Sentences with phrase «lichen woodlands»

(a) Dense lichen woodlands in a fire - free landscape and corresponding to 10 % of the study sites.

(b) Less dense lichen woodlands in a landscape with fire occurring only once during the Holocene.

The longest tree - ring chronology (AD 1398 — 1982) yet available in eastern North America was constructed from living and dead spruces found in the lichen woodland of our study.

Not exact matches

Within the dominant oak - hickory woodlands, one finds a diversity of habitats, from rocky glades inhabited by roadrunners and cacti to wetlands with highly mineralized groundwater — all welcoming spots for lichens to settle in myriad colors and forms.

(f) Lichen - heath tundras caused by deforesting fire 450 years ago adjacent to fire - free lichen - spruce woodLichen - heath tundras caused by deforesting fire 450 years ago adjacent to fire - free lichen - spruce woodlichen - spruce woodlands.

Time - since - fire of all post-fire woodlands and krummholz and several lichen - tundra sites was determined based on 203 radiocarbon - dated charcoal (or wood) fragments located beneath the modern organic topsoil (appendix A).

(a) Old - growth lichen - spruce woodland more than 2000 years old.

Given the fact that the latitudinal position of successful post-fire regeneration of lichen - spruce woodlands is situated approximately 1.5 ° south of the Boniface area (Payette et al. 1989a, b), as a rule of thumb it is probable that a drop of at least 1 °C in mean annual temperature occurred after 900 cal.

Lichen - spruce woodlands in black, lichen - spruce krummholz in medium grey and lichen - heath tundras in lightLichen - spruce woodlands in black, lichen - spruce krummholz in medium grey and lichen - heath tundras in lightlichen - spruce krummholz in medium grey and lichen - heath tundras in lightlichen - heath tundras in light grey.

An evaluation of the former abundance of black spruce in lichen - tundra sites, based on distribution, number and growth form of charred standing or fallen dead stems was done in order to deduce the presence of woodland or krummholz stands at the moment of the last fire event.

The remaining 10 % is an exceptionally fire - free area composed of old - growth, lichen - Empetrum nigrum woodlands and krummholz (figure 7a, b), probably much older than 3000 yr according to 14C dates of the organic matter at the base of modern organic horizons (Payette & Morneau 1993).

Spruce - moss stands are the most important forest type in depressions, whereas lichen - spruce woodlands and krummholz (pygmy forests; distorted spruce less than 2.5 m high) are distributed on slopes and exposed summits along with lichen - heath - dwarf birch (Betula glandulosa Michx.)

The interpretation of radiocarbon dates of charcoal material to infer fire dates requires knowledge on the long - term dynamics of old - growth lichen - spruce woodlands.

Lichen - spruce woodland and lichen - spruce krummholz are two dominant vegetation types having more than 10 % spruce cover, whereas lichen - tundra is a spatially dominant vegetation type having less than 10 % spruce Lichen - spruce woodland and lichen - spruce krummholz are two dominant vegetation types having more than 10 % spruce cover, whereas lichen - tundra is a spatially dominant vegetation type having less than 10 % spruce lichen - spruce krummholz are two dominant vegetation types having more than 10 % spruce cover, whereas lichen - tundra is a spatially dominant vegetation type having less than 10 % spruce lichen - tundra is a spatially dominant vegetation type having less than 10 % spruce cover.

Mosaic of post-fire old - growth woodlands and lichen - heath tundras in the background.

We report here results of the analysis of a ∼ 600 - year response of a lichen — spruce woodland to this long - term trend, which are thought to be the first extensive illustration of these impacts in the Subarctic.