After the initial phase, a period follows in which the stand of the woody planting is very tight, and, although space is created by means of thinning and cutting back, this will, for some time, be restricted to the space needed by the trees and shrubs themselves. The trees and shrubs still have low branches, causing a very dense shade at ground level. Herbaceous plants have no chance of survival at this stage. Only years after the initial planting, when the trees and shrubs have gained height and when purposeful pruning has created more space within the woodland and more light has started to be admitted, can herbaceous plants start growing there. Purposeful maintenance pruning has thus created a variation that will be expanded in the time to come. It will be maintained throughout the complete lifecycle of the woodland planting. Slowly, an environment suitable for some species of herbaceous plants comes into being. The species of herbaceous plants best fitted to the developing woodland depends upon the habitat requirements—foremost the quantity of light—of the species to be used and the degree of refinement of the plantings. The insertion of the herbal layer, therefore, is not done at once but gradually.
Daily and periodical maintenance and overall management should be aimed at the woodland plantings in its totality. This management comprises the tree and shrub layers, the herbaceous layer, the moss and fungus layer, and the fauna pertaining to it. In practice, one’s focus will mainly be on the management of woody and herbaceous plants. If maintenance and management are favourable to them, environments will result that enable the other elements of flora and fauna to spontaneously establish and maintain themselves and to expand. The most important maintenance measures are the pruning of woody plants and the regulation of the herbaceous layer. Although pruning has been dealt with to some degree before, some vital points need to be added. Its practical implications justify some more attention. In addition to maintenance pruning, adapted to the range of woody plants chosen and directed towards a spatial variety that is as large as possible, the frequency of pruning is also important. Thinning and cutting back are performed in the winter season. In the initial phase it is carried out once every two years and in the maintenance phase every three years. This may seem rather intensive, but it turns out that each pruning cycle involves relatively little work. In addition, the vegetation is disturbed less, and this is an important factor in creating a plant community that is well-composed, harmonious, aesthetically attractive and possesses a high quality.
If pruning is executed only once every five, six or more years, the intervention will be on a much larger scale; more work will be involved and much more prunings will be produced. The increase in light and large quantities of shredded wood all contribute to a large-scale disruption, leading to an explosion of mostly unwanted herbaceous species. Conversely, one may (in smaller planting strips) suppress the growth of unwanted herbs by enclosing its fringes to a large extent with a shrub layer. This, however, also impedes the growth of desirable herb species during the summer. In such situations, the main aspect of the herbaceous layer will consist of spring flowering plants, including bulbs and corms. If we do wish to see naturalistic herbaceous plantings at certain spots in these fringes, we will have to resort to intensive summer maintenance.
In older woodland plantings it is desirable, where possible, to leave dead wood where it is, standing after bark-ringing or lying on the ground after felling, with trunks and branches cut in pieces. This is possible where it does not conflict with existing rules and regulations (for example those associated with Dutch Elm Disease). The wood remaining in the system is very valuable to many plants and animals. As it will decay slowly, it can be completely reabsorbed by the system without causing disturbance. How far this is aesthetically acceptable will depend on the scale and the situation in which we apply this. In an older (±20 years) or mature woodland planting, a coverage percentage of 50% for the tree layer, 70% for the shrub layers and 30-90% for the herbaceous layer can result in a very attractive image. The coverage percentage of the herbaceous layer may increase with the nutrient level and the moisture content of the soil.