such solution to uv e g sunlight in the presence of a photosensitizer application_number US 27208194 A description before describing examples of this invention applicant wishes to set forth certain general features of the process all the chlorophenol and dihydroxychlorobenzene standards were obtained from fluka pentachlorophenol was 99 pure from aldrich and was used without further purification technical grade pentachlorophenol manufactured by kmg was provided by a preservative treating plant methylene blue double zinc salt was acquired from matheson coleman and bell phthalocyaninetetrasulfanate sodium salt was purchased from porphyrin products protoporphyrin ix was a gift from professor david dolphin department of chemistry ubc triethanolamine 99 8 certified was purchased from fisher scientific all solvents were spectral grade omnisolvt tm from bdh and all other chemicals were of analytical grade one general procedure adopted was to produce segments from the treated wood generally the outer sapwood while many ways are possible to produce the segments one procedure is to produce the segments by a saw these segments are reduced to flakes it has been found that the use of the flakes in the scf extraction process facilitated the process however it is possible that pole sections could be used without any processing apart from reduction of length it is also possible that the poles could be peeled to produce veneer moreover it may be.