Populus balsamifera is a tall deciduous tree common on the lowlands of British Columbia. It is a member of the willow family (Salicaceae) and is closely related to Balsam poplar and trembling aspen (Klinkenberg 2017).
Description:
P. balsamifera have a straight trunk reaching heights of 50 m (MFLNRO n.d.; Pojar & MacKinnon 1994). They grow rapidly, the rate of which depends on environmental conditions of the site (McKown et al. 2013). The bark is typically green-grey and becomes furrowed with ridges as it ages. The shiny thick leaves are heart-shaped (MFLNRO n.d.; Pojar & MacKinnon 1994; Klinkenberg 2017). Black cottonwood trees produce male and female flowers on separate trees — either a string of small pollen producing male or seed producing female flowers called catkins (MFLNRO n.d.).
Ecology:
Black cottonwood usually grow in wet locations often associated with flood plains, streams, ponds, and rivers. They are not tolerant of shade and are therefore restricted to regions that are too wet for other tree species (MFLNRO n.d.; Pojar & MacKinnon 1994).
The wood of this tree is relatively soft and woodpeckers often create cavities in the tree while searching for insects. These holes can serve as shelter for birds and rodents.
First Nations of B.C. have used black cottonwood in a number of ways. The wood has been used to make small canoes and as fuel. The aromatic resin from leaf buds was used to treat sore throats and stomach troubles (Pojar & MacKinnon 1994).
The wood of this tree is relatively soft and woodpeckers often create cavities in the tree while searching for insects. These holes can serve as shelter for birds and rodents.
First Nations of B.C. have used black cottonwood in a number of ways. The wood has been used to make small canoes and as fuel. The aromatic resin from leaf buds was used to treat sore throats and stomach troubles (Pojar & MacKinnon 1994).
Reproduction and Dispersal:
Pollination occurs in early spring followed by seed development in the female flowers. When ripe, the seeds are covered in white fluffy hairs which catch the wind and carry the seeds to new locations. When the seeds are shed, they look like cotton falling from the sky, hence the common name cottonwood (MFLNRO n.d.).
References cited:
Klinkenberg B, editor. 2017. E-Flora BC: Electronic Atlas of the plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [accessed 2018 Jan22]. http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Populus%20balsamifera.
McKown AD, Guy RD, Klapste J, Geraldes A, Friedmann M, Cronk QCB, El-Kassaby YA, Mansfield SD, Douglas CJ. 2013. Geographical and environmental gradients shape phenotypic trait variation and genetic structure in Populus trichocarpa. New Phytologist. 201(4):1263–1276. DOI: 10.1111/nph.12601.
[MFLNRO] Ministry of Forests, Lands and Natural Resource Operations. n.d. Tree book, Learning to recognize trees of British Columbia. Black cottonwood Populus balsamifera ssp. Trichocarpa, Balsam poplar Populus balsamifera ssp. balsamifera. [accessed 2017 Mar 13].
https://www.for.gov.bc.ca/hfd/library/documents/treebook/blackcottonwood.htm.
Pojar J, MacKinnon A. 1994. Plants of coastal British Columbia: including Washington, Oregon & Alaska. Vancouver: Lone Pine Publishing.
McKown AD, Guy RD, Klapste J, Geraldes A, Friedmann M, Cronk QCB, El-Kassaby YA, Mansfield SD, Douglas CJ. 2013. Geographical and environmental gradients shape phenotypic trait variation and genetic structure in Populus trichocarpa. New Phytologist. 201(4):1263–1276. DOI: 10.1111/nph.12601.
[MFLNRO] Ministry of Forests, Lands and Natural Resource Operations. n.d. Tree book, Learning to recognize trees of British Columbia. Black cottonwood Populus balsamifera ssp. Trichocarpa, Balsam poplar Populus balsamifera ssp. balsamifera. [accessed 2017 Mar 13].
https://www.for.gov.bc.ca/hfd/library/documents/treebook/blackcottonwood.htm.
Pojar J, MacKinnon A. 1994. Plants of coastal British Columbia: including Washington, Oregon & Alaska. Vancouver: Lone Pine Publishing.