Veikko Koski. (1980). On the variation of flowering and seed crop in mature stands of Pinus sylvestris L. Silva Fennica vol. 14 no. 1 article id 5067. https://doi.org/10.14214/sf.a15008

Keywords: Pinus sylvestris; Scots pine; flowering; capacity; periodicity; seed crop

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The paper discusses the variation of flowering and seed crop of Scots pine (Pinus sylvestris L.) stands based on literature published in Finland. According to the studies, the list of good seed years given by different authors do not completely match, and no essentially new about the periodicity of the seed crop or the causes of variation has been found. The difficulty in classification of the seed crops in different years in different stands and locations can be handled through the concept of capacity. It is suggested in the paper that to be able to compare the occurrence of good flowering and seed years of different stands and localities, a case exceeding 50% of the capacity is described as abundant, and a case exceeding 75% as very heavy.

The PDF includes a summary in Finnish.

Koski, E-mail: vk@mm.unknown

Category : Research article

article id 574, category Research article

Hans W. Linderholm. (2001). Climatic influence on Scots pine growth on dry and wet soils in the central Scandinavian mountains, interpreted from tree-ring width. Silva Fennica vol. 35 no. 4 article id 574. https://doi.org/10.14214/sf.574

Keywords: Scots pine; tree-rings; climatic influence; periodicity

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Tree rings are one of the most important proxy data sources for reconstructing past climate variability. In order to understand climate variability, it is necessary to get a spatial and temporal coverage of climate information. Summer temperatures mainly influence tree growth at the altitudinal tree line, while at lower altitudes additional factors affect growth. In addition, the nature of soil where trees grow may affect growth response to climate. To decide climate as well as growth-substrate influences on Scots pine (Pinus sylvestris L.) growing below the tree line, two tree-ring width chronologies, sampled at dry mineral soil and wet peat soil in a mountain valley in the central Scandinavian Mountains, were analysed for climate responses and spectral signals. Temperatures during growth season (May–August) showed the strongest influence on tree growth at both sites. Influence of precipitation in the growing season was low, indicating sufficient amounts of available water during growth. However, at the dry-soil site the influence of late winter/early spring precipitation was significant. Strength of the climate–tree–growth relationship at the dry site was similar to that of trees growing at the present tree line, while weaker at the wet site. Both site chronologies exhibited common spectral peaks at c. 3.5 and 13 years indicating a common growth forcing at those time scales. The wet-site chronology displayed low-frequency variations with a 19-year periodicity, where growth peaks coincided with the lunar tidal maxima indicating a possible influence of lunar forcing. At the dry-site, multi-decadal fluctuations displayed a periodicity of 66 years. Both 13- and 66-year periods can be linked to variations in sea surface temperatures of the North Atlantic Ocean, pointing to a maritime influence, on decadal scales, of pine growth in the area. These results suggest that Scots pine in this environment may be regarded as proxies of North Atlantic Ocean coupled climatic variability.

Linderholm, Department of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm, Sweden E-mail: hasse@natgeo.su.se

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