Holocene Tree Line and Climate Change on the Queen Charlotte Islands, Canada

Abstract

Palynological study of two subalpine ponds on the Queen Charlotte Islands reveals changes in tree line and climate during the Holocene. The findings agree with previous reconstructions, from nearby Louise Pond on the Queen Charlotte Islands, that suggest a warmer-than-present climate and higher-than-present tree lines in the early Holocene (ca. 9600–6600 14C yr B.P.). Basal ages at SC1 Pond and Shangri-La Bog indicate that the basins did not hold permanent water before 7200 14C yr B.P., consistent with a warmer and drier early Holocene previously inferred from Louise Pond. Pollen and plant macrofossils indicate the initial establishment of subalpine conditions by 6090 ± 90 14C yr B.P., similar to the 5790 ± 130 14C yr B.P. age for cooling inferred from Louise Pond. Conditions similar to present were established at SC1 Pond by 3460 ± 100 14C yr B.P., confirming the previous estimate of 3400 14C yr B.P. at Louise Pond. This 3400 14C yr B.P. vegetation shift on the Queen Charlotte Islands corresponds with the beginning of the Tiedemann glacial advance in the south-coastal mountains of British Columbia (ca. 3300 14C yr B.P.), the Peyto and Robson glacial advances between 3300 and 2800 14C yr B.P. in the Rocky Mountains, and climatic cooling inferred from palynological studies throughout southern British Columbia, northern Washington, and southeast Alaska. These findings confirm that changes in regional climate influenced changes in vegetation in coastal British Columbia.

Late Holocene sedimentary response to solar and cosmic ray activity influenced climate variability in the NE Pacific

“…sediment color) ( Table 2). These intervals correlated well with other geological and paleoclimate records from coastal British Columbia (e.g., Pellat and Mathewes, 1997;Nederbragt and Thurow, 2001).…”

“…A growing body of sedimentary and biological studies indicates that extraterrestrial factors are at least partially responsible for climate variability on scales ranging from days to millennia (e.g., Haigh, 1994;Mann et al, 1995;Soon et al, 1996;Pellat and Mathewes, 1997;Svensmark, 1998;Bond et al, 2001). Pacific High (NPH) winds generate the southward Shelf-Break Current at the surface, and a consequent offshore Ekman transport inducing upwelling, thus bringing high-salinity deep water closer to the surface.…”

Carbon dioxide exchange and canopy conductance of two coniferous forests under various sky conditions

“…The annual rainfall and mean air temperature of these sites are around 1,200 mm and 7°C, respectively. P. sitchensis is a native of the west coast of North America (Waring and Franklin 1979;Taylor 1990;Pellatt and Mathewes 1997) well adapted to the cool cloudy conditions of northern Britain.…”

Postglacial vegetation and climate dynamics in the Seymour‐Belize Inlet Complex, central coastal British Columbia, Canada: palynological evidence from Tiny Lake

“…When the AL is on average more eastward and/or stronger than usual, a climate characterised by relatively cool summers and mild winters with high precipitation is experienced in coastal BC. This is in part because (Barnosky, 1981); (2) Lake Washington (Leopold et al, 1982); (3) Crocker Lake and Cedar Swamp (McLachlan and Brubaker, 1995); (4) Kirk Lake (Cwynar, 1987); (5) East Sooke Fen (Brown and Hebda, 2002); (6) Pixie Lake (Brown and Hebda, 2002); (7) Walker Lake (Brown and Hebda, 2003); (8) Whyac Lake (Brown and Hebda, 2002); (9) Saanich Inlet (Pellatt et al, 2001); (10) Porphory Lake (Brown and Hebda, 2003); (11) Marion and Surprise Lakes (Mathewes, 1973;Mathewes and Heusser, 1981); (12) Pinecrest and Squeah Lakes (Mathewes and Rouse, 1975); (13) Brooks Peninsula (Hebda, 1997); (14) Misty Lake (Lacourse, 2005); (15) Bear Cove Bog (Hebda, 1983); (16) (Quickfall, 1987); (17) West Side Pond ; (18) SC1 Pond (Pellatt and Mathewes, 1997); (19) Louise Pond (Pellatt and Mathewes, 1994); (20) Shangri-La Bog (Pellatt and Mathewes, 1997);(21, 22) (Warner, 1984);(23, 24) (Quickfall, 1987); (25) Dogfish Bank ; (26) (Banner et al, 1983); (27) Diana Lake Bog (Turunen and Turunen, 2003); (28) Skinny Lake (Spooner et al, 2002); (29) Susie Lake (Spooner et al, 1997); (30) Pyramid Lake ; (31) Pleasant Island (Hansen and Engstrom, 1996); (32) Waterdevil Lake (Spear and Cwynar, 1997); (33) Kettlehole Pond (Cwynar, 1988); (34) Icy Cape (Peteet, 1986); (35) Little Swift Lake …”