Nutrient Deficiencies

A lack of zinc or potassium drastically reduces growth. Trees affected by zinc deficiency show chlorosis of the leaf tips and leaf margins, their shoots exude much resin, and their older leaves fall off. Those with potassium deficiency show leaf tip and marginal chlorosis and die back (necrosis).8

Other Problems

Fire kills neem seedlings outright. However, mature trees almost always regrow, especially if the dead parts are quickly cut away.

High winds are a potential problem. Large trees frequently snap off during hurricanes, cyclones, or typhoons. Neem is therefore a poor candidate for planting in areas prone to such violent storms.

Seedlings regenerating beneath stands of neem are sensitive to sudden exposure to intense sunlight. Thus, clear-felling neem trees normally produces a massive seedling kill, especially if the seedlings are small.9

In some localities rats and porcupines kill young trees by gnawing the bark around the base. Even when not causing any physical damage, rodents can be pests: wherever they are numerous, the fruits may disappear before the farmer can harvest them.

Neem, with its intensely bitter foliage, is not a preferred browse, but if nothing else is available goats and camels will eat it. In fact, in Asia goats and camels have been known to browse young neem trees so severely in times of scarcity that the plants died.10 In Africa neem is generally ignored by livestock (which makes the tree easy to establish even within villages and courtyards). The reason that livestock treat neem differently in Asia and Africa is unknown at present. It may be differences in the tree specimens, or in the animals' preferences or past experiences.

8  

Zech, 1984.

9  

Information from R.W. Fishwick.

10  

Indeed, leaves could be used as a reserve fodder for camels, sheep, and goats. Despite their repellent bitterness, the leaves have a low fiber content and a high nutritional value (15 percent protein), comparable to that of leguminous leaves. However, there are also records of toxic effects of neem leaves on goats (Sudan).



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