March 22, 2011
Agro forestry APBI 444
“ Dixon Creek Riparian Restoration Project”
With this study we are trying to determine the impact on the local vegetation with the restoration of a riparian area at Dixon Farm in Langley, with the purpose of trying to bring back the natural conditions that use to be there many years ago, and also try to prove how wellthis method works and if it is feasible to continue restoring riparian areas in other places in the future. This will be achieved by analyzing different data sets that contain information about the total volume of shrubs and trees in different areas that have been either restored or are in their original state and survival rate of trees and shrubs transplanted to the areas in restoration process,by analyzing this data we discovered that there was a steady increase in herb, shrub and tree specie diversity and that the plantation of shrubs was very successful while the one of trees had a high mortality rate, overall the restoration process has been a success, but there are still some aspects that can be improved like the use of experienced crews to transplant plants instead of usingvolunteers, to have a higher success rate of transplantation and saving time and money.
“Riparian ecosystems are identified as presence of vegetation that requires free water and conditions that are more moist that normal” (“Principles of integrated food, forestry and conservation objectives in land use”. Theme 5, page 7, Sullivan, Tom). Today there is a growing interest in tryingto restore riparian areas around B.C and the Lower Mainland because of the role they play in the agriculture, some of the benefits of having healthy riparian areas are groundwater recharge, filtration of sediment and increase in biodiversity. This benefits can contribute in having a better ecological and economical sustainability, hence the importance of finding the best way to restore theriparian areas and see how cost-effective they are, to see if it is convenient to apply the same methods in other degraded riparian areas.
The methods used to collect vegetal data was by using plots of different sizes in a larger plot of 25m x 5m, inside this large plot there are 5 plots of 5mx5m in which we count the tree crown index, inside the 5mx5m plots there aresmaller 3mx3m plots in which the crown volume of shrubs is calculated, inside the 3mx3m plots we have 1mx1m plots where we get the crown index of herbs.
Trees (5 x 5 m)
Shrubs (3 x 3 m)
Herbs (1 x 1 m)
We divided the sites of interest in 3 areas: a control group that has not been changed in any way, an area that was restored 2 years ago andanother area that was restored just 1 year ago, all these areas are subdivided into herbs, shrubs and trees and where measured by the method above.
Study area description
The data was collected from the riparian area of a creek in restoration process on Dixon Farm, in the town of Langley, the farm is property of the Township of Langley Parks Department and it is located at a side of Glover Road.4) Results
My research yielded that in the restored areas, the total volume of herbs tend to decrease sharply (See Figure 1.) This is directly related to the removal of the invasive and nutrient depleting “Phalaris arundinaceae” which was the dominant specie in that area, the removal gave the opportunity for other species to develop (See Figure 4.) and therefore the specie diversity of herbsincreased considerably in the restored areas. The research also yielded that there was a slight decline in the shrub total volume overall (See Figure 2.) even though there was an increase in from the 2 year old site compared to the control site, there was a significant decrease in shrub volume in the new restored area probably because they where measured during winter time. There is also a...