Field trials manual for multipurpose tree species

Following an introduction, Section 2 reviews basic issues in designing a statistically valid trial and includes some examples and possible field layouts. Section 3 treats nursery practices, including germination of seeds, care of seedlings, lifting, and transport. It does not discuss nursery location, establishment, or management. Sections 4 and 5, on field establishment and post-planting care, respectively, describe what should be done, but not how (which depends greatly on local tools and practices). Section 6 considers measurements in detail because they must be standardized to ensure meaningful comparisons between trials, even those conducted by the same scientist. Details provided in Section 7 for recording data are applicable only to the Information and Decision Support System (IADSS) prepared under A.I.D."s Forestry/Fuelwood Research and Development (F/FRED) project. The specific forms described are contained in preliminary software for IADSS; a final version is pending. Codes are provided in Section 8 to help reduce the tedium of data entry, conserve computer memory, and speed analysis. Appendices include samples of field trial procedures already underway in the F/FRED-sponsored humid and subhumid network, as well as of those planned for arid and semiarid network trials. The manual stresses the need for standardized methodology to enable scientists to determine site and tree characteristics so that variations represent experimental and not methodological differences. (Author abstract, modified)