The Southern Pine Beetle and its Effect on Pine Trees - 6875 Words

The Southern Pine Beetle and its Effect on Pine Trees, the Timber Industry and the Economy (Research Paper Sample) Content: The Southern Pine Beetle and its Effect on Pine Trees, the Timber Industry and the EconomyName:InstitutionIntroductionThis project explores the effects the Southern Pine beetle, botanical name Dendroctonus frontalis, are having on pine trees especially in areas where these pines are grown in large scale for economic purposes such as in Southern United States Alabama, Kentucky, North and South Carolina, Tennessee, Florida and western Canada. These pine trees that are used as a source of timber, electric poles, recreation and for wildlife have economic value that is compromised when they are infested by the pine beetles. It is reckoned that approximately 60, 000 pine trees are destroyed by the beetle which in economic cost accrues to about $80, 000 monthly. During seasons when infestations are epidemic, these costs can escalate exponentially through the roof. It has been observed that the predisposal factors to SPB include stresses due to drought, intense wild fires, st orm scathe, advanced pine tree age, prevalent diseases, strong winds, interspecies tree competition and infestation by other insects (Leuschner, 2014).There are two species of Sothern pine beetle that are of importance to this study, they include; Ips engraver beetle (IEB) and the southern pine beetle (SPB) that show specificity in the areas of attack in pine trees and invoked by specific antecedents. The species too differ in their rate of attack and spread to other pine trees with the most vicious species being the Southern Pine Beetle. SPB is more host specific compared to the other two. It is noted that it rarely attacks the longleaf or slash pines unless the pines are predisposed by the aforementioned factors. The southern pine beetle is phylogenetically related to the native Mountain Pine Beetle Dendroctonus ponderosae bark beetle that is aboriginal to the North America, geographically spanning from Central British Columbia to Mexico. The pine beetles that inhabited the Scotch , Jack Pine, Whitbark, lodgepole and ponderosa pines were initially beneficial to the forest life by consuming dead, old and weak pine tree thus recycling nutrients and breaking canopy for understory pine trees. Their actions stimulated forest development. However, changes in climate have turned the beetles to lethal, eventually attacking even healthy pine tree in mild winters, hot dry summers developing into epidemics (Foltz Meeker, 2001). The attack in Alabama by southern pine beetles are evolutionarily related to those in western North America by Dendroctonus ponderosae that has destroyed 16 million hectares of lodgepole pine forest. The severity of the epidemic is still currently inclining and is unceasing. Apart from primary impact that the southern pine beetles are causing, secondary effects emanate from the primary impact such as reduced water yield from the water catchment areas into rivers due to receding canopy cover. The reason that southern pine beetles are of great int erest to forest managers is actually due to the economic impact their damage is incurring on the society attributed to damage on private farms, industrial lands, Federal lands and national forests. The south United States is heavily dependable on local and foreign tourism and lumber industry and advocates of endangered species are fearful that the numbers of rare red-cockaded woodpeckers would plummet to extinction. The impact can be assessed and resolved whether it is worthwhile to commit more taxpayers money to fight the menace? More so is the disposition of downed pine trees by the beetles pose as fuel for wildfires that impede transportation along corridor (Leuschner, 2014).Hypothesis and ObjectivesMy hypothesis in this research explores the effects of southern pine beetle on nature, the timber industry and the economy. It states that the perceived economic repercussions of SPB are more stern than currently comprehended and could surmount $100 billion in collateral. The report s eeks to show that with more pine tree falling prey to the southern pine beetle and the ultimate destruction of forest, the less green-house gases are sequestrated from the atmosphere (Bunnell, Squires, Houde, 2004). The economic impact of the pine beetle should be revised upwards of the current $900 million in damages. The criteria of measuring the effects or impact the pine beetles is in determining changes of physical units such as reduced species like the number of birds as a result of SPB, reduction in pulpwood in the timber industry etc. Economic impacts which is calculated in social value are quantified as follows;Economic impact * social value = Impact value;For example, if 2,000 fewer tourists visit the beetle infested forest for camping and each tourist pays a fee of $5 per day in a visit, then the economic impact value is 2,000*5= 10000/day (Leuschner, 2014). Though it might be infeasible or inaccurate to determine the economic value of some impacts such as dollar value of reduced bird species, in such cases only the importance of the effect to the society suffices to determine the impact.Literature ReviewPine trees that have been attacked have the pine beetles residing in their inner bark which causes them to ooze resin masses from their injury spots as a defense mechanism. The resin cascades on the outer bark forming what are referred to as pinch tubes. Adult pine beetles that have penetrated into the pine stem feed on the phloem of the tree and leave s-shaped scars known as serpentine galleries. As the adult pine beetles bear offspring the increased galleries left behind can girdle a tree effectively killing since they mechanically impede the flow of nutrient along the tree phloem vessels (Harvey, Donato, Romme, Turner, 2014). Apart from the physical damage that the southern pine beetles impact on the pine trees, they also bring with them blue-stain fungi that also infiltrate the pine xylem vessels. This obstructs the flow of water and salt ions u p the xylem to the leaves thus infested trees start to wilt and dry up. The fungus released into the sap-wood by the beetle according to researchers abets in inhibiting the tree from producing pitch flow resin as defense mechanism. While the southern pine beetle is endemic to the southern pine forests, during low epidemics, the most vulnerable pine trees are those predisposed due to stresses, senescent and damage. However when the beetle numbers exponentially increase in severe epidemics, even the healthy pines are not spared with SPB spots in forests viewed aerially seemingly expanding rapidly at about 15 meters/day. They could also easily ruin ornamental pine tree such as those in parks and yards (Clarke, 2009).To incisively comprehend the effects of the insects on the pine trees, biological perspective of the process has to be considered. The female pine beetle which is distinct from the female with a transverse ridge (mycangium) along the anterior pronotum is responsible for sel ecting the host tree. The female then bores the galleries into the pine stem when it conquers a pine tree. When the female is ready to mate, it secretes pheromones that emanate from the tree and are carried by air to attract males and even more females to the tree. Biologists have discovered that the resins, secreted by the tree due to injury by the female pine beetles, also augment the pheromones by increasing their potency in attracting more of the insects to the tree (Dordel, Feller, Simard, 2008). A large attack by the Southern Pine Beetles on a pine tree overpowers the trees defense mechanism. Resin that the tree produces is intended to force out the insects from their galleries mechanically and by suffocation. However, in high infestation, this mechanism is not fast enough to avert tree mortality. Mating occurs after pheromones attract more males and females to the tree and when females want to lay their eggs, they create more s-shaped galleries that cross over the others. The males are responsible for bringing in boring materials such as frass to expedite the female drilling. After the drilling, the female then oviposits its eggs of up to thirty per gallery before leaving to within a fortnight of laying the eggs. The beetle could then attack the same tree or another (Clarke, 2009). When the eggs hatch in three to nine days following their oviposition, they start feeding on the phloem tissue and progressively bore more galleries as they feed. These galleries bored by the larvae, head gradually towards the outer bark thereby the last instar of the larvae forms a pupae in the outer bark. The pupae metamorphose to adult after five to seventeen days. The resultant adult remains in the bark for approximately six to fourteen days as its exoskeleton harden before exiting the stem and leaving a shot hole behind in the exit. On average, these adults disperse and travel 0.69-3 kilometers before invading more pine trees. Approximately nine generations can exist in the same SPB population annually. The entire life cycle of the SPB is roughly 26-60 days. During the initial stages of attack, the tree remains green but within the end of an year, the leaves start to turn yellow then red and finally brown which indicates that the tree is dying by which the beetles will moved on from that particular tree. After three to four years the tree foliage is lost and the tree turns grey in color. The pitch tubes, galleries that girdle the cambium under the bark and sawdust from bored holes at the base of the tree are some of the signs that indicate a tree is infested (Bunnell, Squires, Houde, 2004). With climate change, the SPB are seemingly adapting accordingly and are exhibiting seasonal changes with emergence of overwintering variants that maintain infestation over winter, though in a slower pace than in spring and summer. During spring the SPB disperse wildly initiating epidemics which exacerbate ...