00306nam a2200109Ia 450000500170000000800410001708200140005810000210007224500570009326000380015030000080018820260225051121.0260224s9999||||xx |||||||||||||| ||und||  a634.9 WAL  aJohn D. Walstad  0aForest vegetation management for conifer production   aNew York: John Wily & Sons c1987  a523