The whitebark pine tree species contributes greatly in the provision of food and shelter to the wild animals that live in the high mountainous regions. Visitors who visit this region also enjoy the beautiful woodlands created by the whitebark pine tree. The tree grows on crater rims in the Crater Lake national park where it thrives on a region that is higher than 7000 feet. Unfortunately, a fungus called Cronartium ribicola has invaded the region causing a disease called white pine blister rust which poses great danger to the tree species. Although the disease affects all the five-needled pine trees, the whitebark is the most susceptible. (Campbell and Antos, 2000, p 4)
The fungus is transported by moist air and afterwards infects the pine needle trees and currant bushes though it is not as highly fatal as it is in the whitebark pine tree. When the spores come into contact with the leaves of the whitebark pine tree, the infection quickly spreads to the branches. The infection is usually a lot more fatal if the spores affect the main stem of the tree as it will result in the formation topkill which presents quite a dangerous case in which the tree might have extremely low chances of survival. Within one or two years of infection, the fruiting bodies form a canker therefore the living tissue at the region of infection is completely destroyed. The white pine blister rust in collaboration with other damaging agents like the mountain pine beetle and the wind can ultimately contribute to the death of the tree (Diana et al, 2001, p 200)
The disease was initially documented in the park in 1935 but there are no clear records to the damage of the whitebark pine tree. The pathogen was introduced in Europe in the early days during plant movements. They invaded seedlings of the eastern white pine from Germany into North America at about 1898 and the others that were moving from France to Vancouver in1910. The seedlings that originated from North America were shipped to Europe to be grown and then later brought back to America for planting because this was the period when the United States had realised that it had been cutting its forests rapidly and it needed to focus on reforestation and management of its forests. The Europeans had already developed their nurseries and had adequate knowledge on how to produce seedlings but unfortunately during the shipping some seedlings were infected by the pathogens (Murray and Rasmussen, 2000, p 3)
A comparison between the eastern and western side shows that the disease is more common on the western side mainly due to the fact that the climate of these two areas is different. This shows that there are more favourable conditions in the west to the spread of diseases than in the east. This might also be due to the possibility that the eradication programmes in the east were quite more effective than those carried out the west (Sarah, 2001, par 3) The blister rust disease is more hazardous in cool moist areas. These conditions support the production of spores, their dispersal to different areas and infection that finally occurs in pine needles. The spores can be dispersed through a distance of 3-4 kilometres in most cases. Infection normally occurs next to the ground because needles tend to be a lot more moist next to the ground and as a result infections are more frequent in young trees as compared to older trees due to the fact that branches are close to the ground when trees are young (Diana et al, 2001, p 215) The first symptom that indicates a tree has a blister rust infection is the presence of a tiny red or yellow spot on a needle but this is a bit difficult to find. The clearer indications become visible after a period of one or two years where perennial cankers as a somewhat swollen and a yellowish margin can develop. A stunted tree or dead branches are clear indications that a tree is infected. Since blister is a species that is new to the pacific region, the possibilities of genetic resistance are limited and as a result the mortality rate has been extremely high for the past few years The disease poses a major threat to the trees in the national park and the presence of currants seems to support the spread of the diseases according to a study conducted, which showed that areas with currants had a 12% infection rate as compared to an area with no currants which had an infection rate of 4% on average (Campbell and Antos, 2000, p 12).
This fungus has cost this region both economically and ecologically. The whole of north America is has felt the major effects of the disease and extreme damage and loss of money has been lost in the attempts to control this it. The money invested in this program is more than any other that has ever been used in the control of diseases in the other conifer trees. Numerous number of white bark pine trees have been damaged and some have been completely lost. Losses in the Pacific Northwest are estimated to be five million cubic feet (Keane, 2001, p 4).
The white bark pine tree is a tree of great ecological importance as it produces nuts that are consumed by the grizzly bears. Red squirrels and the Clark’s nutcracker also feed these nuts. Water sheds are also protected by the trees’ stature. Despite all this the tree faces a major threat of highly being reduced in numbers by the disease called blister rust (Diana, 2001, p 230).
There are many methods that have been suggested to combat the blister rust disease in the whitebark pine trees but none of these approaches has proven to be successful. There are projects which aim at breeding for resistance in some species such as the P. monticola. Pine can be affected by spores on ribe plants only and the spores are delicate and can only be functional for a short period of time before they loose their viability. The spores can only travel for a distance of up to 300 metres and so, with these in mind, the ribe plants can be eradicated from regions close to the pine trees so that their spores can loose their effectiveness by the time they reach the pines. This project was only successful in the eastern part. The ribe plants in the western region proved to be more elusive and resilient. Therefore, plans to eradicate them in the west using this method did not succeed. (Murray and Rasmussen, 2000, p 5)
The pine trees can also be planted in areas that are less hazardous which include the areas that have low moisture content so as to reduce the methods that facilitate the transportation of the spores such as wind and moisture. (Murray and Rasmussen, 2000, p 8)
Pruning is another favourable method that can be used to prevent continued infections. Infections that occur on the stem are the most lethal and little can be done to stop them but branch infections can be pruned to prevent the spread of the infection to other areas of the tree and especially the stem. Pruning, especially the younger trees reduces the incidents of repeated infections so it is safer to prune the trees while they are still young (Keane, 2001, p 9).
The white pine blister rust disease has affected the ecological system of the Pacific Northwest in a big way as it has reduced the numbers of white bark pine tree which forms a major food source for the grizzly bears. The grizzly bears mainly depend on the whitebark pine tree for survival as it provides most of the animals. The grizzly bears are said to be in great danger of having a major health crisis if the trees survival continues being a threat. The grizzly bears especially the females depend on the high energy content present in the seeds of the whitebark pine tree to increase the fat reserved in their bodies before they hibernate. The seeds comprise of the same amount of proteins and carbohydrates which is 21% and 52% fat which is at least has a high fat content than the other wild bear foods can provide ( Diana et al, 2001, p 275).
Another ecological problem is the fact that the decrease in number of the white bark pine tree is forcing grizzly bears to move to areas close to human settlements and therefore expose themselves to the risk of being killed. Studies show that in recent years the number of human induced mortality has been on the increase since the shortage of whitebark pine tree (Diana et al, 2001, p. 300).
The USDA is an agency involved with the management and conservation of the whitebark pine tree and the effects of the white pine blister rust on these tree species. They are currently trying to find ways to reduce the tree species from becoming extinct in the next 10 years. Research done by the agency shows that the climate change that is being experienced at the moment is a main contributive factor to the alleged extinction because climate is changing to hot and dry which provides a conducive environment for the growth and dispersal of the spores that cause the white pine blister rust disease. The agency is trying to find ways to reduce the effects of this climate change so as prevent the extinction of these trees which have an important ecological role in the regions where is exists ( Sarah, 2008, par 11).
In summary, the whitebark pine tree is an important tree which is facing major threats of becoming extinct due to the white pine blister rust disease. The fungus that causes this disease thrives in moist, cool regions which are conditions that are mostly present in the west and a threat to the Pacific Northwest region. The disease originated from Europe in 1898 and introduced to America from Europe in 1910. Methods aimed at combating this disease are pruning and developing the trees to acquire resistance to the disease. The white pine blister rust disease has affected the ecological system and the grizzly bears are the most affected because they depend on the nuts produced by the whitebark pine tree and the marked reduction in their numbers has placed the bears in danger such as the risk of being killed by human beings and also becoming extinct. The USDA is a government agency that is dealing with the preservation of these trees and finding ways to combat the threatening disease.
Reference List
Campbell, E. M. and Antos, J. (2000). Distribution and severity of white pine blister rust and mountain pine beetle on whitebark pine in British Columbia.
Canadian Journal of Forest Research 30:1051–1059 Diana, T. Stephen, A. andRobert, K. (2001) Whitebark pine tree community: Ecology and restoration. Chicago: University of Chicago Press.
Keane, R. E. (2001). Successional dynamics: Modeling an anthropogenic threat. in Tomback, F., Arno, S. and Keane, R. (Eds). Whitebark Pine Communities: Ecology and Restoration. Island Press: Washington D.C.
Murray, P and Rasmussen, M. (2000). Status of Whitebark Pine in Crater Lake National Park. Unpblished final report. Cooperative Cost-share Agreement No. h9320000035.
Sarah, K. (2008). Seeing climate change through the trees. Web.