We are extremely grateful to Dr Heather McHaffie Edinburgh Network co-ordinator and Scottish Plants Officer at the Royal Botanical Garden in Edinburgh for this wonderful introduction to the usefulness of plants. The second part of her contribution will be published shortly.
The presence of plants is fundamental to our life support systems on this planet; without plants, life could not be sustained. Plants use water, nutrients and energy from the sun to process carbon dioxide (CO2) and give us oxygen. Plants make a major contribution to reducing the amounts of CO2 that our activities have released into the atmosphere. Some of the CO2 that we produce is taken up by the sea and marine algae and is locked up on the sea bed in carbon sinks and was the source of ancient oil deposits. On a similar time-scale trees store carbon which can go into long-term storage in the form of coal. Tropical rain forests store the greatest amounts of carbon, as do peat bogs where the plant remains do not decompose. Damage to these habitats liberates stored carbon and through our use of fossil fuels we are rapidly releasing enormous amounts of carbon that have taken hundreds of millions of years to accumulate. This has not only raised the CO2 in the atmosphere, but is also an unsustainable use of natural resources and poor stewardship of the planet.
All our food supplies are derived from plants. Even if we don’t eat plants directly we might eat animals that have eaten plants, or fish that are part of food chain with algae at the lowest level. A certain amount of food value is lost at each stage and various ratios are quoted on the efficiency of beef cattle converting grain into meat in the order of 7:1. In a world with inadequate food supplies it might provide more food if people ate less meat and ate the grain instead. But cattle can derive a lot of their nourishment from grass at a conversion of 30:1 and this is something that people cannot do. As with everything, a balance is required.
Perhaps a greater issue with food is how we source it. We have become accustomed to a varied diet that depends on a high proportion of non-essential imported food out of season. Considerable amounts of energy are used to transport it and in some cases the local people are growing food to export with very little benefit to themselves, but with large profits to multi-national companies. The growers could be using scarce supplies of local water and pesticides (that might be banned in European countries) to ensure higher yields but without providing adequate protection for the workers. Fair trade schemes provide good conditions for the workers and are receiving well-deserved support. Those of us who are infinitely better off need to be aware of the need to pay real costs for food from these sources so as not to continue to exploit people who are barely living at subsistence level. With greater travel around the world our expectations have been matched by the availability of previously unknown fruit and vegetables. We need to question to what extent it is reasonable that we continue to demand a disproportionate share of the world’s resources.
Closer to home our own farmers do not necessarily receive the support that they need to run viable businesses, with subsidies adding a further complication, more favourable for some, than others. There is an increasing trend to try to source as much as possible from local sources and this has reciprocal benefits in providing local jobs and reducing food miles. Of course, the most accessible food can be grown in our own gardens, with the satisfaction of producing our own crops and re-establishing a link with the seasons.
Most food is probably grown using very different varieties compared with fifty years ago. Modern crop varieties have been selected to produce shorter stems and larger seeds. With greater availability of artificial fertilisers, crop yields have been increasing for some time. But there is a limit to the amount of fertiliser (especially nitrogen) that can be applied without harmful effects to the ecosystem and research is now directed into more sustainable farming maximizing crop yield with minimum additional inputs. Modern farming methods have relied on growing large areas as a monoculture that by the lack of diversity is more vulnerable to pests and diseases and where a minimal amount of ‘weeds’ or wild plants are tolerated. Wild plants are the food plants for caterpillars, the seed source for birds and the bottom of the food chain that enhances our environment with colour: butterflies, a whole range of other insects and bird life. If agriculture is too intensive there is an ever-diminishing space for our native species and a corresponding reduction in the diversity of plants and animals, making our environment all the poorer. The presence of a rich diversity indicates a healthy environment for us all, enhancing our well-being and providing room for us to relax, exercise, and benefit from the natural environment. Fortunately in Scotland we do still have many hedges, edges of fields, woodland, cycle paths and open spaces that should be valued.
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