Trees are such massive and imposing things that we tend to take their needs for granted. We fuss and fret over annual bedding plants, and get all hot and bothered if a small dry spot appears on the lawn. Lawns and flowers though are ephemeral elements in the garden, while the tree is a long term matter. Indeed, it is the one part of the garden that we truly bequeath to future generations. It is of the utmost importance therefore not only to care and nurture it as one would a child, but also to recognize that many processes that potentially threaten its life, take place unseen and unheard, rather like cancer creeping up on a person.
Trees are not good communicators!
Grasses and flowers are pretty effective in telling us how they feel. A lack of moisture in the soil is almost immediately communicated to us by the wilting of the plant. A tree on the other hand can appear healthy and strong, with none of the tell-tale signs of stress, such as drooping leaves. Yet appearances can be very deceptive. In fact it can be stated in general terms that when stress symptoms first appear, the internal damage that has already occurred is so severe, that the tree is well on its way to an early death.
Water shortages
The minimum water requirement for trees is thought to be about 300 mm a year. That is the most drought hardy species in the world, like Pistachio and Tamarisk, need access to some 300 liters of water for every square meter of ground that they cover. So areas with less annual rainfall cannot support trees of any form, other than in localized spots such as valley bottoms, where water may collect.
Most garden trees require a lot more than that. A lemon tree growing in a Mediterranean climate for instance needs some 800 mm of water a year. If the annual rainfall averages say 400 mm, then the remaining 400 has to be supplied by irrigation.
In dry climates therefore it's vital to know the annual water needs of the trees in your garden. Again, it should be pointed out that the tendency of most people is to water those plants that appear to be most in need. Actually, in drought years the exact opposite should be the case. When water is in short supply, the flowers and lawn should be left to dry out, while the trees are given what they require. Grass and flowers can be replaced; a mature tree, 150 years old, never!
Rot and Decay
Rot and decay normally develop in the branches and trunks of trees following poor pruning operations. As with water stress, the signs can take years to show themselves. The incorrect pruning of a major limb could cause that limb to collapse 15 years later or more, as the unseen, unheard progress of the rot eats its way into the heart of the wood. Trees that look entirely healthy, complete with pruning wounds totally calloused over, can suddenly collapse. On examination, the trunk or branch is discovered to be hollow inside, the result of rot and decay working slowly over the years.
Just remember then that "all that glitters is not gold." Tree care, or arboriculture, is the most important part of gardening, because the tree is the garden's most precious item.
Article Source: http://EzineArticles.com/954499
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