Pollen Content of Moss Polsters in Relation to Forest Composition

1949 ◽  
Vol 42 (2) ◽  
pp. 473 ◽  
Author(s):  
Henry P. Hansen
Keyword(s):  
Forest Composition ◽  
Pollen Content ◽  
Moss Polsters

scholarly journals Forest plant and macrofungal differences in the Greater and Lesser Khingan Mountains in Northeast China: A regional-historical comparison and its implications

2021 ◽  
Author(s):  
Yuanyuan Wang ◽  
Hui Wen ◽  
Kai Wang ◽  
Jingxue Sun ◽  
Jinghua Yu ◽  
...  
Keyword(s):  
Northeast China ◽  
Dominant Species ◽  
Local Economy ◽  
Forest Composition ◽  
Historical Records ◽  
Historical Comparison ◽  
Composition And Structure ◽  
Total State ◽  
The 1960S ◽  
Forest Plants

AbstractForests in Northeast China in the Greater and Lesser Khingan Mountains (GKM and LKM) account for nearly 1/3 of the total state-owned forests in the country. Regional and historical comparisons of forest plants and macrofungi will favor biological conservation, forest management and economic development. A total of 1067 sampling plots were surveyed on forest composition and structure, with a macrofungi survey at Liangshui and Huzhong Nature Reserves in the center of two regions. Regional and historical differences of these parameters were analyzed with a redundancy ordination of their complex associations. There were 61–76 families, 189–196 genera, and 369–384 species, which was only 1/3 of the historical records. The same dominant species were larch and birch with Korean pine (a climax species) less as expected from past surveys in the LKM. Shrub and herb species were different in the two regions, as expected from historical records. There was 10–50% lower species diversity (except for herb evenness), but 1.8- to 4-time higher macrofungi diversity in the GKM. Compared with the LKM, both tree heights and macrofungi density were higher. Nevertheless, current heights averaging 10 m are half of historical records (> 20 m in the 1960s). Edible macrofungi were the highest proportion in both regions, about twice that of other fungal groups, having important roles in the local economy. A major factor explaining plant diversity variations in both regions was herb cover, followed by shrubs in the GKM and herb-dominant species in the LKM. Factors responsible for macrofungi variations were tree density and shrub height. Vaccinium vitis-idaea and Larix gmelinii in the GKM but tree size and diversity were important factors in the LKM. Our findings highlighted large spatial and historical differences between the GKM and LKM in plant-macrofungal composition, forest structure, and their complex associations, which will favor precise conservation and management of forest resources in two region in the future.

scholarly journals Over half of western United States' most abundant tree species in decline

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hunter Stanke ◽  
Andrew O. Finley ◽  
Grant M. Domke ◽  
Aaron S. Weed ◽  
David W. MacFarlane
Keyword(s):  
United States ◽  
Tree Species ◽  
Tree Mortality ◽  
Temperate Forests ◽  
Size Structure ◽  
Forest Disturbance ◽  
Population Decline ◽  
Western United States ◽  
Scale Transformation ◽  
Forest Composition

AbstractChanging forest disturbance regimes and climate are driving accelerated tree mortality across temperate forests. However, it remains unknown if elevated mortality has induced decline of tree populations and the ecological, economic, and social benefits they provide. Here, we develop a standardized forest demographic index and use it to quantify trends in tree population dynamics over the last two decades in the western United States. The rate and pattern of change we observe across species and tree size-distributions is alarming and often undesirable. We observe significant population decline in a majority of species examined, show decline was particularly severe, albeit size-dependent, among subalpine tree species, and provide evidence of widespread shifts in the size-structure of montane forests. Our findings offer a stark warning of changing forest composition and structure across the western US, and suggest that sustained anthropogenic and natural stress will likely result in broad-scale transformation of temperate forests globally.

Glacially redeposited pollen in tills of southern Ontario, Canada

1989 ◽  
Vol 26 (9) ◽  
pp. 1667-1676 ◽  
Author(s):  
Aleksis Dreimanis ◽  
Elsbet Liivrand ◽  
Anto Raukas
Keyword(s):  
Analytical Data ◽  
Transitional Period ◽  
Baltic Region ◽  
Pollen Assemblage ◽  
Southern Ontario ◽  
European Model ◽  
Northern European ◽  
Pollen Content ◽  
Eastern Baltic ◽  
Glacial Advance

According to published opinion based on analytical data, the secondary pollen of subglacial till in the eastern Baltic region of Europe reflect the pollen assemblages of the preceding interstadial or interglacial sediment, including abundant thermo-philous pollen. Tills and glaciolacustrine sediments from 10 sites in southern Ontario, including the Don Valley Brickyard section at Toronto, where polynologically investigated to compare the pollen content in glacigenic deposits of various ages. Only one site (upper Bradtville till) contained a secondary pollen assemblage with abundant deciduous pollen, like those found in a Yarmouthian interglacial deposit in Indiana. In all the others, pine (Pinus) pollen dominate. This phenomenon is explained by glacial incorporation of sediments enriched in overproduced Pinus pollen, which had accumulated during either (i) a lengthy cool transitional period between the warm phase of the Sangamonian Interglacial and the first major Early Wisconsinan glacial advance, (ii) the interstadial Middle Wisconsinan, or (iii) the cool nonglacial episode of Illinoian and pre-Illinoian time. Therefore, the northern European model for distinguishing tills of different ages by their secondary pollen assemblages is applicable to southern Ontario only in exceptional cases. Pollen in the glaciolacustrine Early Wisconsinan Sunnybrook Drift sediments resembles those of Sunnybrook till, but are more variable in their preservation and composition and contain more pre-Quaternary palynomorphs.

Landscape Eragmentation and Forest Composition Effects on Grouse Breeding Success in Boreal Forests

Ecology ◽  
2000 ◽  
Vol 81 (7) ◽  
pp. 1985 ◽  
Author(s):  
Sami Kurki ◽  
Ari Nikula ◽  
Pekka Helle ◽  
Harto Linden
Keyword(s):  
Breeding Success ◽  
Boreal Forests ◽  
Forest Composition ◽  
Composition Effects

Pla a_1 aeroallergen immunodetection related to the airborne Platanus pollen content

2013 ◽  
Vol 463-464 ◽  
pp. 855-860 ◽  
Author(s):  
M. Fernández-González ◽  
A. Guedes ◽  
I. Abreu ◽  
F.J. Rodríguez-Rajo
Keyword(s):  
Pollen Content

MODERN POLLEN RAIN STUDIES IN EASTERN ONTARIO

1963 ◽  
Vol 41 (2) ◽  
pp. 243-252 ◽  
Author(s):  
James E. King ◽  
Ronald O. Kapp
Keyword(s):  
United States ◽  
Long Range ◽  
Southwestern United States ◽  
Pollen Trap ◽  
Modern Pollen ◽  
Pollen Rain ◽  
Moss Polsters ◽  
Eastern Ontario

Moss polsters were collected at 15 sites between Toronto and Lake Timagami, Ontario, and at 4 localities in the Lake Timagami area for the purpose of determining the regional pollen rain and its local variations. Pollen percentages of Acer, Quercus, Ambrosia, Chenopodiaceae, Compositae, and Gramineae decrease northward and Picea, Pinus, and Betula increase at the more northerly sites. From the three most northern sites a regional pollen rain was calculated by averaging the percentages from nine pollen spectra. In this area the regional pollen rain is dominated by Picea (15%), Pinus (38%), and Betula (22%). At one site a grain of Ephedra was recovered, apparently carried in by long range drift. The nearest place that it grows naturally is in the southwestern United States. Various pollen trap types were investigated and it was found that all types of moss polsters and some types of decaying stumps (depending on their moisture-holding capacity) were effective in preserving the modern pollen rain.

The composition of Amazonian forests: patterns at local and regional scales

1998 ◽  
Vol 14 (5) ◽  
pp. 645-664 ◽  
Author(s):  
John Terborgh ◽  
Ellen Andresen
Keyword(s):  
Detrended Correspondence Analysis ◽  
Forest Composition ◽  
Level Data ◽  
Tree Communities ◽  
Floristic Patterns ◽  
Edaphic Properties ◽  
Number Of Stems ◽  
Amazonian Forests ◽  
Amazonian Region ◽  
The Guianas

An analysis was conducted of floristic patterns contained in 48 1-ha tree plots distributed at 29 sites in seven neotropical countries, with a primary emphasis on the Amazonian region. Analyses were made with family level data, using detrended correspondence analysis and multidimensional scaling to generate two-dimensional ordinations. Dissimilarity values for all pairs of plots were then used to compare forest composition at both local (flooded vs unflooded forests) and regional scales (e.g., western vs central vs eastern Amazonia). The predominate family of trees in a large majority of Amazonian and Guianan forests (by number of stems) is either Palmae or Leguminosae (sensu latu), followed by Moraceae and Euphorbiaceae. The forests of western Amazonia are particularly rich in palms, Moraceae, and Myristicaceae, whereas those of eastern Amazonia and the Guianas are rich in Lecythidaceae and Chrysobalanaceae. Dissimilarity between sites increases with distance for both flooded and unflooded forests. The tree communities of flooded and unflooded forests within a region tended to resemble one another more closely than forests of either type resembled the homologous forests of the adjoining regions. Within Amazonia the edaphic properties of each region and its geological history are tightly interrelated. It is therefore difficult to distinguish between evolutionary and ecological interpretations of the results.

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