1983 ◽  
Vol 61 (5) ◽  
pp. 970-980 ◽  
Author(s):  
Arthur M. Martell

Changes in small mammal communities following logging were monitored in clear-cut and strip-cut upland black spruce (Picea mariana) stands and in selectively cut mixed wood stands in north-central Ontario. Clear-cutting and subsequent scarification essentially eliminated the vegetative cover. Much of the ground cover recovered within 5 years and shrubs within 12 years, but mosses and lichens took much longer. The small mammal community in both clear-cut and strip-cut stands changed over the first three years after logging from one dominated by southern red-backed voles (Clethrionomys gapperi) to one dominated by deer mice (Peromyscus maniculatus) and then remained relatively stable for up to 13 years after harvest. That shift was not apparent in selectively cut mixed wood stands where the composition of the small mammal community was similar between uncut stands and stands 4–23 years after harvest. There was relatively little change in total numbers of small mammals after logging. In general, the diversity and evenness of small mammals increased or remained stable in the first 1–3 years following harvest, decreased on older (3–16 years) cuts, and then increased to values similar to those in uncut stands on the oldest (19–23 years) cuts.


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