You can be sensitive to touching, coming into contact with, plants and trees, or to touching or inhaling their products. This is caused predominantly by natural chemicals given off as vapour, or exuded by the plants and trees. The symptoms can be either those of allergy or of chemical sensitivity.
This section deals with sensitivity to wood and grass; to fragrances, oils, resins and terpenes from plants and trees; and on how to avoid problems.
Sensitivity to wood itself is actually quite rare. It is known for people to be allergic or sensitive to resinous woods – such as pine, cedar, iroko – which give off traces of volatile fumes from the wood. If these types of wood are sealed with varnish or paint, however, the fumes do not gas out, and the wood should not give any problem. If you appear to react to sealed wood surfaces, the cause is much more likely to be the paint or varnish used than the wood itself.
Problems with resinous woods can arise with furniture of pine or cedar, in which sometimes the inside surfaces (such as drawers or cupboards) are not sealed. They can arise from floorboards which are not sealed, but usually only when these are new and the fumes are still gassing out. Wooden pencils or crayons are sometimes made of cedar wood; the wood in their tips, being unsealed, can be aromatic and sometimes cause trouble. If you work extensively with wood, you can become allergic or sensitive to wood dusts – of wood of any kind, not just resinous woods. Sawn wood also harbours moulds and lichens, and these can cause allergy. These are dispersed when wood is cut or handled (say during construction or repair work), but will disappear as the wood dries out.
If you become sensitive to turpentine, the natural resin in pine wood, you may cross-react to other chemicals and plants that are chemically related to it.
If you appear to be sensitive to grass, but your reactions do not correspond to situations or times when grass pollens are high (for full information, >POLLENS), then the cause may be grass sap or terpenes – the natural chemicals in grass that rise when the grass is growing. Some people develop problems on touching grass; others are sensitive to inhaling the vapours.
Grass sap starts to rise before pollen is produced and if you are extremely sensitive, it will bother you when you are close to grass from April, or even March, when grass starts growing, and also into the autumn until grass stops growing. Grass sap is also given off strongly into the air as grass is mown and just after. Some rush mats, baskets made of grass, and bales of hay, give off traces of grass terpenes for a while.