Here we see organic life and structure expressed in the vigorous spring of inter-dependent and corresponding curves, from the rigid sinuous column of the main stem springing from the ground, presently divided into the main forks of the branches, which again subdivide and subdivide into smaller forks, so that the tree may sustain and spread its life in the air and the sun, both supporting and continuing its existence by this wonderful economic system of co-operative, subdivided, and graduated helpfulness.
The massive green pavilion of summer, which this delicate vaulting of branch-work sustains, gives us another, more sumptuous, but perhaps not a greater beauty in the combination or substitution of form and mass for line composition.
Form and Mass in Foliage
We might express, in an abstract way, the principle of the line-structure of the ramifying tree by super-imposing vertically fork upon fork in gradually diminishing scale, either curvilinear or rectangular; and the principle of the mass-structure in the formation of the foliage might be expressed by a series of overlapping curves, suggestive of scales or cloud masses: to both of which indeed they correspond in principle, illustrating the scale principle in detail and the cloud principle in the mass; thus repeating the same general law of natural roofing, or covering, in different materials (see illustration, p. [145]).
In a mass of foliage each leaf falls partly over the one below it, as by the system of their growth and suspension upon the stem they are of course bound to do, whether symmetric or alternate in their arrangement, the gaps caused by decay or accident being generally filled by new shoots. Each shoot, eager to expand its leaves in the light, ever spreading, forms mass after mass of the beautiful green panoply—the coat armour of the forest, arboreal man's first form of domestic architecture.
