COLLECTING AND STORING TREE SEEDS
Owing to the war there is little doubt that for several years to come
adequate supplies of seeds and young forest trees will not be available
from their usual sources on the Continent. Vast quantities of both are
annually sent to this country from Germany alone, while from other
parts of the Continent coniferous seeds in particular are largely
imported—in fact, we are almost wholly dependent for both seeds and
seedlings on foreign supplies.
Under these circumstances, it behoves the owners of woodlands in every
part of the country to collect seeds, particularly of such trees
as our plantations are mainly composed of. After these have been
properly harvested, they should be stored away in suitable places till
seed-sowing time in the spring. To some extent this will be a new
forest industry, though for long, the seeds both of Scotch Pine and
various hard-wooded trees, particularly the Oak, Ash and Elm, have been
annually collected on various estates throughout the country, and the
young plants raised from such stock have given every satisfaction when
planted out permanently.
For several reasons, however, we cannot compete with foreigners either
in the production of seeds or in raising young forest stock. For some
years to come, owing to the uncertainty of supplies from abroad, both
seeds and seedlings are bound to be scarce and expensive.
In the past, far too little attention has been bestowed on the
collecting and harvesting of the seeds of trees and shrubs, the result,
in not a few cases, being weak and unhealthy plants and an uneven and
irregular crop. The best seeds, it should be remembered, are those
collected from healthy trees in the prime of life, and grown under
conditions favourable to their perfect development. An unhealthy tree
will often bear a heavy crop of seed, but although the inducements to
collect such are great, they should be discarded, those from the most
robust specimens in the prime of life being chosen in preference.
Regarding the best way of collecting tree seeds little need be said,
the exigencies of the case determining the best method to be adopted.
The seeds of not a few trees may be collected as they fall, and this
is especially the case with those of the Oak, Beech, Elm, etc., all of
which may be swept into heaps and gathered in quantity from beneath
desirable trees.
In the case of the various Coniferæ this method of seed collecting
will not answer—indeed, in the majority of instances, the seed should
be gathered, or rather picked, from the trees just before they became
fully ripe, as in falling they get loose from the cone-scales and
are lost. When collecting the cones of coniferous trees, a long,
light hooked staff with which to draw the branches towards one can
conveniently be used to procure an abundant supply. A bag or satchel
should also be in possession of the seed collector, into which may be
put such kinds of cones as fall readily apart, as the seeds from these
are easily lost. Sometimes, as in the case of rare seeds, and when only
a few cones are borne near the top of the tree, the seed collector
must have recourse to climbing; but, in such cases, in order to avoid
injury to the bark, he should be provided with a pair of elastic shoes
or slippers. Great care is required in the collection of such seeds as
those of _Abies nobilis_ and _A. nordmanniana_, the cones, when fully
ripe, falling to pieces on the slightest touch. This, however, applies
equally to almost every species of Abies, whereas, with the Pines and
Spruces, the cones remain intact for an almost indefinite period of
time, even though the seeds may have fallen out on becoming ripe.
The proper harvesting of tree seeds rarely, except in the case of
experienced nurserymen, receives sufficient attention, although this
operation should be as carefully attended to as in the case of the
seeds of any other form of crop. After being collected, the seeds
of all trees, unless such as are mixed with sand for the purpose of
rotting, should be thinly and evenly spread out in a sunny spot, until
thoroughly dry. They may then be deposited in a cool, airy place,
and in thin layers, until wanted for sowing. An occasional turning
is all-important and should never be neglected. The smaller and less
common seeds may, for convenience sake, be hung up in calico bags, but
they, too, should be occasionally examined to prevent dampness and
heating.
The number of plants of various kinds that may be expected from
a bushel of seed of average quality varies very much, and may be
approximately given as follows: Horse Chestnut, 2,500; Oak, 6,000 to
8,000; Spanish Chestnut, about 3,000; Walnut, 5,000; Norway Maple,
12,000; Sycamore, about 12,000; Ash, 14,000; Beech, 10,000; Elm, 1,000;
Birch, fully 16,000; Holly, 17,000; Scotch Fir, 9,000. To 1 lb. of
seed: Spruce Fir, about 9,000; Larch, 3,000; and the Cluster Pine,
Silver Fir, and some others, from about 500 upwards.
For convenience in regulating orders for sowing, the following table
will show at a glance the approximate and relative number of seeds of
the various commonly cultivated forest trees contained in 1 lb. weight:—
Abies nobilis about 19,400
Abies nordmanniana ” 10,000
Ash ” 6,800
Beech ” 2,700
Douglas Fir ” 95,200
Horse Chestnut ” 36
Hornbeam ” 9,968
Larch ” 65,000
Lawson’s Cypress ” 131,400
Lebanon Cedar ” 10,800
Norway Maple ” 4,600
Oak ” 100
Pinus Austriaca ” 35,000
Pinus Laricio ” 43,000
Pinus Pinaster ” 12,000
Pinus Sylvestris ” 75,000
Spruce ” 64,500
Silver Fir ” 14,960
Sycamore ” 4,624
Walnut ” 36
These figures must only be taken as approximate, the seed of various
trees of the same species seeming to vary in the number to the pound
in a marked degree. The results of careful analysis of one or two
kinds may be cited as examples. In one case the number of seeds in 1
lb. weight of Scotch Fir was 69,600, while in another it had increased
to 90,600; and in the Larch the numbers were 33,900 and 68,000. These
differences are, however, mainly due to the individual seeds being
weightier in one case than in another, probably owing to the age and
health of the tree from which they were collected, the situation and
exposure to which it was subjected, etc. However, for all nursery
purposes the above figures may be accepted as a fair standard.
The time of collecting and the after-management of the different
forest seeds vary so much that a brief description of those kinds most
commonly planted will be found useful:—
=Alder= seed should be gathered from the trees in October and sown in
spring, say May.
=Ash= seeds are ripe in October, when they should be collected and kept
in moist sand during the winter, and sown in March.
=Austrian=, =Corsican= and =Weymouth Pine= seeds are treated in every
respect like those of Scotch Fir, varying the kiln heat according to
the looseness of the cone-bracts.
=Beech= seeds are collected in October and November, placed in sand,
and sown in April. The young plants are readily affected by frost, and
the seed should, therefore, not be sown earlier than the time mentioned.
=Birch= seed must be collected from the trees just before it becomes
ripe in August, otherwise it is scattered broadcast and lost for
cultivation. March is the time for sowing.
=Cupressus Lawsoniana= seed is usually ready for collecting in October,
but should not be sown before the first week in April.
=Douglas Fir= seed is, in most cases, readily removed from well-ripened
cones by threshing or by pulling the cone to pieces, but, in some
instances, particularly where the quantity is large, kiln-drying is
resorted to. The seeds are ripe in December and should be gently
watered and sown in May.
=Elm= seeds are ripe in June, when they may either be sown at once, or
dried and kept in stock for planting in March and April.
=Hawthorn= seed, or berries, may be sown when collected, or the outer
coating rotted off by keeping them during the winter in moist sand.
=Hazel= nuts may be collected in autumn and sown at once, or kept till
spring.
=Holly= berries require to be placed in sand for about eighteen months
so as to rot off the fleshy outer coating, and may be sown in March.
The mixture of sand and berries, which should be about in equal
proportions, must be turned frequently. They are usually sown with the
sand in which they have been lying.
=Horse= and =Spanish Chestnut= seeds may be taken together, the method
of collecting and sowing being very similar in both cases. They are
ripe by the middle of October, and may either be sown at once or kept
till spring. One seed to 4 square in. will be close enough.
=Larch= cones, when ripe, are of a rather bright brown colour and
require to be collected from the trees. This should not, however, be
done till spring, though occasionally they are gathered in December.
They part with the seeds far more readily than those of the Scotch Fir,
and consequently require less heat when in the kiln.
=Maple= seeds are ready for collecting about October, and should not be
sown till the beginning of April.
=Mountain Ash=, indeed, all the Pyrus family and others of a like kind,
require the berries to be placed in sand, and when the outer fleshy
coating has rotted away they may be sown either in autumn or spring.
=Oak.=—The acorns may be gathered or swept from the ground in November,
and either sown at once or stored away in a cool, dry place till
Spring. One acorn to every 4 square in. will be ample in the seed-bed.
Sow in spring or autumn.
=Scotch Fir= cones are better not collected till early in January, and
the time may even be extended till March. When quite ripe they have
changed from bluish-green to a light, grey colour. As the cones part
tardily with the seeds, artificial means have to be resorted to, the
cones being placed thinly over a kiln heated to a temperature of from
75° to 112°. They should be turned every third hour, and after about
thirty hours the kiln should be cooled down and the cones extracted
as quickly as possible. By beating with a flail the seeds are readily
removed from the cones, but it is best to do this before the cones have
cooled down or immediately they are removed from the kiln. The seeds
are then swept together and collected, and stored away until wanted
for sowing. When not required for sowing at once, the seeds should
be thinly spread out on the floor and slightly moistened with water
from a fine rose watering-can. They should then be turned about until
perfectly dry before being stored away.
=Silver Fir= seed does not require much, if any, artificial heat to
cause it to part from the cone. By placing the cones in the sunshine,
and heating and turning freely, the seeds come out without much
trouble. In all cases, however, wherever possible, it is wise policy to
dispense with artificial heat or kiln-drying as, unless this is carried
out most carefully, the vitality of the seeds is greatly impaired
thereby.
=Sycamore= seeds are ready for gathering in October, but should not be
sown till the end of March or beginning of April.
=Walnuts= are collected, when ripe, in autumn, and sown in late spring.
=Yew= seeds are usually washed of the pulpy matter before being sown.
In the case of large seeds, such as those of =Araucaria imbricata=,
=Pinus sabiniana=, and =P. macrocarpa=, the best way is to cut the
cones to pieces and carefully remove the seeds. This operation should
be performed with great care, so that the hard seed coating may not be
injured.
With conifers in general I have invariably found it the best plan to
allow the seed to remain in the cones until wanted for sowing. By
keeping the cones in a cool, dry place, and occasionally turning them
over, there need be little fear but that the seeds will turn out well.