Canadian Forest Service Publications

Biomass and root stem production of a colony-forming willow (Salix interior) on highly disturbed, low fertility sites. 2015. Mosseler, A.; Major, J.E. Biomass and Bioenergy 74: 202-212.

Year: 2015

Available from: Atlantic Forestry Centre

Catalog ID: 36306

Language: English

CFS Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1016/j.biombioe.2015.01.019

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Abstract

This study describes biomass production, colony formation, and clonal spread via root stems (RS) of a wide-ranging North American willow species, Salix interior Rowlee (INT), one of the few willows that spread via vegetatively reproduced colonies, which can result in hundreds of upright stems arising from a shallow horizontal root network. Eight INT clones were tested in a common-garden experiment on two distinct site types (shale rock overburden and coarse gravel erosion sediments) with very low nitrogen and nutrients on a former coal mine site. Survival, height growth, aboveground biomass, and number of root stems (NRS) were quantified following 3 years of growth after establishment as rootless stem cuttings. Clonal differences were significant for survival and height at age 3. Survival was significantly greater on the coarse gravel outwash than shale rock overburden after the first and third year, but differences were only significant in the first year. There was a significant positive relationship between height growth and survival, both of which are indicators of plant vigor. Analysis of clonal variation in NRS showed an intermediate level of significance (P = 0.083), and a significant clone by site interaction (P = 0.024). On coarse gravel outwash, the more vigorous clones for height growth also produced more RS, indicating the absence of a potential trade-off in carbohydrate resource allocation between height growth of the ortet (mother plant) and its capacity for colony formation and spread via RS. However, there was no relationship between clonal height growth and NRS on the rock overburden. Loose sand and gravel outwash deposits promoted a more rapid spread of the shallow horizontal root network than the less penetrable shale rock overburden that dominates this former coal mine site.

Plain Language Summary

This study describes biomass production, colony formation, and clonal spread via root stems of a wide-ranging North American willow species, Salix interior (INT), one of the few willows that can produce colonies of hundreds of upright stems arising from a shallow horizontal root network. Eight INT clones were tested in a common-garden experiment on two distinct site types (shale rock overburden and coarse gravel erosion sediments) with very low nitrogen and nutrients on a former coal mine site. Survival, height growth, aboveground biomass, and number of root stems were quantified following 3 years of growth after establishment as rootless stem cuttings. Clonal differences were significant for survival and height. There was a significant positive relationship between height growth and survival, both of which are indicators of plant vigor. On coarse gravel outwash, the more vigorous clones for height growth also produced more root stems. Loose sand and gravel outwash deposits promoted a more rapid spreading of the shallow horizontal root network than the less penetrable shale rock overburden that dominates this former coal mine site. Colony-forming willows such as INT may eliminate the need for periodic plantation re-establishment, providing a major cost advantage over conventional short-rotation, coppice-based woody biomass plantations. Also, this species is a natural invader of oil sands tailings in northern Alberta and provides one of our best prospects for rapid re-vegetation of these mine tailings for eventual forest restoration.

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