In northern North America, the term evergreen is often used as a synonym for conifer and thus excludes foliage-retaining angiosperms.
The needles on the Larch trees are turning a golden yellow, as we drive up to the hill on our last day, it's one of the few conifers that sheds its foliage for the winter.
Increased production of polysaccharides can contribute to cell wall thickening and higher specific leaf mass per area (LMA), as observed in foliage of various conifer and broadleaved tree species in response to elevated CO2 (Tognetti and Johnson 1999; Oksanen et al. 2005; Eller et al. 2011; Pokorny et al. 2011).
An accent is an element that differs from everything around it, as silver-gray foliage against dark green conifers, but is limited in quantity in relation to surrounding elements.
It is a tall, long-lived conifer with soft, flat needles and feathery foliage, and occurs naturally in the Appalachian Mountains from Georgia to New Brunswick, with a range that runs westward through Michigan into Wisconsin.
It and much of the Khabarovskii Krai, just to the north of it, consist of a unique kind of Pacific forest in which tall hardwoods hung with vines grow beside conifers almost equally high, and the lushness of the foliage, especially along the watercourses, often becomes quite jungly.
Regarding secondary compounds, the foliage response to elevated CO2, as measured in different conifer and broadleaved species, is still unclear with either unchanged (Kainulainen et al. 1998; Räisänen et al. 2008), increased (Tognetti and Johnson 1999; Sallas et al. 2001; Veteli et al. 2007; Vapaavuori et al. 2009) or decreased (Peñuelas et al. 1996) amounts of phenolic compounds.
The fall, with alternating cold nights and sunny warm days, is particularly spectacular, as the blazing colours of deciduous foliage contrast with the solid dark greens of conifers.
We note whether the yellow cedars look stressed, and how their neighboring conifers are doing, with numerous classifications for each tree's foliage and position in the canopy.
Illiciums evolved to grow in the dark conditions of the conifer forests of the Cretaceous and most of them suffer significant leaf chlorosis, yellowing of the foliage, and death if exposed to too much sun.
