Treesearch

As now constituted, Gomphiluma consists of two species of small trees limited to the Brazilian Amazon. Formerly submerged in the large genus Pouteria, Gomphiluma was reinstated to generic status by Aubréville in 1961. The pale brown wood of moderate density is quite unlike that of Pouteria and appears more nearly allied with certain species of Micropholis.

Whole-tree chips deteriorate more rapidly than do clean, debarked chips and present a greater hazard for spontaneous ignition when stored in outdoor piles. To prevent ignition, the chips can be stored for only short periods of time and the frequent rotation of the storage piles results in high handling costs. Drying the chips prior to storage will prevent deterioration and heating, provided the chips are stored under cover. In many cases, the costs of drying can be recovered when the chips are burned for fuel. In these instances, drying and covered storage is the least expensive method for...

Gambeya is an African genus to which Aubréville added Gambeya excelsa (Huber) Aubr., based on the Amazonian Chrysophyllum excelsum Huber. Whether Gambeya is the appropriate taxon for the American species remains to be resolved. Wood specimens indicate that several species occur in the Americas ranging from Southern Mexico to the Peruvian Amazon. The woods of the neotropical Gambeya are an off-white color unique among the predominant browns and red browns so typical of the Sapotaceae. The wood is further distinguished by the radial arrangement of the pores, reticulate parenchyma, lack of...

Sandwithiodoxa is a monotypic genus established by Aubréville and Pellegrin based on Pouteria egregia Sandwith, making the new combination Sandwithiodoxa egregia (Sandw.) Aubr. and Pellegr. The wood is light brown, very hard and heavy with an average specific gravity of 1.09. Individual specimens attain a specific gravity of 1.21. Floristically it is said to have affinities with Sarcaulus and Pseudocladia, but anatomically it differs from these genera in several details.

For most uses hardwoods are dried as entire boards that include all defective portions discarded after drying. The United States has a large resource of low-quality hardwoods and the potential exists for significant savings in energy and in dryer capacity by cutting out defects before drying. One approach could use radio frequency drying. In this investigation short lengths of northern red oak were dried rapidly, but energy consumption and honeycomb were excessive in drying to low moisture levels. However, rapid radio-frequency dielectric drying to 25 to 30 percent moisture content...

Computer simulation sawing programs were used to study the sawing of mathematical models of hardwood logs by me live sawing and three 4-sided sawing methods. One of the 4-sided methods simulated "grade sawing" by sawing each successive board from the log face with the highest potential grade. Logs from 10 through 28 inches in diameter were sawn. In addition, a refinement in the live sawing called live rip, in which center-sawn boards are ripped to increase value, was studied. Results generally indicate that all of the 4-sided methods studied gave similar lumber values. Live sawing was...

Large-scale fire tests were conducted on seven 16- by 24-foot structures. Four of these structures were of sandwich construction with cores of plastic or paper honeycomb and three were of wood-frame construction. The wasss were loaded to a computer design loading, and the fire endurance determined under a fire exposure from a typical building contents loading of 4-1/2 lb/ft2 floor area. The results in the large-scale tests generally agreed with results of laboratory ASTM E 119 tests on the same wall constructions if the slower fire buildup time in the large-scale tests is considered....

In fiberboard, the phenomena of smoldering can be visualized as decomposition resulting from the motion of a thermal wave-front through the material. The tendency to smolder is then directly proportional to the velocity of the front. Velocity measurements were made on four fiberboards and were compared to values given in the literature for several substances. Velocities ranged from zero to 4.63 x 10-2 inch per minute (11.8 cm/min). The phenomena of smoldering is also considered in terms of transport processes; a discussion of related literature and theory is provided, culminating in the...

An evaluation is made of the effect of cross grain on the transit time of longitudinal compression stress waves in Douglas-fir 2 by 8 lumber. Cross grain causes the stress wave to advance with a front or contour skewed in the direction of the grain angle, rather than to advance with a front normal to the long axis of lumber. Thus, the timing of the stress wave in lumber with cross grain is complicated. Based on the static bending modulus of elasticity of the lumber evaluated, an average of transit times for determining a stress wave modulus of elasticity (E) was better than two other...

Cutting yields from gang ripping hardwood lumber graded by the National Hardwood Lumber Association standard grades are determined using the technique of mathematical modeling. The lumber used is the same as that in an earlier mathematically modeled determination of cutting yields from traditional rough mill procedures. Mechanical cutting factors such as kerf, cutting lengths, and minimum salvage size are also the same in both studies. A comparison of yields between the two systems is made. While gang ripping produces higher total yields in all grades, the gain tends to be in the medium...