The origin of Lake Cheko and the 1908 Tunguska Event recorded by forest trees

Terra Nova ◽  
2014 ◽  
Vol 26 (6) ◽  
pp. 440-447 ◽  
Author(s):  
Luca Gasperini ◽  
Carlo Stanghellini ◽  
Romano Serra
Keyword(s):  
Forest Trees ◽  
Tunguska Event

The Tunguska event and Cheko lake origin: dendrochronological analysis

2014 ◽  
Vol 14 (3) ◽  
pp. 345-357
Author(s):  
Fantucci Rosanna ◽  
Serra Romano ◽  
Kletetschka Gunther ◽  
Di Martino Mario
Keyword(s):  
Basal Area ◽  
Forest Trees ◽  
Alluvial Deposits ◽  
Continuous Growth ◽  
Dendrochronological Analysis ◽  
Lake Formation ◽  
Growth Increase ◽  
Vigorous Growth ◽  
Tunguska Event ◽  
River Plain

AbstractDendrochronological research was carried out on 23 trees samples (Larix sibirica and Picea obovata) sampled during the 1999 expedition in two locations, close to the epicentre zone and near Cheko lake (N 60°57′, E 101°51′). Basal Area Increment (BAI) analysis has shown a general long growth suppression before 1908, the year of Tunguska event (TE), followed by a sudden growth increase due to diminished competition of trees that died due to the event. In one group of the trees, we detected growth decrease for several years (due to damage to the trunk, branches and crown), followed by growth increase during the following 4–14 years. We show that trees that germinated after the TE, and living in close proximity of Cheko lake (Cheko lake trees) had different behaviour patterns when compared to those trees living further from Cheko lake, inside the forest (Forest trees). Cheko lake trees have shown a vigorous continuous growth increase. Forest trees have shown a vigorous growth during the first 10–30 years of age, followed by a period of suppressed growth. We interpret the suppressed growth by the re-established competition with the surroundings trees. Cheko lake pattern, however, is consistent with the formation of the lake at the time of TE. This observation supports the hypothesis that Cheko lake formation is due to a fragment originating during TE, creating a small impact crater into the permafrost and soft alluvial deposits of Kimku River plain. This is further supported by the fact that Cheko lake has an elliptical shape elongated towards the epicentre of TE.

Forest Trees of North America

1880 ◽  
Vol 9 (234supp) ◽  
pp. 3730-3730
Author(s):  
Charles S. Sargent
Keyword(s):  
North America ◽  
Forest Trees

TWO NEW SEVERE LEAF SPOT DISEASE ON FOREST TREES OF JALGAON (MAHARASTRA) INDIA

2017 ◽  
Vol 23 (2) ◽  
Author(s):  
S. A. FIRDOUSI
Keyword(s):  
Leaf Spot ◽  
Fungal Disease ◽  
Leaf Spot Disease ◽  
Forest Trees ◽  
First Report ◽  
Spot Disease ◽  
Severe Leaf

During the survey of the forest fungal disease, of Jalgaon district, two severe leaf spot diseases on Lannae coromandelica and ( Ougenia dalbergioides (Papilionaceae) were observed in Jalgaon, forest during July to September 2016-17. The casual organism was identified as Stigmina lanneae and Phomopsis sp. respectively1-4,7. These are first report from Jalgaon and Maharashtra state.

Phänologische Trends bei den Waldbäumen in der Schweiz | Phenological trends regarding the forest trees in Switzerland

2005 ◽  
Vol 156 (6) ◽  
pp. 207-210 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Regional Differences ◽  
Early Growth ◽  
Horse Chestnut ◽  
Forest Trees ◽  
Spring Season ◽  
Arrival Times ◽  
The Past ◽  
Early Arrival ◽  
Southern Side ◽  
The Alps

Numerous publications are devoted to plant phenological trends of all trees, shrubs and herbs. In this work we focus on trees of the forest. We take into account the spring season (leaf and needle development) as well as the autumn (colour turning and shedding of leaves) for larch, spruce and beech, and,owing to the lack of further autumn phases, the horse chestnut. The proportion of significant trends is variable, depending on the phenological phase. The strongest trend to early arrival in spring was measured for needles of the larch for the period between 1951 and 2000 with over 20 days. The leaves of the horse chestnut show the earliest trend to turn colour in autumn. Beech leaves have also changed colour somewhat earlier over the past 50 years. The trend for shedding leaves, on the other hand, is slightly later. Regional differences were examined for the growth of needles in the larch where the weakest trends towards early growth are found in Canton Jura and the strongest on the southern side of the Alps. The warming of the climate strongly influences phenological arrival times. Trees in the forest react to this to in a similar way to other plants that have been observed (other trees, shrubs and herbs).

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