We take advantage of the valuable resources provided by trees every single day. From paper products and construction materials, to furniture, and even the air we breathe, it is impossible to live a single day without utilizing the benefits that come from trees.
Since 1990, the world has lost approximately 319 Million acres of forests, according to the Global Forrest Resource Assessment (FAO, 2015). As alarming as that may sound, the good news is that the rate of global deforestation has decreased by more than 50% since then, however, that is not necessarily due to sustainable forestry practices. Unfortunately, only 7% of the worlds forests are comprised of planted forests, which means that the bulk (93%) of trees removed for commercial use by us, still come from naturally occurring forests (FAO, 2012).
So what are the benefits of healthy, sustainable, forests? For starters, the worlds forests make up one of the largest carbon sinks, contributing to the removal and storage of atmospheric carbon dioxide. Altogether, forests removed approximately 296 Gigatons of carbon dioxide from the atmosphere in 2015 (FAO, 2015). Not only do forests provide a natural source for carbon sequestration, but they also play an important role in biodiversity, providing home to over half of the worlds terrestrial dwellers.
But, sustainable forestry practices aren’t just needed on the commercial stage, sustainability can begin right here at home.
The words “urban forestry” might sound like an oxymoron, but it is a profession that is gaining a lot of traction as the world’s population increases. According to the United States Census Bureau, the 15 fastest growing cities have an average growth rate of approximately 5.2%., and the entire U.S population has increased by 5.9% since the 2010 census (USCB, 2018).
A growing population, combined with a rebounding economy inevitably means development is also on the rise, and all of this development has major implications for land use. Naturally occurring surfaces get graded, trees are removed, buildings erected, and the concrete slowly creeps.
However, once everything is leveled and covered in impermeable materials, there is an attempt to mimic what was once there. Planters full of (sometimes) non-native species are installed, gutters and drainage swales re-direct surface flow to the streets, and a lot of grass is planted. It’s a less than ameliorating attempt to reproduce what the natural world already does so effortlessly.
As cities expand, so does the need to effectively mitigate the negative side effects of urbanization. The urban arborist is able to do this through a combination of sustainable horticulture practices and understanding the very nature of the plants they are utilizing.
This week I took the time to interview Michael Webb (click the link. Come on, do it.), an ISA Certified Arborists and practicing Urban Arborist in Santa Cruz, California, to help understand just why tree care is so vital to us and how we can better care for these life sustaining, and giving, organisms.
Q: Why is sustainable tree care so important?
A: Providing preventative tree care is crucial to preserving trees in the landscape. An ounce of prevention is worth a pound of cure. Trees operate on a different time scale than humans. Treatments to problematic trees resolve in years not within days like humans. When we maintain trees in the landscape it is most beneficial when we have a maintenance interval. Over-pruning trees is extremely common in tree care. When we remove foliage from a tree we remove the ability of the tree to produce food. Removing too much foliage can push the tree to become stressed. Frequently, trees on private properties are pruned every single year. This is detrimental to tree health. A maintenance interval should be established so a sustainable landscape solution can be accomplished. Sadly this is usually not the case. Tree care is driven by profits, and non scientific tree care operations are very common. Many operations skew the clients needs and misrepresent the most beneficial service for their trees.
Q: What are some things that people do not typically know about trees?
A: There are a variety of things that people do not understand with trees. Large trees are not always to be feared. Just because a tree is big does not mean that it is going to fall onto a house, car, or structure. Trees are continually growing to become larger year after year. Trees can be inspected by a qualified arborist to ensure structural stability. I see too many trees getting removed due to misinterpreted information that is all too common in our society. There is always a risk in leaving a tree standing, however, a qualified arborists can provide solutions to mitigating this risk to a level acceptable to the client.
Topping trees (A process that removes the upper portion of a trees canopy) is another problem our society perceives as a solution to decrease the likelihood of failure. The truth is that this makes trees a higher risk than before. After topping trees, the tree can no longer produce food. The tree responds by sprouting profusely to compensate for the loss of foliage. These sprouts are poorly attached branches and are very prone to failure when they grow larger. The areas where topping cuts are made will develop extensive decay and lead to the sprouts failure. Topping trees strains the system, and makes the tree susceptible to pests and diseases. This in turn ruins the trees overall structure and function in the landscape. Commonly societies perception of what is good for trees is often detrimental.
Q: What are the benefits of maintaining healthy trees around your house?
A: Trees provide numerous benefits to us directly and our environment. The trees crown intercepts rainfall and limits soil erosion. Additionally, the roots stabilize soil and absorb excess amounts of rainfall. This mitigates the amount of storm water run off. Trees shade our buildings to reduce energy costs in the summer and block cold winds to decrease heating costs. Street-side trees function to mitigate the urban heat island effect. Cities with large amounts of impervious surfaces experience higher temperatures. The concrete, buildings, and asphalt radiate heat absorbed throughout the day resulting in higher localized temperatures. When trees are actively photosynthesizing they are releasing water vapor into the air and cooling the air around them via transpiration. Essentially they function as a natural “air conditioner”. Trees also filter harmful air pollutants. The leaves absorb gases harmful to us in the air. In addition, leaves and bark intercept larger airborne particulates.
Urban trees also provide us a sense of being with nature when surrounded by an unnatural city setting. Cities can be beautified with trees to reduce mental disorders that arise from the stresses of the urban setting. Trees increase property values as well. A home with large trees on the property make it feel established and more attractive to the eye.
Q: How do you keep trees healthy (generally)?
A: In order to maintain high vitality trees we must keep their growing conditions favorable for the tree. Site changes from construction, turf installation, and trenching can seriously stress the tree. Keeping trees well watered, pruning with an objective, and monitoring health is key to healthy trees. In times of drought trees need to be deeply watered to reduce the likelihood of pest and disease outbreaks. A pruning cycle needs to be established in order to ensure that trees are not over pruned.
In closing, this might just give you something to think about the next time you pass by cursing the old tree in your neighbors yard that keeps dropping sap on your poorly parked car. Take a deep breath, and stop to consider all that a single tree is providing for you and I, and what it really means to care for these stationary ecosystems.
Food and Agriculture Organization of the United Nations (FAO), 2015, Global Forrest Resources Assessment 2015: http://www.fao.org/forest-resources-assessment/past-assessments/fra-2015/en/(Accessed July 2018)
Food and Agriculture Organization of the United Nations (FAO), 2012, Planted Forrests: http://www.fao.org/forestry/plantedforests/en/ (Accessed July 2018)
United States Census Bureau (USCB) ,2018, The West and South Lead the Way: https://www.census.gov/newsroom/press-releases/2018/estimates-cities.html (Accessed July 2018)