Diameter growth of black birch and diameter and height growth of white birch and yellow birch were correlated with photon flux density (Table 6).
Black birch, which is intermediate in shade tolerance and is often considered ecologically similar to yellow birch, exhibited little growth response to soil resource congruence.
Data for black birch were normally distributed with equal variance among transects.
Seeds of white birch and black birch were too small to test microdispersal patterns.
Yellow birch: American birch Sweet birch: cherry and black birch
Paper birch: white and canoe birch
"The black birch
is what gives us our yellow," she said while noting she feels the foliage season is getting off to a late start.
"We have a tree here, a big black birch
," Trexler said.
At left, Thom Kyker-Snowman holds a black birch
that has flourished in the cut area.
Elisa Campbell of the Sierra Club said she is concerned that failure to maintain diversity of species through successful regeneration could result in the Quabbin watershed being dominated by white pine, black birch
and red maple.
Peak spectacle demands contrast: dark evergreens juxtaposed against skeletal birches, splashy yellow aspens, larches, ashes, black birches
and beeches clashing with red maples and scarlet oaks, golden hickories, salmon-orange mountain ash berries, and red, yellow and gold sugar maples.
Other trees are prospering, such as tuliptrees, wild black cherries, American beeches, black birches
, sweetgums, and two alien trees with unpopular reputations among urban foresters - Japanese cork and Norway maple.
Red Oaks and Black Birches
: The Science and Lore of Trees, by Rebecca Rupp.