Warner Lake

Vegetation History

Pollen analysis confirmed the fairly constant presence of the following species over the past 2000 years around Warner Lake: spruce (Picea spp.), alder (Alnus spp.), birch (Betula spp.), oak (Quercus spp.), wormwood (Artemisia spp.), sunflower (Asteraceae), grass (Poaceae), and horsetails (Equisetum spp.). Jack pine (Pinus banksiana) and red pine (Pinus resinosa), as well as white pine (Pinus strobus), pollen percentages varied. The base of the core at Warner Lake is between 1945 and 1735 cal. yr BP. The record begins from 1830 to 1470 cal. yr BP as an intermediate composition of species with moderate percentages of major pollen types. During this time period, pollen from meadow-rue (Thalictrum spp.) was present but did not persist into more modern samples of the lake core. From 1470-1320 cal. yr BP composition of forest species changed to a mixed pine assemblage consisting mainly of jack pine, red pine, and white pine. Around 1300 cal. yr BP, the vegetation briefly changed to a jack and red pine dominated woodland with high percentages of hazelnut (Corylus spp.) and grasses. From 1280-1160 cal. yr BP vegetation shifted back and forth between jack pine woodlands to mixed pine and to the original intermediate assemblage. Between 1160-700 cal. yr BP assemblages returned to the jack pine dominated woodland. From 700-650 cal. yr BP, the forest shifted to a mixed pine forest, and then at 300 cal. years BP another major transition occurred from the mixed pine assemblage to jack pine. This jack pine-dominated woodland persisted until the arrival of European-American settlers around 56 cal. yr BP. After which, much lower white pine percentages were present along with higher percentages of oak, sedges (Carex spp.) and weedy forbs such as ragweed (Ambrosia spp.), plantain (Plantago spp.), dock (Rumex spp.), and lamb’s quarters (Chenopodiaceae-Amaranthaceae).

Fire History

Between 1300-1400 cal. yr BP there was a large increase in charcoal accumulation beginning in mixed pine forest assemblages and continuing into the jack pine dominated woodland type. From 1000-550 cal. yr BP charcoal accumulated at a slightly elevated rate and then decreased after 450 cal. yr BP. The average fire return interval between charcoal peaks at Warner Lake is 73 years. High-frequency charcoal records occurred at Warner Lake before 780 cal yr BP in addition to high values of background charcoal. These patterns coincided with forest composition changes between mixed pine forests and jack pine dominated woodlands.