Invasive the wildlife, and replaced most ecological trajectories.

Invasive Species
The goal of this paper is to illustrate how the invasive species are introduced to the environment by the human activities, which can either be intentionally or unintentionally. The international trade, the development of the human pattern, and foreign trade have increased the invasive species in the United States. The forest ecosystem in the United States is at high risk since the invasive species introduced as a result of human activities such as deforestation has reduced the biodiversity, damaged the habitat of the wildlife, and replaced most ecological trajectories. Therefore, invasive species are organisms that might cause adverse effects to the environment or living organism (human, plant, or animal) health when introduced to the new ecosystem (non-native environment). Plant, microbial, or animal kingdoms can be the source of the invasive species. The ecosystem is defined as a sustainable system comprising of the living and non-living things in a community. The report had discussed the invasive species that are difficult to control in the United States that were introduced when there was massive deforestation and during reforestation.
There has been the deliberate or accidental introduction of non-native species (invasive species) in different parts of the world by human activities. Sometimes, the overexploitation of forests leads to the introduction of invasive species in the ecosystem. The introduction of invasive species can have a positive or negative impact on the ecosystem. Negative impact can occur if the invasive species hurt the native species. Kudzu plant was deliberately introduced in the U.S in the 1930s from Japan. The plant was introduced to act as a ground cover to prevent soil erosion in South America deforested parts and to be used as a fodder crop. Kudzu has highly thrived in the new ecosystem because it is drought resistant. The faster growth rate of about one foot per day has resulted in the plant covering the mature trees and regenerating trees in Texas and Carolina hence preventing the beneath plants from obtaining sunlight. The beneath plants are blocked by the invasive plant that grow to height of 71/2 feet.  (Moser, W. Keith, et al). Kudzu also obscures utility posts, road signs and fences. Despite the annual government expenditure of $ 500 million to control the plant, it still rapidly continues to spread. 
The native Japanese tree called Hemlock woolly adelgid (HWA) was introduced in the eastern part of the United States in the 1950s. The Carolina and eastern hemlock have been adversely affected by this invasive species. The Eastern hemlock life cycle is shortened when attacked by the invasive species (Moser, W. Keith, et al). The adelgid seed is easily dispersed by the mammals, wind, migratory birds and sometimes nursery stock that is infested thus increasing its spread. The eastern hemlock is currently covered with invasive adelgid species and extends from Maine to Georgia. The animal and plant communities in the forest have been jeopardized by the strategy currently used to eliminate the invasive species in the United States. Additionally, the adelgid plant relative called balsam woolly has immensely affected the United States fir forest (Moser, W. Keith, et al).
The invasive Garlic mustard originated in the Europe has infested the United States farms since 1850s.The herbaceous plant is nowadays found in the entire eastern United States. The plant invades the second-growth in disturbed forests hence hindering the growth. The tree regeneration as well as ground-level flora is suppressed by the Garlic mustard hence the beta and alpha biodiversity of the forest is altered  (Moser, W. Keith, et al). Upland oak covering a large portion of eastern U.S forest is highly susceptible to invasion by garlic mustard. Also, research has revealed that garlic mustard has allopathic effects on herbs and grasses. Several methods have been used in control of the plant. The spread of garlic mustard has been showed to be preventable by manual removal. However, the method is only effective when there is a small invasion. Application of chemicals can be effective in the control. Herbicides may destroy other unintended plant species hence should be used with caution.  
The high soil erosion in the United States attributed to high deforestation led to the introduction of rambler rose (Multiflora) in 1866. The invasive species originated from Japan, Korea, and eastern China. The control of soil erosion and utilization of rambler rose as the living fence was introduced in the 1930s by the United States Soil Conversation. Later, the northern bobwhite, cottontail rabbit, and pheasant used the invasive species for the protection. The departments of State Conservation distributed the rambler rose to various landowners via the root cuttings. The fallow fields and pasture lands has the problems of pervasive and extensive growth of the rambler rose (New York Invasive Species Information). The Connecticut, Pennsylvania, Massachusetts, and New Jersey considered multiflora species as either invasive species or noxious weed. The United State Forest Service characterized it among the forest invasive species.  The herbicides like glyphosate have been used in the United States to control the invasive species. However, the seed dormancy nature assists the invasive species to evade the chemicals hence making it hard to control it.
The emerald ash borer (EAB) from Asia was unintentionally introduced to the U.S. It is a wood-boring beetle. The beetle was detected in 2002, but researchers believe that it was introduced to Detroit in the 1990s through shipping creates or hidden in the infested wooden packaging materials. It devastates ash trees in North America, and the spread has continued since its introduction. Infested ash tree firewood, logs, and nursery stock has facilitated the spread of EAB. The 2009 statistic reveals that EAB has infested eastern Ontario, Indiana, Ohio, and Lower Michigan.  The ash trees are placed at risk by the EAB introduced to North America as predicted by the Researchers (United States Department of Agriculture). The control method of EAB is banning of firewood transport and culling the infested strands. 
The rate at which invasive species are introduced into the forests of United States is astonishing.  The urban and commercial forest resources may adversely be affected once the invasive species have established in the new environment.  For instance, invasive EAB destroys ash trees, and Kudzu threatens biodiversity in the forests. The invasive species threatens today’s environment as well as the future environment. Therefore, proper regulations should be put in place to prevent their introduction. However, in case there is invasive species introduction, effective control measures should be used to prevent the spread. The U.S government is spending more money in the control of invasive species