Parmelia Lichen Dyes
My property in the Kootenays has an old small shed. The roof was covered in Parmelia lichen (I think) The roof was in need of repair so all of the lichen was scraped off. I managed to recover some of it so thought that I would try to make a natural dye with what I rescued from the firepit.
Harvesting Parmelia Lichen
How Quickly Does Lichen Grow
Scientific Studies about Parmelia lichen Growth
A comparison of the growth curves of the foliose lichen parmelia conspersa determined by a cross-sectional study and by direct measurement Armstrong, July 1992
RGR – Radial Growth Rate
This study which has been quoted many times estimates that Parmelia lichen take 0.5 to 8 mm per year to grow.. so natural dyers are discouraged from picking Parmelia.
I find this odd, because from my observations about Parmelia lichen growing both in British Columbia and the UK, I see new Parmelia growth each year. Some years there is lots, other years there is less.
My shed roof (approx 10 ft x 8 ft) was completely covered with Parmelia lichen growth.
Ask Grok3
So I thought I would ask Grok for a calculation of how long it may have taken for the Parmelia to grow and cover my shed roof.
Here is the reply:
Key Points
Parmelia lichen grows at a radial rate of 0.5 to 8 mm per year, depending on species and environmental conditions.
To cover a 10 ft x 8 ft roof (80 sq ft), we need to estimate the time for lichen to spread across this area, assuming radial growth from initial colonization points.
Calculations suggest a range of approximately 149 to 2,381 years, with realistic estimates leaning toward the higher end due to environmental constraints and non-continuous growth.
To estimate how long it would take for Parmelia lichen to completely cover a 10 ft x 8 ft (80 sq ft) shed roof, we assume radial growth at 0.5 to 8 mm per year, typical for Parmelia species like Parmelia sulcata or Parmelia saxatilis. The time depends on whether growth starts from a single point or multiple colonization points, with environmental factors like moisture and temperature affecting the rate.
Simplified Calculation
Roof Dimensions: 10 ft x 8 ft = 3.048 m x 2.438 m = 7.432 m² (80 sq ft).
Growth Rate: 0.5 mm/year (slowest) to 8 mm/year (fastest).
Single Point Growth: If one thallus starts at the center and grows radially to cover the roof (approximated as a circle with equivalent area), the radius to cover 7.432 m² is about 1.537 m (1537 mm). At 0.5 mm/year, this takes ~3,074 years; at 8 mm/year, ~192 years.
Multiple Points (Realistic): Assuming multiple thalli colonize the roof (e.g., 100 thalli, each covering ~0.07432 m²), each thallus needs a radius of ~154 mm. At 0.5 mm/year, this takes ~308 years; at 8 mm/year, ~19 years. With 10 thalli, times are ~614 years (0.5 mm/year) to ~38 years (8 mm/year).
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Categories: DYES
