80 CONTENTS 13.1 Introduction 13.2 Eucalyptus diseases (gum) 13.3 Acacia diseases (wattle) 13.4 Pinus diseases (pine) 13.1 Introduction This chapter deals only with the major diseases of commercial forestry trees in South Africa.0 CONTENTS 13.1 Introduction 13.2 Eucalyptus diseases (gum) 13.3 Acacia diseases (wattle) 13.4 Pinus diseases (pine) 13.1 Introduction This chapter deals only with the major diseases of commercial forestry trees in South Africa.
The pigment responsible for most light-harvesting by plants is chlorophyll, a green pigment. The green color indicates that it is absorbing all the non-green light-- the blues (~425-450 nm), the reds and yellows (600-700 nm).
These absorb mostly red and blue light, and absorb green the least. If only exposed to green light, the plant will not grow as much as if it were exposed to a full spectrum of colors, or as much as if it were exposed to red or blue light.hlorophyll absorbs all the different coloured wavelengths, but leaves green as the colour it reflects and as the colour we see.  Therefore, white light is best to grow plants under because green light doesn't do much of anything for photosynthesis.