Sap wood

Another example is illustrated in Figure 9 (27). The outer, sap-wood rings of a western redcedar, Thuja plicata Donn, which grew about 50 miles south of Seattle, show an increase in 14C which lags slightly behind the levels of 14C which prevailed in the atmosphere. This lag is attributed to a holdover of food supply from the previous year a sizeable... 

In all reactions, wood of white fir Abies concolor) has been used. For the alkaline nitrobenzene reactions, extractive-free —20+40 mesh heart-wood sawdust containing 28.0% Klason lignin was used. Sequential extraction of the original sawdust with alcohol-benzene, 95% ethanol, and hot water gave extractives amounting to 4.9, 0.5, and 1.2%, respectively. In the other oxidation reactions, nominal 5 -in. wood chips, commonly used in pulping procedures, were employed. The mixed sap wood-heart-wood chips contained 26.5% Klason lignin and sequential extractives of 3.3, 0.5, and 3.2%, respectively. 

The central wood portion of the log depicted in Figure 1 is considerably darker in color than the part adjacent to the bark. The dark-colored wood is termed heartwood and the light-colored wood is termed sapwood. The discoloration is due to the production and secretion of substances which are a by-product of the death of food-storage cells. As new wood, that is sapwood, is formed to the outside of the tree stem, additional interior sap-wood adjacent to the heartwood zone is converted to heartwood. Some trees do not form discolored heartwood upon the death of... 

Fibers and vessels die at an age of a few weeks, after attaining their final shape and chemical composition. Parenchyma cells live much longer, some remaining alive until sap-wood becomes heartwood. One of the tasks of parenchyma cells is to convert sugars into storage starch to serve as food reserves for the... 

Surface-etherified Makamba Beiula maximowieziana Regal) specimens were used for shear strength tests. Other tests used Sugi Cryptomeria japonica D. Don) sap wood. 

Birch (Betula papyrifera) wood chips used in this work were obtained from Scierie John Lewis, a woodmill in the province of Quebec, Canada. The sample was composed of 53.5 % of sap wood and 46.5 % of inner and outer bark. The moisture content was 8.5 % as determined by placing a known quantity of sample in an oven at 102 3 C until a constant weight was reached. The elemental composition of the sample was 51.3 % C, 6.2 % H, 0,7 % N and 41.8 % O (by difference). Its ash content was 2,0 %,... 

The moisture content of heartwood in softwood trees is reduced to a level much lower than that of normal sap-wood (2, 24), During the moisture reduction period, the membranes of bordered pits in sapwood fibers have a strong tendency to become aspirated. This situation, together with that of pit membrane incrustation, greatly reduces the natural permeability of heartwood tissue to liquids and gases. 

When fresh-cut logs are converted quickly into large piles of chips, the living cells of the sapwood, together with the fungi and bacteria mentioned above, rapidly convert the stored food reserves into carbon dioxide (CO2), water, and heat see Reaction 1 for respiration) (45). If this metabolic heat is not dissipated, the pile becomes hot, and under conditions of very poor ventilation can lead to spontaneous combustion (46). For all of these reasons, fresh-cut sap-wood must be considered to be alive and, therefore, must be handled as a perishable raw material. 

Insects eat an incredible variety of foods leaves, roots, plant sap, wood, other insects, other arthropods, blood of birds and mammals, decaying plant material, pollen, nectar, dung, particles of algae, and even fungi. Some, like cockroaches, can digest nearly anything they can get their mandibles (jaws) on, while others must find a particular species of plant to eat or they will die. The disappearance of many butterfly species is due to the loss of their particular host plants as wild areas are cultivated or paved. 

The discoloration is normally limited to the green sap-wood because as a rule there iB neither sufficient food material nor moisture in the dry dead heartwood for the development of the fungus. Hie discoloration is usually most intense in the medullary rayB, since in... 

Durability test on Scots pine exposure to weather in Sweden showed that sap-wood had a higher moisture uptake and a higher mass loss compared with heart-wood [10]. 

The drug is collected mostly in autumn, removed from the white sap wood and dried. 

Starch is the most common extraneous polysaccharide of wood. It is found in angiosperms in the living, ray and longitudinal, parenchymatous cells of sap-wood. It almost never occurs in heartwood. There has been some uncertainty... 

Takehara T, Sasaya T 1979 Studies on the extractives of larch. Phenolic constituents from sap-wood of Larix leptolepis Cork. Hokkaido Daigaku Nogakubu Enshurin 36 681-693... 

Aucuparin has been found to be a fungicidic phytoalexin of the loquat (Eriobotry japonica, Rosaceae) (119) and the compound also occurs in the sap-wood of the apple tree (Malus pumila, Rosaceae) when infected with the fungus that causes silver leaf disease (Chondrostereum purpureum) (70). The infected wood of the closely related pear tree (Pyrus communis, Rosaceae) (69) and the infected wood of Cotoneaster lactea (Rosaceae) (20) contain phytoalexins of the biogenetically related dibenzofuran type (a-, P-, and y-pyrufuran, and cotone-furan, 23 a-d). 

Comstock, G.L. and Cote, W.E., 1968. Factors affecting permeability and pit aspiration in coniferous sap-wood, Wood Sci. TechnoL, 2 279-291. 

Balsam tolu is obtained from the tree trunk of M. balsamum by making V-shaped incisions through the bark and sap wood. The liquid balsam is collected in gourds and solidifies on aging. The balsam is a plastic solid with a brown or brownish-yellow color that darkens and hardens on aging. Like halsam Peru, it is a true balsam. Tolu balsam has an aromatic vanilla-like odor and an aromatic, mildly pungent taste it is insoluble in water but soluble in alcohol, acetone, benzene, and chlorinated hydrocarbons. 

The oils from the sap wood and the twigs contained a considerable amount of cineol. Schmidt and TYeilinger have exam in cd an oil from the bark of the tree, which had the following characters —... 

Under TG and DSC, TPF resin showed good thermal stability together with curing characteristics similar to those of the original PF adhesive. Similar DSC experiments were performed on a commercial phenol-formaldehyde adhesive plus Southern pine Pirns sp.) sap wood treated with a chromated copper arsenate (CCA) preservative [63], The thermograms indicated that curing can be accelerated at lower temperatures than normal depending upon the state of CCA in the wood. 

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