Solar Exposure vs Tall Trees
As the demonstration and research home is developed, design, product selection and earthwork decisions are being carefully made to minimize lifecycle ecological impacts. We are dedicated to reducing harm. We have attempted to minimize the number of trees removed while considering the solar needs of the home and the hazards created by trees in close proximity to the house.
As with almost every home built on the Gulf Islands, we will have to remove some trees. We are confident that with a carefully designed home and site plan, by increasing solar exposure, we can lower the overall ecological impact of the home over its service life. In this way we will honour the sacrifice of any trees removed to maximize sun.
A home exposed to several hours of sunlight a day can greatly reduce:
- the energy used to power light, heat and hot water that could be sourced from the sun
- firewood used for heat over the home’s lifetime that could be sourced from teh sun
- high maintenance and repair needs from a too-damp building envelope
The Eco Healthy Homes Project will maximize solar exposure/harvest and will minimize ecological impact in these ways:
- harvest heat, light, hot water and electricity from the sun
- reduce heating/cooling energy by up to 80%
- support building envelope durability through solar drying
- use strategic limbing instead of full tree removal
- replace any trees removed with a greater number of (food producing) bushes and small trees
- use site-harvested lumber to build the house (to reduce clearcut-sourced construction lumber)
Solar Panels Versus Tall Trees
An article from 2015 posted by the New England Clean Energy newsletter addresses the question that often turns environmentalists against each other. What to do when trees prevent the benefits of solar exposure? The author (Mark Durrenberger), offers calculations based on carbon sequestration science from US Department of Energy. He presents a comparison of the CO2 absorbed by a tree with the CO2 offset of a residential solar panel array. Though this does not represent the full range of ecological services provided by large trees, Durrenberger claims that a medium sized residential solar array installed in 80% of optimal conditions will reduce the same amount of carbon as fifty 30-year old trees. The solar array referenced, (24 320-watt panels), saved 9606 pounds of CO2 per year and each 30 year old tree saves approximately 193 pounds of CO2.
It’s important to note that the author omits other critical considerations such as tree life or other ecological services of a tree (shade, oxygen, habitat, ground protection, soil stabilization, beauty). He also omits the manufacturing/transport related carbon, toxins, and raw material extraction associated with solar panels. Even so, the author’s calculations indicate that reducing shade is a compromise worth considering . This is definitely not a tension that has a simple answer. However, if many of the services provided by a tall tree, (except extensive shade), can be substituted by replanting with drought-resistant, shorter plants which also provide ecosystem and food production services, reducing the canopy of tall trees can be a very beneficial sacrifice.
Eighty percent of the site will be preserved for ‘zero mile’ food production. Landscape design and plant selection will emphasize perennial,evergreen and native plants; food and medicine production; soil stabilization; stormwater management; wildlife habitat; and carbon sequestration. To view the overall design goals for the home, see this page. Click here to learn more about the standards that will guide the project.