Ponderosa pine trees

Table II. Changes in 160 Ponderosa Pine Trees during Exposure to Oxidant Air Pollution from 1969 to 1971 ...

Table VIII. Protection of Felled Ponderosa Pine Trees from Attack by Ips confusus with Lindane Surface and Tissue Deposits...

A mass attack of insects can cause serious devastation to crops, forests, food storehouses, etc. These invasions are usually triggered by the release of a set of pheromones. For example, upon landing on a ponderosa pine tree, the female western pine beetle, Dendroctonous brevicomis, releases exo-brevicomin 16 (Scheme 1.5) to attract males. Shortly after mating, the pioneers start to release a mixture of compounds, 17-19, which carries a sort of you are welcome message to their kinsfolk. The flow of incomers increases a hundredfold and as a result the tree is overwhelmed and killed. ... 

Schaumlbffel, J.C., Filby, R.H., Moore, B.C., 1998. Ponderosa pine tree rings as historical monitors of zinc and cadmium pollution. J. Environ. Qual. 27, 851-859. 

Permeation with the 3-component pheromone over a 0.81 hectare plot prevented the beetles from being trapped on traps baited with the same pheromone in the center of the treated area 536), When verbenone was released from formulations attached to ponderosa pine trees that were also baited with the pheromone, no mass attack occurred on these trees, in contrast to the mass attacks that occurred on trees that were simply baited with the pheromone. Further development of this approach is warranted to develop a method for protecting individual high-value trees. 

Fettig, C. J. et al., Efficacy of Verbenone Plus for protecting ponderosa pine trees and stands from Dendroctonus brevicomis (Coleoptera Curculionidae) attack in British Columbia and California. J. Econ. Entomol. 105 1668-1680, 2012. 

Stark et o/. and Miller et reported that oxidant (ozone) injury to ponderosa pine predisposed the trees to later invasion by pine bark beeides. The beetles increase the rate of decline and may be the final cause of tree mortality (see Chapter 12). It is possible that oxidant stress in other parts of the country contributes to insect infestation in forest areas. Weber (personal communication) has shown that ozone and mixtures of ozone with sulfur dioxide (0.25 ppm, 4 h/day) can decrease the population of four nematodes associated with soybean. These... 

Even that kind of information is not available for forest species. Other than chronic injury to white pine (associated with ozone, sulfur dioxide, and their mixtures), no clearly defined examples of chronic injury from ozone have been reported for eastern forests, and no information is available on PAN. It is of interest that both Virginia and jack pine appear more sensitive than white pine to acute ozone exposures, but chronic symptoms have not been observed in either species. The relationship between oxidant dose and injury in the San Bernardino Mountains area suggests that ponderosa pine is moderately to severely injured in areas that receive oxidant at above 0.08 ppm for 12-13 h each day (Chapter 12). Ponderosa pine seems to be the most sensitive western pine, but in some areas Jeffrey pine is about as sensitive. White fir, incense cedar, and sugar pine all appear more tolerant, even to the high oxidant concentrations in the San Bernardino Mountains. PAN may play some role in the chronic responses noted in the western forest species, particularly by broadleaf deciduous trees and some shrubs. 

Stark, R. W., P. R. Miller, F. W. Cobb, Jr., D. L. Wood, and J. R. Parmeter, Jr. Photochemical oxidant injury and bark beetle (Coleoptera Scolytidae) infestation of Ponderosa pine. 1. Incidence of bark beetle infestation in injured trees. Hilgardia 39 121-126, 1968. 

Early studies suggested that injuiy to ponderosa pine was similar in all size classes, but Cobb and Stark later reported higher mortality rates in understoiy ponderosa pines (9-12 in., or 22.9-30.5 cm, in diameter) than in larger size classes. The probable effect of tree mortality on stand composition can be anticipated to some extent from an example of the present species and size-class composition, as shown in Table 12-5. In this severely damaged stand in the ponderosa pine-white fir subtype, nearly 50% of the overstory and about 22% of the understory is ponderosa pine. 

Tree Size Gass Ponderosa Pine Incense Cedar White Fir Sugar Pine... 

FIGURE 12 18 Relationship between degree of oxidant injury to ponderosa pines and bark-beetle attack (left) and numbers of trees killed by western pine beetle, mountain pine beetle, and the two species together (right). Reprinted with permission from Stark and Cobb. ... 

Oxidant injuiy to ponderosa pine predisposes the trees to later invasion by pine bark beetles. Ozone and ozone-sulfur dioxide mixtures may decrease the population of soybean nematodes. Both greater and smaller effects have been noted when herbicides have been used in the presence of high oxidant concentrations. 

Earentinos, R. C., Capretta, P. J., Kepner, R. E., and Littlefield, V. M. (1981). Selective herbivory in tassel-eared squirrels role of monoterpenes in ponderosa pines chosen as feeding trees. Science 213,1273-1275. 

Relatively little work has been done on allelopathic effects on VAM. Tobiessen and Werner (29) found reduced VAM formation in hardwood tree seedlings growing under pines, and spores of VAM fungi are absent from soil beneath living ponderosa pines, although they are abundant under dead trees ( ). Members of the nonmycorrhizal family Cruciferae sometimes inhibit VAM formation in associated plants though this doesn t always happen (31-3A). 

Ozone and related oxidants are estimated to be responsible for about 95% of the annual 130 million crop loss caused by air pollutants in the United States. Reports have indicated that ozone can seriously damage important crops such as spinach, beans, petunias, citrus, tobacco, soybeans, and alfalfa, and forest trees such as Eastern white pine and Ponderosa pine. 

There is also the possibility that pollutants alter susceptibility of the plant to pathogens (36) or insect attack. Of the latter there is the decreased resistance of ponderosa pine to bark beetle attack caused by ambient oxidant exposure (37). The investigations of others with respect to the effects of fluoride on ponderosa pine indicated that although foliar injury was associated with increased resin exudation pressure, which could be interpreted as an increased capacity of the tree to overcome bark beetle attack, degree of insect infestation was not associated with amount of foliar injury (38). As more is known about pheromones, the botanical investigation of the secondary products of metabolism, such as terpenes and phenolics, may become more important in investigating the mode of action of pollutants in the entire plant. The switch to alternate pathways, while resulting in the same products, may reduce the intermediates needed in biosynthesis and thereby affect the plants resistance to disease or attractiveness to insects. 

Plant substances are said to enhance some insect hormones, to the advantage of the insect. Bedard et al. (44) have described how the western pine beetle (Dendroctonus brevicomis) uses its host pine trees (Firms ponderosa and P. coulteri) to enhance the drawing power of its sex attractant, exobrevicomin. When ready to mate, both sexes emit the attractant. Bedard found the attractant s power (in terms of numbers of insects attracted) was doubled when mixed with myrcene, a normal constituent of pine wood. Myrcene alone was not attractive. Myrcene, however, is not restricted to pine we have seen earlier (10) that it is consistently found in spruce needles, and in general it is not characteristic of any single group of plants. Since the western pine beetle feeds only on pine, of what real ecological significance is Bedard s report of the enhancement of its hormone by myrcene Why isn t a more specific constituent of pine wood involved Perhaps one is, but research has not yet revealed it. Apart from Brower s work with the monarchs, we have not examined the rich area of herbivore—predator interactions. 

Tjhotochemical oxidant air pollution—chiefly ozone—was first identified in 1962 as the agent responsible for the slow decline and death of ponderosa pine (Pinus ponderosa Laws.) trees in southern California (I). Work on identifying this source of damage can be traced to the mid-1950s it was described as chlorotic decline (2). 

On one survey strip, 160 ponderosa pines were tagged and assigned score values in April 1969. The same trees were re-evaluated in May 1971 to determine the change in degree of oxidant injury and the number of deaths. 

Species and Age Composition in Relation to Site. Combining all sites on the study area, the species composition in the understory (seedlings up through poles 11.99 inches dbh) is ponderosa pine, 22.2% incense cedar, 48.6% white fir, 22.8% and sugar pine, 6.3%. In the overstory (trees larger than 12.00 inches dbh) it is ponderosa, 49.6% incense cedar, 22.7% white fir, 19.7% and sugar pine, 8.0%. Table I shows the actual numbers in each size class. 

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