Art. LVII.—On Mottled Kauri.
[Read before the Auckland Institute, 26th August, 1874.]
Regarding the origin of the rich mottled shading of some kauri trees, considerable diversity of opinion exists, some ascribing it to a timber disease, while others believe such trees to belong to a variety of the kauri. The slightest examination, however, seems to show that this is no variety, but a peculiarity due to an abnormal growth in the sap-wood and bark. The mottled kauri is rather a rare tree, but a young mottled kauri is rarer still.
If it were a variety we should expect to find the markings in the roots and stumps; on the contrary, it is believed those parts are never affected, and for some distance up the trunk the timber is often just like that of other kauri. Allowing then, that it is to an abnormal state of the growth of the tree we owe this rich and valuable furniture wood, an enquiry as to the operating cause may not be uninteresting.
On examining a portion of the outer timber and bark of a highly mottled tree such as the specimens now exhibited were cut from, we see the bark entangled in the sap-wood, being pitted and streaked in some places very deeply. The specimens are all sawn from a board showing bark and sap-wood, and little or no heart timber. The bark has mostly fallen away during the seasoning, but the action and growth of the mottling are very clearly shown by examining the sections across grain. The bark is shown to become entangled in the ligneous growth, and has been surrounded and retained, sometimes in cells, sometimes leaving only a trace of non-fibrous barky matter in thin flakes, causing shaded parts, broad or narrow, according as the timber is cut relative to their planes. Nearest the bark the mottlings are nearly pure bark, and as they are found in the tree away from the surface, they are observed to be more and more of a ligneous structure. A close study of the specimens will convey an impression of the connection between the bark and the markings, better than any written description can do, but it is to be observed that all around this, in some degree foreign substance, the true wood is shaded and marked in itself, just as it is to be observed in knotty timber, and as the timber is transformed to the state of heartwood, a deposit of gummy and ligneous matter seems to transform even the largest of the imprisoned flakes into veritable woody fibre.
Any abnormal state of growth seems not to affect the health of the tree, as mottled kauri trees are often the largest and soundest. The beauty of this timber and its effect in furniture are often marred by injudicious selection. Not only do trees vary in their mottled character, but by judicious sawing a great variety can be obtained from one tree, and nothing has a worse appearance in furniture—however well made—than an indiscriminate loading of mouldings, framing, pilaster, and panels, with rich and heavy mottled kauri.