Properties of 50 individual Philippine hardwood barks and mixtures of 22 Ghanaian and 18 Colombian hardwood barks

BECAUSE SO MANY SPECIES OF HARDWOODS ARE MIXED IN TROPICAL FORESTS, TECHNIQUES MUST BE FOUND OF PRODUCING ECONOMICAL PRODUCTS FROM MIXTURES OF HARDWOOD. THIS REPORT PRESENTS METHODS AND RESULTS OF A RESEARCH PROGRAM CONDUCTED TO ASSESS THE PROPERTIES OF BARK FROM 50 SPECIES SAMPLED FROM THE TROPICAL FORESTS OF THE PHILIPPINES. THE RESEARCH WAS CONDUCTED BY THE FOREST PRODUCTS LABORATORY, U.S. FOREST SERVICE, IN COOPERATION WITH THE UNIVERSITY OF WISCONSIN. THE STUDY FINDINGS SHOWED THAT THE SPECIFIC GRAVITY OF THE BARK TENDS TO BE HIGHER THAN THE SPECIFIC GRAVITY OF THE 50 PHILIPPINE HARDWOODS EVALUATED, EXCEPT FOR SPECIES HAVING A SPECIFIC GRAVITY OF 0.70 AND GREATER. SILICA AND ASH CONTENTS OF THE BARKS WERE MUCH HIGHER THAN IN THE WOODS. KRAFT PULP YIELDS FROM BARK WERE SOMEWHAT LESS THAN THOSE FOUND FOR BARKS FROM TEMPERATE ZONE SPECIES. HEAT VALUE WAS SIMILAR TO THAT FOUND IN BARKS OF NATIVE U.S. SPECIES.