Tree ID by pine needles
Conifer leaves are reduced in size, compared with Broadleaf leaves, and adapted to withstand harsh dry conditions. They take two forms, needles or scales. They are compact with photosynthetic tissue surrounding a central vein, protected by a thick layer of cells and a waxy cuticle. They shed snow easily and conserve water.
Needles – The leaves of Pines, ‘true’ Cedars, Larches, Spruces, Firs and the Common Juniper are long and thin and needle-like and are simply called needles. Pine needles are bundled together, usually in clusters of 2,3 or 5. The number in the bundle can help to ID the tree. The needles are joined at the base near the shoot and the bundle of needles is called a fascicle. Where the fascicle joins the shoot there is a basal sheath which is initially transparent. Individual Spruce and Fir needles are arranged in ranks on either side of the shoot. In some the needles are in flat ranks but in others they may stick out in all directions. On some needles there are lines of white dots. These are called stomata. They are pores which allow gases to pass in and out of the leaves. The pattern of dots can be used to ID Conifer Trees. Larch and ‘true’ Cedar needles are in clusters of 20 to 45 on short shoots called spurs. The leaves of the Common Juniper are needle-like and finely pointed.
Scales – Conifer leaves may also be shaped like a scale on a fish or reptile. Cypresses have overlapping scale-like leaves that cover the shoot as in the Lawson Cypress. Sometimes these leaves are just called scale-leaves. Some conifers have main shoots that are covered in long, dark green leaves that resemble scales as in the Giant Sequoia. Some Cypresses have scale leaves that are very closely pressed to the shoot as on the Italian Cypress,