File:The Canadian field-naturalist (1973) (20526805981).jpg

Title: The Canadian field-naturalist
Identifier: canadianfieldnat1973otta (find matches)
Year: 1973 (1970s)
Authors: Ottawa Field-Naturalists' Club
Subjects:
Publisher: Ottawa, Ottawa Field-Naturalists' Club
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library

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1973 Vander Kloet: The Biological Status of Pitch Pines 251
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Figure 1. The distribution of Pinus rigUla in Ontario and adjacent New York. Solid dots indicate isolated populations; shading is used where populations are contiguous, and open triangles indicate slow- weathering outcrops where pitch pine is absent. The solid triangles indicate isolated populations of Pinus banksiana. rare in the Thousand Island region. Only 14 were found; however, 11 of these supported pitch pine. (2) The obverse apparently holds for the granite or granite-gneiss outcrops. Out of the 80 outcrops examined, only 21 had pitch pine; 19 of these occur in the area marked as con- tiguous in Figure 1. Isolated populations occur most frequently on quartzite. Only two isolated populations occur on granite viz. Rock Dunder near Morton and Crow Island in Charleston Lake. However, the soil on these granite ridges and outcrops differs only in quantity from that on quartzite outcrops. (3) The differences between sandstone pave- ments on which pitch pine occur and from which they are absent are more sharply de- fined. On the better developed profiles over sandstone pitch pine was not observed. Description The pitch pine which occurs on top of quart- zite and granitic ridges often has a stunted, clumped appearance; these clumps are com- prised of several twisted crown-forming stems 2-5 m tall. Several disks had been taken to determine the age of these trees: a 3-cm disk had 36 annual rings and 11 false or partial rings; a 4-cm disk had 45 annual rings and 8 false rings; a 16.5-cm disk had 97 annual rings and 17 false rings. In wet depressions on these ridges, or on talus slopes, or on partially de- veloped soil over sandstone, the tree has a single stem and is up to 15 m high; several

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