In these cases
the destruction is frequently to a large extent; great rocks are
detached from the summits of the hills, and sweep off whole lines
of trees in their descent.
Wherever landslips are frequent, they may be taken as an evidence
of a poor, clay subsoil. The rain soaks through the surface; and
not being able to percolate through the clay with sufficient
rapidity, it lodges between the two strata, loosening the upper
surface, which slides from the greasy clay; launched, as it were,
by its own gravity into the valley below.
This is the worst kind of soil for the coffee tree, whose long
tap-root is ever seeking nourishment from beneath. On this soil
it is very common to see a young plantation giving great promise;
but as the trees increase in growth the tap-root reaches the clay
subsoil and the plantation immediately falls off. The subsoil is
of far more importance to the coffee-tree than the upper surface;
the latter may be improved by manure, but if the former is bad
there is no remedy.
The first thing to be considered being the soil, and the planter
being satisfied with its quality, there is another item of equal
importance to be taken into consideration when choosing a
locality for a coffee estate.