Trees Forests and forestry 35 Shrubs 22 Forest ecology 21 History 20 Ecology 17 Diseases and pests 15 Gehiago ... Environmental aspects 14 Plants 14 Growth 11 Symbolic aspects 10 Religious aspects 9 Tree planting 9 Breeding 8 Climatic changes 8 Ecophysiology 8 Arboles 7 Effect of air pollution on 7 Forest genetics 7 Forest management 7 Woody plants 7 Arboriculture 6 Biotechnology 6 Botany 6 Gardening 6 Genetics 6 Identification 6 Wounds and injuries 6 Folklore 5 Human-plant relationships 5 gutxiago ...