Impact of solar activity on the growth of pine trees: case study

Under natural conditions, Siberian pine Pinus sibirica begins to produce commercial cone yields of nuts relatively late (after more than 100 years). The aim of this study was to summarise the experience of the directed formation of Siberian pine forests in Siberia. Experimental objects included plots with traditional thinning of varying intensity and frequency as well as chemical treatment. We assessed the parameters of the stand and its seed production dynamics. Only stands with a minimum density (395–435 trees·ha–1) had a normal seed production energy (1.5 or more cones per shoot). Over-dense stands (830–930 trees·ha–1) were characterised by a low seed production energy (two times or more below the threshold value). In all plots, there were Siberian pine trees with absent or unacceptable seed production energy, which should be removed (DBH up to 28 cm). Seed production energy positively correlated with most tree parameters (age, height, diameter, volume, length and width of crown).

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Postmidnight equatorial plasma irregularities on the June solstice during low solar activity – a case study

Annales Geophysicae ◽

10.5194/angeo-37-657-2019 ◽

2019 ◽

Vol 37 (4) ◽

pp. 657-672

Author(s):

Claudia M. N. Candido ◽

Jiankui Shi ◽

Inez S. Batista ◽

Fabio Becker-Guedes ◽

Emília Correia ◽

...

Keyword(s):

Solar Activity ◽

Low Latitude ◽

Plasma Irregularities ◽

Fabry Perot ◽

June Solstice ◽

Spread F ◽

Plasma Depletions ◽

Dip Angle ◽

Layer Peak

Abstract. We present a case study of unusual spread-F structures observed by ionosondes at two equatorial and low-latitude Brazilian stations – São Luís (SL: 44.2∘ W, 2.33∘ S; dip angle: −6.9∘) and Fortaleza (FZ: 38.45∘ W, 3.9∘ S; dip angle: −16∘). The irregularity structures observed from midnight to postmidnight hours of moderate solar activity (F10.7 < 97 sfu, where 1 sfu = 10−22 W m−2 s−1) have characteristics different from typical post-sunset equatorial spread F. The spread-F traces first appeared at or above the F-layer peak and gradually became well-formed mixed spread F. They also appeared as plasma depletions in the 630.0 nm airglow emissions made by a wide-angle imager located at the nearby low-latitude station Cajazeiras (CZ: 38.56∘ W, 6.87∘ S; dip angle: −21.4∘). The irregularities appeared first over FZ and later over SL, giving evidence of an unusual westward propagation or a horizontal plasma advection. The drift-mode operation available in one of the ionosondes (a digital portable sounder, DPS-4) has enabled us to analyze the horizontal drift velocities and directions of the irregularity movement. We also analyzed the neutral wind velocity measured by a Fabry–Pérot interferometer (FPI) installed at CZ and discuss its possible role in the development of the irregularities.

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The distant future of solar activity: A case study of Beta Hydri. II - Chromospheric activity and variability

The Astrophysical Journal ◽

10.1086/172211 ◽

1993 ◽

Vol 403 ◽

pp. 396 ◽

Cited By ~ 11

Author(s):

D. Dravins ◽

P. Linde ◽

K. Fredga ◽

G. F. Gahm

Keyword(s):

Solar Activity ◽

Distant Future ◽

Chromospheric Activity

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Vertical distribution of epiphytic bryophytes depends on phorophyte type; a case study from windthrows in Kampinoski National Park (Central Poland)

Folia Cryptogamica Estonica ◽

10.12697/fce.2020.57.08 ◽

2020 ◽

Vol 57 ◽

pp. 59-71

Author(s):

Barbara Fojcik ◽

Damian Chmura

Keyword(s):

Vertical Distribution ◽

National Park ◽

Vertical Gradient ◽

Quercus Petraea ◽

Lower Trunk ◽

Central Poland ◽

Pine Trees ◽

The Vertical Distribution ◽

Occurrence Of Species

The vertical distribution of epiphytic bryophytes in European forests are still relatively poorly understood. The aim of the study was to analyse the diversity and vertical zonation of epiphytic mosses and liverworts on selected tree types (Quercus petraea, Betula pendula and Pinus sylvestris) within windthrow areas in the Kampinoski National Park (Central Poland). The investigations were performed in five parts of the trees: the tree base, lower trunk, upper trunk, lower crown, and upper crown. Deciduous trees have more species than pine trees (13 on Quercus and Betula, 8 on Pinus). The type of phorophyte was crucial for the differences in the species composition from the tree base to the upper crown that was observed. The highest richness of bryophytes was recorded on the tree bases, while the lowest was recorded in the upper parts of the crowns. The variability of the habitat conditions in the vertical gradient on the trunk that affected the patterns of the occurrence of species with different ecological preferences was determined using the Ellenberg indicator values. An increase in the value of the light and acidity indicators from the base of the trunk upwards and decreasing tendency in the case of moisture indicator was noted.

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