Trees defenses

Whole Trees Individual Tree Defenses and Group Colonization.85... 

WHOLE TREES INDIVIDUAL TREE DEFENSES AND GROUP COLONIZATION... 

Beetle ability to overcome tree defenses via mass attack, and trees ability to interfere with beetle communication, are incorporated into a tree defense model based on terpene content in Fig. 4.3. These relationships yield no stable outcome. 

We have incorporated this hypothesis into Fig. 4.14, which is an expanded tritrophic version of Fig. 4.9. The top of this diagram now includes feedback between tunneling, which elicits oxygenated terpene and monoterpene emission and resulting arrival by predators and competitors, and impacts of these predators and competitors on beetle reproduction. Both of these relationships are well supported in the literature. " However, this model also proposes that the spatial and temporal patterns of host availability, in terms of both compromised tree defenses and beetle perception of these alterations, affect natural enemy numbers. Natural enemy populations in turn affect beetle population size, which in turn affects host acceptance behavior (Fig. 4.14 center). 

Conifer resin, which is a mixture of monoterpenes and diterpenes is an important protective compound against bark beetles and other conifer herbivores. The volatile monoterpenes emanating from a specific tree is often the cue for bark beetles to find a tree where the tree defenses could be compromised from abiotic or biotic stresses. The synchronized mass attack is the strategy bark beetles use to reduce the effects of resin-based defenses in conifers. Aggregation hormones released by bark beetles are oxidized monoterpenoids such as ipsdienol, ipsenol and verbenol. It is believed that these compounds can be oxidation products of host plant monoterpenes such as myrcene. Recently it has been observed that most of the monoterpenoid aggregation pheromone components are biosynthesized de novo in bark beetles [7]. 

Fig. 94.3 Conifer tree defense against bark beetles with induced resin production, (a) Resin flow on Norway Spruce (Picea abies) bark after attack by bark beetles, (b) The European spruce bark beetle Ips typographus), the most serious bark beetle pest of Norway spruce, attacking spruce bark with phoretic mites, which are probably involved in the transmission of fungal tree pathogens...

Pine oleoresin is an abundant source of useful terpenes. It has two major fractions turpentine, which is the volatile fraction, and rosin, which is the solid fraction. A key element of tree defense, oleoresin is an important nonwood forestry product because of the various conventional and potential uses of its terpenes. Oleoresin derivatives can be used by different industries, including pharmaceutical, cosmetic, and food industries, as well as by the chemical industry in the manufacturing of various products, such as paint, varnishes, adhesives, insecticides, and disinfectants. Biotic and abiotic factors that affect oleoresin production can be used to improve yields by promoting specific... 

Loehle, C. (1988). Forest decline endogenous dyneunics, tree defenses, and the elimination of spurious correlation. Vegetatlo 77, 65-78. 

Boone, C. K. et al. Efficacy of tree defense physiology varies with bark beetle population density A basis for positive feedback in eruptive species. Can. J. For. Res. 41 1174—1188, 2011. 

Extractives and Ash. The amount of extractives in wood varies from 5 to 20% by weight and includes a wide variety of organic chemicals (11). Many of these function as intermediates in tree metaboUsm as energy reserves or participate in the tree s defense mechanism against microbiological attack. The extractives contribute to wood properties such as color, odor, and decay resistance. 

Commission in 1946. Atomic research and development, both for defense and peaceful use, was to he solely in the hands of the Atomic Energy Commission. Its mission was to assure the common dclensc and security, and to improve the public welfare, increasing the standard of living, strengthening tree competition, in private enterprise, and promoting world peace. ... 

The path leads out into the open, where the castle mound spreads wide and low. Here, from farther away, we can see much more. There are more windows, enough for comfort and almost too many for defense, scraps of ornamental battlements, coats of arms carved above a grand doorway. Tufts of greenery grow on the tops of the towers, and a couple of small trees look rather forlorn in the wide space that must once have been leveled to make the killing field. 

On Mey 17, 1971, the Defense Advanced Research Projects Agency [15] funded our proposal that "temperature variations may be evaluated by measuring stable isotope ratios in natural data banks such as tree rings and varves". L. M. Libby had previously calculated [16] the theoretical temperature coefficients of the stable isotope fractionations in manufacture of wood from C02 and H20, finding that the coefficients are small compared with those measured in rain and snow [17]. 

T uomi J, Niemela P, Chapin FS, Bryant JP, Siren S (1988) Defensive responses of trees in relation to their carbon/nutrient balance. In Mattson JB (ed) Mechanisms of woody plant defense against insects search for patterns. Springer, New York, pp 57-72 Van Alstyne KL (1988) Herbivore grazing increases polyphenolic defenses in the intertidal brown alga Fucus distichus. Ecology 69 655-663... 

In Australian tenebrionid beetles, defensive compounds and their patterns seem to be of only low chemotaxonomic value. However, the aforementioned aromatic compounds are restricted to the genus Tribolium. Abdominal defensive compounds were used as chemosystematic characters in order to construct a phylogenetic tree for the genus Tribolium [330]. The defensive secretion of adults of Tenebrio molitor was shown to contain toluquinone 7 and m-cresol 89 [333]. The quantification of benzoquinones in single individuals of Tribolium castaneum at different days after adult eclosion indicates that the amount of toxic quinone only shows a maximum subsequent to cuticle sclerotization. Obviously, there is a need for an adequate cuticular barrier for self-protection from these defensive compounds [334]. 

FIGURE 7.4 A female brown tree snake discharges cloacal defense secretion. (From Greene and Mason, 2000.)... 

Particularly valuable and/or vulnerable parts are protected best. Because of their size and seasonal changes, trees provide instructive examples. In green alder, Alnus crispa, defense compounds, such as pinosylvin, pinosylvin methyl ether and papyriferic acid, are concentrated in buds (2.6% of dry weight) and catkins (1.7%), and least abundant in the internodes (0.05%). Snowshoe hares, L. americanus, reject buds and catkins, while they eat second-year internodes (Bryant etu/., 1983 Clausen eta/., 1986). 

In Sweden, phenols did not protect introduced lodgepole pines, Pinus contorta, particularly well against debarking by the vole M. agrestis. Being an alien tree species may be an important factor (Hansson etal, 1986). The authors pointed out that, in general, any natural defense will work only at low browsing pressure by voles. 

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