Introduction
There are many ways to evaluate the changes within a specific ecosystem in a particular landscape. Among the most efficient methods, a comparison between the historical and the present-day landscape can be used (Hessburg, Agee & Franklin, 2005).
With the help of the latter, it is possible to find out whether the impact on a particular landscape has been positive or negative and what further steps are to be undertaken.
The analysis of the current and the historical landscape in the East Cascades of the Washington State will possibly help determine the pattern of the landscape development, as well as set the strategy for the further course of actions concerning the management of the given landscape.
Methods
To explore the pattern of change within the landscape ecology of the East Cascades of the Washington States, the data assembled by Dr. Paul Hessburg’s research group was used. In the course of research, the Fragstas 3.3 program was used to analyze the landscape. The ArcMap technology was utilized to view the data.
Finally, to conduct the evaluation of the landscape change, the qualitative analysis was used, well as some elements of quantitative analysis.
Results
Considering the data that was sorted according to the principle “‘met06’=Methow subwatershed 06. Last names G-J,” the amount of herbland has changed sufficiently over the course of the East Cascades history, spreading south and southeast.
The forest area, however, remained the same, with few exceptions in the northeastern part of the land. Quite similarly, the nonforest area did not change much, apart from the small patches that disappeared from the southeastern parts of the landscape.
Speaking of the changes in the vegetation system of the forest, or, as Hessburg, Salter, Richmond and Smith defined it, “a theoretical endpoint of succession in the absence of disturbance” (Hessburg, Salter, Richmond & Smith, 2000, p. 166), one must mention that the deforestation process has took its toll, since more parts of the area have been marked as “non-forest” ones.
In addition, the area covered by old forest multi-storey has also decreased, giving more room to the young forest multi-storey parts of the forest. Likewise, old forest single storey has moved northeast, giving its way to the young forest multi-storey elements.
In addition, the area covered by stem exclusion open canopy has grown smaller over the past few decades, with only several elements scattered sideways across the area.
The amount of trees that are currently in the stand initiation stage has also changed; while in the past, only two small areas of SI trees could be found, at present, the central and the southern part of the forest are in the phase of stand initiation.
The amount of trees that are currently in the stage of understory re-initiation has, on the contrary, remained the same.
It is also important to mention that the intensity of firelines in certain parts of the East Cascades has changed over the past few decades. According to the data obtained with the help of the Fragstats 3.3, the amount of instances of fireline has gone down in the western area from 2 (in central parts of the west area) to 1.
The changes in the northern part of the area are also rather gratifying, with the instances of firelines going from 3 to 1 in most parts of the area. Finally, it is noteworthy that the southwestern spot in the East Cascades area, which was notorious for 6 firelines per year, has had only 3 to 5 firelines.
The instances of 7 firelines per year, however, have been noticed in the north and southwest, though previously,.west and north-west were known for suffering 7 firelines running. Generally speaking, one must admit that the number of firelines has declined.
Discussion
When assessing the changes that have taken place in the mean patch area of the landscape in the given time slot, one must admit that there have been radical changes in the development of the landscape of the East Cascades area over the past few years.
According to the obtained data, nowadays, the largest mean patch area in the East Cascades landscape consists of young forest multi-storey patches; the recent data shows that the latter take almost 278 (277,7067) sq. km.
In the past, however, the mean patch area in the East Cascades consisted mostly of non-forest landscape (206,5067 sq. km). Therefore, it can be concluded that the rates of deforestation have dropped considerably and that the forest ecosystem is getting stronger.
The given idea can be supported by the fact that the amount of young trees has increased compared to the previous records, while the amount of old trees has narrowed down. Therefore, such factors as the restoration of the balance between the old and the young trees plays a great role in shaping the mean patch area scale.
It is also important to outline the difference between the mean and the median patch area. According to the existing definition, a median patch area allows to evaluate the “sample median value” (USDA, 1999, p. 66).
Therefore, it can be concluded that, in contrast to the mean patch area, median patch area offers a midpoint of all patch areas in question. As a counterpoint to the mean patch area, it allows to see how even a specific element is distributed across the land.
In the East Cascades, the Shannon diversity index has increased, with the split in the increase of various landscape elements ranging from 248,16 (non-forest) to –597,92 (young forest multi-storey).
Speaking of the shape complexity, however, one has to mention that the rates of the given parameter have also declined, which can be explained by the massive fire that was witnessed in the northern and northwestern parts of the area.
The fires must have also influenced the rates of contagion in the area; according to the recently obtained data, the contagion rates have also risen, allowing for a more rapid fragmentation of the landscape.
It is crucial to stress that the structures that can be classified as young forest multi-storey have increased in size and variety. The given data stands in a sharp contrast to the information concerning the old forest. As it has been previously mentioned, the amount of old forest elements has dropped.
The given change can be the result of the fires that gripped the area in the past few years. At first, the given change might seem deadly to the forest, since so many elements have been taken out of the picture.
On a second thought, one must admit that the fires allowed to make way for the young forest multi-storey, thus, renewing the forest ecosystem. However, judging by the high rates of the areas that are very vulnerable to fires, one must admit that the given area should be managed to protect it from intense exposure to fires.
Literature Cited
Hessburg, P. F. Salter, R. B., Richmond, M. B. and B. G. Smith. 2000. Ecological subregions of the Interior Columbia Basin, USA. Applied Vegetation Science 3, 163–180.
Hessburg, P. F., Agee, G. K. and J. F. Franklin. 2005. Dry forests and wildland fires of the inland Northwest USA: Contrasting the landscape ecology of the pre-settlement and modern eras. Forest Ecology and Management 211, 117–139.
USDA. 1999. Historical and current forest and range landscapes in the interior Columbia River Basin and portions of the Klamath and Great Basins. USDA, Washington, D.C.