Design Life-Cycle

Hitesh Rohra

Christina Cogdell

12/04/2019

DES 040A

                                                                Cat Tree - Raw Materials

        Cat trees are a relatively recent invention that came into existence in the second half of the twentieth century. Frank Crow invented the first cat tree in 1968 and described the invention as, “provide a clawing surface of maximum appeal to a cat", "provide a climbing structure of high appeal and good exercising facility", and finally "provide a facility for playing, feeding and sleeping” ( Sam Jackson). The invention is a must for the cat owners nowadays as it provides a healthy, enjoyable and cozy environment for the pet. A cat tree uses numerous different materials such as pure cedarwood or plywood, sisal ropes, and fiber carpets. Identifying and examining the raw materials used in a cat tree would reveal the life cycle of the materials used, help us better understand the uses and lifetime of the material used, and inform consumers on how it can be built with recycled materials.

Plywood or cedarwood is one of the main materials used to build a cat tree. Plywood is made by the addition of 3 or more layers of wood together (Chris Cavette). Each layer of wood, including its grain, is typically placed perpendicular to other layers to improve the durability of the product and avoid any kind of shrinkage (Chris Cavette). Plywood can be made from hardwoods and softwoods or a combination of both. Some examples of hardwood are ash, maple, teak, and softwood like Douglas fir, cedar, spruce, and redwood (Chris Cavette). The amount of softwood and hardwood depends on what kind of structure is being built. More hardwood for more construction of furniture (Chris Cavette). Cat trees do not have any specific requirements for hardwood or softwood, therefore, any kind of plywood can be used. If the cat tree uses softwood then blood protein or a soybean protein adhesive is used to build the structure. On the other hand, if the tree is made of hardwood then the urea-formaldehyde resin used for construction (Chris Cavette). Similarly, the cedar wood another common type of wood that is used for a cat tree. Cedarwood is a softwood usually obtained from branches and barks of trees at high altitudes such a pine (G&S Specialist Timber, 2013). Cedarwood can most commonly be found in Mediterranean regions such as the Himalayas, Turkey or Algeria (G&S Specialist Timber, 2013). Cedarwood has a large variety of colors and aroma to it which is not preferred by many companies assembling cat trees.

Carpets are made of fibers that include synthetic and natural fibers. The fibers are almost ninety percent synthetic and ten percent natural (Strathmore). The natural fibers mainly include Wool, on the other hand, synthetic fibers included Nylon, Polyester, and Polypropylene (Strathmore). Nylon is the best choice for making carpets for cat trees. Nylon has one of the stronger molecular collections, is stain and heat resistant, and doesn't fade or lose color easily making it the number one choice for using it in the cat tree (Strathmore). The best type of nylon used for cat trees is Nylon Type 6.6 (Strathmore). Wool is a natural fiber making it the most expensive material used in the carpet. Wool is obtained from the wool coat of a sheep. Wool is cut by sheepherders and then sold to manufacturers for further manipulation ( Blackberry 2014). Wool does not have all the properties of synthetic fibers that are important for cat trees but it is easy to clean and it lasts for a long period while maintaining its properties.

Sisal ropes are another important component for making a cat tree. The sisal ropes are wrapped around the wooden part in the cat tree. Sisal ropes can be obtained from the agave plant, also known as American aloe (Jensen, 2017). Most of the sisal fibers are obtained from places such as Brazil, Venezuela, Kenya, etc (The Editors of Encyclopaedia Britannica, 2017). The sisal fiber is used to make the rope which is obtained from the leaves of the plant (The Editors of Encyclopaedia Britannica, 2016). Going further, sisal ropes are used for cat trees because of its durability, scratch-resistant surface and the rough texture it has (Jensen, 2017). 

Once the trees are marked at the cut-down area, they are cut by gasoline-powered chainsaws or by vehicles called fellers. Later, chainsaws are used to trim the branches and cut the extra limbs (Chris Cavette). After cutting and trimming the trunks and barks, the logs are transported to ply mills through vehicles called skidders, where the logs are piled on each other often known as “log decks” (Chris Cavette). The logs in the mill are heated with hot water and put in the peeler followed by a lathe. The process of heating making and numerous trimmings convert the logs into veneers is called “making the Veneers” (Chris Cavette). Once the veneers are perfectly formed they are put in the dryer and glued to make ply sheets. So another material in finally preparing wood involves glue, which is also obtained from chemicals or parts of plants and animals. Furthermore, the sheets are typically covered with plastic or metal to give it more moisture and applying paint on the surface becomes easier. The sheets are then trademarked and put away in the warehouse for distribution. (Chris Cavette).

The manufacturing of carpets involves tufting, adding dye and finishing. In tufting, all the synthetic and natural fibers are woven into a backing material (Strathmore). The tufting machine is used to weave the fibers and the machine typically has 800-200 needles (Strathmore). Dying usually means adding color. In the carpet for a cat tree, the process used to add dye is called yarn dyeing (How it’s Made 077 carpet). The last step in preparing carpets involves shearing which means cutting all the small parts that linger out of the carpet and then inspecting the carpets for uniformity of color or manufacturing defects before they are wrapped and ready to be shipped. (Strathmore).

The sisal fiber plants are usually cut and sent to the local manufacturers or mills. The sisal fibers are obtained from the leaves by the machine called decortication which crushes the leaves between the rollers (The Editors of Encyclopaedia Britannica, 2017). The pulp obtained after crushing is scraped off from the fiber, the fiber is then rigorously cleaned and dried in mechanically or naturally (The Editors of Encyclopaedia Britannica, 2017). The fiber derived is creamy white, with length usually between 100-125 cm and the fiber is extremely coarse and inflexible (The Editors of Encyclopaedia Britannica, 2016). The coarse surface makes it durable and can withstand numerous attempts of scratching by the cats making it an ideal choice for a cat tree (Jensen, 2017).

The transportation of the wood sheets and logs starts from the ply mills and local mills warehouses. The logs are loaded in trucks, trains and large ships that transport the wood from manufacturers to hardware stores and big companies in the United States (Chris Cavette). The companies and stores sell the product to the consumers. Some consumers may order wood directly from the warehouses. Similar to the wood, ropes, and carpet are shipped to local hardware and interior stores through trucks, trains, and ships. The consumers commonly purchase a cat tree from the pet stores where the product is already assembled by the store. Another mode is purchasing cat trees from online websites where all the parts are sent in a box and require the consumer to assemble the product. 

The maintenance and reuse of a cat tree are easy and do not require any additional tools to be maintained. The plywood and sisal rope part of the cat tree is hard, a strong part which is known for its durability which allows the structure to last longer and withstand scratch or shredding attempts by the cat. The carpet, on the other hand, is manipulated to be stain resistant which means the carpet can be easily cleaned with a wet cloth or carpet cleaner of any kind. A cat tree usually lasts 1-3 years, depending upon the wear and tear it suffers. The cat tree is then given away to other cat owners or they are recycled.

The cat tree can be recycled or reused. The wood in the cat tree can be recycled by the person owning the cat tree or by national corporations that take care of the recycled products. The recycled wood is used for generating biomass or bioenergy (Synclair 2017). The wood collected by the cooperation is put into the shredder and mill to turn wood waste into compost (Synclair 2017). The carpet contains mostly synthetic fibers that can not be recycled, whereas the woolen fibers from the carpet can be recycled but are usually not extracted from the carpet as it involves larger tools and more investment. Once the cat tree reaches the landfill the lifecycle of the cat tree has reached its end. In the dump, the cat tree is usually crushed like other garbage by larger vehicles and turned into smaller wastes. The wooden part may be separated and put in with other wood to be recycled. The carpet fibers are usually buried underground and like other plastic are left underground as they are decomposable (Bennet 2014). 

Finally, a cat tree is an extremely useful invention for pet owners. The cat tree provides the cat with a prosperous environment. The raw materials used in the cat tree are not complex and are easily obtained by pet stores and big companies. A cat tree gives the cat a sense of safety as they consider height as safety, helps the cat maintain a healthy lifestyle by climbing and scratching and makes the cat feel more confident and at peace (Selvaggio 2016). A cat tree comes in handy for the pet owners to train the cat and in totality provide a safe and enjoyable home for the pet.

BIBLIOGRAPHY.

1.  "Steps in Processing Wool." Blackberry-Ridge. N.p., n.d. Web. 12 Mar. 2014. <http://www.blackberry-ridge.com/prosdscr.htm>.

2. Cavette, Chris. “Plywood.” How Products Are Made, http://www.madehow.com/Volume-4/Plywood.html.

3. The Editors of Encyclopaedia Britannica. “Monocotyledon.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 29 Mar. 2017, https://www.britannica.com/plant/monocotyledon.

4. “Carpet How It's Made.” Carpet How It's Made, https://strathmoredesign.com/carpethowitsmade.

5. “The Properties of Cedar Wood.” The Properties of Cedar Wood - Designing Buildings Wiki, -G&S Specialist Timber, 13 Mar. 2017, https://www.designingbuildings.co.uk/wiki/The_Properties_of_Cedar_Wood.

6. Jensen, Elle Di. “What Kind of Rope Is Used on Cat Scratchers?” Pets, 14 July 2016, https://pets.thenest.com/kind-rope-used-cat-scratchers-9384.html.

7. “Should You Recycle Old Wood? Yes, If You Care about the Environment.” FA Mitchell, 15 Jan. 2019, https://www.famitchell.com.au/can-old-plywood-be-recycled/.

8. RecycleNation. “How to Recycle Nylon.” RecycleNation, 25 Nov. 2014, https://recyclenation.com/2014/11/recycle-nylon/.

9. Selvaggio, Lisa. “Why Do Felines Love Cat Trees?” PetGuide, 24 July 2018, https://www.petguide.com/blog/cat/why-do-felines-love-cat-trees/.

10. Scheuer, Barbara. “Device for protecting furniture from pet damage.” Google Patents. 24 October 2019. https://patents.google.com/patent/US6367423B1/en

Megan Wang 

Christina Cogdell

DES 40A 

29 November 2019 

The Embodied Energy of a Cat Tree

The pet industry has been growing since more and more people are keeping pets in nowadays. According to the American Pet Products Association, “68 percent of U.S. households owned some sort of pet” and about “94 million are a cat” (Brulliard, Karin and Scott Clement). More cats mean for cat products are needed in the market, and one important product made for cat owners is the cat tree. Cat tree allows the cat to climb up high, it gives them the high ground to be safe. Most cat trees on the market are claimed to be sustainable because of the used of woods for its structure; however, if we look at the energy that is used to build the cat tree, we might have a different opinion. The lifecycle of the cat tree contains the process of extracting raw materials, manufacturing, transportation, maintenance, recycle and waste management; all of these processes cannot be achieved with the use of energy, which shows that energy plays a huge role in forming the lifecycle. 

Two of the main materials of the cat tree are wood and carpet, while wood is a raw material itself, carpet is not, and the way the raw materials are processed is different between these two. For example, wood is processed at sawmills to cut and extract the moisture before sending it to the factory. To get the wood, the tree was cut down by the forest harvester vehicle, which is the vehicle that uses fossil fuel as their primary source. After the tree logs were sent to the sawmill, the manufacturing process happens, and it will turn a tree to multiple lumbers. On the other hand, carpet is made of synthetic fiber, and most of the raw material of the fiber is Nylon. The process of making a nylon fabric is to first extract the diamine acid, then combine the diamine acid with adipic acid to create the polymer, as known as the nylon salt. After the polymer is created, the heating process occurs to liquefied polymer, the substance is then extruded through a spinneret and loaded onto the bobbins. Towards the end, the energy is putting into stretching, drawing, and spinning to increase the strength and elasticity of the nylon fiber(Hodakel, Boris). Both wood and nylon fiber are transported to the manufacturing factory that produces the cat tree. 

To manufacture the lumber, “a logging truck, train, or log drive transport logs to the sawmill facility” (Engineering 360). And at the facility, the log first experienced breaking, then the edge of the log is cut by the band saw. “During this process, next to the wood sawdust, chip, cover, lumberjacks, chock-called waste and scrap of goods occurs”, and these can all be recycled and reused (Colak Mehmet, Tahsin Cetin). After the edge is removed, a gang saw is used to breaks the log into the unfinished logs and unfinished planks. In the end, the lumbers are being trimmed to its size, and the lumber will go over the air-drying process before it shipped. All the machines that were used to process with the logs use electricity to do the work. In the whole process of making wood, the tree is experiencing the physical change, and it turns from the log into the lumber. Following the design blueprint of the cat tree, the lumber is shaped into multiple boards before packaging. On the other hand, carpet is made in a completely different way. The first step of making carpet is to make the yarn from nylon, to do this the nylon is put into a blending machine, then a carding machine will untangle the fibers and gathering them into a larger ban. After the bans, the fiber goes into the drawing frame, which is the machine that draws out five threads to make it into one thread. The tread is sending to spools to improve its strength than two threads are twisted together to form a yarn. The yarn goes through a machine at 132-degree Celsius, then the nylon yarn is made, (How it’s Made 077 carpet). To take that yarn and make it into the carpet, more machines and energy are being used. The first step is tufting, the needles of the tufting machine stitch yarn into the backing material, this can be on a canvas, the next process is to dye the fabric. In the finishing process, glue is applied on both sides of the carpet, and they are squeezed into a large printing press to lock the carpet fiber in place. (Strathmore). After the wood board and the carpet is ready, the nylon yarn is wrapped around the wooden column to make a cat scratcher then the whole set is packaged before sending out.

At the distribution and transportation stage, semi-trucks are commonly used to transport products from the factory to the local retail stores. According to Federal Motor Carrier Safety Administration,” the truck driver may not drive after 60/ 70 hours in duty in ⅞ consecutive days”, which means in an average speed of 50 miles per hour, they would be able to transport up to 550 miles with the product in one day. A semi-truck has the average of “400-600 horsepower” (Taxes Truck Accident Lawyer), and they hold an average of 125 to 300 gallons of fuel. This type of truck uses diesel as their energy source because it produces “better power to weight ration” (Why Do Semi-Trucks Use Diesel?), and with the heavy truckload to carry, diesel helps semi-trucks overcome from mountain region to the flat road. 

There are two ways to get the cat tree. The first type of people bought an assembled cat tree from the pet store, the other type of people orders the product online and have the factory shipped it to their address, in this case, their products will come not assembled. According to Amazon.com Home Service, “typically assembly time [is] 2 hours.” If a human can generate 100 watts per hour, the maximum output to assemble the cat tree is about 200 watts. The hardest part is to assemble the cat tree after it is done, the use and maintenance become fairly easy. To use it, the customers simply just have to let the cat explore and climb by itself. However, to maintain it, a new scratching post made to nylon rope could be replaced by the old worn out one, and some carpet on the cat tree is detachable and washable. 

One way to recycle the cat tree is to disable the cat tree, take out only the wood to be recycled. The carpet is made of synthetic fabric, so it is not recyclable, so as the scratching post made of nylon ropes. Not all wood can be recycled, “to qualify for recycling, the wood must not be treated with materials such as creosote, stained, painted or otherwise contaminated” (Megan). To get wood to recycle, a call will have to make to connect the local wood recycle center, and a truck will come to pick up the wood, or the customer can schedule a drop-off. How the wood is being recycled is that, when the wood waste is created, it is sent over to the lumber yard. The fist process is to hit and fracturing the wood with the machine that has four conveyor chains and a big drum on top to push wood into the mill, then to wood goes to the next machine called Double-decked Vibrating screen to collect material in three different piles, and at this point, the wood in three piles are range from bigger mulch to a tiny sawdust. According to Chula Vista Clean, one pile of the recycled wood can be burned at the power plant to generate steam, which turns on turbines to make electricity, the other two piles are used for landscape, such as fertilizer or children playground. 

Finally, if a cat tree ends up at the dump, it will be taken to the landfill just like other trash. At the landfill, a landfill compactor vehicle is used to compact the trash, it has huge wheels, big drum to push the trash into the compactor to maximize the compaction density. The cat tree at this point will be crushed into pieces, then another machine called Track-Type Tractor will be used to push and spread the compact waste in a thin layer. A Track-Type Tractor “can achieve compaction densities of 800 to 1,000 lb/yd3 (475 to 593 kg/m3) and have no difficulty working in and on the waste material” (CATERPILLAR). When a cat tree ended up at the landfill, its lifecycle ends, it becomes trash like all other products, and they are being covered underground, and it becomes pollution because the material like nylon is decomposable. 

            All in all, the cat tree is a famous product that cat owners buy for their cats. It may seem like the material of the cat tree is sustainable because it is made of wood and carpet. However, the carpet is not made of wool, it is made of synthetic fabric, which uses a lot of energy to produce, yet it is hard to recycle. The energy has been used throughout the lifecycle of the cat tree, from getting the raw material to be processed as waste at the landfill. A better way not to waste all the energy is to reuse the product, perhaps, the factory could offer to take back the used product and reuse the material. 

Bibliography

            Amazon.com Home Service. “Cat Tree Assemble.” “Amazon.com.” 28 November 2019. https://www.amazon.com/Cat-Tree-Assembly/dp/B00TX97OR6

Brulliard, Karin, Scott Clement. “How many Americans have pets? An investigation of fuzzy statistic.” “The Washington Post.” 31 January 2019. https://www.washingtonpost.com/science/2019/01/31/how-many-americans-have-pets-an-investigation-into-fuzzy-statistics/

CATERPILLAR. “Waste Landfills.” “HOLT CAT.” 28 November 2019. https://www.holtcat.com/Documents/PDFs/waste/Waste%20Landfill%20CAT%20Equipment%20Selection%20Application.pdf

Chula Vista Clean. “CLEAN Curiosity Quest Goes Green.” “Chula Vista Clean.” 28 November 2019. https://www.chulavistaca.gov/departments/clean/clean-videos

Colak Mehmet, Tahsin Cetin. “Waste management in the industry of small and medium sized Turkish furniture enterprises (SMEs).” “International Symposium on New Horizons in Forestry.” 20 October 2017. http://ormanweb.isparta.edu.tr/isfor2017/documents/pdf/322.pdf

            “Engineering 360.” “Lumber and Sawmill Equipment Information.” “GlobalSpec.” 28 November 2019.

https://www.globalspec.com/learnmore/specialized_industrial_products/wood_processing_products/lumber_sawmill_equipment

Federal Motor Carrier Safety Administration. “Summary of Hours of Service Regulations.” “Federal Motor Carrier Safety Administration.” 9 March 2017. https://www.fmcsa.dot.gov/regulations/hours-service/summary-hours-service-regulations

            Hodakel, Boris. “What is Nylon Fabric: Properties, How its Made and Where.” “sewport.” 29 November 2019. https://sewport.com/fabrics-directory/nylon-fabric

            “How Its Made - 077 Carpets.” “How Its Made.” 22 December 2014. https://www.youtube.com/watch?v=UkC_y8F8Mto

Megan. “How Do I Recycle Wood?” “SFGATE.” 19 October 2019. https://homeguides.sfgate.com/recycle-wood-79134.html

            Strathmore. “CARPET-HOW IT’S MADE.” “Strathmore Design.” 28 November 2019. https://strathmoredesign.com/carpethowitsmade

            Taxes Truck Accident Lawyer. “FACTS YOU SHOULD KNOW ABOUT SEMI TRUCKS.” “Taxes Truck Accident Lawyer.” 28 November 2019. https://www.texas-truckaccidentlawyer.com/blog/facts-you-should-know-about-semi-trucks/

            “Why Do Semi-Trucks Use Diesel” “TruckFreighter.” 28 November 2019. https://truckfreighter.com/why-semi-trucks-use-diesel/

Brendan Gerrity

Professor Christina Cogdell

DES 40A

December 4, 2019

Cat Trees: Waste and Emissions

This paper will explore and report on the wastes and emissions produced as the consequence of manufacturing and disposing of a cat tree. The waste and emission byproducts resulting from the production of raw materials and intermediaries will be explored on a case-by-case basis. As with other types of furniture, cat trees allow alternative materials to be used in their construction. For this reason, a search of online home-goods retailers’ websites and catalogs was performed; this basic exploration showed that plywood and wood independently serve as the primary structural material; in some cases, one augments the other rather than simply substituting. Carpet was also observed as the near-universal cladding material. This is distinct from scratching posts that are integrated into the cat tree in some examples; such non-critical accessories are beyond the scope of this paper.

Finally, as appropriate, the practical options of disposal and recycling will be explored with a focus on the byproduct waste and emissions from the handling of the constituent materials. Details on the actual waste diversion and recycling rates will be used in the analysis as possible. With this inspection, the waste and emission resulting from production and disposal of conventional cat trees should be understood.

Wood

Lumber is a renewable resource; it offers the benefits of reduced carbon impact relative to alternatives used for furniture production such as plastic, metal, or cement (Bergman). Critically, the production of lumber (via tree farm or managed forest) naturally requires the capture of atmospheric carbon as the tree grows. The handling of the material’s sequestered carbon has an immense impact on its waste and emissions. The “cradle-to-gate” covers the emissions impact of wood up until its final processing into a usable product.

The branches, bark, and tops comprise approximately 30 to 50 percent of a harvested tree – they are collectively labeled as logging residue. The residue can be left in the forest during harvest. When left, it biodegrades, maintaining the sustainability of the managed forest. This practice of conservation is standard procedure but, in some cases, the logging residue is collected and burned for energy. This leads to the net release of carbon into the atmosphere; a net carbon-neutral managed forest used to harvest lumber requires that the residue be left and reintegrated via decay, according to Bergman.

Maintaining a carbon neutral harvest is dependent on the environment and type of lumber being harvested: At extremes, the interval between harvests can be less than a decade or require waiting many. Accelerating this would prevent effective carbon sequestration and lead to net carbon emissions.

The collective waste product from processing logs into useful lumber material at the mill is descriptively referred as mill residue. Due to its creation and accumulation at the mill, practically all of this waste product is used for energy production. The use of this waste product and other wood provides about 2 percent of the energy in the United States. The burning occurs in both the commercial and residential sector (EIA). Doing so reduces the carbon sequestration of lumber but maintains net neutral emissions as the original carbon source was atmospheric. Notably, residential lumber waste burning in older, dirtier stoves can change the emissions profile due to incomplete combustion (EPA). This skews the atmospheric emissions toward more noxious gases and particulate matter with a greater greenhouse footprint.

Coal, oil, natural gas, diesel, and various other petroleum products are consumed and burned during the processing and transportation of lumber as it is produced and used. All of these result in greenhouse gas emissions (carbon dioxide and methane being conspicuous) beyond the raw wood product. The sequential distance between harvested forest, saw mill, and factory is directly correlated to increased greenhouse gas (GHG) emissions; this is particularly significant considering the bulk of lumber and the large quantities used.

Plywood

Like many articles of furniture, cat trees are often constructed using plywood as the primary structural component. As a substitute engineered wood, it offers lower cost and weight relative to conventional lumber framing; depending on application, it can be stronger per pound than wood (illustratively, plywood has had historical applications in the structural components of aircraft, include World War II fighters planes).

The production of plywood requires thin layers (called “plies”) of wood to peeled from a sizeable log. These layers are aligned, glued, and baked under pressure.

Due to their effectiveness, versatility, and low cost, the manufacturing of plywood and related engineered wood products have become massive industries in developing countries such as China (Jia).

The production and application of plywood presents several issues that are not present in the wood or metal it frequently substitutes for (though such issues can arise with polymers used for the same purpose). The principal material issue is found in the resin that binds plies of shaved wood into the composite referred to as plywood: This resin used to glue the sheet together is typically formaldehyde-based.

According to Jia, these formaldehydes have many opportunities to escape during the production process: They are released as they are applied to the plies, they vent when the composite it baked and pressed into plywood, and they off-gas during regular use. This in-house release of formaldehyde and other chemicals, along with their release if the plywood is accidentally burned or improperly disposed of via combustion, is a significant health concerns if plywood is improperly handled (EPA).

The ongoing development and industrial introduction of alternative resins, namely renewable bio-oil, substituting for conventional, non-renewable inputs, could potentially allow for the manufacturing of plywood products free of formaldehyde, according to Jia; at this time, it is not standard practice and the EPA advises reducing exposure to formaldehyde off-gasses rather than actively avoiding plywood.

In terms of carbon (i.e. CO2) releases, the largest contributor over the lifecycle of the plywood is the production of plies (the physical drying of plies prior to their layering) and the compositing of the layers. Together, these two steps represent 66.86% of the greenhouse gas emission impact, according to Jia. Notably, both these stages are extremely energy intensive and emission impactful due to the electrical energy required to pressurize and repeatedly heat the product throughout the manufacturing process.

Coal is the dominant source of energy for electrical power in both China and the US: Notably, as these processes are significant consumers of electrical energy, the emissions that are the byproduct of that coal power are accountable to the plywood tally. There is a significant release of sulfur dioxide (SO2) and nitrogen oxides (NOx) from the generation of coal power; beyond their aforementioned role as greenhouse gases, the two also are major factors in the acidification of water.

Standard industrial practice in China and other countries is to utilize the waste wood as an energy source for the heating steps: This practice results in further greenhouse gas and particulate emissions when the wood burning is compared to cleaner burning non-renewables.

Additionally, the chemical processing and creation of the epoxies used for compositing the wood veneer plies represent significant energy inputs along with a myriad of chemical runoffs associated with petrochemical processing.

Modern developments suggest the adaptation of gluing green (i.e. undried) veneers would significantly reduce the greenhouse gas (overall an approximate 30% reduction) as the energy-intensive, initial veneer drying phase would be bypassed.

Solid wastes byproducts of plywood manufacturing include wood detritus from processing the log (branches and foliage), wood dust from sanding, excess epoxy, and various chemicals used to finish the plywood product. Liquid wastes directly from production are largely dependent on the type of plywood and epoxy: Formaldehyde in a number of forms is one such byproduct generated by conventional practices.

Finally, while transportation represents a relatively small proportion of emissions, locating the processing facilities close to rich lumber sources would significantly reduce overall emissions by cutting back diesel consumption, according to Jia.

Unfortunately, a search of the literature did not turn up information on the recycling of plywood: The broader category of wood suggests a low diversion rate for plywood. According to the EPA, the overwhelming bulk (67.48% of 17.99 million tons in 2017) of wood produced in the US is sent to the landfill.

Carpet

Cat trees, being furniture for cats, are often detailed in a similar manner to the human living spaces they occupy. While the structural components (wood or plywood) are often exposed, browsing the online catalogs of household goods retailers suggests that cat trees are typically detailed with carpeting. Besides the optional integrated scratch post (outside the purview of this paper), carpeting is the only common finishing detail.

Synthetic fibers represent more than 99 percent of the fibers used by the U.S. carpet industry; according to the EPA, technical limitations mean collecting the synthetic fibers for reprocessing into carpet is largely impractical though other sources of fibers can be used to provide recycled content and the reclaimed fiber from carpet can be used for other purpose. Doing so requires highly specialized facilities and extensive transportation: Each type of carpet requires individual reprocessing lines and must be further broken down into its separate component layers before the materials can be reclaimed. Consequently, industrial estimates put U.S. recycling rates at only 3.8 percent of discarded carpet material and industry sources suggest the bulk of this recycling is from commercial work rather than residential or consumer. Carpet accounts for 1 percent of municipal waste by weight or 2 percent by volume, according to the EPA.

The most common types of synthetic fibers used in carpets are derived from petroleum products (Potting). All of these synthetic fibers require petroleum inputs as both raw material and as an energy source; Potting’s analyzed synthetic fibers required multiples of the energy input (and consequently multiples of the power generation GHG emissions) compared to using natural wool materials.

That is not to say the natural wool fibers are a lower waste option: Raising the sheep generates wastes and emission akin to any other livestock. Growing the feed for the sheep requires nitrogen fertilizer inputs which itself is a high energy cost, petroleum-based process; excess fertilizer becomes runoff which causes eutrophication as the excess nitrogen escapes the fields. Further, about 75 percent of tropospheric ozone is attributable to methane produced during sheep farming.

According to Potting, the impact of the waste and emissions products from these competitive carpeting materials is dependent on local conditions and agricultural considerations.

Carpet, being a bulky material consumed in large volumes, presents significant challenges for disposal. Placed in a landfill, it does not biodegrade, so while the full bulk of the carpet becomes waste, emissions are limited to relatively minor transportation costs, but significant landfill volume is consumed. While recycling carpet massively reduces its CO2 footprint (even after factoring in the transportation-related emissions) doing so is exceedingly uncommon. Using the waste carpet as a substitute fuel for coal results in substantial decreases in greenhouse gases: It is more energy dense and cleaner burning than coal; this option is nearly comparable to recycling in terms of net emission reduction.

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