The photographs in the earlier part of the book will give the layman some conception of the enormous amount of labour that must be expended in the opening up, planting, trenching, and weeding the plantations which have replaced the virgin jungle. The authors are indebted for most of these photographs to Mr. H. Sutcliffe, one of the mycologists of the Rubber Growers' Association. The pictures of spotless coagulating tanks and tiled verandahs regularly hosed down will indicate the cleanliness necessary for the preparation of the beautifully clean sheet and crepe rubber which became available with the advent of plantation rubber. These results are largely due to the work of Sidney Morgan and his colleagues, on whom the planters have relied for technical guidance and advice. As regards my own contribution this is confined to a general outline of the subject. I have, therefore, omitted reference to a number of matters which would have been dealt with in detail had space permitted. The information given is based on researches on vulcanisation carried out for the Rubber Growers' Association by the writer over a period of nine or ten years. It was not found practicable to give detailed references in all cases. The reports on which the conclusions are based will, however, be found among the regular quarterly reports made by the writer for the Association up to June, 1919. Subsequent reports have been published in the Monthly Bulletin of the Rubber Growers' Association. We are indebted to the Association for permission to publish details from these reports, and also for the use made of numerous earlier reports published both in London and in the East. CONTENTS PART I _FIELD OPERATIONS_ PAGE CHAPTER I PLANTING Seeds--Seed selection--Strain improvement by bad propagation-- Nurseries--Stumps--Seed at stake--Basket plants--Preparation of land--Danger of disease--Clean clearing--Loss of top-soil-- Silt-trenches on slopes 1 CHAPTER II FIELD MAINTENANCE Clean weeding--Selective weeding--Loss of top-soil--Grass ridges--Lallang eradication--_Mimosa gigantea_ (_M. invisa_)--Green cover-plants--Connection between weeding, soil conservation, and soil improvement 13 CHAPTER III THINNING OF AREAS Original planting per acre--Ultimate stand per acre--Close- planting _versus_ wide-planting--When to commence thinning operations--How to select in preliminary rounds-- Later selections based on yields of individuals--Yields per tree, present and future--Trees per acre 19 CHAPTER IV TAPPING SYSTEMS