Home About edenarb Contracting Contact Details - Tree Basics Leaves Branches & Trunk Root Systems Health CODIT Leaves Trunk & Branches Root System Structural Care Tools Hand Power Safety Pruning Formative Small Branch Large Branch Advanced Selection Planting Identification Native UK Trees Environment Legislation Photo Gallery EDENARB Trees Miscellaneous Credits Links   Leaves   Trees, like plants, produce their own food through photosynthesis (made with light). When exposed to sunlight the leaf reacts combining water (H2O) and carbon dioxide (CO2) to form sugar and oxygen (O2). It may be easier to get a clear picture by looking at each element individually.   H2O - The tree transports H2O through the xylem - part of its vascular system – by transpiration. Transpiration is the loss of water vapour from tiny pores on the leaf; this creates a siphoning effect pulling H2O to the leaf where it vaporises (this also helps cool the leaf).   CO2 – Absorbed by the leaf from the atmosphere.   O2 – Given off by the leaf as the water vaporises during the transpiration process.   Sugar – The trees food created by photosynthesis. Some of the sugar is used to provide energy and growth and the rest is transported via the phloem – part of the vascular system – and stored as starch in either the trees ray cells or roots.     A trees leaf can be an indication of the environment in which it initially developed, with the size and shape specially adapted to suit different climatic conditions. A tree can shed its leaves annually (deciduous such as Oak) or keep them for several years (evergreens such as Pine). Evergreens waste less energy because they do not have to produce new leaves every year.