Species coniferous

Penetrating Stains. Penetrating or no-wipe stains are used in a variety of appHcations. The most common use of these direct-to-wood stains is on smaH-pore species of wood. Maple, cherry, and coniferous species such as pine are good candidates for penetrating stains. 

Figure 3. Changes in dominant species of trees in the upper elevation, coniferous ecosystem of Camels Hump based on density (upper graph) and on basal area (lower graph).

The receptors of interest are soils of agricultural (arable lands, grasslands) and non-agricultural (forests, steppes, heath lands, savanna, etc.) ecosystems. In non-agricultural ecosystems, the atmospheric deposition is the only input of heavy metals. Regarding the Forest ecosystems, a distinction should at least be made between Coniferous and Deciduous Forest ecosystems. When detailed information on the areal distribution of various tree species (e.g., pine, fir, spruce, oak, beech and birch) is available, this should be used since tree species influence the deposition and uptake of heavy metals and the precipitation excess. On a world scale, soil types can be best distinguished on the basis of the FAO-UNESCO Soil Map of the World, climate and ecosystem data from NASA database (1989). 

Oxygenated monoterpenes which are found in almost every bark beetle species attacking coniferous trees, include czs-verbenol 246, frans-verbenol 247, and myrtenol 248, representing primary products of allylic oxidation of the host terpene a-pinene 45. Further oxidation of 247 or 248 leads to the... 

Davtt. D. D., and F. A. Wood. The relative susceptibility of eighteen coniferous species to ozone. Phytopathology 62 14-19. 1972. 

These materials seem best adapted for deweeding coniferous tree species, such as pines and junipers, which have considerable resistance to the oil sprays. Broadleaf species such as elm and walnut are seriously damaged or killed by moderate dosages of the oil sprays, and much research is needed to find if any of this group of plants are sufficiently resistant to warrant use of the mineral spirits as a selective herbicide. 

Gilgut (5) in 1945 noted that Stoddard solvent gave good control of weeds in beds of coniferous species, but that there was considerable variation in the oil resistance of the evergreens the yews were sensitive to oil injury, while jimipers were resistant. 

In North America, the name hemlock refers to species of Tsuga (Pinaceae), a group of coniferous trees, which should not be confused with the poison hemlock. 

Several species of pine and fir are considered to be among the most fluoride-susceptible plants. Needles of these coniferous trees are most sensitive to HF while they are elongating and growing rapidly in the spring. Necrosis starts at the tip and progresses toward the base as fluorides accumulate. The injured tissue becomes chlorotic and subsequently changes to reddish-brown or sometimes to a lighter shade of brown. One-year-or-more-old needles are seldom, if ever, injured by fluorides in the atmosphere. 

The present scarcity of data only allows limited speculation about the community changes expected to be induced by oxidant air pollution in the coniferous forest. An enormous amount of new information must be compiled for each important overstory and understory species in a life table format. This procedure identifies the relative importance of the various mortality factors which act upon each age or size class of each important species in the mixture from seedling to maturity. 

Wood is converted into pulp by mechanical, chemical, or semichemical processes. Sulfite and kraft (sulfate) are the common chemical processes, and neutral sulfite is the principal semichemical process (NSSC). Coniferous wood species (softwoods) are the most desirable, but the deciduous, broad-leaved species (hardwoods) have gained rapidly in their usage and constitute about 25 percent of pulp-wood. Table 28.2 summarizes the conditions utilized with the various pulping processes,... 

---