Posts Tagged ‘GIS’

While working on the Appalachian Trail, I realized that many of the campsites used year in and year out by Thru-hikers are growing in size and degree of impact. Yet, many of the organizations tasked with monitoring campsites keep records in paper form and have no tangible concept of the way impacts are adding up.

In the video above, I used ArcMap to enter in a hypothetical centerpoint for a campsite. I then compile polygons, representing monitoring trips. Ideally, this data would be collected in such a way as to contain monitoring metrics in the attribute table, so the symbology can be classified by the severity of impact.

The video shows how one campsite grows over time. Typically, however, campsites don’t exist in isolation. This technique can be expanded to show multiple campsites bleeding into each other.

The area data can be compiled in either excel or R, and used as an input to a linear regression analysis. This can be used to project, that if impacts continue at the current rate, they would result in campsites over ever increasing size, until you wind up with giant camping areas.

By finding trouble spots on the trail and analyzing them over a five year period, enough data can be compiled to extrapolate useful modelling, which can help inform better management decisions.

Currently management decisions are being made without data to show whether they are working or not. Anecdotally, the impacts appear to get worse every year. Management and monitoring need to go hand in hand. When a decision is made, the impacts of that decision need to be monitored and that data needs to inform future decisions. Otherwise, we cannot be said to be making rational decisions.


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In order to successfully conserve land, you must first understand what you are trying to conserve and why. Land Trusts typically spell out, in their mission statements, what their goals are. It is often better to be narrow, in this regard, than to try and “drink from a firehose.” There are, after all, many lands out there that need to be conserved, and not enough resources to conserve them. On the organizational level, this fact is most magnified.


In order to be successful, conservation organizations must be thoughtful about each step of the process. For instance, what grants should be applied for, will they build capacities for the organization’s mission or stretch the organization thin with new requirements. It is rare that a grant will cover an entire program. Often there is thee requirement that the organization receiving the money match it with a certain amount of their own fund-raising capacity. Grants come with requirements, so organizations do better to find grants with requirements they can easily meet, without building new capacities.


This is why it is important to define, as specifically as possible, what a conservation organization wishes to conserve. Many Land Trusts conserve land as wildlands, and others conserve agricultural land. It is more difficult to try and do both well. Many organizations that conserve wildlands, conserve forests, riparian zones, different types of wetlands, etc. Even in this regard, a degree of specificity is important. When trying to decide whether a particular tract is work putting resources into conserving, it helps to use Overlays. If any organization decides to preserve forested land, it can favor forested lands that are near other protected lands, in order to expand the conserved landscape. It may choose the favor those near riparian zones or wetlands. It may choose the favor those with endangered species habitat or certain soil types. All of these aspects can be represented spatially, and GIS can be used to better construct an effective overlay.


It is important to identify a geographic region of importance. In this case, I have identified South Whitehall Township as an important area, because of its low percentage of total lands being conserved. (An organization can choose to value areas with a high level of conserved land instead). Since I have chosen South Whitehall, all the other layers will be clipped to focus on just South Whitehall.


Overlay Map2

Percent of Land Conserved


Lets say an organizations wish to favor forested properties, near protected lands, riparian zones and wetlands, with a presence of endangered species. One can make a model, taking land use layers, protected lands layers, riparian and wetlands layers and endangered species habitat layers. Each of these can be used to create a buffer (how close to the object should the protected land be). Again, this is derived by deciding how much certain layers should be valued. After making buffers, these can be merged into a single layer and joined to a tax parcel map. The join will maintain the geometry of the conservation layers, and tell you which properties are intersected by the conservation buffers, and thus a high priority for conservation. The output, in the example of South Whitehall Township, near Allentown, Pennsylvania, would look like this:

Overlay Map

The Green shows properties of potentially high conservation value.


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Land Cover Map of Olympic National Park

Land Cover Map of Olympic National Park

Summary of Land Usage: Olympic National Park.
Authored by: Glenn Nelson
Created & Updated: Thursday, November 5, 2015

Olympic National Park was first preserved in 1897 as a forest preserve by President Grover Cleveland. In 1938 the level of protection was expanded to that of National Park, by President Franklin Roosevelt. The United Nations recognized the park’s global value, by distinguishing it as a UNESCO World Heritage Site in 1981. Today Olympic National Park protects 922,651 acres, 81% of which is classified as Temperate Rainforest. Temperate Rainforest ecosystems receive, on average, 150 inches of rain per year and are the most productive forest type. Olympic NP is home to over 1,633 species with 9 endangered and 11 threatened species amongst them. The park managers take an ecosystems view of species protection, which views healthy ecosystems as the best way to protect threatened species. Beyond just being home to a plethora of wild species, Olympic NP also offers a host of ecosystem services, such as; primary production (Temperate Rainforests accumulate and store more organic material than any other forest type), soil formation, nutrient dispersal, climate regulation, water retention, recreation, scientific discovery and spiritual renewal.


(Measured in raster pixels. 1 pixel = 15.6 acres).

(Measured in raster pixels. 1 pixel = 15.6 acres).

(Measured in pixels. 1 pixel = 15.6 acres).

Olympic National Park preserves 746,238 acres of Temperate Rainforest, as well as 71,302 acres of temperate shrub lands, 61,015 acres of glacial ice (that contain fresh water reserves), and 18,003 acres of fresh water. The preservation of these land cover types help to protect and manage natural resources such as timber and fresh water, but also creates habitat for rare and endangered species like the Northern Spotted Owl, and the Western Snowy Plover. The park has also been evaluated for its potential for reintroduction of the extirpated Grey Wolf.

Spotted Owl Range

(Spotted Owl Range Map: Shows range in relation to Olympic NP)

Gray Wolf Historical Range

Gray Wolf Present Range
These maps show the former and present ranges of the Gray Wolf on the Olympic Peninsula. With the vast majority of the park falling within areas formerly known to support Gray Wolf populations, we can extrapolate that the preserved ecosystems within the park could again provide habitat for the gray wolf.

Furthermore, 436,694 acres of high priority conservation land have been identified within a 20 mile radius of the park’s boundary, including 347,887 acres, both within and near the park, identified by Washington State’s Natural Heritage Program, as having occurrences of rare and endangered species. These lands have been identified as high priority because of their propensity to support rare and endangered species. By preserving the park lands, as well as these high priority lands, we can conserve a contiguous corridor of habitat, which would allow for the plasticity in range movement and migration amongst species.

Olympic National Park has been studied as an ideal location for the reintroduction of the Gray Wolf, and recent research notes that the absence of the Gray Wolf has been damaging to the park. It has been long known that the removal of keystone species leads to an over-population amongst grazing animals in lower trophic levels. Such has been the case with the park’s Elk population. The over-population of Elk has predictably led to over-grazing in the park.

Finally, Olympic National Park also provides excellent recreation opportunities for the 609,000 residents in nearby Seattle.

Professional Recommendations:
Any decision besides that of full funding for Olympic NP would have the potential to negatively impact not only a UNESCO World Heritage Site, recognized for its extraordinary value to the global ecosystem, but one that provides vital habitat to rare and endangered species, as well as regional ecosystem services to the Pacific Northwest. Damaging even a small part of the ecosystem, in such a highly productive forest type, would certainly have ramifications across trophic levels. The park boundary represents the most contingent habitat on the Olympic Peninsula for rare keystone predators, whose removal from the ecosystem would likely have repercussions amongst lower trophic levels. Full funding would help to evaluate the habitat needs for existing species, as well as for the reintroduction of the endangered Gray Wolf. Given what is at stake, the only option is full funding.

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Dying Norway Maple

Over the last few years I have noticed that the Norway Maples in the Lehigh Valley were not looking so great. The most immediately apparent problem  was the crown die-back, and increasingly completely dead trees. This stands in stark contrast to the way things looked when I was a kid. The Maple lined streets were lush and green then… So, what happened?

After reading up on Norway Maples and Crown Die-Back, and listening to several episodes of You Bet Your Garden on NPR, I came up with a number of theories. First, I though, as Mike McGrath often suggests on the aforementioned show that over-mulching was causing root girdling. Basically, how this occurs is, when you over-mulch it concentrates the water over too small an area. The tree’s roots concentrate in that area, instead of spreading into a wider radius, and eventually strangulate themselves. Another issue that came up was decline from road salt. This relationship has long been noted in relationship with the New England Sugar Maple population, and the symptoms typically include crown die-back. Finally, I came across evidence of a fungal blight that is found throughout the northeast called Verticillium Wilt.

Verticillium Wilt is a fungus that starts in the soil, enters the trees through its roots, and causes a blight in the pith wood. Amongst the common symptoms are stunted growth in the tree’s new growth, discoloration of pith wood and, of course, crown die-back. Because the blight offers several diagnosis points, I was able to study the trees in the area, and found they exhibited all three tell-tale symptoms.

Discolored wood fibers around a rotten pith, characteristic of Verticillium Wilt.

Discolored wood fibers around a rotten pith, characteristic of Verticillium Wilt.

On the left is stunted new growth, characteristic of Verticillium Wilt. Compare to healthy growth on the right.

On the left is stunted new growth, characteristic of Verticillium Wilt. Compare to healthy growth on the right.

Various states of die-back.

Various states of die-back.

So how is Verticillium Wilt spread and why are so many trees dying. After reading that Verticillium Wilt can survive in soil or mulch for ten years without a host plant, I had an ahah! moment. I now have a hypothesis about the vector for this disease. When a tree contacts Verticillium Wilt it is typically fatal. When these trees that die are in people’s yards, they call the tree removal service, and they come by and fell and remove the tree. Typically the tree is then mulched, and the mulch is sold to contractors to then mulch people’s yards. This then spreads the disease to more suburban trees, which then die and are themselves mulched and so on.

I have started to study this with the aid of GIS. I have a suburban sample, which is mulched and an urban sample which is not mulched. In the suburban sample 54% of the trees examined show signs of Verticillium Wilt. Meanwhile, in the urban sample I found no trees that exhibit clear signs of the blight. I then ran a correlation on diameter, to see if the age of the tree could be affecting the sample. However, I found a -0.62 correlation, which is a weak correlation between an increase in diameter and decrease in occurrence of the crown die-back. This suggests that there may be a resistance in older trees, that older planting methods were more effective, or that mulching may indeed play a role. I did find a 0.41 correlation between mulching and die-back. Again this is a weak correlation and will need more data to flesh it out. I am hoping to add a  forest plot to expand the available data.

This is the sample of the suburban neighborhood, where Verticillium Wilt is present.

This is the sample of the suburban neighborhood, where Verticillium Wilt is present.

Test Plot at Kutztown Park. Verticillium Wilt is not present and there is not mulching around the trees.

Test Plot at Kutztown Park. Verticillium Wilt is not present and there is not mulching around the trees.

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I established a test plot today. I plan to measure both biomass of the plot in general and the diameter and height of a currently healthy White Ash, to try and understand forest growth. It is a hobby I have taken up, to ensure that my skills stay honed, for the next time I am out in the field.

Biomass and Carbon Sequestration:

It has long been known that plants take in CO2 gas, during photosynthesis, to create carbohydrates for the plant to use. Plants also release CO2 during respiration, but the net uptake exceeds that released during respiration, meaning that the plant stores carbon. It is said that up to 50% of a tree’s mass is carbon, and much of that carbon is stored in the extensive root systems. In order to calculate how much carbon a tree contains, first we must find out the total mass of the tree.

Mass=Volume*Density, so to find the biomass of a tree, we must first find the volume of the tree.

Since, for our purposes, trees are cones, we would find Volume with the following formula (many of you remember from geometry).

Volume=1/3*Basal Area*Height




Height can be found by taking a tape measure, and by standing back approximately as far as the tree is high, you use the tape measure to find the point on the tree that is about 10% of the tree. You then measure the height of that point and multiply by 10.

Basal area is found by first measuring the diameter of the tree at breast height, which is considered to be 1.6 meters. Then you plug that into the following equation (DBH/200)²  * π.



You now have volume, but you still need density. To find density, you first must identify the tree. You can then use the following site to find the density (http://www.csudh.edu/oliver/chemdata/woods.htm).

Finally your biomass equations should go as follows: Biomass(kg)=stem volume(m³)*density(kg)+40% of the answer to factor in other biomass such as roots and leaves.

If for instance, you take the White Ash from the test plot, which has a volume of 17.8 m³ and has a density of 650 Kg/m³, you get a stem mass of 11,570 Kg.

11,570*.4 = 4,628.

Total mass = 16,198 Kg or 16.2 tons of biomass.

About half of that is made up  of carbon, so about 8 tons of carbon.



For the entire wood lot, the equation looks like this.

126(m2/Ha) * 15.24(m) * 1/3=640(m3/Ha)

640(m3/Ha) * .65 (t/Ha)=416(t/Ha) * .4=166.4

416+166.4=582.4(t/Ha) of Biomass of which 291.2 tons are made up of carbon.

Just in my little wood lot (about 2.5 acres,  or 1 hectare) alone, the trees are  sequestering nearly 300 tons of carbon. When we consider carbon’s role in the greenhouse effect, (being an unstable element, it releases heat to stabilize, thus, the more carbon in the atmosphere the more warming will be expected) we can see that even a small forest can help to make a big difference.

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