from The Century Dictionary.
- noun The lighter-colored and softer part of the wood of exogenous plants, between the inner bark and the heart-wood.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Bot.) The white and softer part of wood, between the inner bark and the hard wood or duramen; sapwood.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
sapwood; the thin white layer between the bark and wood of a tree
from Wiktionary, Creative Commons Attribution/Share-Alike License
This consists in cutting a ring round the tree with axes through the bark and sapwood, or alburnum, into the brown wood beneath.
The growth of the trunk or stem of all exogenous plants, or those which increase in size on the outside of the stem, is brought about by the descent of certain formative tissue called cambium, elaborated by the leaves and descending between the old wood and the bark, where it is formed into alburnum or woody matter.
Wood is composed of duramen or heartwood, and alburnum or sapwood, and when dry consists approximately of 49 per cent by weight of carbon, 6 per cent of hydrogen, 44 per cent of oxygen, and 1 per cent of ash, which is fairly uniform for all species.
Because it is formed by branches of those returning vessels that deposit the new alburnum.
When he saw that Madame Delmare was obliged to make an effort to listen to him, he held his peace, and naught could be heard save the innumerable little voices whispering in the burning wood, the plaintive song of the log as it becomes heated and swells, the crackling of the bark as it curls before breaking, and the faint phosphorescent explosions of the alburnum, which emits a bluish flame.
Incisions are made into the alburnum of the seringueiras; below the wound small pots are attached, which twenty-four hours suffice to fill with a milky sap.
The giant's heart had disappeared, the alburnum had been dissipated into soft whitish dust; but if the tree did not depend so much on its powerful roots as on its solid bark, it could still keep its position for centuries.
The tree was evidently hollow throughout its length; but perhaps some portion of the alburnum still remained intact.
It was probably an effect of the season, for Knight states that he never could discover the least trace of saccharine matter during winter in the alburnum either of the stem or of the roots of the sycamore.
Resources of the Southern Fields and Forests, Medical, Economical, and Agricultural. Being also a Medical Botany of the Confederate States; with Practical Information on the Useful Properties of the Trees, Plants, and Shrubs
In dicotyledonous plants its main current is through the liber, or inner portion of the bark, but it also descends through the alburnum or most recently formed wood, through which, in the same plants, flows the main current of the ascending sap.