Md difficult to regard coniferous forests as a natural ecological group. At much higher altitudes, in the south-west of the Mediterranean region, forests occur of the Atlantic cedar (Cedrus atlantica).
Amongst Conifers Cedrus is especially noteworthy; it is represented by geographical races in the north-west Himalaya, in Syria, Cyprus and North Africa.
The only timber in ordinary use obtained from the Himalaya proper is the deodar, Cedrus deodara.
Cedrus Libani, the far-famed Cedar of Lebanon, is a tree which, on account of its beauty, stateliness and strength, has always been a favourite with poets and painters, and which, in the figurative language of prophecy, is frequently employed in the Scriptures as a symbol of power, prosperity and longevity.
The genus Cedrus contains two other species closely allied to C. Libani - Cedrus Deodara, the deodar, or "god tree" of the Himalayas, and Cedrus atlantica, of the Atlas range, North Africa.
The members of the genus Larix are distinguished from the firs, with which they were formerly placed, by their deciduous leaves, scattered singly, as in Abies, on the young shoots of the season, but on all older branchlets growing in whorl-like tufts, each surrounding the extremity of a rudimentary or abortive branch; they differ from cedars (Cedrus), which also have the fascicles of leaves on arrested branchlets, not only in the deciduous leaves, but in the cones, the scales of which are thinner towards the apex, and are persistent, remaining attached long after the seeds are discharged.
On the alpine range itself and its immediate branches, at a height of 6000 to 10,000 ft., we have abundant growth of large forest trees, among which conifers are the most noble and prominent, such as Cedrus Deodara, Abies excelsa, Pinuslongifolia, P. Pinaster,P. Pinea (the edible pine) and the larch.
The deodar (Cedrus Deodara), which is indigenous to the mountains of Afghanistan and the north-west Himalaya, is nearly allied to the Atlantic cedar and to the cedar of Lebanon, a form of which is found in Cyprus.
Deodar (Cedrus Deodara).
In the less exposed localities, on northern slopes and sheltered valleys, the European forms become more numerous, and we find species of alder, birch, ash, elm, maple, holly, hornbeam, Pyrus, &c. At greater elevations in the interior, besides the above are met Corylus, the common walnut, found wild throughout the range, horse chestnut, yew, also Picea Webbiana, Pinus, excelsa, Abies Smithiana, Cedrus Deodara (which tree does not grow spontaneously east of Kumaon), and several junipers.
The needle-form represented by Pinus, Cedrus, Larix, &c., the linear flat or angular leaves, appressed to the branches, of Thuja, Cupressus, Libocedrus, &c. The flat and comparatively broad leaves of Araucaria imbricata, A.
Long and short shoots occur also in Cedrus and Larix, but in these genera the spurs are longer and stouter, and are not shed with the leaves; this kind of short shoot, by accelerated apical growth, often passes into the condition of a long shoot on which the leaves are scattered and separated by comparatively long internodes, instead of being crowded into tufts such as are borne on the ends of the spurs.
Abies pectinata, &c.) the ripe cone differs from those of Pinus, Picea and Cedrus in the large size of the carpellary scales, which project as conspicuous thin appendages beyond the distal margins of the broader and more woody seminiferous scales; the long carpellary scale is a prominent feature also in the cone of the Douglas pine (Pseudotsuga Douglasii).
Pinus and Picea) - in which the cone-scales persist for some time after the seeds are ripe - the cones hang down and so facilitate the fall of the seeds; in Cedrus, Araucaria and Abies the scales become detached and fall with the seeds, leaving the bare vertical axis of the cone on the tree.
In the wood of Cypressus, Cedrus, Abies and several other genera, parenchymatous cells occur in association with the xylem-tracheids and take the place of the resin-canals of other types.
The mesophyll of Pinus and Cedrus is characterized by its homogeneous character and by the presence of infoldings of the cell-walls.
In the Mediterranean region occur Cupressus sempervirens, Pinus Pinea (stone pine), species of juniper, Cedrus atlantica, C. Libani, Callitris quadrivalvis, Pinus montana, &c. Several conifers of economic importance are abundant on the Atlantic side of North America - Juniperus virginiana (red cedar, used in the manufacture of lead pencils, and extending as far south as Florida), Taxodium distichum (swamp cypress), Pinus rigida (pitch pine), P. mitis (yellow pine), P. taeda,P. palustris, &c. On the west side of the American continent conifers play a still more striking role; among them are Chamaecyparis nutkaensis, Picea sitchensis, Libocedrus decurrens, Pseudotsuga Douglasii (Douglas fir), Sequoia sempervirens, S.
In the far East conifers are richly represented; among them occur Pinus densiflora,Cryptomeria japonica, Cephalotaxus, species of Abies, Larix, Thujopsis, Sciadopitys venticillata, Pseudolarix Kaempferi, &c. In the Himalaya occur Cedrus deodara, Taxus, species of Cupressus, Finns excelsa, Abies Webbiana, &c. The continent of Africa is singularly poor in conifers.
Cedrus atlantica, a variety of Abies Pinsapo, Juniperus thurifera, Callitris quadrivalvis, occur in the north-west region, which may be regarded as the southern limit of the Mediterranean region.