One of the most important factors in the growth of timber is climate. This accounts for the wide distribution of many types, for instance, pines, firs, and spruces are almost universally distributed, and it will be found upon examination of general conditions that differences in zones are compensated by altitude. Thus the northern pine is generally regarded as belonging to North Europe; in Northern Norway it grows at a height of 700 ft. above sea-level and 6500 ft. on the Sierra Nevada of Southern Spain. This feature of timber growth is further dealt with in Chart II.

Reference to the above chart will show graphically the general distribution of some timbers, and illustrate the fact that most timbers are largely affected by particular climatic conditions. The quality of the soil is another important factor, the rich soils and humid atmosphere of tropical countries producing very hard, slow-growing, and well-figured and marked woods, whilst the temperate climates are favourable to the growth of moderately rapid-growing timber trees, which are, however, not so richly marked-with the exception of the oak-nor so hard in texture as the former. The situation of timber trees is another important factor affecting the quality of the wood, swampy land generally producing softer material, whilst rich soils, and especially those of tropical and sub-tropical countries, produce hard, close grained and richly grained woods. This general principle is especially applicable to trees belonging to the same order, as, for instance, Honduras mahogany, which ranges from very soft to moderately hard material. The tall, slender, and straight growth of trees in closely wooded land is a familiar feature, favouring an upward growth, and acting against a proper development of the branches. Those grown in open situations display the full characteristics of the tree to best advantage, as seen in our oaks, ashes, and elms. The quality of timber and its value from a commercial standpoint is also directly affected by its situation. If exposed to high winds an erratic growth is characteristic, and the wood exhibits considerably twisted grain, affecting its strength when submitted to tensile strain or compression. For this reason also branch-wood is not favourably regarded from a woodworker's standpoint. Australian timbers afford an interesting study relative to the effect of situation upon quality and growth. The sub-tropical jungle forests with heavy undergrowth and humid atmosphere favour the growth of numerous grasses and palms in addition to trees of exceptional hardness, richness of colouring, and beauty of grain, including silky oak and Australian tulip-wood; whilst the ironstone ridge belts in Western Australia favour the growth of a remarkably strong, though coarse timber, i.e. jarrah. The more temperate climate of New Zealand conduces to the growth of moderately hard timber, such as New Zealand or kauri pine.