ON THE KINDS OF TIMBER BEST ADAPTED FOR DIFFERENT SITUATIONS.
That the growth and quality of timber will be influenced by the nature
of the soil is a matter so well understood that it would scarcely
require to be treated of in this place, if we did not daily see examples
of planting in which all laws of growth have been set at defiance;
still, occasionally, experience has lent her aid and produced some
satisfactory results; and, as an exemplification of our meaning, and as
showing the influence of geological position upon planting, we would
direct attention to the following section:—
[Illustration: ALICE HOLT FOREST.
Beech. Hops. Larch. Oak. Larch. Hops. Beech.
4. Chalk. 3. Chalk Marl. 2. Upper G. S. 1. Gault Clay.]
Here we have the oak—of both varieties known to planters, to be
hereafter described—flourishing most luxuriantly on the stiff soil of
the gault; the chalk-marl, upper green sand, and gault—the two latter
only partially—being engaged in hop cultivation. The green sand
surrounding the forest is mostly devoted to the growth of larch or
spruce, the thinnings of which are used for hop-poles and the larger
trees are left as timber-belts; whilst the beech will be found to favour
the chalk. Hops and other cultivated plants flourish according to
geological position.
That the geology of a district affects vegetation mainly, according to
the mechanical and chemical structure of its individual rocks and the
climate in which they are situate, is quite true; and yet the following
table will show that different formations favour the growth of trees
upon other conditions than those named.
Choosing figures to represent relative values, the annexed table is
intended to show the amount of influence exercised by certain geological
rocks in the growth of different fruit and forest trees met with in
England.
+-----------+---+------------------+------+-----+----+----+------+-----+
| |No.|Rocks. |Apple.|Pear.|Oak.|Elm.|Beech.|Firs.|
+-----------+---+------------------+------+-----+----+----+------+-----+
|Cretaceous{| 1 |Chalk | 2 | 0 | 2 | 4 | 8 | 5 |
|Rocks. {| 2 |Green Sands | 3 | 1 | 3 | 7 | 0 | 3 |
| {| 3 |Gault | 4 | 1 | 6 | 6 | 0 | 0 |
|Jurassique}| 4 |Oxford Clay | 6 | 0 | 10 | 8 | 0 | 1 |
|Rocks. }| 5 |Oolite Freestone | 2 | 0 | 1 | 4 | 10 | 5 |
| }| 6 |Lias | 10 | 3 | 5 | 10 | 0 | 1 |
| | 7 |New Red Sandstone | 8 | 10 | 7 | 12 | 0 | 2 |
| | 8 |Mountain Limestone| 1 | 0 | 2 | 2 | 3 | 1 |
| | 9 |Old Red Sandstone | 15 | 8 | 8 | 10 | 0 | 1 |
+-----------+---+------------------+------+-----+----+----+------+-----+
These figures may serve to express—although roughly—the capacities of
different formations for the production of fruit and forest trees, and
it may be curious to note that, while the chalk and the oolite
freestones, both composed of carbonate of lime, offer a remarkable
agreement in point of dendrological productions, the mountain limestone,
also consisting of carbonate of lime, affords very different results;
here, no doubt, the different kinds of scenery presented by the rocks
themselves have a decided influence on the general results.
Much, however, of any geological influence in the growth of trees must
depend upon the material rather than upon the position of the rocks
forming the subsoil upon which they occur, and thus it may be expected
that clays, limestones, and sands, and different mixtures of these, will
each favour the growth of a peculiar spontaneous or native vegetation;
so that, if we looked to a larger list of trees and coupled it with
lists of herbaceous plants, we might make out even a stronger case,
either for the effects of geological or lithological conditions; but
enough has been said to point out that various trees naturally affect
one position more than another, and so they succeed as the results of
planting and cultivation in one kind of soil in preference to another,
and it may be laid down as a rule, that pomaceous fruits and hard-wooded
trees, as oak and elm, only _flourish_ in strong soils, though they may
be imperfectly grown in all soils, whilst soft-wooded trees, as beech,
lime, and the coniferæ, succeed best in lighter soils; hence, then, the
planter who would try to grow vigorous oak on sandbeds would be
disappointed, and while beech is the “weed” of the Cotteswold oolite,
whoever tries to grow an orchard upon the freestone rocks is sure to
meet with disappointment.
As regards forest trees we shall, for the most part, confine our remarks
to those of the following list, as, although of recent years many new
genera and species have been introduced, they are not yet in general
cultivation even for ornamental purposes, much less as a source of
profit.
LIST OF NATIVE OR NATURALIZED FOREST TREES.
Oak }
Chestnut } Our more common timber trees used
Walnut } in buildings, furniture, cooperage,
Elm } turnery, &c.
Ash }
Beech }
Birch } Employed in furniture, turnery, &c.
Larch } The British Coniferæ are not used
Spruce } for timber, except for fencing and
Scotch Fir } other common purposes.
Poplar }
Plane }
Mountain Ash } Employed for turnery, picture-frames,
Maple } and occasional useful purposes.
Lime }