Trees of Peninsula Park

Entering on the north side of the park, you’re immediately met with large Douglas fir stands that align the walk way. They are pretty close to one another, so the canopy gives
adequate shade. The temperature is
noticeably cooler along the path.

Walking toward the rose garden, there is an enclosure of both a brick partition and of shrubbery. As mentioned in my other posts, this successfully creates an impression of two parks rather than just one. In the pictures below you can see the silver linden trees that surround the rose garden and the Douglas fir on the north side of the partition.

Trees on either side are unique in their layout. On the north side of the partition, trees are considerably denser, whereas the trees on the south side have considerable spacing in between them. Additionally, the south side and north east side appeared fairly heterogeneous in regard to vegetation types.

There were a few European white birches in this location, directly opposite from the gazebo, but two were removed in 2019. This is an example of the additions and removals that occur over the years. I couldn’t find a reason for their removal, but according to Oregon State University extension service, this tree species is pretty susceptible to the bronze birch borer, which are known to target and infest these trees throughout Oregon. This could be one possible explanation for their removal.

Below are figures and tables illustrating the annual services provided by the trees within Peninsula Park. The data was found by the Parks and Recreation, which I made into graphs and tables of only the highest values for the sake of space. As seen in figure 1 and 2, the Douglas-firs and silver lindens both sequester and store the most atmospheric carbon. The other trees also store and sequester a considerable amount of carbon, however the graph is exceptionally skewed by the highest values given by Douglas-fir. One speculation being that Doug-fir tree density and age may be a contributing factor.

Figure 1 The amount of carbon (in lbs) removed from the atmosphere by the tree, annually.

Figure 2 The amount of carbon (in lbs) that is bound up in both the above-ground and below-ground parts of the tree. The trees with the highest values are reported.

Table 1 shows the amount of air pollution that is removed from the atmosphere (in oz) by trees. Pollution removal in this table is calculated for nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), carbon monoxide (CO), and particulate matter less than 2.5 microns (PM2.5). Trees remove gaseous air pollution primarily by uptake via leaf stomata, though some gases are removed by the plant surface. Trees also remove pollution by intercepting airborne particles. Once more, we can see Douglas-fir and silver linden taking the lead with 3574 and 1085 oz, respectively.

Pollution removal
Douglas-fir	3574
Silver linden	1085
Northern red oak	164
Pin oak	126
European beech	125
Kentucky coffeetree	109
Green ash	96
American elm	89
American hornbeam, blue beech	79
Japanese flowering cherry	77
Common hackberry	68
Oregon white oak	62
American yellowwood	57
Flowering pear	45
European white birch	37
Sycamore maple	36
Western redcedar	35
Scarlet oak	33
Coulter pine	33
Southern catalpa	33

Table 2 shows the amount (in cubic feet) of avoided stormwater runoff because of rainfall interception by the tree on leaves and other surfaces.

Stormwater
Douglas-fir	13287.4
Silver linden	4031.8
Northern red oak	609.1
Pin oak	469.2
European beech	465.7
Kentucky coffeetree	403.2
Green ash	356.5
American elm	331.8
American hornbeam, blue beech	293.4
Japanese flowering cherry	287.5
Common hackberry	252.6
Oregon white oak	229.1
American yellowwood	209.7
Flowering pear	167.4
European white birch	138.4
Sycamore maple	135.3
Western redcedar	129.9
Scarlet oak	123.8
Coulter pine	123.5
Southern catalpa	120.8
Sugar maple	114.1
American linden	111.8
Littleleaf linden	111.3
Jeffrey pine	102.6
Box elder	86.1
Pacific dogwood	79.5

In conclusion, these data is a brief overview of the services Peninsula park provides. The park’s ecosystem services are considered to be is an asset to human health and greatly benefits the community within the Piedmont neighborhood. The park not only provides outdoor recreation, but also sequesters carbon, purifies the air, filters water, and provides habitat for an array of species as well as many other factors not mentioned (i.e. noise reduction and micro-climate mitigation, etc). Additionally, the economic damages associated with runoff and costs of stormwater control, pollution emissions, and carbon dioxide emissions are offset to some degree. Peninsula park, with its fascinating history, is an urban park among many that improves quality of life for the people of North Portland.

Sources

https://www.portlandoregon.gov/parks/

https://today.oregonstate.edu/news/serious-pest-targets-popular-white-bark-birch-trees