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Swedish University of Agricultural SciencesDepartment of Forest Products
Run-off quality from sprinkled debarked logs and logs with bark from Picea abies
and Pinus contorta
PhD Maria JonssonSwedish University of Agricultural Sciences
Dept. of Forest [email protected]
Swedish University of Agricultural SciencesDepartment of Forest Products
Sprinkling (wet storage) of roundwood
• Necessary for wood protection during storage at industries
• Used by 84% of the larger Swedish sawmills during May to September
• Large problems with great volumes of polluted run-off (TOC, P, phenols, low pH) affecting surrounding ground and watercourses
• Traditionally logs with bark• Pollutants probably origins from the bark,
could debarked logs be the solution?• In addition, measuring and grading of
debarked logs are easier and more effective compared to logs with bark
Swedish University of Agricultural SciencesDepartment of Forest Products
Aim of the study
To investigate differences in run-off quality from sprinkled storage of Norway spruce (Picea abies) and Lodgepole pine (Pinus contorta)
saw logs with and without bark.
Swedish University of Agricultural SciencesDepartment of Forest Products
Location of experiments
Swedish University of Agricultural SciencesDepartment of Forest Products
Materials and methods• Two experimental sites in
central Sweden• Pilot scale and full scale• Newly felled trees of
Norway spruce and Lodgepole pine
• Half of the logs were debarked in a sawmill barker
Swedish University of Agricultural SciencesDepartment of Forest Products
Materials and methods
• Sprinkled storage for 10 to 12 weeks• Sprinkling intensity of 100 to 200 mm/day• Run-off water was collected under the piles with
two different methods, see below• Run-off was analysed for total organic carbon
(TOC), phosphorus, phenols, and pH
Swedish University of Agricultural SciencesDepartment of Forest Products
Results• Clearly rised
concentrations of pollutants compared to the sprinkling water
• Similar results from both sites
• Differences between run-off from logs with bark and debarked logs were in most cases larger for Norway spruce than Lodgepole pine
• Run-off from debarked logs has significantly higher pH
Swedish University of Agricultural SciencesDepartment of Forest Products
Results
• Run-off from debarked logs has significantly lower concentrations of phenols
• Phenols can be toxic to living organisms
• Surprising peak in the middle of the period
Swedish University of Agricultural SciencesDepartment of Forest Products
Results• Run-off from debarked
logs has lower concen-trations of total organic carbon (TOC)
• Organic carbon is important for oxygen consumption
• Phosphorus? • Higher concentrations in
run-off from debarked logs and bigger difference for Lodgepole pine
• Effect on eutrophication uncertain or negative?
Swedish University of Agricultural SciencesDepartment of Forest Products
Results• High, but rapidly
decreasing initial concentrations
• The first three weeks most important at log yards
• Could be used when planning storage at a log yard – keep piles sprinkled for longer periods while new wood is processed
• Preliminary results show that wood quality is preserved when storing debarked logs
Swedish University of Agricultural SciencesDepartment of Forest Products
Conclusions
• Run-off from debarked logs contains less pollutants compared to run-off from logs with bark
• Storing debarked logs is a good alternative to storing logs with bark
• Wood processing industries should consider the method much more than they do today. Tradition must sometimes be questioned!
Swedish University of Agricultural SciencesDepartment of Forest Products
Thank you for your attention!
The study was financed by Ångpanneföreningens Foundation for Research and Development, SCA Timber, and the Skogsägarna Norrskogs Research Foundation.
